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Question 3541Question →

A 26-year-old woman, gravida 2, para 1, is evaluated in the emergency department for progressive lower abdominal pain, severe chills, and a foul-smelling vaginal discharge. Her symptoms began yesterday and have rapidly worsened over the past 12 hours. Four days ago, she underwent an uncomplicated suction dilation and curettage for an elective pregnancy termination at 10 weeks gestation. Her temperature is 39.2°C (102.6°F), blood pressure is 98/60 mm Hg, pulse is 114/min, and respirations are 20/min. Abdominal examination shows diffuse lower abdominal tenderness with voluntary guarding. Pelvic examination reveals a patulous cervical os, copious purulent discharge pooling in the vaginal vault, and severe uterine tenderness on bimanual palpation. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Intravenous broad-spectrum antibiotics and suction curettage

Answer

Intravenous broad-spectrum antibiotics and suction curettage
The correct answer is to administer intravenous broad-spectrum antibiotics and perform a suction curettage. This patient's presentation of high fever, lower abdominal pain, purulent discharge, and a patulous cervix four days after a surgical abortion is classic for postabortal endometritis, a dangerous complication often caused by retained products of conception. Because she exhibits signs of early sepsis (tachycardia, borderline hypotension), immediate administration of intravenous broad-spectrum antibiotics followed by prompt evacuation of the uterus is required to achieve source control and prevent progressive hemodynamic collapse.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and timeline.
The patient is on postoperative day 4 following a surgical abortion and presents with high fever, tachycardia, borderline hypotension, purulent vaginal discharge, and an exquisitely tender, open cervix.
Establishing the timeline and key physical exam findings is necessary to narrow the differential diagnosis for postoperative fever and abdominal pain.
2
Formulate a primary diagnosis based on the gynecologic findings.
The clinical picture is highly specific for postabortal endometritis, likely secondary to retained products of conception serving as a nidus for infection.
The triad of recent pregnancy termination, fever, and a tender, patulous uterus is the classic presentation for this complication.
3
Determine the most appropriate management for the diagnosis.
Immediate administration of intravenous broad-spectrum antibiotics followed by suction curettage to evacuate the infected retained tissue.
Source control via surgical evacuation is required in addition to antimicrobial therapy to prevent progression to profound septic shock.

Key Concept

Postabortal endometritis typically presents within a few days of a uterine procedure with fever, purulent discharge, and a tender, boggy uterus. Management requires prompt administration of broad-spectrum antibiotics and surgical evacuation of any retained products.
Estimated Time:1m 15s
Question 3542Question →

A 2121-year-old female university student is evaluated in the emergency department for severe muscle cramps, palpitations, and dizziness when standing. She says she has been overwhelmed by her coursework and admits to having episodes where she eats excessively large quantities of food in a short period. Following these episodes, she induces vomiting because she is terrified of gaining weight. Her body mass index is 22.5 kg/m222.5 \text{ kg/m}^2. Blood pressure is 98/60 mm Hg98/60 \text{ mm Hg} supine and 82/50 mm Hg82/50 \text{ mm Hg} upon standing. Heart rate is 105/min105/\text{min}. Physical examination reveals bilateral painless swelling of the cheeks and callous formation on the dorsum of her right hand. Laboratory studies reveal the following:

Laboratory TestResultReference Range
Sodium137 mEq/L137 \text{ mEq/L}136−145 mEq/L136-145 \text{ mEq/L}
Potassium2.6 mEq/L2.6 \text{ mEq/L}3.5−5.0 mEq/L3.5-5.0 \text{ mEq/L}
Chloride86 mEq/L86 \text{ mEq/L}98−106 mEq/L98-106 \text{ mEq/L}
Bicarbonate37 mEq/L37 \text{ mEq/L}22−28 mEq/L22-28 \text{ mEq/L}
TSH1.2 \muU/mL1.2 \text{ \mu U/mL}0.4−4.0 \muU/mL0.4-4.0 \text{ \mu U/mL}
Free T40.9 ng/dL0.9 \text{ ng/dL}0.9−1.7 ng/dL0.9-1.7 \text{ ng/dL}
Free T365 ng/dL65 \text{ ng/dL}80−200 ng/dL80-200 \text{ ng/dL}
Arterial blood gas on room air:
ParameterResult
pH7.537.53
pCO2_248 mm Hg48 \text{ mm Hg}
pO2_292 mm Hg92 \text{ mm Hg}

In addition to acute intravenous fluid and electrolyte resuscitation, which of the following is the most appropriate step in the management of this patient's condition?

Show answer & explanation

Answer: Initiation of fluoxetine to reduce the frequency of binge-eating and purging episodes

Answer

The most appropriate long-term management step is the initiation of fluoxetine to reduce the frequency of binge-eating and purging episodes.
The patient's presentation of binge eating, self-induced vomiting, normal body mass index (22.5 kg/m222.5 \text{ kg/m}^2), parotid swelling, and Russell sign confirm a diagnosis of bulimia nervosa. Her labs reflect severe hypokalemic, hypochloremic metabolic alkalosis, a direct result of gastric acid and volume loss. Alongside nutritional rehabilitation and psychotherapy (Cognitive Behavioral Therapy), Selective Serotonin Reuptake Inhibitors (SSRIs) are the pharmacologic treatment of choice. Fluoxetine is FDA-approved for bulimia nervosa and has been proven to significantly decrease both binge-eating and purging frequencies, regardless of comorbid depression.

Step-by-Step Solution

1
Diagnose the primary psychiatric condition based on clinical presentation.
The patient has Bulimia Nervosa, evidenced by recurrent binge eating, compensatory purging (self-induced vomiting), normal BMI, parotid gland enlargement, and Russell sign (calluses on knuckles).
Establishing the correct diagnosis distinguishes bulimia nervosa from anorexia nervosa, which typically presents with significantly low body weight (BMI < 18.5).
2
Interpret the laboratory and arterial blood gas findings.
The patient has severe hypokalemic, hypochloremic metabolic alkalosis (pH 7.53, high HCO3). The pCO2 of 48 is expected respiratory compensation (Expected pCO2 = 40 + [0.7 * (37 - 24)] = 49.1). The thyroid panel shows euthyroid sick syndrome.
Understanding the systemic complications of purging allows the clinician to avoid inappropriate interventions for expected compensatory mechanisms and lab anomalies.
3
Select the safest and most effective long-term pharmacotherapy.
Fluoxetine is selected as it is the first-line SSRI for bulimia nervosa. Bupropion is contraindicated due to seizure risk.
After acute medical stabilization of electrolytes and volume depletion, long-term pharmacological management alongside cognitive behavioral therapy is required to prevent relapse.

