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Internal Medicine

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Question 1141Question →

An occupational health physician evaluates a 4949-year-old man who reports a progressive decline in energy levels, persistent chills, and lower extremity swelling over the past six months. The patient mentions he struggles to stay awake during daytime meetings and feels short of breath when climbing the stairs to his office. He takes no daily medications. His temperature is 36.1∘C36.1^{\circ}\text{C} (97.0∘F97.0^{\circ}\text{F}), blood pressure is 105/65 mm Hg105/65\text{ mm Hg}, pulse is 52/min52/\text{min}, and respiratory rate is 12/min12/\text{min}. Physical examination demonstrates non-pitting edema of the bilateral lower extremities, coarse hair, and delayed relaxation of deep tendon reflexes. Lung fields are clear to auscultation. Laboratory results show a serum free T4 level of 0.3 ng/dL0.3\text{ ng/dL} (Normal: 0.9−1.7 ng/dL0.9-1.7\text{ ng/dL}) and a thyroid-stimulating hormone (TSH) level of 1.8 mIU/L1.8\text{ mIU/L} (Normal: 0.5−5.0 mIU/L0.5-5.0\text{ mIU/L}). Which of the following is the most appropriate next step in the management of this patient?

Show answer & explanation

Answer: Measurement of early morning serum cortisol

Answer

Measurement of early morning serum cortisol is the appropriate next step to rule out concurrent central adrenal insufficiency before initiating levothyroxine therapy.
The correct answer addresses the critical sequence of evaluating pituitary hormone deficiencies. This patient presents with classic symptoms of severe hypothyroidism, including bradycardia, non-pitting edema (myxedema), delayed deep tendon reflexes, and fatigue. However, the laboratory results reveal a low free T4 level with an inappropriately normal TSH. This pattern confirms central (secondary) hypothyroidism, localizing the defect to the anterior pituitary gland or hypothalamus. Because pituitary pathology often impairs multiple hormone axes simultaneously, patients with central hypothyroidism frequently have coexisting central adrenal insufficiency. Initiating levothyroxine therapy accelerates the basal metabolic rate and the hepatic clearance of cortisol. If levothyroxine is given to a patient with unrecognized and untreated adrenal insufficiency, it can rapidly deplete their minimal cortisol reserves and precipitate a life-threatening adrenal crisis. Therefore, it is mandatory to assess the adrenal axis with an early morning serum cortisol level (and potentially an ACTH stimulation test) before initiating thyroid hormone replacement. If adrenal insufficiency is confirmed, glucocorticoids must be started before or simultaneously with levothyroxine.

Step-by-Step Solution

1
Interpret the thyroid function laboratory results.
The patient has a low free T4 but an inappropriately normal TSH.
This specific pattern indicates central (secondary) hypothyroidism, pointing to a pituitary or hypothalamic disorder, rather than primary thyroid failure (which would present with an elevated TSH).
2
Identify potential coexisting endocrine abnormalities associated with the diagnosis.
A pituitary disorder that causes central hypothyroidism often concurrently causes central adrenal insufficiency (secondary hypocortisolism).
The anterior pituitary secretes multiple hormones, and mass lesions or structural defects typically affect multiple endocrine axes simultaneously.
3
Determine the safest management sequence for initiating hormone replacement.
Evaluate the adrenal axis with an early morning cortisol level before administering levothyroxine.
Levothyroxine increases the basal metabolic rate and hepatic clearance of cortisol. If a patient has undiagnosed adrenal insufficiency, starting levothyroxine can acutely deplete remaining cortisol stores and trigger a fatal adrenal crisis.

Key Concept

Patients with central hypothyroidism must be evaluated for concomitant central adrenal insufficiency before starting levothyroxine therapy to prevent the precipitation of an adrenal crisis.
Question 1142Question →

A 68-year-old woman is evaluated in the preoperative clinic prior to an elective right total knee arthroplasty. Her past medical history is notable for osteoarthritis and well-controlled hypertension. The patient reports feeling well and specifically denies any dysuria, urinary frequency, suprapubic pain, or fever. Her vital signs are within normal limits. As part of her preoperative workup, a urinalysis is obtained which demonstrates 15 white blood cells per high-power field and is positive for leukocyte esterase and nitrites. A subsequent urine culture grows >10510^5 colony-forming units/mL of *Escherichia coli*. Susceptibility testing shows the organism is sensitive to nitrofurantoin, trimethoprim-sulfamethoxazole, ciprofloxacin, and ceftriaxone. Which of the following is the most appropriate next step in the management of this patient?

Show answer & explanation

Answer: Proceed with the scheduled surgery without specific treatment for the bacteriuria

Answer

Proceed with the scheduled surgery without specific treatment for the bacteriuria
The correct approach is to proceed with the scheduled surgery without specific treatment for the bacteriuria. This patient has asymptomatic bacteriuria (ASB), which is defined as the isolation of a specified quantitative count of bacteria in an appropriately collected urine specimen from a person without signs or symptoms of a urinary tract infection. According to current guidelines, screening for and treating ASB is NOT indicated for patients undergoing non-urologic surgeries, including orthopedic procedures like total knee arthroplasty. Treatment in this scenario does not reduce the risk of surgical site infections or symptomatic urinary tract infections. Instead, unnecessary antibiotic use contributes to antimicrobial resistance, increases the risk of *Clostridioides difficile* infection, and exposes the patient to potential drug toxicities. The only widely accepted indications for screening and treating ASB are pregnancy and prior to urologic procedures where mucosal bleeding is anticipated.

Step-by-Step Solution

1
Evaluate the patient's symptoms and laboratory findings to establish a clinical diagnosis.
The patient has positive urine culture and urinalysis findings but absolutely no urinary or systemic symptoms.
Differentiating asymptomatic bacteriuria from a true urinary tract infection is based entirely on the presence or absence of clinical symptoms.
2
Determine the indications for treating asymptomatic bacteriuria.
The patient is not pregnant and is undergoing an orthopedic procedure (total knee arthroplasty), not a urologic procedure.
Asymptomatic bacteriuria is only treated in specific populations (pregnant women) or prior to urologic procedures with anticipated mucosal bleeding.
3
Select the appropriate management strategy based on the diagnosis and patient context.
No antibiotic therapy is indicated for the bacteriuria; the surgery can proceed as planned.
Treating asymptomatic bacteriuria in this setting does not improve outcomes and contributes to antibiotic resistance.

Key Concept

Asymptomatic bacteriuria should not be screened for or treated in the general population, including prior to non-urologic surgeries such as orthopedic joint replacements.
Question 1143Question →

A 68-year-old man with a history of ischemic cardiomyopathy (left ventricular ejection fraction 35%), severe chronic obstructive pulmonary disease (COPD), and type 2 diabetes mellitus is evaluated in the intensive care unit. He was admitted 3 days ago for urosepsis after presenting with fever, hypotension, and altered mental status. On admission, he received 4 liters of intravenous normal saline and was started on empiric intravenous vancomycin and cefepime.

Blood cultures from admission grew *Escherichia coli* at 24 hours. Today, sensitivities resulted showing the organism is susceptible to ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole, but resistant to ampicillin.

The patient is now afebrile and his blood pressure has stabilized off vasopressors. However, the nurse reports that he has developed worsening dyspnea over the last 12 hours.

