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Question 3381Question →

During surgical rounds, an attending physician is reviewing the classic timeline of postoperative complications with the medical team to establish a diagnostic protocol. Arrange the following common causes of postoperative fever in the correct chronological order of their typical onset, starting with the earliest expected complication and ending with the latest.

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Answer

The correct chronological sequence is Atelectasis (Days 1-2), Catheter-associated urinary tract infection (Days 3-5), Surgical site infection (Days 5-7), and Drug-induced fever (Days >7).
The classic timeline for postoperative fever follows a highly predictable sequence based on the underlying pathogenesis. It begins with atelectasis (days 1-2) due to hypoventilation, followed by urinary tract infections (days 3-5) from catheter colonization, then surgical site infections (days 5-7) as bacteria multiply in the wound, and finally drug-induced fever (>7 days) which requires a longer period for immune sensitization.

Step-by-Step Solution

1
Identify the etiology with the earliest onset.
Atelectasis occurs on postoperative days 1-2.
Immediate postoperative pain and anesthesia effects lead to shallow breathing and alveolar collapse.
2
Identify the etiology that follows early pulmonary complications.
Urinary tract infection occurs on postoperative days 3-5.
Bacterial colonization of indwelling Foley catheters takes a few days to progress into a symptomatic clinical infection.
3
Identify the timing of wound-related complications.
Surgical site infection occurs on postoperative days 5-7.
Pathogens introduced during surgery require a multiday incubation period to multiply and cause an invasive tissue infection.
4
Identify the etiology with the most delayed onset.
Drug-induced fever occurs after postoperative day 7.
Hypersensitivity reactions require a sensitization period to the new medication, which typically takes a week or longer to develop.

Key Concept

Chronological timeline of postoperative fever etiologies (The '5 Ws' mnemonic)
Question 3382Question →

A 25-year-old female fashion model is evaluated in the emergency department for severe muscle cramps, dizziness, and palpitations. She says her symptoms began this morning and have progressively worsened. The patient is under immense pressure from her agency to meet strict body measurement requirements for an upcoming international campaign. Vital signs show a temperature of 36.8∘36.8^\circ C (98.2∘98.2^\circ F), heart rate of 115115/min, respiratory rate of 2020/min, and blood pressure of 102/62102/62 mm Hg. BMI is 19.519.5 kg/m 2^2. Physical examination reveals dry mucous membranes and hyperactive bowel sounds. There is no parotid gland enlargement, and the dorsal surfaces of her hands are unremarkable.

Laboratory results are as follows:

TestResult
Serum sodium140140 mEq/L
Serum potassium2.42.4 mEq/L
Serum chloride116116 mEq/L
Serum bicarbonate1414 mEq/L
Blood urea nitrogen3232 mg/dL
Serum creatinine1.21.2 mg/dL
Arterial blood gas (room air):
ParameterResult
pH7.287.28
pCO2_22929 mm Hg
pO2_29595 mm Hg

Which of the following is the most likely cause of this patient's current presentation?

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Answer: Frequent self-administration of bisacodyl

Answer

The correct answer is frequent self-administration of bisacodyl, which is a stimulant laxative.
The correct answer describes surreptitious laxative abuse. This patient has a primary metabolic acidosis (pH 7.287.28, low HCO3−\text{HCO}_3^-). Her anion gap is calculated as 140−(116+14)=10140 - (116 + 14) = 10, which indicates a normal anion gap metabolic acidosis (NAGMA). The pCO2\text{pCO}_2 of 2929 mm Hg reflects appropriate respiratory compensation according to Winter's formula (Expected pCO2=1.5×14+8=29\text{pCO}_2 = 1.5 \times 14 + 8 = 29). In a young woman with immense professional pressure to maintain a low body weight, a hypokalemic NAGMA combined with signs of volume depletion (BUN:Cr ratio >20> 20) and hyperactive bowel sounds strongly indicates surreptitious laxative abuse. Laxatives stimulate rapid colonic transit, leading to profound gastrointestinal loss of both potassium and bicarbonate.

Step-by-Step Solution

1
Analyze the primary acid-base disturbance using the arterial blood gas.
The patient has a low pH (7.287.28) and low bicarbonate (1414 mEq/L), indicating a primary metabolic acidosis.
Establishing the primary disorder is the mandatory first step in evaluating any electrolyte/acid-base derangement.
2
Calculate the serum anion gap to narrow the differential diagnosis.
Anion Gap = Na+−(Cl−+HCO3−)=140−(116+14)=10\text{Na}^+ - (\text{Cl}^- + \text{HCO}_3^-) = 140 - (116 + 14) = 10 mEq/L. This falls within the normal range (8−128-12 mEq/L).
Differentiating between High Anion Gap (HAGMA) and Normal Anion Gap (NAGMA) completely changes the underlying physiological etiology.
3
Determine if the respiratory compensation is appropriate using Winter's formula.
Expected pCO2=1.5×[HCO3−]+8±2=1.5×14+8±2=29±2\text{pCO}_2 = 1.5 \times [\text{HCO}_3^-] + 8 \pm 2 = 1.5 \times 14 + 8 \pm 2 = 29 \pm 2 mm Hg. The actual pCO2\text{pCO}_2 is 2929 mm Hg, indicating perfect respiratory compensation.
This rules out any concomitant primary respiratory acidosis or alkalosis (e.g., respiratory failure or primary hyperventilation).
4
Synthesize the lab findings (hypokalemic NAGMA, high BUN/Cr ratio > 20) with the clinical vignette (young woman under pressure to be thin, hyperactive bowel sounds).
The combined picture of gastrointestinal bicarbonate and potassium loss, resulting in a volume-depleted NAGMA, strongly points to surreptitious laxative abuse.
Eating disorder patients often use different purging methods. Differentiating them relies heavily on specific lab patterns: vomiting causes alkalosis, laxatives cause acidosis.

Key Concept

Surreptitious laxative abuse in eating disorders presents clinically with volume depletion, severe hypokalemia, and a normal anion gap metabolic acidosis (NAGMA) due to massive gastrointestinal bicarbonate loss.
Question 3383Question →

A 32-year-old man with a recent diagnosis of schizophrenia is admitted to the inpatient psychiatric unit due to worsening paranoia and command auditory hallucinations. Due to severe agitation, he is treated with multiple doses of intramuscular haloperidol over a 48-hour period. On hospital day 3, the patient develops profound "lead-pipe" muscle rigidity, a temperature of 39.4°C (102.9°F), profuse diaphoresis, and mutism. His blood pressure fluctuates between 160/100 mmHg and 90/60 mmHg, and his pulse is 122/min. Laboratory testing reveals a serum creatine kinase level of 4,500 U/L.

Arrange the following steps in the most appropriate chronological order for the acute management and subsequent follow-up of this patient's condition.

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Answer

The correct sequence for managing neuroleptic malignant syndrome (NMS) is: 1) Discontinue the offending agent, 2) Initiate supportive care, 3) Administer targeted pharmacotherapy, 4) Consider ECT for refractory cases, and 5) Wait at least two weeks before cautiously re-challenging with an alternative antipsychotic.
The algorithm for managing Neuroleptic Malignant Syndrome (NMS) requires a strict stepwise approach to minimize mortality and morbidity. The very first step is to remove the offending cause by discontinuing all dopamine antagonists. Because NMS can cause severe dehydration, hyperthermia, and rhabdomyolysis leading to acute renal failure, aggressive supportive care (IV fluids, cooling blankets) is the immediate next priority. If the patient does not respond adequately to these foundational steps, specific medical therapies that reverse dopamine blockade (e.g., bromocriptine, amantadine) or act as direct muscle relaxants (e.g., dantrolene) are administered. In the most severe, treatment-refractory cases, or those presenting with profound catatonia, electroconvulsive therapy (ECT) is highly effective. Finally, for the long-term management of the patient's underlying schizophrenia, it is critical to wait at least two weeks after complete resolution of NMS symptoms before cautiously re-challenging with a different, usually lower-potency, antipsychotic to prevent a recurrence.