Key Concept

Bulimia nervosa is characterized by binge eating and compensatory behaviors at a normal or overweight BMI. Treatment involves nutritional rehabilitation, cognitive behavioral therapy, and SSRIs (specifically fluoxetine). Bupropion is contraindicated due to seizure risk.
Question 3543Question →

A 41-year-old construction worker is brought to the emergency department after falling approximately 25 feet from a scaffold. On arrival, he is moaning and only withdraws his extremities in response to painful stimuli. His temperature is 36.1°C (97.0°F), blood pressure is 74/40 mm Hg, pulse is 142/min, and respiratory rate is 26/min. Pulse oximetry is 94% on high-flow oxygen. The airway is patent, and breath sounds are present and equal bilaterally. A chest radiograph demonstrates no pneumothorax or hemothorax. The pelvis is mechanically stable to anterior-posterior and lateral compression. Abdominal examination reveals diffuse rigidity and involuntary guarding. Bilateral thigh deformities are noted. Intravenous access is established, and a massive transfusion protocol is initiated. A bedside focused assessment with sonography for trauma (FAST) is attempted but is technically inadequate due to massive subcutaneous emphysema and overlying bowel gas. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Immediate exploratory laparotomy

Answer

Immediate exploratory laparotomy
The correct next step is immediate exploratory laparotomy. This patient is in severe hemorrhagic shock following blunt trauma. According to Advanced Trauma Life Support (ATLS) protocols, clinical signs of peritonitis—such as a diffusely rigid abdomen and involuntary guarding—in a hemodynamically unstable trauma patient constitute an absolute indication for immediate surgical exploration. Although the FAST examination is technically inadequate (which would algorithmically prompt a diagnostic peritoneal aspiration to evaluate for intraperitoneal blood in an otherwise equivocal abdomen), the unequivocal physical examination findings of an acute abdomen supersede the need for further diagnostic testing. Proceeding directly to the operating room is critical to achieve prompt hemorrhage control and manage a likely hollow viscus or solid organ injury.

Step-by-Step Solution

1
Assess the patient's hemodynamic status and primary survey.
The patient is in class IV hemorrhagic shock (BP 74/40 mm Hg, HR 142/min) with a patent airway and intact breathing.
To prioritize life-threatening injuries according to the ATLS ABCDE algorithm.
2
Evaluate the abdominal physical examination and FAST results.
The FAST exam is inconclusive, but the physical examination reveals a rigid abdomen with involuntary guarding.
To determine the source of hemorrhage and the need for operative intervention.
3
Determine the next best step based on the clinical findings.
The presence of frank peritonitis (rigidity, guarding) in an unstable patient mandates immediate exploratory laparotomy, bypassing further diagnostic steps like diagnostic peritoneal aspiration.
Peritonitis indicates a ruptured hollow viscus or massive hemoperitoneum requiring urgent surgical control.

Key Concept

In a hemodynamically unstable trauma patient, the presence of frank peritonitis (e.g., rigid abdomen, involuntary guarding) is an absolute indication for immediate exploratory laparotomy, regardless of ultrasound (FAST) findings.
Estimated Time:1m 30s
Question 3544Question →

A 32-year-old woman is evaluated in the outpatient psychiatric clinic for worsening mood. She delivered a healthy full-term infant 2 months ago. For the last 3 weeks, she has experienced profound sadness, anhedonia, loss of appetite resulting in a 3-kg (6.6-lb) weight loss, and extreme guilt about being a "terrible mother." For the past week, she reports hearing a persistent, derogatory voice telling her she should "disappear." Her husband notes that 6 years ago, she had a 3-week period where she abruptly quit her job, slept only 2 hours per night but felt fully energetic, exhibited pressured speech, and maxed out their credit cards. This previous episode required a brief psychiatric hospitalization, but she stopped taking her prescribed medications 5 years ago. She currently takes no medications. Vital signs are within normal limits. On examination, she exhibits a blunted affect and psychomotor retardation. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Initiate quetiapine monotherapy

Answer

The most appropriate next step is to initiate quetiapine monotherapy.
The correct action is to initiate quetiapine monotherapy. This patient is currently experiencing a major depressive episode with psychotic features (auditory hallucinations, profound sadness, guilt, weight loss). However, her history of a distinct episode characterized by a decreased need for sleep, pressured speech, impulsivity, and hospitalization definitively indicates a past manic episode. Therefore, her underlying diagnosis is bipolar I disorder, and she is currently experiencing bipolar depression with psychotic features. Quetiapine is an atypical antipsychotic that is FDA-approved for bipolar depression; it will simultaneously target both her severe mood symptoms and her psychotic features without carrying the risk of inducing a manic switch.

Step-by-Step Solution

1
Identify the current clinical syndrome from the presentation.
The patient has a 3-week history of severe depressive symptoms and a 1-week history of auditory hallucinations, indicating a major depressive episode with psychotic features.
Characterizing the current episode is necessary before determining the overarching psychiatric diagnosis.
2
Review the patient's psychiatric history for previous mood episodes.
The patient had a distinct 3-week episode of decreased need for sleep, pressured speech, and reckless behavior requiring hospitalization.
A history of a manic episode changes the diagnosis from unipolar major depressive disorder to bipolar I disorder.
3
Formulate the correct comprehensive diagnosis.
The diagnosis is bipolar I disorder, currently in a depressive phase with psychotic features, with postpartum onset.
Accurate diagnosis prevents the use of contraindicated medications like SSRI monotherapy.
4
Select the appropriate pharmacological treatment.
Quetiapine is chosen as the next step in management.
Bipolar depression with psychotic features requires an agent that provides mood stabilization and antipsychotic effects. Quetiapine is an atypical antipsychotic approved for bipolar depression.

Key Concept

Discrimination between unipolar and bipolar depression with psychotic features, and selection of appropriate mood-stabilizing pharmacotherapy.
Question 3545Question →

A 34-year-old man is brought to the emergency department by paramedics after being found confused and severely agitated in his apartment. Beside him are empty bottles of tranylcypromine and fluoxetine. In the emergency department, he is delirious and thrashing violently. His temperature is 39.5°C (103.1°F), blood pressure is 170/105 mm Hg, and pulse is 135/min. Physical examination reveals pronounced diaphoresis, hyperreflexia, and sustained ankle clonus bilaterally. Shortly after the initial assessment, the patient develops a generalized tonic-clonic seizure.

The patient's electronic health record contains a legally executed medical power of attorney designating his long-term partner as his sole healthcare proxy. The partner is currently on an international flight and cannot be reached. The patient's biological parents, who were notified of the emergency by the landlord, arrive at the hospital. They declare themselves as his legal next-of-kin and demand that all medications be withheld, insisting he 'just needs to sleep it off without chemical interference.'

Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Administer intravenous lorazepam immediately under the doctrine of implied consent

Answer

The most appropriate next step is to administer intravenous lorazepam immediately under the doctrine of implied consent.
The patient is experiencing severe serotonin syndrome (precipitated by the overdose of an MAOI and an SSRI) complicated by a generalized tonic-clonic seizure. This is a life-threatening medical emergency requiring immediate pharmacological intervention with intravenous benzodiazepines (e.g., lorazepam) to control the seizures, agitation, and hyperthermia. In a life-threatening emergency where a patient lacks decision-making capacity and their legally appointed healthcare proxy is unreachable, physicians must provide necessary life-saving treatment under the doctrine of implied consent (the emergency exception to informed consent). The biological parents have no legal authority to direct care because a legally executed medical power of attorney supersedes the default state next-of-kin hierarchy. Therefore, the immediate administration of lorazepam is both medically essential and legally justified.

Step-by-Step Solution

1
Diagnose the patient's acute clinical condition based on the presentation and history.
The patient has severe serotonin syndrome (due to MAOI and SSRI overdose) complicated by a generalized tonic-clonic seizure, which is a life-threatening medical emergency.
Accurate clinical diagnosis dictates the urgency and type of pharmacological intervention required.
2
Determine the appropriate legal decision-maker for the incapacitated patient.
The legally appointed healthcare proxy is unreachable. The biological parents present do not hold decision-making authority because the medical power of attorney supersedes the default next-of-kin hierarchy.
Identifying the legal surrogate is necessary for informed consent, but strict hierarchy rules apply in law.
3
Apply the appropriate medical ethics doctrine for an emergency situation where the proxy is absent.
The physician must apply the emergency exception to informed consent (implied consent) to immediately administer life-saving standard of care (intravenous lorazepam).
Delaying treatment in a rapidly deteriorating, life-threatening situation to find a proxy, or obeying unauthorized demands that cause harm, constitutes medical negligence.

Key Concept

Emergency Exception to Informed Consent and Surrogate Hierarchy
Question 3546Question →

A 28-year-old pregnant woman at 14 weeks gestation is brought to the emergency department by her husband. Over the past week, she has been sleeping for only one to two hours a night, exhibiting rapid and pressured speech, and making impulsive, large financial investments that they cannot afford. Three weeks ago, she visited a different clinic reporting severe sadness, hypersomnia, and anhedonia, at which time fluoxetine monotherapy was initiated. She is currently taking fluoxetine and prenatal vitamins. When approached by the physician, she refuses any new medications or hospital admission, stating her high energy is a "divine gift for the baby" and demands to leave immediately. Which of the following are the most appropriate next steps in the management of this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Discontinue the fluoxetine immediately.; Assess her decision-making capacity and place an involuntary psychiatric hold if she is deemed a danger to herself or others.

Answer

The most appropriate steps are to immediately discontinue the fluoxetine and to perform a formal assessment of her decision-making capacity, placing an involuntary hold if she is deemed a danger to herself.
The patient's presentation of markedly decreased need for sleep, pressured speech, and grandiose, impulsive behavior following the initiation of an SSRI is diagnostic of an antidepressant-induced manic episode. The essential first pharmacological step is to discontinue the offending agent (fluoxetine). Because the patient is exhibiting poor insight and potentially dangerous impulsivity but is refusing care, the physician must formally assess her decision-making capacity. If her mania has impaired her capacity and she poses a danger to herself or others, placing her on an involuntary psychiatric hold is the appropriate legal and ethical next step to ensure safety.

Step-by-Step Solution

1
Identify the patient's current clinical syndrome and its likely trigger.
The patient is experiencing an acute manic episode, likely precipitated by the recent initiation of fluoxetine for depression (antidepressant-induced manic switch).
Recognizing the iatrogenic trigger is essential for deciding the most urgent pharmacological intervention.
2
Determine the immediate pharmacological management strategy.
The fluoxetine must be discontinued.
Continuing an antidepressant during an acute manic episode will prolong and worsen the manic symptoms. Antidepressant monotherapy is contraindicated in bipolar spectrum disorders.
3
Evaluate the ethical and legal obligations regarding her refusal of care.
A formal capacity assessment is required. If she lacks capacity due to mania and poses a danger to herself (e.g., severe financial ruin, lack of self-care), an involuntary hold is indicated.
While competent pregnant women have the right to refuse medical care even if it risks the fetus, acute mania often impairs decision-making capacity. Intervention must be based on her lack of capacity and risk of harm, not solely on fetal protection.

Key Concept

Management of antidepressant-induced mania and maternal-fetal ethics in psychiatric emergencies
Estimated Time:1m 15s
Question 3547Question →

A 31-year-old man comes to the clinic accompanied by his husband due to daytime sleep attacks and episodes of sudden muscle weakness. Over the last 5 months, he has been sleeping 9 to 10 hours per night but still struggles to stay awake during his work as a financial analyst. He reports that when he laughs heartily at a joke, his knees buckle and he occasionally drops his briefcase, though he remains fully conscious. Last month, while falling asleep, he saw a terrifying shadowy figure in his room and was unable to move his limbs for approximately a minute. His medical history is notable for a manic episode at age 22, leading to a diagnosis of bipolar I disorder. He was previously taking valproate but discontinued it a year ago due to weight gain. He is currently taking only tranylcypromine, which was prescribed 2 months ago for an acute depressive episode. Vital signs are within normal limits. Physical examination is unremarkable. Laboratory studies show a thyroid-stimulating hormone (TSH) level of 7.2 µU/mL (normal: 0.5-5.0 µU/mL) and a free thyroxine (T4) level of 1.2 ng/dL (normal: 0.9-1.7 ng/dL).

Which of the following is the most appropriate pharmacotherapy for this patient's sleep-related symptoms?

Show answer & explanation

Answer: Sodium oxybate

Answer

Sodium oxybate
Sodium oxybate is an FDA-approved, highly effective treatment for both the excessive daytime sleepiness and cataplexy associated with Narcolepsy Type 1. It acts as a central nervous system depressant (via GABA-B and GHB receptors) to consolidate fragmented nighttime sleep. Crucially, in this complex patient, sodium oxybate does not carry serotonergic activity, meaning it can be safely co-administered with his current monoamine oxidase inhibitor (tranylcypromine) without causing serotonin syndrome. Furthermore, unlike activating antidepressants, it does not carry a high risk of precipitating a manic episode in a patient with bipolar I disorder who is currently off mood stabilizers.

Step-by-Step Solution

1
Identify the primary diagnosis based on the clinical presentation.
The patient's excessive daytime sleepiness, cataplexy (muscle weakness triggered by laughter), hypnagogic hallucinations, and sleep paralysis are diagnostic of Narcolepsy Type 1.
Recognizing the full tetrad of narcolepsy symptoms differentiates it from other causes of fatigue, such as hypothyroidism or depression.
2
Evaluate the patient's current medication regimen and medical history for potential contraindications.
The patient has Bipolar I disorder not covered by a mood stabilizer, and is currently taking tranylcypromine, a monoamine oxidase inhibitor (MAOI).
Standard off-label cataplexy treatments (SSRIs/SNRIs) pose extreme risks in this specific patient, including manic switch and serotonin syndrome.
3
Select the appropriate therapy that safely addresses the core symptoms.
Sodium oxybate is chosen as the most appropriate pharmacotherapy.
It treats both excessive daytime sleepiness and cataplexy effectively without interacting with the MAOI or precipitating mania.