Vital signs are:
Blood pressure: 128/78 mmHg128/78 \text{ mmHg}
Heart rate: 102/min102/\text{min}
Respiratory rate: 26/min26/\text{min}
SpO2SpO_2: 89%89\% on room air

Physical examination reveals an elevated jugular venous pressure of 11 cm H2O11 \text{ cm } H_2O. Lung auscultation demonstrates bibasilar crackles and scattered expiratory wheezes. There is 2+ bilateral pitting lower extremity edema.

Laboratory results:
ParameterValue
Serum sodium136 mEq/L136 \text{ mEq/L}
Serum potassium4.2 mEq/L4.2 \text{ mEq/L}
Serum chloride104 mEq/L104 \text{ mEq/L}
Serum bicarbonate12 mEq/L12 \text{ mEq/L}
Blood urea nitrogen42 mg/dL42 \text{ mg/dL}
Serum creatinine1.9 mg/dL1.9 \text{ mg/dL}
Thyroid-stimulating hormone (TSH)0.2 μU/mL0.2 \ \mu\text{U/mL} (Normal: 0.4−4.0 μU/mL0.4-4.0 \ \mu\text{U/mL})
Free T40.7 ng/dL0.7 \text{ ng/dL} (Normal: 0.8−1.8 ng/dL0.8-1.8 \text{ ng/dL})

Arterial blood gas (room air):
pH: 7.277.27
pCO2pCO_2: 26 mmHg26 \text{ mmHg}
pO2pO_2: 64 mmHg64 \text{ mmHg}

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

Show answer & explanation

Answer: Administer intravenous furosemide and change antibiotics to intravenous ceftriaxone

Answer

The most appropriate management is to administer intravenous furosemide to treat the acute decompensated heart failure and de-escalate the antibiotic regimen to intravenous ceftriaxone for targeted treatment of the E. coli bacteremia.
The correct sequence of actions requires synthesizing multiple systemic issues. First, the patient's severe dyspnea, wheezing, and bibasilar crackles following 4 liters of normal saline indicate acute decompensated heart failure (ADHF). Because the patient has underlying COPD, it is critical to rule out a COPD exacerbation. The ABG shows a metabolic acidosis (HCO3−HCO_3^- of 12) with a calculated high anion gap (136−104−12=20136 - 104 - 12 = 20), typical in resolving sepsis or uremia. Using Winter's formula to determine expected respiratory compensation: pCO2=(1.5×12)+8=26±2pCO_2 = (1.5 \times 12) + 8 = 26 \pm 2. Since the measured pCO2pCO_2 is exactly 26 mmHg, there is no superimposed respiratory acidosis. If the patient were having a severe COPD exacerbation causing his current distress, he would have relative CO2 retention. Therefore, the treatment is diuresis (furosemide). Second, the patient has *E. coli* bacteremia susceptible to ceftriaxone. Continuing empiric vancomycin and cefepime violates antibiotic stewardship; therapy must be de-escalated. Finally, the abnormal thyroid labs reflect euthyroid sick syndrome, which requires no treatment.

Step-by-Step Solution

1
Assess the cause of respiratory distress using the physical exam and arterial blood gas.
The patient has elevated jugular venous pressure, crackles, edema, and a high anion gap metabolic acidosis. Applying Winter's formula (1.5×12+8=26±21.5 \times 12 + 8 = 26 \pm 2), the expected pCO2pCO_2 perfectly matches the measured pCO2pCO_2 (26 mmHg26 \text{ mmHg}).
This rules out a superimposed respiratory acidosis (which would be expected in a severe COPD exacerbation causing dyspnea) and confirms the dyspnea and wheezing ('cardiac asthma') are due to acute decompensated heart failure from aggressive fluid resuscitation.
2
Evaluate the current antibiotic regimen against the culture sensitivity data.
The patient is on empiric vancomycin and cefepime, but blood cultures grew *Escherichia coli* susceptible to ceftriaxone.
According to antimicrobial stewardship principles, therapy must be de-escalated to the most targeted, narrow-spectrum effective agent once sensitivities are known.
3
Interpret the thyroid function tests in the context of critical illness.
The patient has low TSH and low free T4.
In the ICU setting, this pattern is classic for euthyroid sick syndrome (nonthyroidal illness syndrome). Administration of exogenous thyroid hormone is not indicated and can be deleterious.

Key Concept

Management of acute decompensated heart failure (ADHF) in critically ill patients, utilizing Winter's formula to differentiate ADHF from COPD exacerbation, paired with mandatory antibiotic de-escalation.
Estimated Time:3m 0s
Question 1144Question →

A 55-year-old man is admitted to the hospital after a lymph node biopsy confirmed the diagnosis of a highly aggressive non-Hodgkin lymphoma. He is scheduled to receive his first cycle of multi-agent chemotherapy in 2424 hours. He currently has no acute complaints. Vital signs are within normal limits. Laboratory studies reveal the following:

Laboratory TestResultReference Range
Hemoglobin11.2 g/dL11.2 \text{ g/dL}13.5−17.5 g/dL13.5-17.5 \text{ g/dL}
Leukocyte count45,000/mm345,000/\text{mm}^34,500−11,000/mm34,500-11,000/\text{mm}^3
Platelet count140,000/mm3140,000/\text{mm}^3150,000−400,000/mm3150,000-400,000/\text{mm}^3
Serum creatinine0.9 mg/dL0.9 \text{ mg/dL}0.6−1.2 mg/dL0.6-1.2 \text{ mg/dL}
Uric acid9.8 mg/dL9.8 \text{ mg/dL}4.0−8.5 mg/dL4.0-8.5 \text{ mg/dL}
Lactate dehydrogenase (LDH)1,500 U/L1,500 \text{ U/L}140−280 U/L140-280 \text{ U/L}

Which of the following is the most appropriate next step in management to prevent acute renal complications in this patient?

Show answer & explanation

Answer: Initiate aggressive intravenous hydration and administer allopurinol

Answer

Initiate aggressive intravenous hydration and administer allopurinol
The correct answer is to initiate aggressive intravenous hydration and administer allopurinol. This patient has a highly aggressive lymphoma with a high tumor burden, as evidenced by significantly elevated baseline lactate dehydrogenase (LDH) and uric acid levels. He is at very high risk for tumor lysis syndrome (TLS) once multi-agent chemotherapy is initiated. TLS results from the massive destruction of tumor cells, leading to the rapid release of intracellular contents, including potassium, phosphate, and nucleic acids (which are metabolized into uric acid). The precipitation of uric acid and calcium-phosphate crystals in the renal tubules can cause severe acute kidney injury. Therefore, the standard of care for high-risk patients is prophylaxis with aggressive intravenous hydration to maintain robust urine output and the administration of a xanthine oxidase inhibitor (allopurinol) or a recombinant urate oxidase (rasburicase) to lower serum uric acid levels before chemotherapy begins.

Step-by-Step Solution

1
Evaluate the patient's clinical presentation and baseline laboratory values.
The patient has a highly aggressive lymphoma with markedly elevated baseline uric acid and LDH.
These findings indicate a high tumor burden and rapid cellular turnover.
2
Identify the primary risk associated with initiating multi-agent chemotherapy in this specific setting.
The patient is at exceptionally high risk for developing tumor lysis syndrome (TLS).
Chemotherapy will cause massive lysis of tumor cells, releasing intracellular contents (potassium, phosphate, and nucleic acids) into the systemic circulation, which can precipitate acute kidney injury.
3
Determine the most appropriate prophylactic intervention to prevent TLS-induced renal failure.
Aggressive intravenous hydration and a uric acid-lowering agent (such as allopurinol or rasburicase) must be started.
Intravenous fluids maintain high urine output to flush out metabolites, while allopurinol inhibits xanthine oxidase, preventing the formation of uric acid from released nucleic acids.

