Case Report: fat embolism syndrome

A previously healthy 18-year-old woman, Student, smoker of 2 P/Y, was injured in an accident with sledge on the 01.01.2016 (head against a wall). She was admitted to the Tappeiner Hospital of Meran (South Tirol) with a fracture of the left Femurs. She went in to the orthopaedic surgery correction of the fracture on the same day (TriGgen Nagel 10/36). Respiratory and hemodynamic status were stable.

1day after the accident, the patient's consciousness suddenly deteriorated. She became restless, confused, with tachypnea and tachycardia. The clinical appearance suggested an effect of the Morphine with quite normalisation of the symptoms after administration of the Narcan i.m.. No focal neurologic deficit observed. Toxicology screening were not been performed.

Blood gas analysis showed mild hypoxemia.

4 days after the patient went to the Intensive Care Unit, because a CT scan (requested for the doubt of pulmonary embolism) showed multiple lobar consolidation and infiltration and light pleural effusion. They were supposed as infiltrate/ARDS/alveolar haemorrhagic/ Else? The patient has suddenly deteriorated and supportive treatment was given, and minimal haemoglobin and platelet levels were monitored. A non-contrast CT scan of the brain showed no abnormalities while MRI of the brain showed multiple nodular or punctate foci in the white matter (mostly in the frontal subcortical white matter) On the DW-MRI trace images, with a b value of 1000 mm/s2, these lesions were seen as high signal intensity dots on a dark background. The diagnosis of cerebral fat emboli was proposed. Petechiae were not observered.

She became Oxygen, Steroid i.v. and Antibiotics with a rush normalisation of the clinical sign in a couple of days.

The patient was discharged from the hospital 21 days after the admission in normal clinical condition.

Discussion: The term fat embolism syndrome refers to a clinical entity that consists of pulmonary, central nervous system, and cutaneous manifestations. It is an uncommon, but potentially life-threatening, complication of long bone fractures. Hypoxia, deteriorating mental status, and petechiae are the main diagnostic criteria; secondary diagnostic signs include tachycardia, fever, anaemia, and thrombocytopenia. The incidence of fat embolism syndrome after bone fractures is in the range of 0.9% to 2.2%. The pathogenesis remains controversial, many theories have been proposed.

Many cases occur as subclinical events and remain undiagnosed.

Clinical diagnosis of cerebral fat embolism syndrome can be aided by noting the presence of respiratory failure, hypoxemia, and cutaneous petechiae.

Our case demonstrates that the addition of DW-MRI may enhance the sensitivity and specificity of the neuroradiological diagnosis by the presence of the starfield pattern of scattered bright spots on a dark background.

In conclusion, any non-head-injured trauma patient who is initially lucid and subsequently develops an acute mental status deterioration should undergo immediate evaluation for possible cerebral fat embolism or neck vessel injury.