Wed3November0844PM 9

A 45-year-old publican is admitted to hospital having sustained comminuted fractures of the left femur and tibia. There are no other apparent injuries. Later that day, following surgical fixation, he becomes aggressive and confused.

His temperature is 37.6°C, pulse rate 110 beats per minute, BP 130/80 mmHg and respiratory rate 25 breaths per minute. He is breathing 45% oxygen and his SpO2 is 90%.

What is the most likely cause?

(Please select 1 option)

Head injury

Sepsis

Venous thromboembolism

Alcohol withdrawal syndrome Incorrect answer selected

Fat embolism This is the correct answer

Explanation

The history and clinical features of this case suggest fat embolism syndrome. Fat embolism syndrome is a clinical diagnosis secondary to the presence of fat globules in the lung parenchyma and circulation that are typically released following long bone fractures. It requires high index of suspicion and usually presents 12-72 hours after initial injury.

There is a classic triad of:

Respiratory changes - Dyspnoea, tachypnoea and hypoxaemia are early findings. These may progress to respiratory failure and ARDS requiring mechanical ventilation.

Neurological features - Cerebral emboli produce neurological signs in up to 86% cases. They often occur after onset of respiratory symptoms, with a wide spectrum ranging from mild confusion and drowsiness to seizures. Usually there is an acute confusional state with or without focal signs. Most neurological deficits are transient and reversible.

Petechial rash - This is the final component of the triad to develop and occurs in 60% of cases. Rash is seen in the conjunctiva, mucous membranes, skin folds of upper body particularly neck and axilla, appearing within the first 36 hours.

Patients may also develop:

pyrexia

tachycardia

ECG changes (ST segment depression and right heart strain)

fluffy retinal exudates

coagulopathy, and

renal changes (oliguria, lipiduria, proteinuria or haematuria).

The neurological symptoms might fit with alcohol withdrawal but the patient is unlikely to have the pyrexia and respiratory symptoms. Likewise, the development of sepsis, venous thromboembolism and the deterioration of a head injury do not fit with the clinical scenario.

Answer Statistics

1

1%

2

3%

3

4%

4

9%

5

85%

Times answered: 280