Key Concept

Patients with bulky, rapidly proliferating tumors (e.g., high-grade non-Hodgkin lymphoma, acute leukemia) are at high risk for tumor lysis syndrome when starting chemotherapy. Prophylaxis with aggressive intravenous hydration and allopurinol (or rasburicase) is essential to prevent acute uric acid nephropathy and subsequent renal failure.
Estimated Time:1m 0s
Question 1145Question →

A 3232-year-old man comes to the clinic for routine sexually transmitted infection screening. He is currently asymptomatic and has no history of genital ulcers, diffuse rashes, or neurologic symptoms. He reports having unprotected intercourse with a new male sexual partner 22 months ago. He has no known prior history of syphilis or other sexually transmitted infections. Vital signs are within normal limits. Physical examination reveals no oral, genital, or perianal lesions, and no lymphadenopathy is appreciated. The clinic laboratory utilizes the reverse sequence algorithm for syphilis screening. The initial *Treponema pallidum* enzyme immunoassay (EIA) returns reactive. A reflex rapid plasma reagin (RPR) test is nonreactive. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Perform a Treponema pallidum particle agglutination (TP-PA) test

Answer

The most appropriate next step is to perform a second, different treponemal test, specifically the Treponema pallidum particle agglutination (TP-PA) test.
The correct answer is to perform a Treponema pallidum particle agglutination (TP-PA) test. The reverse sequence algorithm for syphilis screening starts with a highly sensitive treponemal test (like an EIA or CIA). If reactive, it reflexes to a non-treponemal test (like RPR) to gauge disease activity. When results are discordant (reactive EIA, nonreactive RPR), it is unclear if the patient has early syphilis (RPR not yet positive), a history of treated syphilis (treponemal tests remain positive for life), or a false-positive EIA. Because this patient has no history of treated syphilis, a false-positive EIA must be differentiated from early infection. The CDC mandates running a second, different treponemal test (such as TP-PA) to resolve this discordance. If the TP-PA is reactive, the patient has syphilis and requires treatment; if nonreactive, the initial EIA was a false positive.

Step-by-Step Solution

1
Identify the screening algorithm being used.
The clinic uses the reverse sequence algorithm (treponemal test first, followed by a non-treponemal test).
Understanding the algorithm is necessary to interpret the sequence of laboratory results.
2
Interpret the specific laboratory results provided in the vignette.
The initial EIA (treponemal) is reactive, but the reflex RPR (non-treponemal) is nonreactive. This is a discordant result.
Discordant results in the reverse algorithm require further investigation because they can represent early primary syphilis, previously treated syphilis, or a false-positive EIA.
3
Determine the guideline-directed next step for discordant reverse sequence results.
The CDC recommends performing a second, different treponemal test (like TP-PA) to confirm if the initial EIA was a true positive or a false positive.
If the TP-PA is nonreactive, the EIA was a false positive, and no treatment is needed. If the TP-PA is reactive, the patient has syphilis (either early or latent) and requires treatment since he has no history of prior therapy.

Key Concept

In the reverse sequence algorithm for syphilis screening, a reactive treponemal test (EIA/CIA) followed by a nonreactive non-treponemal test (RPR/VDRL) must be followed by a second, different treponemal test (TP-PA) to rule out a false-positive initial result.
Estimated Time:1m 30s
Question 1146Question →

A 42-year-old woman is evaluated in the hospital on the fourth day of admission for acute severe pancreatitis. She has been receiving intravenous fluids via a right internal jugular central venous catheter placed on admission. Yesterday, her temperature briefly spiked to 38.3°C (100.9°F). One set of peripheral blood cultures and one set from the central venous catheter were obtained at that time. Today, she reports that her abdominal pain is improving. Her temperature is 37.1°C (98.8°F), blood pressure is 118/76 mm Hg, pulse is 82/min, and respirations are 14/min. Physical examination shows a clean central catheter insertion site with no surrounding erythema or induration. Laboratory studies show a leukocyte count of 9,200/mm³. The aerobic bottle of the peripheral blood culture set is growing coagulase-negative staphylococci after 24 hours of incubation. The anaerobic peripheral bottle and both bottles from the central catheter show no growth. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Observation without antimicrobial therapy

Answer

Observation without antimicrobial therapy
Observation without antimicrobial therapy is the correct management because the culture result most likely represents contamination. Coagulase-negative staphylococci (CoNS) are common commensals of the human skin. While they can cause true device-associated infections (such as central line-associated bloodstream infections), true bacteremia typically presents with positive growth in multiple culture bottles drawn from different sites. In this patient, only one of the four bottles grew CoNS, and the patient is clinically stable with a clean catheter site. Therefore, this finding represents a contaminated blood draw, and no antibiotics or line removal is indicated.

Step-by-Step Solution

1
Assess the patient's clinical stability and potential sources of infection.
The patient is hemodynamically stable, afebrile, and clinically improving from her pancreatitis. The central catheter site appears uninfected.
Determines the urgency of intervention and identifies localized signs of true infection.
2
Interpret the blood culture results in the context of the clinical picture.
Only one out of four total bottles (one peripheral aerobic) is positive for coagulase-negative staphylococci (CoNS).
CoNS are ubiquitous skin flora. Determining if they represent true bacteremia requires multiple positive bottles drawn from separate venipunctures.
3
Determine the appropriate management step.
Observation without antimicrobial therapy is indicated.
A single positive bottle for CoNS in the absence of prosthetic hardware or severe clinical deterioration strongly points to sample contamination during phlebotomy, requiring no treatment.

Key Concept

Interpretation of blood culture contamination versus true bacteremia, emphasizing antibiotic stewardship by avoiding treatment for single-bottle positive coagulase-negative staphylococci.
Question 1147Question →

An oncologist is called to evaluate a 5858-year-old man in the hospital who has a history of metastatic non-small cell lung cancer. The patient reports a 11-week history of worsening, band-like thoracic back pain that is particularly severe when lying supine. Over the last 2424 hours, he has noticed progressive heaviness in both legs and has not voided urine since the previous evening. On neurologic examination, there is 3/53/5 muscle strength in the lower extremities bilaterally, pronounced hyperreflexia at the patellae, and a sensory deficit to pinprick extending distally from the umbilicus. Arrange the following steps in the most appropriate chronological order for the management of this patient's current condition.

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Answer

The correct sequence for managing suspected malignant epidural spinal cord compression is to first administer intravenous dexamethasone, followed by an emergent whole-spine MRI, evaluating the imaging for spinal stability, and finally proceeding with definitive surgery or radiation.
The correct chronological sequence prioritizes immediate neurologic preservation over diagnostic confirmation. In a patient with known malignancy who presents with classic signs of epidural spinal cord compression (ESCC)—such as severe back pain, lower extremity weakness, and autonomic dysfunction (urinary retention)—the immediate priority is the administration of high-dose intravenous glucocorticoids (e.g., dexamethasone). This step is critical to reduce vasogenic edema and prevent irreversible paraplegia, and it must not be delayed for imaging. Once corticosteroids are given, an emergent MRI of the entire spine is obtained to confirm the diagnosis and detect multiple lesions. The imaging is then evaluated to assess spinal mechanical stability (e.g., via the SINS score). Finally, definitive therapy is initiated, choosing between surgical decompression (often preferred for unstable spines or radioresistant tumors) and external beam radiation therapy.