Step-by-Step Solution

1
Identify the clinical presentation as Neuroleptic Malignant Syndrome (NMS).
The patient's classic tetrad of altered mental status, autonomic instability, hyperthermia, and "lead-pipe" muscle rigidity, combined with recent high-dose haloperidol use and elevated creatine kinase, confirms the diagnosis of NMS.
Accurate diagnosis is required to initiate the specific, stepwise, life-saving management protocol.
2
Determine the first and most critical acute intervention.
The immediate discontinuation of all dopamine receptor antagonists (in this case, haloperidol) is the paramount first step.
Continued exposure to the offending agent will worsen the dopamine blockade driving the syndrome, rendering other treatments ineffective.
3
Sequence the subsequent acute stabilization interventions.
Aggressive supportive care (IV fluids, cooling) must be instituted next. If this fails, targeted pharmacotherapy (bromocriptine, dantrolene, amantadine) is added. If the patient remains refractory and severely ill, ECT is the definitive acute treatment.
Treatment escalates from least invasive/fundamental (supportive care) to targeted medical therapy, and finally to highly invasive procedures (ECT) based on clinical response.
4
Establish the long-term management strategy for the underlying psychosis.
After full recovery from NMS, a washout period of at least two weeks is mandatory before cautiously re-challenging the patient with a different antipsychotic (typically an atypical, lower-potency agent like quetiapine or clozapine).
Premature re-introduction of antipsychotics carries an unacceptably high risk of NMS recurrence.

Key Concept

Neuroleptic Malignant Syndrome (NMS) Stepwise Management Algorithm
Estimated Time:1m 30s
Question 3384Question →

An 80-year-old man, a former university professor, visits his outpatient provider accompanied by his daughter. She expresses concern that over the past 18 months, he has been repeatedly misplacing important documents, forgetting appointments, and struggling to manage his finances. Last week, he was found wandering several blocks from his house, unable to remember the route back. Vital signs are stable, and the neurological examination shows no focal deficits. The provider plans a comprehensive evaluation and anticipates a long-term management strategy for presumed Alzheimer disease.

Arrange the following clinical steps in the appropriate chronological sequence for the standard diagnostic evaluation and progressive longitudinal management of this patient's condition.

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Answer

The correct sequence begins with the objective quantification of the cognitive deficit, followed by ruling out secondary causes via labs and imaging, initiating first-line monotherapy for mild-to-moderate disease, escalating to combination therapy as the disease reaches the moderate-to-severe stage, and finally focusing on palliative and skilled care in the terminal stages.
The standard of care for evaluating and managing progressive memory loss follows a strict chronological pathway. First, the physician must objectively confirm the impairment using validated cognitive scales. Second, neuroimaging and laboratory tests must be obtained to exclude reversible causes such as hypothyroidism, neurosyphilis, B12 deficiency, or structural intracranial lesions. Only after a clinical diagnosis of major neurocognitive disorder (likely Alzheimer disease) is established should first-line pharmacotherapy with an acetylcholinesterase inhibitor (donepezil) be started. As the disease naturally progresses over years to a moderate-to-severe stage, the addition of an NMDA receptor antagonist (memantine) is indicated. Finally, in the late/terminal stages of the disease, when the patient is fully dependent and medications offer little to no functional benefit, the focus appropriately shifts toward skilled nursing and palliative care.

Step-by-Step Solution

1
Administer a cognitive screening tool (e.g., MoCA or MMSE).
Establishes the presence and severity of objective cognitive decline.
It is necessary to confirm that the patient's cognitive deficits are genuine and measurable before proceeding with an extensive medical workup.
2
Order screening labs (TSH, B12, CMP, CBC) and a noncontrast Head CT or Brain MRI.
Excludes potentially reversible causes of dementia.
Guidelines mandate ruling out metabolic disturbances, nutritional deficiencies, and structural lesions before diagnosing Alzheimer disease.
3
Start an acetylcholinesterase inhibitor (AChEI).
Provides symptomatic benefit for mild-to-moderate Alzheimer disease.
AChEIs (donepezil, rivastigmine, galantamine) are the standard first-line pharmacotherapy following a formal diagnosis.
4
Add memantine.
Augments therapy for advancing disease.
Memantine, an NMDA receptor antagonist, is indicated only when the patient's condition progresses from mild to moderate-to-severe Alzheimer disease.
5
Implement palliative care and skilled nursing transition.
Ensures safety and comfort in end-stage dementia.
When patients completely lose the ability to perform basic activities of daily living (ADLs) and require 24/7 care, the clinical focus shifts to custodial and palliative care.

Key Concept

Diagnostic algorithm and progressive pharmacological management of Alzheimer disease
Question 3385Question →

Match the following clinical vignettes to the most likely underlying neurocognitive disorder etiology.

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Items

A 75-year-old man presents with abrupt worsening of cognitive function followed by periods of stability, and asymmetric hyperreflexia on examination.
A 68-year-old woman exhibits socially inappropriate behaviors, loss of empathy, and a new habit of consuming large amounts of sweets, with intact navigation skills.
A 78-year-old man experiences fluctuating alertness, detailed visual hallucinations of animals, and violent movements during sleep, alongside new-onset parkinsonism.
A 74-year-old woman displays a gradual, progressive decline in episodic memory and gets lost in her own neighborhood, with no focal motor deficits.
An 80-year-old man develops a 'magnetic' wide-based gait, urinary urgency, and prominent psychomotor slowing over several months.

Matches

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Answer

Vignette 1 maps to Vascular dementia, Vignette 2 maps to Frontotemporal dementia, Vignette 3 maps to Dementia with Lewy bodies, Vignette 4 maps to Alzheimer disease, and Vignette 5 maps to Normal pressure hydrocephalus.
Each neurocognitive disorder has a distinct initial clinical presentation. Alzheimer disease presents with insidious memory loss. Frontotemporal dementia presents with early personality and behavioral changes. Lewy body dementia is characterized by visual hallucinations, parkinsonism, and fluctuating cognition. Vascular dementia shows a step-wise decline with focal neurological deficits. Normal pressure hydrocephalus presents with the classic triad of gait apraxia, urinary incontinence, and dementia.

Step-by-Step Solution

1
Analyze the first vignette for the pattern of decline and presence of neurologic signs.
Identified a step-wise progression and focal neurologic deficits.
These are hallmark features of a vascular etiology due to sequential ischemic events.
2
Evaluate the second vignette for predominant early symptoms.
Identified prominent behavioral changes and hyperorality overshadowing memory loss.
Behavioral disinhibition is the core diagnostic criterion for frontotemporal lobar degeneration.
3
Review the third vignette for characteristic symptom triads.
Recognized the combination of visual hallucinations, parkinsonism, and REM sleep behavior disorder.
This combination is highly specific for an alpha-synucleinopathy with Lewy bodies.
4
Assess the fourth vignette for onset speed and the domain of impairment.
Noted an insidious onset of purely episodic memory and visuospatial deficits.
This represents the typical amnestic presentation of Alzheimer disease.
5
Examine the fifth vignette for a classic symptom triad.
Identified the 'wobbly, wet, and wacky' triad.
This constellation is pathognomonic for idiopathic normal pressure hydrocephalus.

