**12. Pulmonary**

It is uncommon to develop FES in the absence of respiratory manifestations. A great majority of patients present with varying degrees of respiratory insufficiency that can range from nearly asymptomatic hypoxemia to severe hypoxemia and ARDS requiring mechanical

Non-Thrombotic Pulmonary Embolism 83

al., 1973; Peltier, 1984; Peltier, 1988). Elevation of ESR & CRP, presence of fat globules in the urine, sputum or blood, elevation of serum lipase and phospholipase A2 have been

Presence of lipid inclusions in alveolar macrophages in the BAL has been associated with various traumatic and nontraumatic conditions, especially aspiration pneumonia and lipid infusion. Quantification of cells containing fat droplets in bronchial alveolar lavage (BAL) fluid within the first 24 hours after trauma have also been shown to correlate with clinical fat embolism in some studies ) (Al-Khuwaitir et al., 2002; Chastre et al., 1990; Mellor & Soni, 2001; Mimoz et al., 1995). In the absence of an exogenous source of fat, BAL fluid that contains more than 30% macrophages laden with lipid inclusions is highly suggestive

The findings are nonspecific and appear after a variable lag period as related to clinical symptoms. Chest roentgenogram may reveal diffuse evenly distributed alveolar and interstitial densities suggestive of pulmonary edema or acute lung injury. Computed tomography (CT) of the chest may rarely show fat in the pulmonary artery. Multiple subcentimeter, ill-defined centrilobular and subpleural nodules can be seen in the acute phase of FES. Diffuse lung calcifications located in the branches of the pulmonary arteries have been described in the late course of FES (Hamrick-Turner et al., 1994). Ventilation perfusion

Computed tomography (CT) of the brain may show nonspecific signs of cerebral edema and hemorrhagic infarcts in multiple areas (Meeke et al., 1987). Magnetic resonance imaging (MRI) of the brain and MR spectroscopy seem to be the most sensitive method in detection of cerebral emboli, but nonspecific (J. J. Chen et al., 2008; Eguia et al., 2007; Guillevin et al., 2005; Sasano et al., 2004; Satoh et al., 1997; Stoeger et al., 1998). Diffusion-weighted imaging may reveal bright spots on a dark background, a finding known as the ''Starfield pattern'' (Parizel et al., 2001). Cerebral micro-emboli can be detected in vivo after long bone fracture

Transesophageal Echo (TEE) is most useful for diagnosing intra-operative FES. TEE has sensitivity of 80% and specificity of 100% in patients with fat embolism large enough to cause hemodynamic instability (Pruszczyk et al., 1997). TEE cannot reliably distinguish fat

Given the extremely heterogeneous pattern of presentation, precise diagnosis of FES remains elusive. Various diagnostic criteria have been proposed. However given the lack of gold standard diagnostic tests and lack of pathognomic signs, it is difficult to determine validity of these criteria. Therefore the diagnosis of FES is based on a constellation of clinical and laboratory findings and exclusion of other potential diagnoses (Taviloglu & Yanar,

scan (V/Q scan) may reveal subsegmental perfusion defects (H. M. Park et al., 1986).

by transcranial Doppler (Barak et al., 2008; Forteza et al., 1999).

The following diagnostic criteria are widely used.

described.

of FES.

**18. Imaging** 

emboli from tumor emboli.

**19. Diagnosis** 

2007).

**17. Role of bronchial alveolar lavage (BAL)** 

ventilation (Bernard et al., 1994). The most "fulminant" form of FES presents as "acute cor pulmonale" with respiratory failure causing death within a matter of few hours, usually after a major trauma (Mellor & Soni, 2001; Parisi et al., 2002; Peltier, 1984; Schonfeld et al., 1983). Although frequently clinically inapparent, hypoxemia is nearly universal (Peltier et al., 1974; A. P. Ross, 1970).
