CLINICAL QUESTIONS

Rapid, high-yield Q→A for rounds, the OR, and specialty clinics.

Cardiology
Infectious
Endocrine
Nephrology
Gatrointestinal
Pulmonology

  • Fixed outflow obstruction → inability to increase cardiac output during exertion → cerebral hypoperfusion.

  • Severe AS = valve area <1.0 cm² or mean gradient ≥40 mmHg.

  • IV Calcium Gluconate

  • Calcium stabilizes membrane, does NOT lower potassium.

Cardiology

  • RCA supplies SA and AV node.

  • Inferior MI + hypotension → always check for RV infarct. Give fluids, not nitrates.

  • Arrhythmia, structural cardiac disease (AS), orthostatic hypotension, vasovagal, neurogenic.

  • Cardiac syncope = sudden, no prodrome, high mortality.

  • RV preload dependent → nitrates reduce preload → hypotension.

  • Inferior MI + hypotension + clear lungs → think RV infarct.

  • Cardiorenal syndrome (renal hypoperfusion + venous congestion).

  • AKI, hyperkalemia, hypotension.

  • Don’t stop ACE lightly in HFrEF unless clear reason.

  • Pain, hypovolemia, infection, PE, anemia, withdrawal.

  • Persistent tachycardia = something is wrong until proven otherwise.

  • Severe volume depletion.

  • From osmotic diuresis. If K <3.3, replete before insulin.

Endocrine

  • Activates Na/K ATPase → intracellular shift.

  • Also stimulated by beta-2 agonists.

  • Decreased cardiac output → ↑ ADH.

  • Hyponatremia in hypothyroidism is usually mild. Severe hyponatremia → look for another cause.

  • 8 mEq/L in 24 hours.

  • Risk = osmotic demyelination.

  • Ammonia-mediated astrocyte dysfunction.

  • Treat with lactulose until 2–3 soft stools daily.

Gastrointestinal

  • 2-3 soft stools daily

  • Tissue hypoperfusion → anaerobic metabolism.

  • Lactate clearance predicts prognosis.

Infectious

  • Pregnancy, before urologic procedures.

  • Do NOT treat if no symptoms.

  • Infection, stress, steroids, malignancy.

  • Always look at differential and patient presentation.

  • Infection, steroids, stress response.

  • Cortisol and catecholamines increase insulin resistance.

  • AEIOU: Acidosis (pH < 7.1), Electrolytes (refractory hyperkalemia), Intoxication/Ingestion (toxic alcohols, salicylates, lithium), Overload (CHF), Uremia (uremic pericarditis, encephalopathy).

  • If potassium >6.5 with EKG changes → act immediately.

Nephrology

  • FeNa is unreliable if patient is on diuretics. Use FeUrea (<35% suggests pre-renal).

  • Symptomatic aneurysm  emergent repair, regardless of size.

  • Damaged tubules can’t reabsorb sodium.

  • UA is more useful than FeNa: muddy brown casts clinch diagnosis.

  • Decreased GFR from hypoperfusion, obstruction, nephrotoxins.

  • Always review meds (NSAIDs, contrast, ACEi, antibiotics).

  • Chronic intermittent hypoxia → pulmonary vasoconstriction.

  • Longstanding OSA can lead to cor pulmonale.

Pulmonology

  • Worsening acidosis, altered mental status, fatigue.

  • BiPAP if stable.

  • Ventilated but not perfused alveoli.

  • PE = increased dead space; pneumonia = shunt.