Step-by-Step Solution

1
Administer high-dose intravenous dexamethasone.
Decreases peritumoral vasogenic edema.
Immediate corticosteroid therapy reduces pressure on the spinal cord and preserves neurologic function, taking absolute priority over diagnostic imaging.
2
Obtain an emergent MRI of the entire spine.
Visualizes the spinal cord, vertebrae, and epidural space.
MRI is required to confirm the diagnosis, locate the exact level of compression, and identify any synchronous asymptomatic lesions elsewhere in the spine.
3
Evaluate imaging for degree of compression and spinal stability.
Determines the mechanical integrity of the spine.
The choice of definitive therapy depends heavily on whether the spine is mechanically stable and the radiosensitivity of the underlying tumor.
4
Proceed with targeted surgical decompression or radiation therapy.
Provides definitive local control of the metastatic lesion.
Surgical resection or radiation relieves the compression long-term and prevents future irreversible neurologic deterioration.

Key Concept

The initial management of suspected neoplastic epidural spinal cord compression (ESCC) requires immediate administration of systemic glucocorticoids before obtaining confirmatory imaging.
Question 1148Question →

Match the following clinical scenarios of oncologic therapy and associated toxicities with the most appropriate pharmacological rescue or prophylactic agent.

Click a left item, then click its matching right item

Items

A 42-year-old woman with breast cancer receives a chemotherapy agent known to cause dose-dependent generation of free radicals, leading to cumulative, irreversible dilated cardiomyopathy.
A 35-year-old man with non-Hodgkin lymphoma receives an alkylating agent that is metabolized in the kidney to acrolein, placing him at high risk for severe hemorrhagic cystitis.
A 22-year-old man with acute lymphoblastic leukemia receives a high-dose antimetabolite that competitively inhibits dihydrofolate reductase, leading to severe myelosuppression.
A 15-year-old boy with Burkitt lymphoma is initiating induction chemotherapy for a massive tumor burden, placing him at high risk for acute kidney injury from profound hyperuricemia.

Matches

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Answer

The correct matches align each specific chemotherapy-induced toxicity mechanism with its targeted pharmacological rescue or prophylactic agent: Anthracycline cardiotoxicity requires Dexrazoxane; Acrolein-induced cystitis requires Mesna; Methotrexate myelosuppression requires Leucovorin; and hyperuricemia in Tumor Lysis Syndrome is treated with Rasburicase.
Each pair correctly matches a specific oncologic toxicity or complication with its mechanistically appropriate pharmacological intervention. Dexrazoxane chelates iron to prevent anthracycline cardiotoxicity. Mesna binds acrolein to prevent cyclophosphamide-induced cystitis. Leucovorin bypasses DHFR inhibition to rescue normal cells from methotrexate. Rasburicase degrades uric acid to prevent nephropathy in tumor lysis syndrome.

Step-by-Step Solution

1
Analyze the first scenario to identify the underlying chemotherapy agent and its toxic mechanism.
The agent described is an anthracycline (e.g., doxorubicin), which causes free-radical mediated dilated cardiomyopathy.
Recognizing the pathophysiology is required to select the correct cardioprotectant, which is Dexrazoxane.
2
Identify the cause and prevention of hemorrhagic cystitis in the second scenario.
The alkylating agent (cyclophosphamide) produces acrolein, which is neutralized by Mesna.
Mesna specifically concentrates in the bladder to bind acrolein, preventing urothelial toxicity.
3
Determine the rescue agent for the patient receiving the dihydrofolate reductase inhibitor in the third scenario.
The drug is methotrexate, and its toxicity is mitigated by Leucovorin (folinic acid).
Leucovorin provides the active form of folate, bypassing the blocked enzyme and rescuing rapidly dividing normal cells.
4
Select the most appropriate prophylactic agent for severe hyperuricemia in the fourth scenario.
The high tumor burden puts the patient at risk for tumor lysis syndrome, which is aggressively managed with Rasburicase.
Rasburicase enzymatically degrades uric acid to allantoin, rapidly preventing urate crystal nephropathy in high-risk patients.

Key Concept

Pharmacological prevention and rescue of specific chemotherapy-induced toxicities and oncologic emergencies.
Estimated Time:2m 0s
Question 1149Question →

A 2222-year-old woman is brought to the emergency department by her college roommate due to bizarre behavior over the past 44 days. The roommate states that the patient has locked herself in her room, claims that hidden cameras are recording her thoughts, and frequently talks to people who are not present. She has no personal or family history of psychiatric illness. Over the past month, the patient has complained of severe fatigue, diffuse joint pain, and increased hair shedding. Her temperature is 37.9∘C37.9^{\circ}C (100.2∘F100.2^{\circ}F), blood pressure is 146/92146/92 mm Hg, and pulse is 9898/min. Physical examination reveals an erythematous, scaling rash across her cheeks and the bridge of her nose that spares the nasolabial folds. Painless ulcers are noted on the hard palate. The proximal interphalangeal and metacarpophalangeal joints are mildly swollen, warm, and tender to palpation bilaterally.

Laboratory studies show:
TestResult
Hemoglobin9.69.6 g/dL
Leukocytes3,100/mm33,100/mm^3
Platelets98,000/mm398,000/mm^3
Serum creatinine1.61.6 mg/dL
Thyroid-stimulating hormone (TSH)2.42.4 mU/L (normal: 0.5−5.00.5-5.0 mU/L)
Free T41.21.2 ng/dL (normal: 0.9−2.40.9-2.4 ng/dL)
Urinalysis3+3+ protein, 10−1510-15 erythrocytes/hpf, negative leukocyte esterase

Which of the following is the most appropriate initial treatment targeting the underlying etiology of this patient's condition?

Show answer & explanation

Answer: Intravenous methylprednisolone

Answer

Intravenous methylprednisolone
The correct answer is high-dose intravenous corticosteroids. This patient presents with acute psychosis in the setting of severe, undiagnosed Systemic Lupus Erythematosus (SLE). Her clinical picture features multiple classic SLE criteria: malar rash, painless oral ulcers, inflammatory arthritis, alopecia, pancytopenia, and lupus nephritis (proteinuria, hematuria, and elevated creatinine). The acute onset of hallucinations and paranoia represents neuropsychiatric SLE (lupus cerebritis), a severe, organ-threatening manifestation of the disease. The primary treatment for life-threatening or organ-threatening SLE flares is immediate immunosuppression with high-dose intravenous corticosteroids (e.g., methylprednisolone), often followed by cyclophosphamide or mycophenolate mofetil.

Step-by-Step Solution

1
Analyze the patient's systemic symptoms and physical examination findings.
The patient has a malar rash, oral ulcers, nondeforming polyarthritis, and alopecia.
These are classic clinical criteria for Systemic Lupus Erythematosus (SLE).
2
Evaluate the laboratory results.
Pancytopenia (anemia, leukopenia, thrombocytopenia) and acute kidney injury with proteinuria and hematuria are present.
These findings confirm hematologic and renal (lupus nephritis) involvement of SLE, demonstrating a severe systemic flare.
3
Interpret the acute psychiatric presentation in the context of the systemic disease.
The acute onset of hallucinations and paranoia over 4 days in a patient with an active SLE flare points to neuropsychiatric SLE (lupus cerebritis/psychosis).
Medical causes of psychosis must be ruled out before diagnosing primary psychiatric conditions.
4
Determine the appropriate disease-modifying treatment for organ-threatening SLE.
High-dose intravenous corticosteroids are required.
Severe SLE manifestations (CNS involvement and active nephritis) require aggressive immunosuppression to halt end-organ damage.