Key Concept

Differentiation of major neurocognitive disorders based on core clinical features and initial presentation.
Estimated Time:1m 30s
Question 3386Question →

A 59-year-old woman comes to the clinic due to a persistent, itchy rash on her right breast that has been present for the past 4 months. She initially thought it was dry skin and applied over-the-counter moisturizers and a low-potency topical hydrocortisone cream for several weeks, but the lesion has progressively worsened. On physical examination, there is an erythematous, sharply demarcated, scaling, and crusted plaque restricted to the right nipple and extending slightly onto the areola. The right nipple appears partially inverted. Palpation reveals no discrete underlying breast mass, and axillary lymph nodes are not palpable. Bilateral mammography performed today shows no distinct masses or suspicious microcalcifications. Which of the following is the most appropriate next step in management?

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Answer: Punch biopsy of the nipple-areolar complex

Answer

Punch biopsy of the nipple-areolar complex is the most appropriate next step in management.
The correct answer is a punch biopsy of the nipple-areolar complex. This patient's persistent, unilateral, eczematous, and scaling nipple rash that is refractory to topical corticosteroids is highly suspicious for Paget disease of the breast. Paget disease is a rare intraepithelial adenocarcinoma of the nipple epidermis, almost always associated with an underlying in situ or invasive breast malignancy. Even in the absence of a palpable mass or suspicious mammographic findings, the definitive diagnostic step for a suspected Paget lesion is a full-thickness skin biopsy (such as a punch biopsy) of the nipple to identify malignant intraepithelial cells.

Step-by-Step Solution

1
Analyze the clinical presentation.
The patient has a 4-month history of a persistent, unilateral, eczematous, and scaling nipple rash that has not responded to conservative topical therapies.
Identifying the chronic and refractory nature of the lesion helps rule out simple benign dermatologic conditions.
2
Correlate the findings with potential breast pathologies.
A scaling, crusted plaque on the nipple accompanied by nipple inversion is the classic clinical presentation of Paget disease of the breast.
Recognizing the pathognomonic signs of Paget disease is essential for guiding the diagnostic workup.
3
Determine the most appropriate next step in management.
A full-thickness tissue biopsy of the skin lesion is required.
Even with negative mammography, a persistent unilateral nipple lesion must be biopsied to histologically confirm the presence of malignant intraepithelial cells.

Key Concept

Any persistent, unilateral, eczematous, or scaling lesion of the nipple-areolar complex that does not respond to topical treatments must be biopsied to rule out Paget disease of the breast.
Estimated Time:1m 0s
Question 3387Question →

A 32-year-old elementary school teacher schedules a telehealth appointment with a psychiatrist, reporting overwhelming distress that is threatening her career. Over the last 5 months, she has experienced relentless, horrific mental images of herself physically striking her students. She describes these images as 'sickening' and completely contrary to her morals. To neutralize her anxiety, she spends up to 3 hours each day securing any heavy or sharp objects in her classroom and repeatedly reviewing her actions at the end of the day. She tearfully states she would never actually hurt a child and has absolutely no desire to do so, but the thoughts will not stop. She has no prior psychiatric history and takes no medications.

Which of the following are appropriate clinical actions for the physician to take? (Select all that apply)

Select all that apply

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Answer: Referral for exposure and response prevention therapy; Initiation of fluoxetine pharmacotherapy

Answer

The appropriate clinical actions are referral for exposure and response prevention therapy and initiation of fluoxetine pharmacotherapy.
The correct actions involve initiating evidence-based treatments for obsessive-compulsive disorder (OCD). This patient is presenting with classic ego-dystonic harm obsessions—intrusive, unwanted thoughts of causing harm that are highly distressing and contrary to her actual desires. Her behavior of securing objects and engaging in mental review represent compulsions performed to alleviate the intense anxiety caused by these thoughts. Because she has no intent or desire to act on these thoughts, she does not pose a danger to her students. First-line treatment for OCD consists of a specialized form of cognitive-behavioral therapy known as exposure and response prevention (ERP), as well as pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs) like fluoxetine, which are typically utilized at higher doses than those required for depression.

Step-by-Step Solution

1
Diagnose the patient's underlying psychiatric condition based on her clinical presentation.
The patient is suffering from obsessive-compulsive disorder (OCD), characterized by ego-dystonic harm obsessions (intrusive thoughts of striking students) and neutralizing compulsions (securing objects, mental reviewing).
Accurate diagnosis is strictly required to differentiate the symptoms of OCD from true homicidal ideation or psychosis.
2
Assess the patient's risk of violence and evaluate the ethical duty to report.
The patient finds the thoughts sickening, has no intent to act, and actively uses compulsions to prevent harm. She poses no imminent threat, meaning confidentiality must be strictly maintained.
Breaching confidentiality is only legally and ethically permissible when there is a specific, imminent threat to a third party or suspected active abuse.
3
Select first-line, evidence-based treatments for the diagnosed condition.
First-line treatments for OCD include exposure and response prevention (ERP) therapy and SSRI pharmacotherapy (e.g., fluoxetine).
These two modalities have the strongest evidence base for effectively reducing obsessive-compulsive symptoms.

Key Concept

Harm obsessions in obsessive-compulsive disorder are ego-dystonic and do not indicate true homicidal intent; therefore, they do not warrant a breach of confidentiality. First-line management involves exposure and response prevention (ERP) and SSRI pharmacotherapy.
Estimated Time:1m 0s
Question 3388Question →

Match each of the following distinct clinical scenarios to the most appropriate legal or ethical course of action.

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Items

A 45-year-old man hospitalized on an involuntary 72-hour psychiatric hold for acute psychosis develops a fever and cough. He refuses a recommended chest x-ray, stating, 'The x-ray machine is a government tool designed to extract my memories.' His vital signs are stable.
A 30-year-old woman with bipolar disorder is admitted voluntarily but becomes acutely agitated, actively throwing heavy chairs at staff members. She has a legally valid psychiatric advance directive explicitly refusing the administration of any antipsychotic medications.
A 16-year-old boy presents alone to an outpatient clinic seeking buprenorphine therapy for severe opioid use disorder. He demonstrates full understanding of the treatment but explicitly forbids the physician from contacting his parents, fearing he will be kicked out of his home.
A 28-year-old man voluntarily admitted for major depressive disorder becomes intensely angry and states, 'As soon as I discharge myself tomorrow, I am going to buy a gun and shoot my former boss, John Smith.' He refuses to elaborate further.

Matches

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Answer

Scenario 1 matches to seeking surrogate consent; Scenario 2 matches to overriding the advance directive; Scenario 3 matches to providing confidential care without parental notification; Scenario 4 matches to initiating an involuntary hold and breaching confidentiality to warn the victim.
Each scenario tests a nuanced boundary of psychiatric law and ethics. Scenario 1 requires distinguishing psychiatric holds from global medical incapacity. Scenario 2 tests the emergency safety exception to advance directives. Scenario 3 applies the emancipated/specific-condition consent rules for minors regarding substance abuse. Scenario 4 requires applying the duty to protect in the setting of a voluntary psychiatric admission.

