General Internal Medicine Flashcards

A 58-year-old man with type 2 diabetes, CKD stage 3b (eGFR 32 mL/min/1.73m²), and HFrEF (EF 35%) presents for medication reconciliation. His current regimen includes metformin, lisinopril, carvedilol, and furosemide. His HbA1c is 8.9%. Which adjustment is MOST appropriate?

Answer: Discontinue metformin and initiate empagliflozin 10 mg daily

Metformin is contraindicated when eGFR falls below 30 mL/min/1.73m² and should be used with caution below 45. With eGFR of 32, it should be discontinued. Empagliflozin (an SGLT2 inhibitor) has robust evidence for cardiovascular and renal benefit in HFrEF patients with T2DM, reducing hospitalizations and mortality. While its glucose-lowering efficacy diminishes at lower eGFRs, its cardiorenal benefits persist down to eGFR ≥20. GLP-1 agonists lack dedicated HFrEF outcome data comparable to SGLT2i, and sitagliptin requires dose reduction but does not provide cardiorenal protective benefits. Insulin glargine is reasonable but does not address the cardiorenal risk reduction opportunity.

A 44-year-old woman is found to have a serum calcium of 11.8 mg/dL on routine labs. PTH is 78 pg/mL (normal 15–65), PTHrP is undetectable, 25-OH vitamin D is 18 ng/mL, and 24-hour urine calcium is 95 mg/day (normal >200 mg/day for diagnosis of PHPT). Urine calcium-to-creatinine clearance ratio is 0.008. She is asymptomatic. What is the MOST likely diagnosis and appropriate next step?

Answer: Familial hypocalciuric hypercalcemia; no treatment required, reassure and screen family members

Familial hypocalciuric hypercalcemia (FHH) is characterized by mildly elevated calcium, inappropriately normal or elevated PTH, and — critically — low urine calcium excretion. The calcium-to-creatinine clearance ratio (CCCR) below 0.01 (especially 0.02. FHH results from an inactivating mutation in the calcium-sensing receptor (CaSR), causing the kidney and parathyroid to 'sense' a higher calcium setpoint. Surgery is not indicated and will not resolve the hypercalcemia. Bisphosphonates and vitamin D repletion are not appropriate for FHH. Genetic testing (CaSR mutation) can confirm the diagnosis.

A 67-year-old man with COPD (on tiotropium and salmeterol/fluticasone) is admitted for an acute exacerbation. On hospital day 3, he develops new-onset AF with RVR (HR 138 bpm), BP 102/68 mmHg, and SpO2 88% on 4L NC. He has no prior history of AF and no structural heart disease by recent echo. Which rhythm-control strategy is MOST appropriate at this time?

Answer: IV amiodarone infusion

In a COPD exacerbation complicated by new AF with hemodynamic compromise (hypotension and hypoxia), amiodarone is the preferred agent. Beta-blockers (including metoprolol) are relatively contraindicated in acute COPD exacerbations due to risk of bronchospasm, particularly with significant airflow obstruction. Flecainide (a class IC agent) is contraindicated in patients with structural or ischemic heart disease and is not appropriate for acute inpatient management of this complexity. Electrical cardioversion, while appropriate for hemodynamic instability, should be preceded by attempts at pharmacological rate/rhythm control when the patient is not in immediate hemodynamic collapse (BP 102, not in shock). Amiodarone has both rate-control and rhythm-conversion properties, lacks significant bronchoconstriction risk, and is guideline-recommended for AF cardioversion in critically ill patients.

A 52-year-old woman presents with a 6-month history of fatigue, arthralgias, and a malar rash. Labs reveal ANA 1:640 (homogeneous), anti-dsDNA positive, anti-Smith positive, complement C3 45 mg/dL (low), C4 7 mg/dL (low), and urinalysis showing 3+ protein and 10–20 RBCs/hpf with RBC casts. Creatinine is 1.9 mg/dL (baseline unknown). Renal biopsy shows diffuse proliferative glomerulonephritis with wire-loop lesions and subendothelial immune complex deposits. Which of the following best represents the ISN/RPS classification and standard induction regimen?