Key Concept

Neuropsychiatric Systemic Lupus Erythematosus (SLE) requires urgent recognition of underlying autoimmune etiology and immediate treatment with high-dose intravenous corticosteroids.
Question 1150Question →

A 54-year-old woman is evaluated in the emergency department for a 24-hour history of severe headache, fever, and progressive confusion. Her temperature is 39.4°C (102.9°F), blood pressure is 110/68 mm Hg, and pulse is 114/min. On physical examination, the patient is lethargic and oriented to person only. Neck stiffness is elicited upon flexion. There are no focal neurologic deficits. Arrange the following management steps in the most appropriate chronological sequence for this patient.

Drag items to arrange them in the correct order

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Answer

The correct sequence is to obtain blood cultures, followed immediately by administering empiric antibiotics and dexamethasone, then performing a computed tomography of the head, and finally performing a lumbar puncture.
In patients with suspected bacterial meningitis who have altered mental status, new-onset seizures, focal neurologic deficits, or papilledema, a computed tomography scan of the head is required before a lumbar puncture to rule out increased intracranial pressure. However, obtaining the imaging can delay definitive diagnosis. Therefore, blood cultures should be drawn immediately, followed by the administration of empiric antibiotics and dexamethasone. Once therapy is initiated, the computed tomography scan can be performed safely, followed by the lumbar puncture. This sequence prevents dangerous delays in treatment while mitigating the risk of brain herniation.

Step-by-Step Solution

1
Identify the suspected diagnosis and the need for urgent intervention.
The patient has signs of acute bacterial meningitis along with altered mental status (lethargy, confusion).
Recognizing the triad of meningitis alongside altered mental status dictates the specific diagnostic and therapeutic algorithm to avoid complications.
2
Determine if there are indications for cranial imaging before a lumbar puncture.
The patient's altered mental status is a direct indication for head imaging prior to a lumbar puncture.
Performing a lumbar puncture in the presence of increased intracranial pressure or a mass lesion can precipitate fatal brain herniation.
3
Sequence the required interventions prioritizing rapid antimicrobial delivery.
Blood cultures must be drawn first, followed by antibiotics, then the CT scan, and finally the lumbar puncture.
Antibiotics must never be delayed by the wait for a CT scan. Blood cultures must be drawn before antibiotics to avoid sterilizing the sample.

Key Concept

Algorithmic management of suspected bacterial meningitis in patients with indications for imaging prior to lumbar puncture.
Estimated Time:1m 30s
Question 1151Question →

A 32-year-old man who recently immigrated from a region with high tuberculosis endemicity presents to the emergency department with a 4-week history of low-grade fevers, night sweats, productive cough, and unintended weight loss. Temperature is 37.8°C (100.0°F), blood pressure is 110/70 mmHg, pulse is 88/min, and respiratory rate is 18/min. Physical examination reveals bronchial breath sounds and crackles over the right upper lung field. A chest radiograph demonstrates a cavitary opacity in the right upper lobe. Arrange the following steps in the most appropriate chronological order for the clinical management of this patient.

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Answer

The correct chronological sequence is: Implement airborne precautions, followed by collecting sputum specimens, then initiating empiric multidrug therapy, and finally modifying the regimen based on susceptibility testing.
In the management of suspected active pulmonary tuberculosis, public health and infection control dictate that airborne isolation is the immediate first step. Following isolation, securing sputum for acid-fast bacilli and culture is critical to ensure high diagnostic yield and guide future therapy. Only after samples are collected should empiric four-drug therapy (isoniazid, rifampin, pyrazinamide, ethambutol) begin. Weeks later, when phenotypic drug susceptibility testing results are available, the regimen can be appropriately de-escalated or modified.

Step-by-Step Solution

1
Recognize the clinical presentation of active pulmonary tuberculosis
Identify that the patient is a high transmission risk
The triad of chronic cough, night sweats, and apical cavitary lesions strongly suggests TB.
2
Prioritize infection control
Patient is placed in a negative-pressure room
Prevents aerosolized spread of Mycobacterium tuberculosis to others in the healthcare setting.
3
Secure diagnostic workup before treatment
Sputum AFB smears and cultures obtained
Antibiotic administration can rapidly sterilize sputum or reduce yield, hindering definitive diagnosis and susceptibility testing.
4
Start empiric treatment and refine later
Patient is started on RIPE therapy, which is narrowed weeks later
Early empiric treatment is necessary for patient recovery, while final narrowing prevents antibiotic resistance.

Key Concept

The chronological management of active pulmonary tuberculosis emphasizes immediate airborne isolation, followed by diagnostic sampling prior to the initiation of empiric antimicrobial therapy.
Estimated Time:1m 0s
Question 1152Question →

A 26-year-old man comes to the office due to a 5-day history of right knee swelling and pain. He also reports a mild burning sensation during urination and bilateral eye redness that started around the same time. He has no significant past medical history and takes no medications. Three weeks ago, he had a 4-day episode of abdominal cramps and watery diarrhea that resolved without medical treatment. His temperature is 37.6°C (99.7°F), blood pressure is 120/80 mm Hg, and pulse is 82/min. Physical examination reveals bilateral conjunctival injection. The right knee is swollen, warm, and tender to palpation with a moderate effusion. Arthrocentesis is performed. Synovial fluid analysis shows a leukocyte count of 24,000/mm³ with a negative Gram stain and no crystals. Which of the following is the most appropriate initial management for this patient's condition?

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Answer: Oral ibuprofen

Answer

The correct answer is oral ibuprofen, as nonsteroidal anti-inflammatory drugs are the preferred first-line treatment for reactive arthritis.
This patient's presentation of asymmetric oligoarthritis, conjunctivitis, and urethritis following a recent gastrointestinal illness is the classic triad of reactive arthritis. Reactive arthritis is a seronegative spondyloarthropathy that typically develops 1 to 4 weeks after a gastrointestinal (e.g., Salmonella, Shigella, Campylobacter) or genitourinary (e.g., Chlamydia) infection. Synovial fluid analysis characteristically reveals an inflammatory effusion (often 2,000 to 50,000 leukocytes/mm³) with a negative Gram stain and no crystals, confirming a sterile inflammatory process. The initial and most effective treatment for the acute joint inflammation in reactive arthritis is a nonsteroidal anti-inflammatory drug (NSAID), such as oral ibuprofen.

Step-by-Step Solution

1
Identify the patient's clinical syndrome based on the history and physical examination.
The combination of asymmetric oligoarthritis, conjunctivitis, and urethritis following a recent diarrheal illness is classic for reactive arthritis.
To establish the underlying diagnosis before determining the appropriate treatment.
2
Evaluate the synovial fluid analysis results.
The synovial fluid shows an inflammatory leukocyte count (24,000/mm³) but is sterile (negative Gram stain) and free of crystals.
To safely rule out septic arthritis and crystal arthropathies, which require entirely different management.
3
Select the most appropriate initial therapy for the diagnosed condition.
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are selected.
NSAIDs are the first-line symptomatic treatment for the immune-mediated joint inflammation seen in reactive arthritis.