Step-by-Step Solution

1
Analyze Scenario 1 (Psych hold + medical refusal).
Identify that the patient's refusal is based on a delusion, meaning he lacks capacity for this decision. Recognize that psych holds do not cover non-psychiatric medical care.
Determines that surrogate consent is legally required for non-emergent medical procedures when a psychiatric patient lacks capacity.
2
Analyze Scenario 2 (Advance directive + violence).
Identify that the patient is an imminent danger to staff.
Establishes that the emergency exception applies, allowing physicians to override psychiatric advance directives to administer chemical restraints for immediate safety.
3
Analyze Scenario 3 (Minor + SUD treatment).
Identify that the 16-year-old is seeking substance use disorder treatment and wishes to keep it confidential from parents.
Applies the legal exception allowing minors to consent to specific treatments (SUD, STI, contraception) without parental involvement.
4
Analyze Scenario 4 (Specific threat + voluntary patient).
Identify a specific, credible threat against a named individual by a patient planning imminent discharge.
Triggers the Tarasoff duty to protect, requiring the physician to breach confidentiality to warn the victim/police and to hold the patient involuntarily.

Key Concept

Complex intersections of medical jurisprudence in psychiatry: capacity vs. involuntary holds, emergency overrides of advance directives, minor consent exceptions, and the duty to protect.
Estimated Time:2m 0s
Question 3389Question →

A 21-year-old woman is evaluated in the emergency department after fainting during a ballet rehearsal. Over the past month, she has experienced profound fatigue, recurrent dizziness, and muscle cramps. The patient states she feels immense pressure to maintain a thin physique for her upcoming dance performance. Her mother, who accompanied her, mentions finding several empty packages of bisacodyl in the patient's bathroom. The patient exercises for three hours daily and rigidly restricts her caloric intake, although she admits to occasionally consuming large quantities of food before feeling intensely guilty.

Vital signs show a temperature of 36.4∘C36.4^\circ\text{C} (97.5∘F97.5^\circ\text{F}), blood pressure of 92/58 mm Hg, and pulse of 114/min. Her current body mass index (BMI) is 17.0 kg/m217.0 \text{ kg/m}^2.

Physical examination reveals poor skin turgor and hyperactive bowel sounds.

Laboratory results are as follows:
Serum sodium: 139 mEq/L
Serum potassium: 2.4 mEq/L
Serum chloride: 115 mEq/L
Serum bicarbonate: 14 mEq/L
Blood urea nitrogen: 26 mg/dL
Serum creatinine: 1.1 mg/dL

Arterial blood gas analysis on room air:
pH: 7.27
PaCO2PaCO_2: 30 mm Hg
PaO2PaO_2: 96 mm Hg

Which of the following represents the most accurate psychiatric diagnosis and the correct interpretation of this patient's acid-base status?

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Answer: Anorexia nervosa, binge-eating/purging subtype; normal anion gap metabolic acidosis with appropriate respiratory compensation

Answer

Anorexia nervosa, binge-eating/purging subtype; normal anion gap metabolic acidosis with appropriate respiratory compensation
The correct answer accurately identifies both the psychiatric condition and the acid-base disturbance. The patient's significantly low body weight (BMI of 17.0 kg/m^2) combined with an intense fear of weight gain confirms anorexia nervosa, while her objective binges and laxative abuse specify the binge-eating/purging subtype. Laxative abuse causes significant gastrointestinal loss of potassium and bicarbonate, resulting in a normal anion gap metabolic acidosis. The anion gap is calculated as 139 - (115 + 14) = 10 mEq/L, which is within the normal range of 8-12 mEq/L. To evaluate for appropriate respiratory compensation, Winter's formula is applied: expected PaCO2 = 1.5 * (14) + 8 +/- 2 = 29 +/- 2 mm Hg. The patient's measured PaCO2 of 30 mm Hg falls exactly within this expected compensatory range.

Step-by-Step Solution

1
Identify the primary psychiatric diagnosis based on physical measurements and behavior.
The patient's BMI is 17.0 kg/m^2 (below the 18.5 kg/m^2 threshold), establishing anorexia nervosa. Her episodes of eating large quantities of food and using bisacodyl confirm the binge-eating/purging subtype.
Differentiating anorexia nervosa from bulimia nervosa relies heavily on the BMI threshold; diagnosing the subtype relies on the presence of binge/purge behaviors versus pure restriction.
2
Determine the primary acid-base disorder from the ABG and basic metabolic panel.
The pH of 7.27 indicates acidemia, and the low serum bicarbonate of 14 mEq/L confirms a primary metabolic acidosis, commonly caused by laxative-induced bicarbonate loss in the stool.
Identifying the primary disturbance is the first step in acid-base interpretation.
3
Calculate the anion gap to classify the metabolic acidosis.
Anion Gap = Na+ - (Cl- + HCO3-) = 139 - (115 + 14) = 139 - 129 = 10 mEq/L. This falls in the normal range (8-12 mEq/L).
Calculating the anion gap distinguishes between hyperchloremic acidosis (diarrhea/laxatives) and high anion gap acidosis (starvation ketoacidosis).
4
Apply Winter's formula to determine if respiratory compensation is appropriate.
Expected PaCO2 = 1.5 * (14) + 8 = 29 (+/- 2). The expected range is 27-31 mm Hg. Since the patient's measured PaCO2 is 30 mm Hg, the respiratory compensation is appropriate.
Winter's formula determines if there is a mixed acid-base disorder. If the measured PaCO2 falls within the expected range, no superimposed respiratory disorder is present.

Key Concept

Patients with anorexia nervosa, binge-eating/purging subtype due to laxative abuse present with a BMI < 18.5 kg/m^2 and typically develop a normal anion gap (hyperchloremic) metabolic acidosis with appropriate respiratory compensation.
Estimated Time:2m 0s
Question 3390Question →

Match each clinical scenario describing a patient with a substance use disorder to the most appropriate pharmacologic intervention for their long-term management.

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Items

A 45-year-old man with alcohol use disorder and decompensated cirrhosis (Child-Pugh class C) who recently completed medical detoxification and desires medication to reduce cravings.
A 29-year-old woman with severe co-occurring alcohol and opioid use disorders who completed medical detoxification from all substances 18 days ago and seeks a single medication to prevent relapse of both disorders.
A 34-year-old pregnant woman at 12 weeks gestation with severe opioid use disorder who is experiencing active withdrawal. She seeks treatment that can be prescribed and managed by her specially waivered outpatient obstetrician.
A 52-year-old man with alcohol use disorder who is highly motivated to maintain abstinence. He requests a daily medication that will induce a severe physical reaction, including palpitations and flushing, if he consumes any alcohol.

Matches

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Answer

The clinical scenarios correctly match with Acamprosate for the patient with decompensated cirrhosis, Naltrexone for the patient with dual alcohol and opioid use disorders, Buprenorphine for the pregnant patient seeking office-based treatment, and Disulfiram for the patient seeking aversion therapy.
Each clinical scenario presents a unique medical constraint or requirement that dictates the specific pharmacotherapy for substance use disorder management. The correct matches perfectly align the patient's medical comorbidities, dual diagnoses, prescribing setting restrictions, and personal preferences with the distinct pharmacokinetic and pharmacodynamic profiles of acamprosate, naltrexone, buprenorphine, and disulfiram.