Key Concept

Management of Narcolepsy Type 1 in patients with psychiatric comorbidities and complex medication regimens.
Question 3548Question →

On postoperative day 3 following an open reduction and internal fixation of a right tibial fracture, a 51-year-old male is evaluated by the on-call physician for acute, severe agitation and confusion. The fracture was sustained during a motor vehicle collision. The patient lives alone and a comprehensive medical history is unavailable. Current temperature is 38.7°C (101.7°F), pulse is 126/min, blood pressure is 168/102 mm Hg, and respirations are 22/min. On examination, the patient is profoundly diaphoretic and continuously attempts to pull out his intravenous catheter. When approached, he points frantically toward the ceiling and claims that swarms of insects are dropping onto his bed. Neurological examination reveals a coarse, bilateral resting tremor of the upper extremities. The surgical incision is clean, intact, and without erythema. Cardiopulmonary auscultation is unremarkable. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Intravenous administration of diazepam

Answer

The most appropriate next step is the intravenous administration of a long-acting benzodiazepine, such as diazepam.
The patient's presentation of fever, marked autonomic hyperactivity (tachycardia, hypertension, diaphoresis), coarse resting tremor, and visual hallucinations occurring roughly 72 hours (postoperative day 3) after an unplanned hospital admission is the classic presentation of delirium tremens. Delirium tremens is a severe, life-threatening manifestation of alcohol withdrawal. Because patients often live alone and do not disclose their alcohol use history upon admission for trauma, the withdrawal syndrome unmasks itself a few days into their stay. The gold standard for treating severe alcohol withdrawal is the administration of benzodiazepines (e.g., diazepam, lorazepam, or chlordiazepoxide). These drugs enhance the inhibitory effect of GABA, counteracting the glutamate-driven excitatory state of withdrawal, thereby reducing agitation, stabilizing vital signs, and preventing withdrawal seizures.

Step-by-Step Solution

1
Analyze the patient's timeline and physical exam findings.
The patient developed fever, severe autonomic hyperactivity (tachycardia, hypertension, diaphoresis), coarse tremor, and visual hallucinations ('insects') on postoperative day 3.
Recognizing the '48 to 96 hour' window after hospital admission is critical for identifying alcohol withdrawal in patients who have abruptly ceased covert drinking.
2
Establish the most likely diagnosis.
The clinical picture is pathognomonic for delirium tremens (severe alcohol withdrawal).
Alcohol acts as a CNS depressant by enhancing GABA and inhibiting glutamate. Abrupt cessation leads to a hyper-excitable state, manifesting as the symptoms seen in this patient.
3
Determine the optimal acute pharmacological management.
Select a medication that safely replaces the inhibitory effect of alcohol, which is a benzodiazepine.
Benzodiazepines stimulate GABA receptors, mitigating the severe withdrawal symptoms, correcting autonomic instability, and preventing fatal complications such as seizures.

Key Concept

Patients with undisclosed alcohol use disorder often present with delirium tremens (hallucinations, tremor, autonomic instability) 48 to 96 hours after hospital admission; first-line treatment is a benzodiazepine.
Question 3549Question →

Match each clinical presentation of an adrenal mass with the most appropriate specific perioperative or surgical management step.

Click a left item, then click its matching right item

Items

A 45-year-old patient with episodic palpitations, diaphoresis, elevated plasma fractionated metanephrines, and a 4.5-cm adrenal mass.
A 38-year-old patient with resistant hypertension, muscle cramps, low serum potassium, high aldosterone-to-renin ratio, and a 2-cm unilateral adrenal mass.
A 50-year-old patient with central adiposity, proximal muscle weakness, elevated 24-hour urine free cortisol, suppressed ACTH, and a 3.5-cm adrenal mass.
A 55-year-old patient with abdominal pain, a rapidly enlarging 9-cm heterogeneous adrenal mass with irregular margins on CT, and elevated serum DHEA-S.

Matches

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Answer

Pheochromocytoma pairs with alpha/beta blockade; Conn syndrome pairs with aldosterone antagonists; Adrenal Cushing syndrome pairs with postoperative glucocorticoids; Adrenocortical carcinoma pairs with open en bloc resection.
Each adrenal pathology requires distinct surgical planning. Pheochromocytoma requires sequential alpha then beta blockade to prevent intraoperative hypertensive crisis. Primary hyperaldosteronism requires potassium repletion and mineralocorticoid receptor blockade. Adrenal Cushing syndrome causes contralateral gland atrophy, necessitating perioperative stress-dose glucocorticoids to prevent acute adrenal insufficiency after tumor removal. Large, suspicious masses (adrenocortical carcinoma) require open en bloc resection to avoid capsular rupture and tumor seeding, which are risks with laparoscopic approaches and percutaneous biopsies.

Step-by-Step Solution

1
Analyze the clinical, laboratory, and imaging findings for each adrenal mass presentation to establish the underlying diagnosis.
Identified diagnoses are pheochromocytoma, primary hyperaldosteronism, adrenal Cushing syndrome, and adrenocortical carcinoma.
Each type of functional or malignant adrenal tumor has distinct physiologic consequences that dictate perioperative management.
2
Determine the specific pathophysiologic risks associated with the surgical removal of each tumor type.
Pheochromocytoma risks hypertensive crisis; Conn syndrome involves potassium wasting and hypertension; Cushing syndrome risks postoperative adrenal crisis due to HPA axis suppression; Adrenocortical carcinoma risks tumor spillage and local invasion.
Surgical and perioperative strategies are tailored to mitigate these life-threatening complications.
3
Match the diagnosis with the standard-of-care surgical and perioperative intervention.
Correct pairings are made based on surgical guidelines for endocrine pathology.
Ensures adherence to best practices in endocrine surgery and patient safety.

Key Concept

Perioperative and surgical management of functioning and malignant adrenal tumors
Question 3550Question →

A 68-year-old man is brought to the clinic by his son for evaluation of cognitive decline. The son reports that his father's memory has worsened significantly over the past 4 months, which coincided with the unexpected death of his wife. The patient frequently misplaces his glasses and forgets the names of acquaintances. During the interview, the patient appears visibly distressed about his memory, stating, "My brain is completely useless now. I can't remember a single thing." When asked orientation questions and to perform a three-word delayed recall, he frequently answers "I don't know" with little initial effort. However, with gentle encouragement and extra time, he is able to correctly recall two of the three words. The patient also reports early morning awakenings, poor appetite, and a 5-kg (11-lb) weight loss over the past 3 months. His medical history includes hypertension well-controlled on lisinopril. Vital signs are within normal limits. Physical and neurological examinations reveal no abnormalities. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Initiate trial of a selective serotonin reuptake inhibitor

Answer

Initiate trial of a selective serotonin reuptake inhibitor
The patient's clinical picture is classic for major depressive disorder with prominent cognitive impairment, a condition historically termed 'pseudodementia'. Key distinguishing features from a primary neurocognitive disorder (such as Alzheimer disease) include the relatively acute onset following a significant life stressor, the patient's severe distress and retained insight regarding his memory loss, and the characteristic 'I don't know' responses on cognitive testing that improve with encouragement. In true dementia, patients typically have an insidious onset, lack insight (anosognosia), try to conceal their deficits, and genuinely cannot recall information despite encouragement. The presence of vegetative symptoms (weight loss, early morning awakenings) further supports the diagnosis of major depression. The most appropriate next step is to initiate a trial of an antidepressant medication, such as an SSRI.