Key Concept

The classic presentation of reactive arthritis (arthritis, urethritis, and conjunctivitis following a gastrointestinal or genitourinary infection) and its initial management with nonsteroidal anti-inflammatory drugs.
Question 1153Question →

A 42-year-old woman is evaluated for progressive central weight gain, severe fatigue, easy bruising, and proximal muscle weakness over the past 8 months. Examination reveals facial plethora, prominent supraclavicular fat pads, and wide violaceous striae on the lower abdomen. Her blood pressure is 158/96 mm Hg. The physician suspects Cushing syndrome. Assuming the evaluation ultimately reveals an ACTH-dependent etiology but initial localization imaging is equivocal, arrange the following diagnostic steps in the most appropriate sequential order, from initial evaluation to definitive confirmation.

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Answer

The correct sequential order for evaluating suspected Cushing syndrome is: 1) Review for exogenous glucocorticoids, 2) Biochemical confirmation of hypercortisolism, 3) Measurement of plasma ACTH, 4) MRI of the pituitary, and 5) Inferior petrosal sinus sampling (IPSS).
The evaluation of Cushing syndrome follows a strict chronological hierarchy to maximize diagnostic accuracy and avoid the pitfalls of incidentalomas. The most common cause of Cushingoid features is exogenous glucocorticoid use, which must be ruled out by a careful medication history before any biochemical testing. Once excluded, endogenous hypercortisolism must be definitively established using at least one first-line test (e.g., 24-hour urine free cortisol, 1-mg overnight dexamethasone suppression test, or late-night salivary cortisol). Only after hypercortisolism is confirmed should a plasma ACTH level be drawn to differentiate ACTH-dependent (pituitary or ectopic) from ACTH-independent (adrenal) causes. For ACTH-dependent disease, an MRI of the pituitary is the initial localizing step because Cushing disease (pituitary adenoma) is the most common etiology. However, because small pituitary incidentalomas are common and small corticotroph adenomas can be missed on MRI, an equivocal scan (e.g., a normal MRI or a lesion <6 mm) requires inferior petrosal sinus sampling (IPSS) to definitively differentiate a pituitary source from an occult ectopic ACTH-secreting tumor.

Step-by-Step Solution

1
Exclude exogenous glucocorticoid use.
Prevents unnecessary diagnostic workup.
Exogenous administration (even via topical or inhaled routes) is the most common cause of Cushing syndrome.
2
Perform initial biochemical screening for hypercortisolism.
Confirms the presence of endogenous hypercortisolism.
Establishing the diagnosis biochemically is required before attempting to localize the source, as non-diagnostic testing can lead to false-positive incidentalomas.
3
Measure plasma ACTH concentration.
Categorizes the hypercortisolism as ACTH-dependent or ACTH-independent.
A suppressed ACTH indicates an adrenal source (requiring adrenal imaging), while a normal or elevated ACTH indicates a pituitary or ectopic source (requiring pituitary imaging).
4
Perform a pituitary MRI.
Identifies potential pituitary corticotroph adenomas.
Since the majority of ACTH-dependent Cushing syndrome is caused by Cushing disease (pituitary adenoma), dedicated imaging of the sella turcica is the first localization step.
5
Perform inferior petrosal sinus sampling (IPSS).
Differentiates between pituitary and ectopic ACTH production.
In cases of ACTH-dependent Cushing syndrome where the pituitary MRI is equivocal or shows a lesion <6 mm, IPSS is the gold standard to confirm a central source and guide surgical management.

Key Concept

The sequential diagnostic algorithm for Cushing syndrome progresses from excluding exogenous causes to confirming endogenous hypercortisolism, determining ACTH dependence, and finally localizing the source with imaging and invasive sampling.
Estimated Time:2m 0s
Question 1154Question →

A 72-year-old man with a history of metastatic prostate cancer is brought to the emergency department with a 2-day history of progressively worsening lower back pain, bilateral leg weakness, and new-onset urinary incontinence. Neurologic examination reveals decreased sensation to pinprick below the umbilicus, 2/5 motor strength in both lower extremities, and hyperreflexia in the knees and ankles. Anal sphincter tone is decreased. You suspect malignant epidural spinal cord compression. Arrange the following management steps in the most appropriate chronological order.

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Answer

The correct sequence is to first administer intravenous dexamethasone, then obtain an MRI of the spine, followed by consulting neurosurgery or radiation oncology, and finally initiating definitive surgical decompression or radiation therapy.
Malignant epidural spinal cord compression (MESCC) is an oncologic emergency. The first and most critical step in management is the immediate administration of high-dose intravenous glucocorticoids (e.g., dexamethasone) based purely on clinical suspicion. This reduces peritumoral edema, relieves pressure on the spinal cord, and preserves neurologic function. Once steroids are given, an urgent MRI of the entire spine is obtained to confirm the diagnosis and delineate the extent of the disease. Following imaging, surgical or radiation oncology specialists are consulted to determine the best definitive treatment, which is then initiated.

Step-by-Step Solution

1
Administer high-dose intravenous dexamethasone
Reduces spinal cord edema and pressure
Prevents permanent neurologic damage while waiting for confirmatory imaging.
2
Obtain an urgent MRI of the entire spine
Confirms the diagnosis and level of compression
Gold standard imaging is required to map the exact location of the lesion before surgery or radiation.
3
Consult neurosurgery or radiation oncology
Determines the optimal definitive management plan
Specialist input is necessary to decide between surgical and radiotherapeutic options.
4
Initiate definitive surgical decompression or radiation therapy
Provides long-term relief of cord compression
Treats the underlying malignant lesion causing the mechanical compression.

Key Concept

Malignant epidural spinal cord compression is an oncologic emergency requiring empiric high-dose glucocorticoids immediately upon clinical suspicion, prior to any confirmatory imaging.
Question 1155Question →

An emergency department physician evaluates a 71-year-old man for progressively blurred vision, recurrent severe epistaxis, and confusion over the past two weeks. On physical examination, the patient appears lethargic. Fundoscopy reveals tortuous, engorged retinal veins with a classic 'sausage-link' appearance alongside bilateral retinal hemorrhages. Initial laboratory studies show:

Laboratory ParameterValue
Hemoglobin9.2 g/dL
Total serum protein10.8 g/dL
Albumin3.4 g/dL

Subsequent serum protein electrophoresis identifies a prominent monoclonal spike in the gamma-globulin region. His serum viscosity is markedly elevated at 5.8 centipoise (normal: 1.4-1.8).

Arrange the following steps in the most appropriate and safe chronological sequence for the management of this patient:

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Answer

The correct sequence is to first draw diagnostic blood tests, followed by emergent therapeutic plasmapheresis to stabilize the patient, then perform a bone marrow biopsy for definitive tissue diagnosis, and finally initiate systemic chemoimmunotherapy.
The correct sequence prioritizes securing diagnostic evidence before altering it, immediately managing the life-threatening emergency, confirming the underlying pathology safely, and finally treating the root cause. First, blood must be drawn for immunofixation to capture accurate baseline immunoglobulin levels. Second, emergent plasmapheresis is performed to rapidly reverse the life-threatening hyperviscosity syndrome. Third, after the patient is stabilized and bleeding risk is reduced, an invasive bone marrow biopsy is safely obtained for definitive tissue diagnosis. Finally, systemic chemoimmunotherapy is initiated to treat the underlying Waldenström macroglobulinemia, ensuring this occurs post-plasmapheresis to avoid a dangerous rituximab-induced IgM flare.