Step-by-Step Solution

1
Analyze the first patient's comorbidities (decompensated cirrhosis) and indication (alcohol use disorder).
The patient requires a medication that is not metabolized by the liver.
Medications like naltrexone and disulfiram carry risks of hepatotoxicity. Acamprosate is renally excreted and therefore safe in severe liver disease.
2
Analyze the second patient's diagnoses (alcohol and opioid use disorders) and period of abstinence (18 days).
The patient needs a dual-efficacy medication and has safely passed the required washout window.
Naltrexone effectively treats both disorders but will precipitate severe withdrawal if given to a patient who has used opioids within the past 7 to 14 days.
3
Analyze the third patient's condition (pregnancy) and preferred treatment setting (office-based outpatient clinic).
The patient requires medication-assisted treatment that can be legally prescribed outside of a federal methadone program.
Buprenorphine is safe during pregnancy and can be prescribed by waivered physicians in a standard clinic, offering greater flexibility than methadone.
4
Analyze the fourth patient's specific request (noxious physical reaction to alcohol) and high motivation level.
The patient is explicitly asking for aversion therapy.
Disulfiram inhibits aldehyde dehydrogenase, leading to toxic acetaldehyde accumulation and severe physical symptoms if alcohol is ingested.

Key Concept

Pharmacotherapy selection for substance use disorders must be individualized based on medical comorbidities, specific patient needs, and regulatory treatment settings.
Question 3391Question →

A 9-year-old boy is brought to the clinic by his parents due to academic difficulties and new behavioral habits. Over the past 14 months, his parents have noticed him frequently and forcefully blinking his eyes, shrugging his shoulders, and clearing his throat. The parents initially attributed the throat clearing to seasonal allergies, but a two-month trial of daily cetirizine provided no relief. His teacher reports that he frequently leaves his seat during class, interrupts others, and struggles to sustain focus on assignments, which is severely impacting his grades. He has no history of sudden behavioral changes following infections. The physician diagnoses a neurodevelopmental disorder and recommends starting a medication that can simultaneously address both his movement symptoms and his behavioral difficulties. Which of the following describes the mechanism of action of the most appropriate initial pharmacotherapy for this patient?

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Answer: Agonism at central alpha-2 adrenergic receptors

Answer

Agonism at central alpha-2 adrenergic receptors
The patient's clinical presentation of multiple motor tics (eye blinking, shoulder shrugging) and at least one vocal tic (throat clearing) persisting for over a year is diagnostic of Tourette syndrome. Concurrently, his inattention, hyperactivity, and impulsivity causing academic impairment are diagnostic of comorbid Attention-Deficit/Hyperactivity Disorder (ADHD). When Tourette syndrome and ADHD co-occur, central alpha-2 adrenergic agonists (such as guanfacine and clonidine) are the most appropriate initial pharmacological choice because they demonstrate efficacy in simultaneously reducing the severity of tics and improving ADHD symptoms. Their mechanism of action is agonism at central alpha-2 adrenergic receptors, which enhances prefrontal cortical regulation of attention and impulse control.

Step-by-Step Solution

1
Analyze the patient's movement and vocal symptoms.
The patient has multiple motor tics (eye blinking, shoulder shrugging) and a vocal tic (throat clearing) lasting more than 1 year (14 months).
To establish the diagnosis of Tourette syndrome and rule out transient tic disorder or allergies.
2
Analyze the patient's behavioral and academic symptoms.
The patient exhibits hyperactivity (leaving seat), impulsivity (interrupting), and inattention (struggles to sustain focus) causing severe academic impairment.
To establish the comorbid diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD).
3
Determine the optimal pharmacological management for the combined diagnoses.
Alpha-2 adrenergic agonists (guanfacine or clonidine) are indicated.
They uniquely provide dual efficacy, reducing both tic severity and ADHD symptoms, making them the preferred initial monotherapy for this specific comorbidity.
4
Identify the mechanism of action of the chosen medication.
Guanfacine and clonidine act via agonism at central alpha-2 adrenergic receptors.
To answer the specific question asked in the stem regarding the neuropharmacology of the optimal drug.

Key Concept

Patients with comorbid Tourette syndrome and Attention-Deficit/Hyperactivity Disorder (ADHD) are typically best managed initially with central alpha-2 adrenergic agonists (e.g., guanfacine, clonidine), which effectively target both symptom clusters.
Question 3392Question →

A 20-year-old man is brought to the university health clinic by his parents due to increasingly concerning behavior. The parents state that for the past 6 weeks, he has barricaded himself in his bedroom, claiming he can hear the voices of "federal agents" plotting to abduct him, and frequently shouting back at these unseen voices. When asked about his prior baseline functioning, his parents note that he was a highly sociable honors student until approximately 8 months ago. At that time, he began to progressively withdraw from his friends, stopped maintaining his personal hygiene, and displayed a markedly blunted affect. Concurrently, he began expressing vague theories about "sensing electromagnetic fields," which coincided with a severe decline in his academic performance leading to academic probation. His vital signs are within normal limits. A comprehensive metabolic panel and urine toxicology screen are unremarkable. Which of the following is the most likely diagnosis?

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Answer: Schizophrenia

Answer

Schizophrenia
The correct diagnosis is schizophrenia. According to DSM-5 criteria, a diagnosis of schizophrenia requires the presence of active-phase symptoms (e.g., delusions, hallucinations, disorganized speech) for at least 1 month, alongside continuous signs of the disturbance lasting for a minimum of 6 months. Crucially, this 6-month requirement includes the prodromal, active, and residual phases of the illness. This patient has a 6-week history of active hallucinations and delusions, which was preceded by an approximately 6.5-month prodromal phase characterized by negative symptoms (blunted affect, social withdrawal, poor hygiene) and attenuated positive symptoms (odd beliefs about electromagnetic fields). Because the total duration of the disturbance is 8 months, the diagnostic threshold for schizophrenia is met.

Step-by-Step Solution

1
Identify the active-phase psychotic symptoms and determine their duration.
The patient has auditory hallucinations and persecutory delusions that have been present for 6 weeks.
Establishing the duration of the active phase is necessary to meet Criterion A for psychotic disorders.
2
Identify any prodromal or residual symptoms and determine the total duration of the illness.
The patient experienced social withdrawal, blunted affect, declining hygiene, and odd beliefs starting 8 months ago. The total duration of the disturbance is therefore 8 months.
The total duration of all phases (prodromal + active + residual) is the primary metric used to differentiate between brief psychotic disorder, schizophreniform disorder, and schizophrenia.
3
Differentiate between the primary psychotic disorders based on the established timeline.
Because the active phase is > 1 month and the total illness duration is > 6 months, the clinical picture meets the criteria for schizophrenia.
Brief psychotic disorder is < 1 month total; schizophreniform disorder is 1 to 6 months total; schizophrenia is > 6 months total.

Key Concept

The 6-month minimum duration criterion for schizophrenia encompasses the entire disturbance, including the prodromal, active, and residual phases.
Question 3393Question →

Approximately 24 hours following an uncomplicated open appendectomy, a 34-year-old man is noted to have an elevated temperature. He has no significant past medical history and takes no routine medications. He currently complains only of expected mild pain at the surgical site. Vital signs show a temperature of 38.2°C (100.8°F), a heart rate of 90/min, blood pressure of 124/78 mm Hg, and a respiratory rate of 16/min. Oxygen saturation is 96% on room air. Auscultation of the chest demonstrates diminished breath sounds at the bilateral lung bases. Examination of the abdomen shows a dry, intact surgical dressing with no surrounding erythema or induration. Which of the following is the most appropriate next step in the management of this patient?