Step-by-Step Solution

1
Analyze the onset and nature of the cognitive symptoms.
The cognitive decline had an abrupt onset 4 months ago following a major stressor (spouse's death), and the patient shows significant distress and insight regarding his memory loss.
Differentiating between neurocognitive disorders and psychiatric conditions requires evaluating the timeline, precipitating factors, and the patient's awareness of their deficits.
2
Evaluate the patient's performance on cognitive testing.
The patient gives 'I don't know' answers and displays poor initial effort, but performs adequately with encouragement.
Patients with true dementia typically make genuine attempts to answer but confabulate or fail, whereas patients with depression often show poor effort but intact underlying cognition.
3
Identify the primary underlying pathology.
The combination of depressed mood, weight loss, early morning awakenings, and cognitive complaints points to major depressive disorder (pseudodementia).
Recognizing the somatic and psychological criteria for major depression is necessary to guide treatment.
4
Determine the most appropriate management.
Treating the underlying depression with a selective serotonin reuptake inhibitor (SSRI) is the correct next step.
Reversing the depressive episode will likely resolve the secondary cognitive impairment.

Key Concept

Major depressive disorder in the elderly can present with prominent cognitive deficits (pseudodementia), which are distinguished from true dementia by the patient's prominent distress over memory loss, poor effort on testing that improves with encouragement, and an acute onset associated with a stressor. The primary treatment is targeted at the underlying depression.
Question 3551Question →

A 65-year-old man is evaluated in the surgical intensive care unit on postoperative day 5 following a low anterior resection for rectal adenocarcinoma. The nurse calls due to a sudden change in the patient's clinical status. He is now lethargic and confused. His temperature is 39.4°C (102.9°F), blood pressure is 78/40 mmHg, pulse is 135/min, and respirations are 28/min. Pulse oximetry shows 88% on room air. Abdominal examination reveals diffuse rigidity, severe rebound tenderness, and involuntary guarding. Arrange the following management steps in the correct chronological sequence for this acute postoperative complication.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence prioritizes the ABCs of resuscitation (Airway and Oxygen), followed immediately by circulatory support (Fluid bolus). Once stabilized, diagnostic cultures must be drawn prior to administering broad-spectrum antibiotics. Finally, the unstable patient with generalized peritonitis must undergo emergent surgical source control.
The management of an acute, life-threatening postoperative complication like an anastomotic leak with septic shock requires a strict adherence to resuscitation and sepsis algorithms. First, the airway and breathing must be secured with supplemental oxygen. Second, circulation is supported via aggressive crystalloid resuscitation. Third, source identification begins by drawing blood cultures. Fourth, broad-spectrum antibiotics are given to treat the systemic infection. Finally, because the patient exhibits generalized peritonitis and hemodynamic instability, emergent operative source control (exploratory laparotomy) is the definitive step, deliberately bypassing any radiographic imaging delays.

Step-by-Step Solution

1
Assess airway patency and administer high-flow supplemental oxygen.
The patient's severe hypoxia and altered mental status are addressed.
Airway and Breathing take absolute precedence in any acute resuscitation scenario.
2
Establish large-bore intravenous access and administer a rapid crystalloid bolus.
Intravascular volume is expanded to counteract profound sepsis-induced vasodilation.
Circulatory support is the immediate next priority for a patient in septic shock.
3
Obtain peripheral blood and relevant fluid cultures.
Diagnostic samples are secured before they can be altered by medications.
Cultures must precede antimicrobial administration to ensure accurate pathogen identification and targeted therapy.
4
Administer broad-spectrum intravenous antibiotics.
Empiric treatment for suspected intra-abdominal sepsis is initiated.
Early antibiotic administration is critical for survival in septic shock and should follow culture acquisition.
5
Transport the patient to the operating room for emergent exploratory laparotomy.
Definitive source control of the likely anastomotic leak is achieved.
Hemodynamically unstable patients with peritonitis require immediate surgery without delaying for radiographic imaging.

Key Concept

Algorithm for postoperative septic shock and acute surgical abdomen management.
Question 3552Question →

A 15-year-old boy is brought to the emergency department by his parents due to severe, sudden-onset right scrotal pain that woke him from sleep 2 hours ago. He reports nausea and has vomited twice. He has no history of trauma, dysuria, or urethral discharge. His temperature is 37.1°C (98.8°F), heart rate is 105/min, and blood pressure is 125/80 mmHg. Physical examination reveals a swollen, exquisitely tender, and high-riding right testicle with a transverse lie. The right cremasteric reflex is absent, while the left is intact. Scrotal elevation does not relieve the pain. Which of the following is the most appropriate next step in the management of this patient?

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Answer: Immediate surgical exploration

Answer

The most appropriate next step is immediate surgical exploration.
The correct answer is immediate surgical exploration. This patient presents with the classic triad of testicular torsion: sudden onset of severe scrotal pain, a high-riding transversely oriented testicle, and an absent cremasteric reflex. Testicular torsion is a urologic emergency caused by twisting of the spermatic cord, leading to venous congestion, arterial compromise, and eventual testicular infarction. The window for testicular salvage is extremely narrow, typically 4 to 6 hours from symptom onset. Therefore, when the clinical diagnosis is highly suspected based on history and physical examination, the standard of care is immediate urologic consultation and surgical exploration. Bilateral orchiopexy (fixation of the testicles to the scrotal wall) is performed to prevent recurrence. Ordering any diagnostic imaging, including a Doppler ultrasound, is contraindicated in this scenario as it will delay definitive care and increase the likelihood of orchiectomy.

Step-by-Step Solution

1
Analyze the patient's demographics and history of present illness.
A 15-year-old adolescent boy presents with acute, severe, sudden-onset scrotal pain that woke him from sleep, accompanied by nausea and vomiting.
Sudden onset of severe scrotal pain in an adolescent is highly suspicious for a vascular event like testicular torsion.
2
Evaluate the physical examination findings.
The physical exam shows a high-riding, transversely oriented testicle with an absent cremasteric reflex on the affected side.
An absent cremasteric reflex is the most sensitive physical finding for testicular torsion. A high-riding, transverse lie indicates a 'bell clapper' deformity predisposing to torsion.
3
Determine the optimal management strategy based on clinical suspicion.
The clinical diagnosis of testicular torsion is highly likely, necessitating definitive treatment.
Testicular torsion is a surgical emergency. The testicle can suffer irreversible ischemic damage within 4 to 6 hours of symptom onset. Therefore, when clinical suspicion is high, immediate surgical exploration and bilateral orchiopexy are required without delaying for confirmatory imaging.

