Three days after intramedullary nailing of bilateral femoral shaft fractures, a 24-year-old man develops fever, tachypnea, confusion, and a petechial rash over the anterior chest wall and axillae. Arterial blood gas shows PaO2 of 58 mmHg. The most likely diagnosis is:
- A Thromboembolic pulmonary embolism
- B Fat embolism syndrome ✓
- C Transfusion-related acute lung injury
- D Hospital-acquired pneumonia
Correct answer: B. Fat embolism syndrome
Explanation
Fat embolism syndrome presents 24 to 72 hours after long-bone fractures with the classic triad of respiratory distress, cerebral symptoms, and a petechial rash in a non-dependent distribution such as the chest and axillae, plus hypoxemia. Pulmonary embolism typically occurs later, lacks petechiae, and produces pleuritic pain. Petechiae result from fat globules occluding dermal capillaries and are the discriminating clinical feature here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.