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Answer: Encourage incentive spirometry and early ambulation

Answer

Encourage incentive spirometry and early ambulation
The most appropriate next step in management is to encourage incentive spirometry and early ambulation. This patient's presentation of a low-grade fever within the first 24 to 48 hours after surgery, combined with diminished breath sounds at the lung bases, is the classic presentation of atelectasis. Atelectasis is a very common postoperative complication caused by shallow breathing and impaired cough mechanics secondary to pain or anesthesia. It is considered a non-infectious cause of early postoperative fever. The standard treatment is pulmonary toilet, encompassing early ambulation, deep breathing exercises, and incentive spirometry, which help to re-expand collapsed alveoli.

Step-by-Step Solution

1
Analyze the patient's timeline
The patient is 24 hours (postoperative day 1) status post open appendectomy.
The timing of postoperative fever is the most critical factor in determining its etiology.
2
Evaluate the clinical signs and symptoms
The patient has a low-grade fever, diminished breath sounds at the bases, normal oxygen saturation, and no wound abnormalities.
Physical exam findings correlate with the expected physiologic changes, specifically alveolar collapse (atelectasis).
3
Determine the appropriate management
Identify atelectasis as the diagnosis and select non-pharmacologic respiratory interventions.
Atelectasis is managed and prevented effectively with pulmonary toilet, which includes incentive spirometry, deep breathing, and early ambulation.

Key Concept

Postoperative fever on days 1-2 is most commonly caused by atelectasis, which is managed preventatively and therapeutically with incentive spirometry and early ambulation.
Question 3394Question →

A 62-year-old man with a long-standing history of severe, untreated schizophrenia is evaluated in the emergency department for a gangrenous right foot. The surgical team recommends an urgent below-the-knee amputation to prevent systemic sepsis, which carries a high risk of mortality if left untreated. The patient refuses the procedure, stating, "The aliens are using this foot as a transmitter; if you cut it off, they will destroy the hospital." His vital signs are stable, but he requires surgical intervention within the next 24 hours to prevent deterioration. Arrange the following steps in the most appropriate legal and ethical sequence to navigate this patient's refusal of life-saving care.

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Answer

The correct sequence begins with assessing the patient's decision-making capacity, followed by determining and documenting that he lacks capacity due to a delusion. Next, the physician must search the medical record for an appointed healthcare proxy. If none exists, the next of kin is contacted to act as a surrogate. Finally, if no surrogate can be found, the hospital ethics committee or legal counsel must be consulted.
The algorithm for medical decision-making when a patient refuses life-saving care follows a strict legal and ethical hierarchy. First, capacity must be evaluated, as patients with intact capacity have the absolute right to refuse any treatment. Once it is determined and documented that the patient lacks capacity (in this case, due to a delusion directly impairing judgment), the physician must seek a surrogate decision-maker. The search for a surrogate must follow the legal hierarchy: checking for a patient-appointed healthcare proxy or advance directive first, followed by seeking a default surrogate (next of kin). If no surrogate can be located and the situation is urgent but not an immediate 'split-second' emergency, an ethics committee or legal consultation is required before forcing an invasive procedure on an objecting patient.

Step-by-Step Solution

1
Assess decision-making capacity
Identifies whether the patient has the cognitive ability to make this specific medical decision.
A psychiatric diagnosis (e.g., schizophrenia) does not inherently remove a patient's right to refuse care; capacity must be formally assessed on a decision-by-decision basis.
2
Determine and document lack of capacity
Establishes the legal and ethical grounds to seek a surrogate decision-maker.
Because the patient's refusal is based entirely on a psychotic delusion, he cannot appreciate the true nature of his condition, rendering him legally incapacitated for this choice.
3
Check for a healthcare proxy or advance directive
Identifies if the patient previously designated someone to make medical decisions on their behalf.
Patient-designated surrogates (proxies) always take precedence over default family members in the surrogate hierarchy.
4
Contact next of kin
Identifies a default surrogate decision-maker based on state law.
When no proxy is formally designated, physicians must turn to family members (e.g., spouse, adult children, parents) to make decisions using the principle of substituted judgment.
5
Consult ethics/legal department
Provides institutional guidance and authorization for treatment.
Because this is an urgent but not immediately emergent situation (the patient is currently stable), proceeding with surgery over the patient's objection without a surrogate requires formal ethics or legal intervention.

Key Concept

Algorithm for Assessing Decision-Making Capacity and Surrogate Hierarchy
Question 3395Question →

A 28-year-old man with a recent diagnosis of schizophrenia is started on haloperidol. His physician is reviewing the adverse effect profile with the patient and his family. Arrange the following extrapyramidal symptoms associated with high-potency typical antipsychotics in chronological order of their characteristic onset, from earliest to latest.

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Answer

The correct sequence is: Acute dystonia, Akathisia, Pseudoparkinsonism, and Tardive dyskinesia.
The correct chronological order for the onset of extrapyramidal symptoms associated with antipsychotic medications can be remembered using the mnemonic ADAPT: Acute Dystonia (hours to days), Akathisia (days to weeks), Pseudoparkinsonism (weeks to months), and Tardive dyskinesia (months to years).

Step-by-Step Solution

1
Identify the extrapyramidal symptom with the most rapid onset following initiation of a typical antipsychotic.
Acute dystonia appears within hours to days.
It is an acute reaction to sudden dopamine D2 receptor blockade.
2
Determine the symptom that typically follows dystonia in the expected timeline.
Akathisia generally presents within days to weeks.
It represents a subacute response to dopamine blockade and often emerges soon after or concurrently with dystonia resolution.
3
Identify the symptom that emerges in the weeks to months following treatment initiation.
Pseudoparkinsonism is the third in the sequence.
The drug-induced disruption of the nigrostriatal dopamine pathway gradually produces parkinsonian signs over weeks to months.
4
Identify the long-term complication of typical antipsychotic use.
Tardive dyskinesia is the final symptom in the sequence.
It occurs after months to years of exposure due to dopamine receptor upregulation and supersensitivity.

Key Concept

The chronological onset of extrapyramidal symptoms (EPS) due to antipsychotics typically follows the pattern: acute dystonia (hours-days), akathisia (days-weeks), pseudoparkinsonism (weeks-months), and tardive dyskinesia (months-years).
Question 3396Question →

A 28-year-old man is currently hospitalized on an inpatient psychiatric unit for an acute exacerbation of bipolar I disorder, current episode manic. Over the past hour, he has become increasingly irritable, pacing the hallways rapidly. Suddenly, he begins shouting profanities, claims the nursing staff are 'demons trying to harvest his organs,' and hurls a metal trash can at the nurses' station wall, shattering a plastic clock. He clenches his fists and takes an aggressive combat stance toward an approaching psychiatric technician. Arrange the following interventions in the most appropriate sequence of escalation for managing this patient's acute agitation, according to standard psychiatric emergency protocols.

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Answer

The correct sequence for managing acute psychiatric agitation follows the principle of least restrictive alternative: first evacuate bystanders to ensure safety, attempt verbal de-escalation, offer voluntary oral medications, utilize involuntary intramuscular medications (chemical restraint), and finally apply physical restraints strictly as a last resort.
The management of acute agitation in the psychiatric setting is strictly guided by the principle of the 'least restrictive alternative.' Providers must sequentially escalate interventions only when lesser restrictive measures fail, or if the clinical scenario presents an immediate, catastrophic danger. The first priority is invariably environmental safety—clearing bystanders, removing dangerous objects, and ensuring an exit path for staff. Once safety is established, verbal de-escalation is the first clinical tool. If ineffective, voluntary oral medications should be offered, as they preserve patient autonomy and avoid physical confrontation. If the patient refuses and remains an active threat to themselves or others, involuntary intramuscular medications (chemical restraint) are administered, often requiring a coordinated 'show of force' by trained personnel to prevent injury. Physical restraints are the most restrictive measure possible and are strictly reserved as a last resort when chemical restraint is ineffective, or when the immediate risk of severe bodily harm precludes waiting for medications to take effect.