Key Concept

Management of high-suspicion acute testicular torsion
Question 3553Question →

A 16-year-old boy is brought to the emergency department by his parents due to the sudden onset of severe right scrotal pain that awoke him from sleep 2 hours ago. He has had one episode of vomiting since the pain started. His temperature is 37.1°C (98.8°F), blood pressure is 120/78 mmHg, and pulse is 98/min. Physical examination reveals a swollen, exquisitely tender, and high-riding right testicle with a transverse lie. The right cremasteric reflex is absent. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Immediate surgical exploration

Answer

Immediate surgical exploration
The patient's presentation of sudden-onset, severe scrotal pain during sleep, accompanied by nausea or vomiting, an absent cremasteric reflex, and a high-riding testicle, is highly characteristic of testicular torsion. Testicular torsion is a urologic emergency caused by the twisting of the spermatic cord, which compromises the blood supply to the testicle. Because testicular viability decreases significantly after 6 hours of ischemia, a patient with a classic clinical picture should be taken directly to the operating room for immediate surgical exploration and bilateral orchiopexy. Delaying surgery for imaging is contraindicated when the diagnosis is highly likely.

Step-by-Step Solution

1
Identify the primary clinical presentation
Sudden onset of severe scrotal pain, high-riding testicle with transverse lie, and absent cremasteric reflex.
These are the hallmark signs of testicular torsion, an acute ischemic condition.
2
Determine the necessity of diagnostic imaging
Imaging is not needed when the clinical suspicion for testicular torsion is high.
Time is critical; testicular salvage rates drop significantly after 6 hours of ischemia.
3
Select the appropriate intervention
Immediate surgical exploration.
Surgery allows for definitive diagnosis, manual detorsion, and bilateral orchiopexy to prevent recurrence.

Key Concept

Testicular torsion requires emergent surgical exploration without delay for imaging when the clinical presentation is classic (sudden pain, absent cremasteric reflex, high-riding testis).
Question 3554Question →

A 42-year-old woman comes to the clinic for evaluation of a newly noticed lump in her anterior neck. She reports no pain, hoarseness, dysphagia, or recent changes in her weight. Physical examination reveals a non-tender, 2.5-cm, mobile nodule in the right lobe of the thyroid gland. A neck ultrasound confirms a 2.5-cm solid, hypoechoic nodule in the right thyroid lobe with regular margins. Laboratory studies show a serum thyroid-stimulating hormone (TSH) level of 0.1 mU/L (normal: 0.4-4.0 mU/L). Which of the following is the most appropriate next step in management?

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Answer: Radionuclide thyroid scan

Answer

Radionuclide thyroid scan
According to the standard diagnostic algorithm for thyroid nodules, the initial evaluation requires a serum TSH level and a thyroid ultrasound. If the TSH is subnormal (suppressed), a radionuclide thyroid scan (e.g., using Iodine-123 or Technetium-99m) is indicated to assess the functional status of the nodule. Hyperfunctioning ('hot') nodules are rarely malignant and typically require evaluation and treatment for hyperthyroidism rather than biopsy. Non-functioning ('cold') nodules have a higher risk of malignancy and generally require a subsequent fine-needle aspiration biopsy.

Step-by-Step Solution

1
Identify the primary clinical problem and initial findings.
The patient has a palpable 2.5-cm solid thyroid nodule confirmed by ultrasound.
Establishing the baseline clinical scenario is required before interpreting the diagnostic algorithm.
2
Evaluate the initial laboratory results.
The serum TSH level is 0.1 mU/L, which is suppressed (below the normal range).
The TSH value dictates the diagnostic pathway for evaluating a thyroid nodule.
3
Determine the next indicated step based on the TSH level.
A radionuclide thyroid scan is chosen.
When TSH is subnormal, a radionuclide scan is required to determine if the nodule is hyperfunctioning (hot) or non-functioning (cold), as hot nodules are rarely malignant.

Key Concept

Evaluation of a thyroid nodule with a suppressed TSH level
Question 3555Question →

A randomized controlled trial is conducted to evaluate a new lipid-lowering medication for the prevention of myocardial infarction in patients with stable angina. Over a 5-year period, 1,000 patients receive the new medication and 1,000 patients receive a placebo. At the end of the study, 50 patients in the new medication group and 100 patients in the placebo group have experienced a myocardial infarction. Based on these results, what is the number needed to treat to prevent one myocardial infarction?

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Answer: 20

Answer

20
The number needed to treat (NNT) is calculated as the inverse of the absolute risk reduction (ARR). First, determine the control event rate (CER): 1001000=0.10\frac{100}{1000} = 0.10. Next, determine the experimental event rate (EER): 501000=0.05\frac{50}{1000} = 0.05. The absolute risk reduction is CER−EER=0.10−0.05=0.05CER - EER = 0.10 - 0.05 = 0.05. The NNT is 1ARR=10.05=20\frac{1}{ARR} = \frac{1}{0.05} = 20. Therefore, 20 patients need to be treated with the new medication to prevent one myocardial infarction.

Step-by-Step Solution

1
Calculate the Experimental Event Rate (EER) and Control Event Rate (CER).
EER=501000=0.05EER = \frac{50}{1000} = 0.05. CER=1001000=0.10CER = \frac{100}{1000} = 0.10.
Event rates must be determined to calculate the absolute risk reduction.
2
Calculate the Absolute Risk Reduction (ARR).
ARR=CER−EER=0.10−0.05=0.05ARR = CER - EER = 0.10 - 0.05 = 0.05.
ARR represents the absolute difference in disease risk between the intervention and control groups.
3
Calculate the Number Needed to Treat (NNT).
NNT=1ARR=10.05=20NNT = \frac{1}{ARR} = \frac{1}{0.05} = 20.
NNT is defined as the inverse of the absolute risk reduction.

Key Concept

Number Needed to Treat (NNT)
Question 3556Question →

A 68-year-old woman is evaluated in the emergency department for a 2-day history of progressive, crampy abdominal pain, nausea, and bilious vomiting. She has not passed flatus or stool for the past 24 hours. Her medical history is significant for a total abdominal hysterectomy performed 10 years ago for benign disease. Her temperature is 38.1°C (100.6°F), pulse is 112/min, blood pressure is 105/65 mm Hg, and respirations are 20/min. Physical examination reveals a markedly distended and tympanitic abdomen. Bowel sounds are high-pitched and tinkling. There is focal tenderness to deep palpation in the right lower quadrant with guarding, but no generalized rigidity is present. Laboratory studies show a leukocyte count of 16,500/mm³ (80% segmented neutrophils, 8% bands) and a serum lactate level of 2.8 mmol/L. A CT scan of the abdomen and pelvis with intravenous contrast demonstrates dilated loops of small bowel up to 4.5 cm in diameter with a discrete transition point in the distal ileum. The bowel wall at the transition point is mildly thickened and shows notably decreased contrast enhancement compared to adjacent small bowel loops. A small amount of free fluid is noted in the pelvis; there is no pneumoperitoneum. Which of the following is the most appropriate next step in management?

