Source / episode info

• **Episode:**559
• **Title:**DIP Ep 559: 2024 USMLE Step 3 Free 137 Discussion Part 6b (Q55-60, super helpful for Step 2!)
• **Published:**2025-01-12
• Source:Episode page

One-liner

This episode provides high-yield clinical reasoning on diagnosing pulmonary embolism (PE) in the setting of acute dyspnea; identifying pre-renal azotemia due to volume depletion; applying ethical principles regarding patient autonomy and surrogate decision making; recognizing pressure ulcer pathophysiology; and managing acutely ill, cognitively impaired elderly patients.

High-yield summary

• Pulmonary Embolism (PE): Acute onset of dyspnea/tachycardia with markedly elevated D-dimer, especially when cardiac enzymes are normal and CXR is unremarkable, strongly suggests PE. Rule out common mimics like COPD exacerbation or heart failure first.
• Pre-renal AKI: Characterized by oliguria, concentrated urine (high specific gravity), and signs of volume depletion (e.g., vomiting/diarrhea). Labs show rising BUN and creatinine due to decreased GFR from reduced renal perfusion pressure.
• Ethical Principles in Medicine: In non-emergent settings, utilize the "reliable historian" principle by contacting primary care physicians or pharmacists for medication reconciliation rather than relying on family members or assuming emergency action is needed.
• Patient Autonomy (DNR/Advanced Directives): A patient's current, lucidly expressed wishes regarding life support (e.g., refusing dialysis) supersede the recommendations of a surrogate decision maker (daughter/proxy).
• Pressure Ulcers: These are caused by prolonged immobility and pressure ischemia. If an ulcer progresses to muscle or bone, debridement is mandatory; do not rely on memorizing specific staging criteria for board questions.

Learning objectives

• Differentiate the clinical presentation of PE from other causes of acute dyspnea.
• Identify laboratory and physical exam findings indicative of pre-renal AKI versus intrinsic renal failure.
• Apply ethical principles (autonomy, reliable historian) to complex patient management scenarios in medicine.
• Recognize the pathophysiology and required management steps for pressure ulcers.
• Understand the hierarchy of decision-making regarding life support when a patient's capacity is compromised.

Board exam buzzwords