Solve with reason
Reading File
Finding Sources
Finding Sources
Answer: D) Massive Pulmonary Embolism
Clinical Reasoning
| Feature | Significance |
|---|---|
| 70-year-old male | Advanced age = major VTE risk factor |
| Hip fracture surgery, 4 days post-op | Orthopedic surgery is one of the highest-risk procedures for DVT/PE; peak incidence is days 3–7 post-op |
| Acute onset dyspnea | Sudden onset strongly favors embolic etiology over infectious or inflammatory causes |
| Hypotension | Hemodynamic instability = hallmark of massive (high-risk) PE — indicates ≥50% obstruction of the pulmonary vascular bed |
| SpO₂ 70% on room air | Severe hypoxemia consistent with massive ventilation-perfusion mismatch from large clot burden |
Why the Other Options Are Wrong
A) Atelectasis — Common post-op, but causes mild hypoxia and does NOT cause hemodynamic collapse (hypotension). SpO₂ of 70% is far too low.
B) Pneumonia — Gradual onset, fever, productive cough expected. Does not cause sudden cardiovascular collapse 4 days post-op.
C) Fat embolism syndrome — Occurs after long bone/pelvis fractures, but typically presents 24–72 hours post-injury (not 4 days), and the classic triad is hypoxia + neurological changes + petechial rash. Hypotension is not the dominant feature.
D) Massive pulmonary embolism ✓ — The combination of:
- High-risk surgical context (hip fracture surgery)
- Timing (days 3–7)
- Acute onset dyspnea
- Hypotension (right heart failure from outflow obstruction)
- Profound hypoxia (SpO₂ 70%)
...perfectly matches massive (high-risk) PE, defined as PE causing sustained hypotension (SBP <90 mmHg) or shock. The illustration in the question also shows thrombus occluding pulmonary vasculature.
E) ARDS — Requires a precipitating cause (sepsis, aspiration, trauma), has a more gradual course (hours), and the radiographic pattern is bilateral infiltrates. Does not cause acute hypotension without septic shock.
Pathophysiology of Massive PE
Hip fracture surgery causes:
- Venous stasis (immobility) + endothelial injury (surgical trauma) + hypercoagulability (inflammatory response) → Virchow's triad → DVT → PE
- Large clot burden obstructs >50% of pulmonary circulation → acute right ventricular pressure overload → RV failure → decreased LV preload → systemic hypotension
- V/Q mismatch + intracardiac shunting → severe hypoxemia
The answer is D — Massive Pulmonary Embolism.
Solve with reason
Finding Sources
Finding Sources
Answer: B) Iatrogenic Cushing's Syndrome
Clinical Reasoning
| Clue | Interpretation |
|---|---|
| Long-term steroid use for RA | Exogenous glucocorticoid administration — the #1 cause of Cushing's syndrome in clinical practice |
| Weight gain + moon face | Classic centripetal fat redistribution from cortisol excess |
| Easy bruising | Cortisol impairs collagen synthesis → skin fragility and capillary fragility |
The textbooks confirm it directly:
"Cushing syndrome is most often iatrogenic because of glucocorticoid therapy." — Washington Manual of Medical Therapeutics
"In clinical practice, most cases of Cushing syndrome are due to administration of exogenous glucocorticoids (iatrogenic)." — Robbins & Kumar Basic Pathology
Why the Other Options Are Wrong
A) Cushing's disease — This specifically refers to a pituitary ACTH-secreting adenoma causing endogenous cortisol excess. The pituitary gland is the culprit here. In this patient, the cause is clearly the prescribed steroids, not pituitary pathology. Cushing's disease accounts for ~80% of endogenous cases — but endogenous cases are far less common than iatrogenic ones overall.
B) Iatrogenic Cushing's syndrome ✓ — "Iatrogenic" means caused by medical treatment. Long-term exogenous glucocorticoids (prednisone for RA) suppress the HPA axis and produce the full cushingoid phenotype: moon face, truncal obesity, buffalo hump, striae, easy bruising, osteoporosis, hyperglycemia.
C) Adrenal insufficiency — Also a consequence of long-term steroid use (HPA axis suppression), but presents with the opposite picture: fatigue, weight loss, hypotension, hyperpigmentation (in primary), hyponatremia. Does NOT cause moon face or weight gain.
D) Conn's syndrome — Primary hyperaldosteronism (adrenal adenoma secreting aldosterone). Presents with hypertension + hypokalemia. Has no connection to exogenous steroid use and does not cause the cushingoid features described here.
Key Distinction: Cushing's Disease vs. Cushing's Syndrome
| Term | Cause |
|---|---|
| Cushing's syndrome | Any source of cortisol excess (endogenous or exogenous) |
| Cushing's disease | Specifically a pituitary ACTH-secreting adenoma |
| Iatrogenic Cushing's syndrome | Exogenous glucocorticoid administration ← this patient |
The answer is B — Iatrogenic Cushing's Syndrome.
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