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Answer: Immediate exploratory laparotomy

Answer

Immediate exploratory laparotomy
The most appropriate next step is immediate exploratory laparotomy because this patient presents with a small bowel obstruction (SBO) complicated by signs of bowel ischemia (strangulation). While uncomplicated SBO is typically managed non-operatively with nasogastric decompression and intravenous fluids for the first 24-48 hours, this patient exhibits multiple 'red flags' indicating vascular compromise. These include systemic signs (low-grade fever, tachycardia, marked leukocytosis with a left shift, elevated serum lactate) and localized signs (focal right lower quadrant guarding). Most importantly, the CT scan reveals decreased contrast enhancement of the bowel wall at the transition point, which is a highly specific radiographic sign of ischemia. Immediate open surgical intervention is required to resect the compromised bowel segment and prevent imminent perforation and overwhelming sepsis.

Step-by-Step Solution

1
Analyze the patient's presentation and diagnostic findings to establish the primary diagnosis.
The history of prior abdominal surgery, bilious vomiting, obstipation, distended tympanitic abdomen, and CT findings of dilated loops with a transition point confirm an adhesive small bowel obstruction (SBO).
Establishing the baseline pathology is necessary before determining the severity and required intervention.
2
Evaluate for 'red flag' clinical and radiographic signs indicating complicated SBO.
The patient exhibits fever (38.1°C), tachycardia (112/min), focal tenderness with guarding, marked leukocytosis with a left shift (16,500/mm³, 8% bands), elevated lactate (2.8 mmol/L), and decreased bowel wall enhancement on CT.
Differentiating between simple and complicated (strangulated) SBO dictates whether management should be conservative or surgical.
3
Determine the most appropriate intervention based on the severity of the obstruction.
The presence of ischemia/strangulation mandates bypassing conservative measures and proceeding directly to the operating room for definitive surgical management.
Ischemic bowel will rapidly progress to transmural necrosis and perforation if blood flow is not surgically restored or the non-viable segment is not resected.

Key Concept

Patients with a small bowel obstruction who exhibit clinical (fever, tachycardia, leukocytosis, focal tenderness, lactic acidosis) or radiographic (decreased wall enhancement) signs of ischemia require immediate surgical exploration.
Question 3557Question →

A 22-year-old male is brought to the emergency department via ambulance after being struck on the right side of the head with a baseball bat. Paramedics report that he was briefly unconscious at the scene but awoke and conversed normally during the initial transport. Upon arrival at the emergency department 30 minutes later, he is unresponsive. His Glasgow Coma Scale score is 7 (Eye opening: 2, Verbal response: 2, Motor response: 3). Vital signs are temperature 37.1°C (98.8°F), blood pressure 180/105 mm Hg, heart rate 48/min, and respiratory rate 8/min. Neurologic examination reveals a right pupil that is 7 mm and unreactive to light, and a left pupil that is 3 mm and reactive. A left-sided hemiparesis is noted. Which of the following is the most appropriate next step in the management of this patient?

Show answer & explanation

Answer: Endotracheal intubation and mechanical ventilation

Answer

Endotracheal intubation and mechanical ventilation
The patient presents with classic signs of an acute epidural hematoma complicated by uncal herniation. This is evidenced by the lucid interval followed by rapid neurologic decline, Cushing triad (hypertension, bradycardia, irregular and depressed respirations), an ipsilateral dilated and fixed pupil (due to compression of the right oculomotor nerve), and contralateral hemiparesis (due to compression of the right cerebral peduncle). In any trauma patient, the Advanced Trauma Life Support (ATLS) protocol dictates prioritizing the airway (ABCs). A Glasgow Coma Scale (GCS) score of 8 or less is an absolute indication for endotracheal intubation to protect the airway and ensure adequate oxygenation and ventilation. Once the airway is secured, the patient should rapidly undergo a non-contrast head CT and emergent surgical decompression.

Step-by-Step Solution

1
Assess the patient's level of consciousness and vital signs.
GCS is 7, with bradycardia, severe hypertension, and bradypnea (Cushing triad).
To identify life-threatening compromises in airway, breathing, or circulation.
2
Evaluate pupillary and motor findings.
Right unreactive pupil and left hemiparesis.
To localize the neurologic lesion, indicating right-sided uncal herniation.
3
Determine the most immediate life-saving intervention.
Secure the airway via endotracheal intubation.
A GCS < 8 and depressed respirations necessitate definitive airway protection before diagnostic imaging or surgical evacuation.

Key Concept

Airway management in acute traumatic brain injury with signs of uncal herniation and a Glasgow Coma Scale score less than 8.
Estimated Time:1m 30s
Question 3558Question →

A 4646-year-old woman is referred to the endocrine surgery clinic for evaluation of a neck mass discovered 33 weeks ago. She reports a 66-month history of severe fatigue, generalized weakness, and a 55 kg (1111 lb) unintended weight gain. She has not seen a physician in several years. Her medical history is notable for a complicated vaginal delivery 1515 years ago that required multiple blood transfusions and an extended intensive care unit stay. She currently takes no medications. Vital signs are blood pressure 92/5892/58 mmHg and heart rate 6262/min. Physical examination reveals a 3.53.5 cm, firm, mobile nodule in the right thyroid lobe. She is noted to have pale skin and sparse axillary and pubic hair.

Laboratory studies show:
Thyroid-stimulating hormone (TSH): 0.20.2 μ\mu U/mL (Normal: 0.50.5 - 5.05.0 μ\mu U/mL)
Free thyroxine (T4): 0.50.5 ng/dL (Normal: 0.90.9 - 1.71.7 ng/dL)

An ultrasound-guided fine-needle aspiration of the nodule reveals findings suspicious for papillary thyroid carcinoma (Bethesda Category V). The surgical team is planning to schedule a total thyroidectomy. Which of the following is the most appropriate next step in management prior to surgical intervention?

Show answer & explanation

Answer: Measurement of early morning serum cortisol

Answer

Measurement of early morning serum cortisol to evaluate for concomitant central adrenal insufficiency.
The patient's laboratory results demonstrate a low free T4 with an inappropriately low TSH, which is diagnostic of central (secondary) hypothyroidism. Combined with her history of a complicated delivery with severe hemorrhage, hypotension, and sparse body hair, this clinical picture strongly suggests Sheehan syndrome (postpartum pituitary necrosis). In panhypopituitarism, central adrenal insufficiency (decreased ACTH and cortisol) typically coexists with central hypothyroidism. A major physiological stressor like a total thyroidectomy for her newly diagnosed papillary thyroid carcinoma can precipitate a life-threatening acute adrenal crisis (severe shock and cardiovascular collapse) if cortisol is not replaced. Additionally, initiating thyroid hormone replacement (levothyroxine) accelerates hepatic cortisol metabolism and can independently trigger an adrenal crisis. Therefore, the essential next step before initiating any medical or surgical treatment is to evaluate the adrenal axis with an early morning serum cortisol level.