Step-by-Step Solution

1
Draw peripheral blood for immunofixation electrophoresis and quantitative immunoglobulins
Establishes baseline immunoglobulin levels and characterizes the monoclonal protein as IgM.
Must be performed prior to plasma exchange; otherwise, the therapeutic removal of immunoglobulins will artificially lower the diagnostic levels and obscure the true nature of the gammopathy.
2
Perform emergent therapeutic plasmapheresis
Rapidly clears high-molecular-weight IgM pentamers from the intravascular space, decreasing serum viscosity.
Hyperviscosity syndrome with end-organ damage (confusion, retinal hemorrhages) is an emergency requiring immediate mechanical removal of the offending protein to prevent irreversible ischemic strokes or coma.
3
Obtain a bone marrow aspiration and biopsy
Provides tissue to definitively identify a lymphoplasmacytic cellular infiltrate.
An invasive biopsy is safely performed after the patient is stabilized and hyperviscosity-induced platelet dysfunction is corrected. It is required for the definitive diagnosis of Waldenström macroglobulinemia.
4
Initiate systemic chemoimmunotherapy (e.g., rituximab and bendamustine)
Targets the underlying malignant clonal B-cells to provide long-term disease control.
Definitive therapy is started after pathologic confirmation. Importantly, administering rituximab prior to plasmapheresis is contraindicated here, as it can trigger a paradoxical 'IgM flare' that sharply increases viscosity.

Key Concept

Waldenström Macroglobulinemia and Hyperviscosity Syndrome Management
Estimated Time:2m 0s
Question 1156Question →

Match each autoantibody profile to the rheumatologic condition with which it is most specifically associated.

Click a left item, then click its matching right item

Items

Anti-Scl-70 (anti-topoisomerase I) antibodies
Anti-Jo-1 (anti-histidyl-tRNA synthetase) antibodies
Anti-U1 ribonucleoprotein (anti-U1 RNP) antibodies
Anti-cyclic citrullinated peptide (anti-CCP) antibodies

Matches

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Answer

Anti-Scl-70 pairs with Diffuse cutaneous systemic sclerosis; Anti-Jo-1 pairs with Polymyositis / Dermatomyositis; Anti-U1 RNP pairs with Mixed connective tissue disease; Anti-CCP pairs with Rheumatoid arthritis.
Each autoantibody has a distinct clinical association that aids in differentiating various rheumatologic diseases. Anti-Scl-70 is linked to diffuse systemic sclerosis. Anti-Jo-1 is tied to inflammatory myopathies (polymyositis/dermatomyositis). Anti-U1 RNP defines mixed connective tissue disease. Anti-CCP is a highly specific marker for rheumatoid arthritis.

Step-by-Step Solution

1
Analyze the first antibody, Anti-Scl-70.
It pairs with diffuse cutaneous systemic sclerosis.
Anti-Scl-70 (anti-topoisomerase I) is a classic marker for the diffuse variant of systemic sclerosis.
2
Analyze the second antibody, Anti-Jo-1.
It pairs with polymyositis / dermatomyositis.
Anti-Jo-1 is an anti-synthetase antibody strongly associated with inflammatory myopathies.
3
Analyze the third antibody, Anti-U1 RNP.
It pairs with mixed connective tissue disease.
The defining serologic feature of mixed connective tissue disease is the presence of high-titer anti-U1 RNP antibodies.
4
Analyze the fourth antibody, Anti-CCP.
It pairs with rheumatoid arthritis.
Anti-CCP antibodies have very high specificity for rheumatoid arthritis and often appear before clinical symptoms.

Key Concept

Specific autoantibody profiles in rheumatologic conditions
Question 1157Question →

A 65-year-old man presents to the preoperative clinic for medical clearance prior to an elective open abdominal aortic aneurysm (AAA) repair. His medical history is significant for hypertension, type 2 diabetes mellitus, and stable angina. He reports that he lives a sedentary lifestyle and experiences mild chest tightness when walking up a single flight of stairs, prompting him to stop and rest. His current medications include lisinopril, metformin, atorvastatin, and aspirin. His vital signs are within normal limits, and his physical examination is unremarkable. His resting electrocardiogram shows normal sinus rhythm without acute ischemic changes.

Arrange the following steps for the preoperative cardiac risk evaluation and management of this patient in the correct algorithmic sequence according to current standard guidelines.

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Answer

The correct sequence requires first calculating the clinical/surgical risk of MACE, followed by assessing the patient's functional capacity (METs). Because functional capacity is poor, the next step is noninvasive pharmacologic stress testing, and finally invasive coronary angiography if the stress test demonstrates severe ischemia.
The standard evaluation of preoperative cardiac risk follows a strict step-wise algorithm. First, emergency surgery and acute coronary syndrome are ruled out. Next, baseline risk of Major Adverse Cardiac Events (MACE) is estimated using a tool like the Revised Cardiac Risk Index (RCRI). If the risk is elevated (>1%>1\%), functional capacity is assessed. If functional capacity is poor (<4<4 METs), noninvasive pharmacologic stress testing is indicated. Finally, if the stress test is markedly abnormal, invasive coronary angiography is pursued.

Step-by-Step Solution

1
Determine the baseline perioperative risk of major adverse cardiac events (MACE).
The patient is undergoing high-risk vascular surgery (AAA repair) and has multiple clinical risk factors (diabetes, angina), placing him in an elevated risk category (>1%>1\%).
Initial risk stratification determines whether a patient can proceed directly to surgery (if low risk) or requires further evaluation (if elevated risk).
2
Evaluate the patient's functional capacity in metabolic equivalents (METs).
The patient experiences chest tightness walking up a single flight of stairs, indicating a functional capacity of <4<4 METs.
Patients with an elevated clinical risk but excellent or good functional capacity (≥4\ge 4 METs) can safely proceed to surgery without further cardiac testing. Poor functional capacity necessitates the next step in the algorithm.
3
Order noninvasive pharmacologic stress testing.
A pharmacologic stress test is arranged to quantify ischemic burden.
In a patient with elevated risk and poor functional capacity (<4<4 METs) undergoing high-risk surgery, noninvasive stress testing is recommended to evaluate if changes in perioperative management are required.
4
Evaluate the stress test results to determine the need for invasive angiography.
Coronary angiography is considered as a follow-up intervention.
If the noninvasive test shows extensive reversible ischemia, invasive angiography and potential revascularization are indicated before the elective AAA repair to reduce perioperative mortality.

Key Concept

Preoperative cardiac risk assessment for noncardiac surgery relies on a stepwise algorithm: estimating MACE risk, evaluating functional capacity (METs), and utilizing noninvasive stress testing if the patient has elevated risk combined with poor functional capacity (<4<4 METs).
Estimated Time:1m 30s
Question 1158Question →

A first-year surgical resident is assisting in the repair of a complex lower extremity laceration in the emergency department. The patient is known to have untreated HIV with a recent viral load of 120,000120,000 copies/mL. During the procedure, the resident accidentally sustains a deep percutaneous puncture wound to their left index finger with a hollow-bore needle that is visibly contaminated with the patient's blood. The resident immediately stops assisting and removes their surgical gloves.

Arrange the following steps in the most appropriate chronological sequence for the management of this occupational exposure.

