Fat Embolism - Signs and Symptoms

Signs and Symptoms

A thorough knowledge of the signs and symptoms of the syndrome and a high index of suspicion are needed if the diagnosis is to be made. An asymptomatic latent period of about 12–48 hours precedes the clinical manifestations. The fulminant form presents as acute cor pulmonale, respiratory failure, and/or embolic phenomena leading to death within a few hours of injury.

Clinical fat embolism syndrome presents with tachycardia, tachypnea, elevated temperature, hypoxemia, hypocapnia, thrombocytopenia, and occasionally mild neurological symptoms.

A petechial rash that appears on the upper anterior portion of the body, including the chest, neck, upper arm, axilla, shoulder, oral mucous membranes and conjunctivae is considered to be a pathognomonic sign of FES, however, it appears late and often disappears within hours. It results from occlusion of dermal capillaries by fat, and increased capillary fragility.

CNS signs, including a change in level of consciousness, are not uncommon. They are usually nonspecific and have the features of diffuse encephalopathy: acute confusion, stupor, coma, rigidity, or convulsions. Cerebral edema contributes to the neurologic deterioration. Hypoxemia is present in nearly all patients with FES, often to a Pa02 of well below 60 mmHg. Arterial hypoxemia in these patients has been attributed to ventilation-perfusion inequality and intrapulmonary shunting. Acute cor pulmonale is manifested by respiratory distress, hypoxemia, hypotension and elevated central venous pressure.

The chest X-ray may show evenly distributed, fleck-like pulmonary shadows (Snow Storm appearance), increased pulmonary markings and dilatation of the right side of the heart.