Step-by-Step Solution

1
Interpret the thyroid function tests.
The patient has both a low TSH and a low free T4.
This discordant pattern indicates central (secondary) hypothyroidism due to a pituitary or hypothalamic failure, rather than primary thyroid pathology.
2
Synthesize laboratory findings with the clinical history and physical exam.
History of postpartum hemorrhage requiring transfusions, coupled with fatigue, hypotension, and loss of axillary/pubic hair, strongly suggests Sheehan syndrome (postpartum pituitary necrosis).
Ischemic necrosis of the pituitary gland results in panhypopituitarism, affecting multiple hormone axes (TSH, ACTH, FSH/LH, etc.).
3
Identify the immediate life-threatening risk associated with surgery in this patient.
The patient is at extremely high risk for an acute adrenal crisis.
Panhypopituitarism implies a lack of ACTH, causing secondary adrenal insufficiency. The physiological stress of total thyroidectomy requires a robust cortisol response that this patient cannot mount.
4
Determine the necessary preoperative intervention.
Measure early morning serum cortisol (and potentially ACTH) to confirm adrenal insufficiency before giving any treatments or proceeding to surgery.
Glucocorticoids must be replaced before surgery to survive the stress response, and absolutely before initiating levothyroxine, which increases cortisol metabolism.

Key Concept

Preoperative evaluation of central hypothyroidism and the necessity of ruling out concomitant adrenal insufficiency before initiating levothyroxine or proceeding to surgery.
Question 3559Question →

A randomized controlled trial is conducted to evaluate the efficacy of a novel antiplatelet agent in reducing the incidence of recurrent ischemic stroke. A total of 1,000 patients with a history of recent ischemic stroke are enrolled and randomly assigned to receive either the novel agent or standard aspirin therapy. The patients are followed for three years. In the group receiving the novel agent (n=500n=500), 15 patients experience a recurrent ischemic stroke. In the group receiving standard aspirin therapy (n=500n=500), 40 patients experience a recurrent ischemic stroke. Based on these trial results, how many patients need to be treated with the novel antiplatelet agent for three years to prevent one additional recurrent ischemic stroke?

Show answer & explanation

Answer: 20

Answer

20 patients need to be treated with the novel antiplatelet agent to prevent one additional recurrent ischemic stroke.
The Number Needed to Treat (NNT) is an epidemiological measure that indicates how many patients must receive a specific intervention instead of the control therapy to prevent one additional adverse outcome. It is calculated by taking the inverse of the Absolute Risk Reduction (ARR). The formula is NNT=1ARRNNT = \frac{1}{ARR} First, determine the risk of the outcome in both study arms. The risk in the standard therapy (control) group is 40500=0.08\frac{40}{500} = 0.08. The risk in the novel agent (intervention) group is 15500=0.03\frac{15}{500} = 0.03. Next, calculate the ARR by finding the difference: 0.08−0.03=0.050.08 - 0.03 = 0.05. Finally, calculate the NNT: 10.05=20\frac{1}{0.05} = 20. Therefore, 20 patients need to be treated with the novel agent for three years to prevent one stroke.

Step-by-Step Solution

1
Calculate the absolute risk (incidence) of the event in the control group (standard aspirin therapy).
Control Event Rate (CER) = 40500=0.08\frac{40}{500} = 0.08 (or 8%8\%).
This establishes the baseline risk of recurrent stroke without the new intervention.
2
Calculate the absolute risk (incidence) of the event in the intervention group (novel agent).
Experimental Event Rate (EER) = 15500=0.03\frac{15}{500} = 0.03 (or 3%3\%).
This establishes the risk of recurrent stroke while on the novel treatment.
3
Calculate the Absolute Risk Reduction (ARR).
ARR=CER−EER=0.08−0.03=0.05ARR = CER - EER = 0.08 - 0.03 = 0.05 (or 5%5\%).
ARR represents the absolute difference in risk between the control and intervention groups.
4
Calculate the Number Needed to Treat (NNT).
NNT=1ARR=10.05=20NNT = \frac{1}{ARR} = \frac{1}{0.05} = 20.
NNT is defined as the inverse of the Absolute Risk Reduction.

Key Concept

Number Needed to Treat (NNT) and Absolute Risk Reduction (ARR)
Question 3560Question →

A 24-year-old man is brought to the emergency department 3 hours after a skateboarding accident in which he struck the right side of his head against a curb. Witnesses report he lost consciousness for approximately 1 minute at the scene, but then awoke, appeared completely normal, and walked home. Over the past hour, he has developed a severe headache, nausea, and progressive lethargy. His temperature is 37.0°C (98.6°F), blood pressure is 165/90 mm Hg, pulse is 52/min, and respirations are 12/min. Glasgow Coma Scale score is 10 (E2, V3, M5). Neurologic examination reveals a dilated and sluggishly reactive right pupil. Non-contrast CT of the head reveals a hyperdense, biconvex fluid collection between the skull and the dura mater over the right cerebral convexity. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Emergent craniotomy and hematoma evacuation

Answer

Emergent craniotomy and hematoma evacuation
The patient's clinical presentation (head trauma, lucid interval, rapid neurologic decline, Cushing reflex) and CT findings (hyperdense biconvex shape) are classic for an acute epidural hematoma. The ipsilateral dilated pupil indicates uncal herniation due to a rapidly expanding intracranial volume. The definitive and life-saving treatment for a symptomatic epidural hematoma causing mass effect is an emergent craniotomy and surgical evacuation of the blood clot.

Step-by-Step Solution

1
Analyze the clinical history and physical examination findings.
The patient experienced head trauma followed by a classic 'lucid interval' and subsequent rapid neurologic decline. Vitals show hypertension and bradycardia (Cushing reflex), and he has an ipsilateral dilated pupil.
These findings are highly suspicious for an expanding intracranial mass causing elevated intracranial pressure and uncal herniation.
2
Interpret the provided imaging results.
The non-contrast CT shows a hyperdense, biconvex (lens-shaped) collection.
This specific imaging pattern definitively diagnoses an acute epidural hematoma, typically caused by rupture of the middle meningeal artery.
3
Determine the most appropriate management for the diagnosed condition.
Immediate surgical intervention is required.
An epidural hematoma causing neurologic compromise and signs of herniation is a surgical emergency requiring emergent craniotomy for evacuation of the clot and source control of the bleeding.

Key Concept

Diagnosis and emergency management of acute epidural hematoma
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