Step-by-Step Solution

1
Prioritize environmental and personal safety.
Other patients are removed, and staff maintain a safe distance with an open exit.
Ensuring no one is in immediate physical danger is the absolute prerequisite for attempting any further psychiatric intervention.
2
Attempt verbal de-escalation.
The provider uses a calm voice, offers space, and sets clear behavioral limits.
This is the least restrictive patient-directed intervention and can often defuse acute agitation without the need for medication or physical force.
3
Offer voluntary oral chemical restraint.
The patient is given the choice to take medications by mouth.
Oral administration respects autonomy, avoids the physical trauma associated with involuntary injections, and maintains the least restrictive effective approach.
4
Administer involuntary intramuscular medication.
Chemical restraint is applied with the assistance of a security team's 'show of force'.
When voluntary measures fail and the patient remains an active physical threat, rapid-acting intramuscular medications (e.g., haloperidol, lorazepam) are required to prevent violence.
5
Apply physical restraints.
The patient's limbs are secured to a specialized bed.
This is the absolute last resort, utilized only when all lesser restrictive measures have failed and the patient poses an immediate, unmanageable risk of severe physical harm.

Key Concept

Management of acute psychiatric agitation using the step-care protocol of least restrictive interventions.
Question 3397Question →

Match each clinical presentation of psychotic and mood symptoms to the most accurate DSM-5 psychiatric diagnosis based on the symptom timeline and the temporal relationship between the affective and psychotic episodes.

Click a left item, then click its matching right item

Items

A 28-year-old man with a 36-month history of continuous auditory hallucinations and paranoia. During this entire period, he experienced two distinct 2-month episodes of severe depression. For the remaining 32 months, he has had no mood symptoms but continued to experience psychosis.
A 26-year-old woman with a 24-month history of prominent auditory hallucinations. She has concurrently met the criteria for a major depressive episode for 22 of those months. She had a single 4-week period where her mood was completely normal, but the hallucinations persisted.
A 33-year-old man with a 6-week history of depressed mood, terminal insomnia, and significant weight loss. For the past 4 weeks, he has also heard voices stating he deserves to be punished. He has never experienced psychotic symptoms prior to this depressive episode.
A 23-year-old woman who developed sudden-onset paranoid delusions and disorganized speech. Her symptoms persisted for 4 months, after which she experienced a full recovery with a short course of antipsychotic medication and returned to her previous level of baseline functioning.

Matches

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Answer

The 36-month history with 4 months of depression matches Schizophrenia. The 24-month history with 22 months of depression and 4 weeks of isolated psychosis matches Schizoaffective disorder. The 6-week history of depression with 4 weeks of concurrent psychosis matches Major depressive disorder with psychotic features. The 4-month history of psychosis with full recovery matches Schizophreniform disorder.
The correct matches rely on the DSM-5 timeline criteria for psychotic disorders. Schizophrenia requires symptoms for >6 months, with any mood episodes accounting for a minority of the duration. Schizoaffective disorder requires mood symptoms for the majority of the illness, plus >2 weeks of isolated psychosis. Major depressive disorder with psychotic features requires psychosis only during the mood episode. Schizophreniform disorder requires psychotic symptoms lasting between 1 and 6 months.

Step-by-Step Solution

1
Analyze the temporal relationship between mood and psychotic symptoms in the 28-year-old man.
Psychosis duration is 36 months, mood episode duration is 4 months. Mood symptoms are present for a minority of the illness.
If mood symptoms are not present for the majority of the illness, the diagnosis remains schizophrenia, not schizoaffective disorder.
2
Analyze the timeline for the 26-year-old woman.
Mood symptoms are present for 22 out of 24 months (majority of illness), and there are 4 weeks of isolated psychosis.
Satisfies the criteria for schizoaffective disorder (majority of illness with mood symptoms + at least 2 weeks of isolated psychosis).
3
Evaluate the 33-year-old man's symptom onset and duration.
Psychosis only occurs during the active mood episode (4 weeks of psychosis within 6 weeks of depression).
Psychotic symptoms exclusively in the context of a mood episode indicate major depressive disorder with psychotic features.
4
Assess the total duration of symptoms for the 23-year-old woman.
Total duration of psychosis is 4 months with a full return to baseline.
Psychosis lasting between 1 and 6 months defines schizophreniform disorder.

Key Concept

Differential diagnosis of psychotic disorders relies heavily on symptom duration (e.g., <1 month, 1-6 months, >6 months) and the temporal relationship between psychotic symptoms and mood episodes (majority vs. minority of illness duration).
Question 3398Question →

A 45-year-old woman comes to a new primary care clinic to establish care. For the past 12 months, she has experienced chronic, migratory abdominal pain, generalized muscle aches, and perceived shortness of breath. She has been evaluated by a gastroenterologist, a rheumatologist, and a pulmonologist. Extensive diagnostic workups, including endoscopy, autoimmune panels, and pulmonary function tests, have all been completely normal. She states, "I know I have a terrible systemic disease that everyone is missing, and I cannot stop thinking about it." She reports spending at least 3 hours daily researching her symptoms on medical forums, which has led to a recent leave of absence from her job. During today's visit, she becomes acutely anxious and begins to hyperventilate, stating that her "lung disease is flaring up." Her lungs are clear to auscultation bilaterally, and there is no wheezing. An arterial blood gas on room air reveals:

pH: 7.557.55
pCO 2_2: 24 mm Hg24 \text{ mm Hg}
pO 2_2: 105 mm Hg105 \text{ mm Hg}
HCO 3−_3^-: 21 mEq/L21 \text{ mEq/L}

She urgently requests a referral to a quaternary care pulmonology center.

Based on the clinical presentation and laboratory findings, which of the following is the most accurate interpretation of this patient's acid-base status and the most appropriate next step in management?

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Answer: Acute primary respiratory alkalosis; establish regular, time-limited visits with this primary care provider

Answer

The acid-base status is an acute primary respiratory alkalosis, and the best management is to establish regular, time-limited visits with this primary care provider.
The correct answer accurately identifies two key elements of this clinical vignette: the acid-base interpretation and the psychiatric management. The patient's arterial blood gas shows a pH of 7.55 (alkalemia) and a pCO2 of 24 mm Hg, which characterizes an acute primary respiratory alkalosis due to her acute hyperventilation. Psychiatrically, she exhibits classic signs of Somatic Symptom Disorder: at least one distressing somatic symptom, disproportionate and persistent thoughts about the seriousness of the symptoms, and high levels of anxiety lasting more than 6 months despite extensive negative medical evaluations. The most effective initial management strategy for Somatic Symptom Disorder is to establish a strong therapeutic alliance via regular, scheduled, time-limited appointments with a single primary care provider. This approach provides ongoing reassurance, prevents "doctor shopping," and mitigates the risk of iatrogenic harm from unnecessary diagnostic tests and specialist referrals.