Answer: Class IV lupus nephritis; high-dose glucocorticoids plus mycophenolate mofetil or cyclophosphamide

The biopsy findings — diffuse proliferative pattern, wire-loop lesions (thickened GBM from massive subendothelial deposits), and subendothelial immune complex deposits on EM — are classic for ISN/RPS Class IV (diffuse) lupus nephritis, the most severe and common form. Standard induction therapy consists of high-dose glucocorticoids combined with either mycophenolate mofetil (MMF; preferred due to equivalent efficacy with better tolerability) or low-dose IV cyclophosphamide (Euro-Lupus regimen). Class III is focal proliferative (affecting <50% of glomeruli). Class V is membranous pattern (subepithelial deposits). Rituximab is used in refractory cases; belimumab has emerging data as an add-on but is not standard induction. Tacrolimus monotherapy is not guideline-recommended for Class IV induction.

A 71-year-old man with metastatic non-small cell lung cancer on pembrolizumab presents with progressive dyspnea over 3 weeks. CT chest shows new bilateral ground-glass opacities with peripheral consolidation. SpO2 is 91% on room air. BAL shows lymphocytic alveolitis. Cultures and PCR for PJP, CMV, and bacteria are negative. The most appropriate management is:

Answer: Permanently discontinue pembrolizumab, initiate high-dose prednisone 1–2 mg/kg/day, and arrange pulmonology follow-up

This presentation is consistent with grade 3 immune checkpoint inhibitor (ICI)-related pneumonitis: bilateral GGOs, SpO2 <95%, and lymphocytic alveolitis on BAL with negative infectious workup. Per ASCO/NCCN guidelines, grade 3 ICI pneumonitis requires permanent discontinuation of the checkpoint inhibitor and initiation of high-dose systemic corticosteroids (prednisone 1–2 mg/kg/day or methylprednisolone 1–2 mg/kg/day IV), tapered over at least 6 weeks. Antibiotics alone are insufficient given negative cultures and classic ICI toxicity pattern. Re-challenge with pembrolizumab after grade 3 pneumonitis is generally not recommended. Mycophenolate mofetil is reserved for steroid-refractory cases and is typically used in addition to, not instead of, corticosteroids.

A 38-year-old woman is evaluated for episodic hypertension (BPs reaching 210/120 mmHg) associated with palpitations, diaphoresis, and headache, occurring 2–3 times per week and lasting 20–30 minutes. Between episodes her BP is 118/74 mmHg. 24-hour urine metanephrines: normetanephrine 3,200 mcg/24h (normal <900), metanephrine 1,800 mcg/24h (normal <400). MRI abdomen shows a 4.2 cm right adrenal mass. She undergoes preoperative preparation. Which of the following represents the CORRECT sequence and pharmacologic approach prior to surgery?

Answer: Alpha-blockade first (phenoxybenzamine or doxazosin) for at least 7–14 days, then add beta-blockade only after adequate alpha-blockade is achieved

Preoperative management of pheochromocytoma requires alpha-blockade FIRST, followed by beta-blockade only after adequate alpha-blockade is established (typically after 7–14 days). Initiating beta-blockade first or simultaneously without prior alpha-blockade can precipitate a hypertensive crisis: beta-2 blockade eliminates vasodilatory compensation while catecholamine-driven alpha-1 stimulation remains unopposed, causing severe vasoconstriction. Phenoxybenzamine (non-competitive, non-selective alpha-blocker) is the classic choice; selective alpha-1 blockers (doxazosin, prazosin) are also used. Beta-blockers are then added to control reflex tachycardia from alpha-blockade. Calcium channel blockers may be used as adjuncts but are not adequate monotherapy for operative preparation in high-output pheo.