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Answer

The correct sequence for managing an occupational percutaneous HIV exposure is to first decontaminate the wound, followed by reporting to occupational health, obtaining baseline serologies, rapidly initiating a three-drug antiretroviral prophylaxis regimen, and finally conducting long-term serological follow-up.
This sequence strictly aligns with CDC guidelines for occupational exposure to bloodborne pathogens. Immediate local wound care (washing copiously with soap and water) is the absolute first priority to mechanically reduce the inoculum. Caustic agents or squeezing the wound to induce bleeding are not recommended. Next, reporting the incident allows occupational health to coordinate the formal exposure protocol. Baseline serologies must then be drawn from the healthcare worker to establish their pre-exposure serostatus. Crucially, a three-drug post-exposure prophylaxis (PEP) regimen must be initiated immediately after blood is drawn, ideally within 1-2 hours, without waiting for those baseline laboratory results to return. Finally, because PEP is not universally effective, the exposed worker requires serial follow-up testing at 6 weeks, 12 weeks, and 6 months to monitor for late seroconversion.

Step-by-Step Solution

1
Wash the wound
Decreased viral bioburden
Immediate mechanical removal of the pathogen reduces the total inoculum and subsequent transmission risk.
2
Report to occupational health
Formal risk assessment and protocol activation
Institutional protocols require documentation and authorized personnel to facilitate appropriate testing and medication dispensing.
3
Draw baseline laboratory tests
Established pre-exposure serostatus
Essential to determine if the healthcare worker was already infected prior to this specific occupational exposure.
4
Initiate a 3-drug PEP regimen
Systemic antiretroviral blockade
Early initiation (within 1-2 hours) maximizes the prevention of viral replication and systemic integration.
5
Schedule serial follow-up testing
Long-term serological monitoring
PEP does not guarantee prevention; delayed seroconversion must be monitored over a 6-month window.

Key Concept

Management of occupational HIV exposure follows a strict protocol: immediate local decontamination, reporting, baseline serological testing, rapid initiation of a 3-drug PEP regimen (ideally within 1-2 hours, without waiting for lab results), and longitudinal follow-up.
Estimated Time:1m 30s
Question 1159Question →

Match each autoantibody to its most characteristic associated rheumatologic condition or clinical feature.

Click a left item, then click its matching right item

Items

Anti-cyclic citrullinated peptide (anti-CCP) antibodies
Anti-double-stranded DNA (anti-dsDNA) antibodies
Anti-centromere antibodies
Anti-Scl-70 (anti-topoisomerase I) antibodies

Matches

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Answer

The correct matches are: Anti-CCP with Rheumatoid Arthritis; Anti-dsDNA with Systemic Lupus Erythematosus; Anti-centromere with Limited Cutaneous Systemic Sclerosis; and Anti-Scl-70 with Diffuse Cutaneous Systemic Sclerosis.
Autoantibodies serve as crucial diagnostic and prognostic markers in rheumatology. Anti-CCP is highly specific for Rheumatoid Arthritis. Anti-dsDNA is specific for SLE and tracks disease activity. Anti-centromere and anti-Scl-70 help differentiate between limited and diffuse cutaneous systemic sclerosis, respectively, with each carrying distinct clinical features and visceral risks.

Step-by-Step Solution

1
Identify the disease association for anti-CCP antibodies.
Matches with Rheumatoid Arthritis.
Anti-CCP is the most specific serological marker for RA.
2
Identify the disease association for anti-dsDNA antibodies.
Matches with Systemic Lupus Erythematosus.
Anti-dsDNA is specific to SLE and its titer correlates with disease flares and renal involvement.
3
Identify the disease association for anti-centromere antibodies.
Matches with Limited Cutaneous Systemic Sclerosis.
It is the defining serological feature of limited systemic sclerosis (CREST syndrome).
4
Identify the disease association for anti-Scl-70 antibodies.
Matches with Diffuse Cutaneous Systemic Sclerosis.
It distinguishes the diffuse form of systemic sclerosis from the limited form and predicts a higher risk of interstitial lung disease.

Key Concept

Clinical utility of specific autoantibodies in the diagnosis and prognostication of systemic autoimmune diseases.
Question 1160Question →

During morning rounds, the internal medicine team evaluates a patient who was recently admitted for high-grade non-Hodgkin lymphoma. The patient, a 4848-year-old male, started induction chemotherapy 4848 hours ago. The nursing staff reports that he acutely developed profound nausea, intense muscle cramping, and palpitations over the last hour. Vital signs show a temperature of 37.1∘C37.1^\circ\text{C} (98.8∘F98.8^\circ\text{F}), blood pressure of 100/60100/60 mm Hg, an irregular pulse of 118118/min, and a respiratory rate of 2020/min. He appears visibly lethargic. Cardiac auscultation reveals an irregular rhythm without murmurs, and the lungs are clear to auscultation. A stat electrocardiogram (ECG) is obtained, which reveals tall, peaked T waves and a prolonged PR interval. Laboratory analysis yields the following results:

TestResult
Potassium6.86.8 mEq/L
Calcium6.86.8 mg/dL
Phosphorus6.56.5 mg/dL
Uric acid14.214.2 mg/dL
Blood urea nitrogen4545 mg/dL
Creatinine2.82.8 mg/dL

Based on the clinical presentation and laboratory findings, which of the following is the most appropriate initial step in the management of this patient?

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Answer: Administration of calcium gluconate via intravenous infusion

Answer

The most appropriate initial step is the administration of calcium gluconate via intravenous infusion.
The correct intervention is the administration of intravenous calcium gluconate. This patient is experiencing Tumor Lysis Syndrome (TLS), an oncologic emergency characterized by the massive release of intracellular contents following the initiation of cytotoxic therapy for rapidly proliferating tumors. This results in hyperkalemia, hyperphosphatemia, hyperuricemia, and secondary hypocalcemia. The most life-threatening complication is hyperkalemia, evidenced by his elevated level of 6.86.8 mEq/L and characteristic ECG changes (peaked T waves, prolonged PR interval). The immediate, most critical step in management is myocardial stabilization with intravenous calcium gluconate (or calcium chloride) to raise the threshold potential and prevent fatal ventricular arrhythmias. Once the myocardium is stabilized, subsequent therapies to shift potassium intracellularly (e.g., insulin and glucose) and treat the underlying TLS (e.g., aggressive hydration, rasburicase) should be initiated.

Step-by-Step Solution

1
Analyze the patient's history and current presentation.
A patient with newly treated high-grade lymphoma presents acutely with muscle cramps, arrhythmias, and acute kidney injury.
Recent initiation of cytotoxic chemotherapy in high-grade lymphomas strongly predisposes to massive cellular breakdown.
2
Interpret the laboratory and ECG findings.
Labs show hyperkalemia, hyperuricemia, hyperphosphatemia, and hypocalcemia. ECG shows peaked T waves and prolonged PR interval.
These findings definitively confirm Tumor Lysis Syndrome (TLS) complicated by severe, symptomatic hyperkalemia.
3
Determine the most critical priority in management.
The most immediate threat to the patient's life is a fatal ventricular arrhythmia induced by the hyperkalemia.
While treating the underlying TLS (e.g., hydration, rasburicase) and lowering total body potassium are necessary, stabilizing the cardiac membrane is the most urgent, time-sensitive intervention.

Key Concept

Tumor Lysis Syndrome (TLS) can cause life-threatening hyperkalemia; when accompanied by ECG changes, the immediate priority is myocardial stabilization with intravenous calcium.
Estimated Time:1m 30s
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