General Internal Medicine Flashcards

A 58-year-old man with chronic kidney disease (eGFR 22 mL/min) presents with a serum potassium of 6.8 mEq/L, peaked T waves on EKG, and normal P waves with a PR interval of 210 ms. His medications include lisinopril, carvedilol, and furosemide. Which intervention is most immediately critical before any other measure?

Answer: Administer IV calcium gluconate

IV calcium gluconate (or calcium chloride) is the first and most immediately critical step in severe hyperkalemia with EKG changes. It does not lower serum potassium but stabilizes the cardiac membrane within minutes, reducing the risk of fatal arrhythmia. All other agents (bicarbonate, insulin/dextrose, albuterol) shift potassium intracellularly but take longer to act. Kayexalate removes potassium from the body but has no role in acute cardiac stabilization.

A 44-year-old woman presents with episodic severe hypertension (BP 210/115 mmHg), diaphoresis, and headache. Plasma-free metanephrines are markedly elevated. CT abdomen/pelvis reveals a 4.2 cm right adrenal mass. She is scheduled for adrenalectomy in 3 weeks. Which pre-operative pharmacologic sequence is correct?

Answer: Start phenoxybenzamine first, then add a beta-blocker after adequate alpha-blockade

In pheochromocytoma, alpha-blockade must be established BEFORE beta-blockade. If a beta-blocker is given first, the unopposed alpha-adrenergic stimulation from circulating catecholamines can cause a hypertensive crisis. Phenoxybenzamine (a non-competitive, non-selective alpha-blocker) is the preferred agent; a beta-blocker is only added afterward if reflex tachycardia persists. Simultaneous initiation risks the same unopposed alpha effect.

A 67-year-old man with a history of alcohol use disorder presents with confusion, ophthalmoplegia, and ataxia. He is given IV thiamine and admitted. On hospital day 2 he becomes agitated, tremulous, and diaphoretic, with a BP of 168/96 mmHg and HR of 118 bpm. His CIWA-Ar score is 22. Which is the most appropriate next step?

Answer: Administer lorazepam per CIWA-Ar symptom-triggered protocol

A CIWA-Ar score of 22 indicates severe alcohol withdrawal requiring benzodiazepine therapy. Lorazepam (or diazepam) given in a symptom-triggered, CIWA-guided protocol is the standard of care and reduces total benzodiazepine requirements compared to fixed schedules. Phenobarbital is sometimes used in refractory cases or as adjunctive therapy but is not the first-line agent in this scenario. Haloperidol does not treat withdrawal seizures and lowers the seizure threshold. Propofol is an ICU-level intervention not indicated before benzodiazepines are tried.

A 52-year-old woman with rheumatoid arthritis on methotrexate 20 mg/week and folic acid presents with macrocytic anemia (MCV 108 fL), hypersegmented neutrophils, and a serum B12 of 310 pg/mL (normal >200). Serum folate is 3.2 ng/mL (normal >4). Which finding would most specifically confirm that methotrexate — rather than dietary folate deficiency — is the primary etiology?

Answer: Elevated serum homocysteine with normal methylmalonic acid (MMA)

Methotrexate inhibits dihydrofolate reductase, impairing conversion of folate to its active tetrahydrofolate form — a functional folate deficiency even when serum folate stores appear adequate. Both dietary folate deficiency and methotrexate toxicity impair the folate-dependent step in homocysteine methylation, elevating homocysteine. However, MMA elevation is specific to B12 deficiency (B12 is required for the MMA→succinyl-CoA reaction). A pattern of elevated homocysteine with normal MMA points to folate pathway dysfunction (as seen with methotrexate) rather than true B12 deficiency.

A 71-year-old man with type 2 diabetes (HbA1c 9.2%), heart failure with reduced ejection fraction (EF 32%), eGFR 48 mL/min, and albuminuria (UACR 380 mg/g) is on metformin, lisinopril, and carvedilol. Which addition to his regimen most comprehensively addresses both his cardiovascular mortality risk and his progression of diabetic kidney disease based on current evidence?

Answer: Add empagliflozin (SGLT2 inhibitor)

SGLT2 inhibitors (e.g., empagliflozin, dapagliflozin) have robust trial evidence (EMPEROR-Reduced, DAPA-HF, CREDENCE, DAPA-CKD) demonstrating reduction in cardiovascular mortality, HF hospitalization, and progression of CKD with albuminuria — making them the single agent that addresses all three dimensions in this patient (HFrEF, diabetic nephropathy, and glycemic control). GLP-1 agonists reduce MACE and have emerging renal data but are not indicated for HFrEF per current guidelines. Pioglitazone causes fluid retention, worsening HF. DPP-4 inhibitors are glycemically neutral with no mortality or renal-protection benefit comparable to SGLT2i.

A 38-year-old woman presents with recurrent deep vein thromboses (DVTs) despite therapeutic anticoagulation with warfarin (INR consistently 2.5–3.0). She has a history of two first-trimester pregnancy losses. Labs show: lupus anticoagulant positive on two occasions 12 weeks apart, anti-cardiolipin IgG antibody titer >99th percentile, and anti-β2-glycoprotein I IgG positive. Which statement about her ongoing anticoagulation management is most accurate?

Answer: She meets criteria for triple-positive antiphospholipid syndrome; continue warfarin with a target INR of 2.0–3.0 indefinitely

This patient has triple-positive antiphospholipid syndrome (APS) — the highest-risk serologic profile (lupus anticoagulant + anti-cardiolipin + anti-β2-GPI all positive). For venous thrombosis in APS, warfarin with an INR target of 2.0–3.0 remains the standard of care indefinitely. Critically, DOACs (rivaroxaban, apixaban) have been shown in randomized trials (RAPS, ASTRO-APS, TRAPS) to be INFERIOR to warfarin in triple-positive APS, with higher rates of arterial thrombosis. Raising the INR target to 3.0–4.0 increases bleeding risk without proven additional benefit for venous APS. LMWH indefinitely is used in pregnancy but not standard long-term management.