Step-by-Step Solution

1
Analyze the patient's psychiatric clinical presentation and timeline.
The patient has multiple distressing somatic symptoms for >6 months with excessive worry, research, and functional impairment despite normal medical workups. This meets the criteria for Somatic Symptom Disorder.
Accurate diagnosis of the underlying psychiatric condition is required to determine the long-term management strategy.
2
Interpret the arterial blood gas results to identify the primary acid-base disturbance.
The pH is 7.55 (alkalemia). The pCO2 is low (24 mm Hg), which aligns with the high pH, indicating a primary respiratory alkalosis caused by acute hyperventilation.
The patient is acutely hyperventilating due to anxiety. Checking the expected compensatory decrease in HCO3- (2 mEq/L drop for every 10 mm Hg drop in pCO2) confirms this is an acute phase.
3
Select the most appropriate evidence-based next step in management for Somatic Symptom Disorder.
The standard of care is scheduling regular, time-limited appointments with a single primary care physician.
This strategy prevents excessive specialist referrals, limits unnecessary diagnostic testing, and provides the patient with a reliable source of reassurance and care.

Key Concept

Patients with Somatic Symptom Disorder (SSD) present with significant distress regarding physical symptoms despite negative medical workups. The cornerstone of management is establishing a strong physician-patient relationship through regular, scheduled, time-limited visits with a single primary care provider to minimize unnecessary diagnostic testing.
Estimated Time:1m 30s
Question 3399Question →

A 54-year-old postmenopausal woman presents to the physician's office after discovering a firm lump in her left breast three weeks ago. The patient has no history of breast trauma, nipple discharge, or skin dimpling. She experienced natural menopause at age 51. Her maternal aunt was diagnosed with breast cancer at age 68. Vital signs are within normal limits. Physical examination reveals a 2.5-cm, hard, irregular, and immobile mass in the upper outer quadrant of the left breast. There are no overlying skin changes, and no axillary or supraclavicular lymphadenopathy is appreciated.

Assume that subsequent evaluation confirms early-stage, estrogen receptor-positive, HER2-negative invasive ductal carcinoma, and the patient opts for breast-conserving management.

Arrange the following diagnostic and therapeutic steps in the most appropriate chronological order for this patient.

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Answer

The correct chronological sequence is: Perform diagnostic mammography and targeted breast ultrasound -> Obtain an image-guided core needle biopsy of the breast mass -> Perform breast-conserving surgery and sentinel lymph node biopsy -> Administer adjuvant whole-breast radiation therapy -> Initiate long-term adjuvant endocrine therapy with an aromatase inhibitor.
The proper sequence for managing a new palpable breast mass in a patient aged 30 or older begins with diagnostic imaging (mammography and targeted ultrasound) to characterize the lesion. If imaging indicates a suspicious mass, an image-guided core needle biopsy is necessary for definitive histologic diagnosis and receptor testing. Following a diagnosis of early-stage breast cancer, the patient undergoes definitive surgical management; breast-conserving surgery (lumpectomy) combined with sentinel lymph node biopsy is appropriate for clinically node-negative disease. Because breast-conserving surgery leaves remaining breast tissue at risk, it must be followed by adjuvant whole-breast radiation therapy to reduce local recurrence. Finally, for hormone receptor-positive tumors in postmenopausal women, long-term adjuvant systemic therapy with an aromatase inhibitor is initiated to decrease the risk of distant recurrence and contralateral breast cancer.

Step-by-Step Solution

1
Evaluate a new palpable breast mass in a patient ≥ 30 years of age.
Diagnostic mammography and targeted ultrasound are performed.
These imaging modalities are first-line for patients over 30 to characterize the lesion and evaluate for multifocal or contralateral disease prior to any intervention.
2
Obtain a definitive tissue diagnosis for a suspicious solid mass.
Image-guided core needle biopsy is performed.
Core needle biopsy is required to confirm malignancy, determine histology (e.g., invasive ductal carcinoma), and assess receptor status, which guides subsequent surgical and medical treatment.
3
Provide definitive local surgical treatment for early-stage invasive breast cancer.
Breast-conserving surgery (lumpectomy) with sentinel lymph node biopsy is performed.
This is the surgical standard of care for early-stage breast cancer with clinically negative axillary nodes when the patient desires breast conservation.
4
Reduce the risk of local recurrence following breast-conserving surgery.
Adjuvant whole-breast radiation therapy is administered.
Radiation is a mandatory adjunct to lumpectomy because it eliminates residual microscopic disease in the remaining breast tissue.
5
Provide systemic therapy for hormone receptor-positive disease.
Adjuvant endocrine therapy with an aromatase inhibitor is initiated.
In postmenopausal women with estrogen receptor-positive tumors, systemic endocrine therapy reduces the risk of distant recurrence and contralateral breast cancer.

Key Concept

The standard evaluation and management of early-stage, hormone receptor-positive breast cancer in a woman ≥ 30 years old follows a strict chronological sequence of diagnostic imaging, tissue biopsy, surgical resection with axillary staging, local adjuvant radiation, and systemic adjuvant endocrine therapy.
Question 3400Question →

Law enforcement officers transport an unidentified young male to the emergency department. He was apprehended while running through a busy intersection, violently striking passing vehicles, and screaming about extraterrestrial entities. In the resuscitation bay, he exhibits extreme combativeness, vertical nystagmus, profuse diaphoresis, and flushed skin. Vital signs reveal a heart rate of 152152/min, blood pressure of 188/112188/112 mm Hg, and a core temperature of 39.6∘C39.6^\circ\text{C} (103.3∘F103.3^\circ\text{F}). The patient requires physical restraint by multiple staff members to prevent immediate harm to himself and others.

Arrange the following clinical interventions in the most appropriate chronological order for managing this patient's acute presentation and subsequent care.

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Answer

The correct sequence prioritizes immediate staff and patient safety via chemical sedation, followed by stabilization of life-threatening hyperthermia, subsequent diagnostic evaluation for complications like rhabdomyolysis, and finally, long-term psychiatric rehabilitation.
In the emergency management of severe psychomotor agitation due to substance intoxication (e.g., phencyclidine, synthetic cathinones, or cocaine), the strict chronological priority is safety and stabilization. The patient must first be chemically sedated with benzodiazepines to prevent harm to staff and themselves. Only after sedation can interventions like active cooling and fluid resuscitation be safely and effectively implemented. Once the patient is physiologically stabilized, diagnostic tests (e.g., creatine kinase to check for rhabdomyolysis) are obtained. Finally, psychiatric interventions and substance use counseling are deferred until the patient is fully sober and cognitively intact.

Step-by-Step Solution

1
Chemically sedate the severely agitated patient.
Intravenous benzodiazepine administration.
Controls extreme agitation, stops excessive heat generation from muscle hyperactivity, reduces sympathetic drive, and allows staff to safely approach the patient for further medical care.
2
Address life-threatening physiologic derangements.
External cooling and intravenous fluids.
High core temperatures (>39.5∘C>39.5^\circ\text{C}) and profound diaphoresis are life-threatening and require immediate correction once the patient can be safely managed.
3
Evaluate for systemic end-organ complications.
Check creatine kinase and renal function.
Extreme physical exertion against restraints combined with hyperthermia puts the patient at high risk for rhabdomyolysis and subsequent acute kidney injury.
4
Address the underlying substance use disorder.
Motivational interviewing and outpatient referral.
Ensures long-term recovery and prevents recurrent episodes; this can only occur after acute delirium has resolved.

Key Concept

Management of acute phencyclidine (PCP) or sympathomimetic intoxication prioritizes chemical sedation before medical workup, followed by cooling/fluids, complication screening, and psychiatric care.
Estimated Time:1m 0s
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