Question

12 yr old Child admitted to ICU with blunt trauma and femur fracture - \(Pa_{O_2}\) 60% despite 100% \(O_2\) and rebreather mask, CXR shows lung fields clear but the patient remains confused. What is most likely the diagnosis ?

• A. Pulmonary contusion.
• B. Fat embolism syndrome.
• C. Hypovolaemic shock.
• D. Pulmonary embolism.

Answer 1

The Correct Option is B

The patient is a 12-year-old child with blunt trauma and a femur fracture, presenting with \(Pa_{O_2}\) of 60% despite being on 100% \(O_2\), and a clear CXR. This condition indicates hypoxemia that is not due to lung parenchymal damage, as the chest X-ray is clear. The persistent confusion is an additional symptom. Considering these clinical details, the most likely diagnosis is Fat Embolism Syndrome (FES).

• Fat Embolism Syndrome (FES): This condition often follows fractures of long bones, like the femur, leading to fat globules entering the bloodstream and lodging in pulmonary capillaries, causing respiratory distress without lung infiltrate on imaging. Neurological changes, such as confusion, are typical due to cerebral involvement.
• Pulmonary Contusion: Typically results in opacities on a chest X-ray, which contrasts with the clear lung fields observed here.
• Hypovolaemic Shock: Would present with low blood pressure and tachycardia, explanations not given explicitly in the scenario.
• Pulmonary Embolism: While it could cause hypoxemia, it is less likely related to bone fracture directly compared to FES.

Thus, the symptoms of hypoxemia, confusion, and recent fracture without radiographic evidence of lung consolidation strongly suggest Fat Embolism Syndrome is the most likely diagnosis.