Onset after the injury is variable, with a symptom free period ranging from a few hours to rarely over 72 hours.
Major criteria:
(1) petechial rash
(2) respiratory symptoms (hypoxia, cyanosis and/or tachypnea) AND bilateral signs AND positive radiographic changes (diffuse bilateral infiltrates)
(3) cerebral signs (delirium, restlessness, confusion, altered mental status) unrelated to head injury or any other condition
Minor criteria:
(1) tachycardia (> 110 beats per minute)
(2) pyrexia (body temperature > 38.5°C)
(3) retinal changes on fundoscopic examination (presence of petechiae and/or fat)
(4) urinary changes (anuria, oliguria and/or fat globules)
(5) sudden unexplained drop in hemoglobin level
(6) sudden unexplained drop in platelet count (sudden onset of thrombocytopenia)
(7) elevated erythrocyte sedimentation rate (ESR)
(8) presence of fat globules in the sputum
Diagnosis (from Androvulakis and Demetriades):
(1) at least 1 major criteria AND at least 3 minor criteria; Gurd used at least 4 minor criteria (top of page 733)
(2) at least 2 major criteria AND at least 2 minor criteria
Differential diagnosis:
(1) thromboembolism
(2) sepsis
Limitations:
• A small amount of fat embolization may be subclinical.
