Diagnosis
Diagnosis often follows a process of elimination. Diagnostic criteria for FES are wide in the literature but none is routinely used in practice.15 Most accepted are the modified Gurd’s criteria.14 When using modified Gurd’s criteria, the chance of underdiagnosis is greater, however fat droplets could be found in many patients in lab results without any clinical significance.
In 1983 Schonfeld proposed a clinical score. He assigned scores to seven clinical signs. A cumulative score >5 is required for a diagnosis of FES. 15 (Table 1) Several other scoring systems were still proposed but all these criteria are based on small series and none of them are validated on prospective studies.
Arterial blood gas analysis will show hypoxia along with the presence of hypocapnia. Thrombocytopenia, anaemia and hypofibrinogenemia are seen in FES but are all nonspecific findings. ECG is usually non-specific, but ECG changes can be detected if FES leads to myocardial necrosis.
On chest radiography bilateral pulmonary infiltrates, fleck-like pulmonary shadows (snowstorm appearance) are seen.
High-resolution Computed Tomography (CT) shows patchy ground glass opacities and consolidation with intralobular thickening. The extent of the CT findings is well correlated with the disease severity.15
POCUS (Point-of-care ultrasound) may aid to establish the diagnosis. Few recent case reports have described that transthoracic echocardiography (TTE) can detect fat emboli, seen as flowing hyperechoic particles in inferior vena cava.16
Brain CT is mostly normal or may reveal diffuse white matter petechial haemorrhages consistent with microvascular injury.
Bronchoalveolar lavage may also aid in the diagnosis, although fat in the lungs is nonspecific and can be seen in multiorgan failure and sepsis.