fat emboli syndrome can manifest as shock and nonconvulsive seizure

This patient has fat embolism syndrome (FES) complicated by shock and nonconvulsive status epilepticus (NCSE). In FES, bone marrow (or other source of fat particles) is displaced into the circulation by long-bone fracture, orthopedic surgery, sickle cell crisis, or even cosmetic surgery that involves withdrawal or injection of fat. FES is associated with direct endothelial injury and microvascular occlusion, as well as systemic inflammatory changes.

Clinically, FES often manifests with hypotension, neurological dysfunction, and rash. In severe cases, pulmonary vascular resistance increases, which may lead as in this case to right ventricular cardiogenic shock. The clips from transthoracic echocardiography show right heart failure, with some evidence of impingement of the right ventricle on the left ventricle (the D-shaped septum on the parasternal short axis view) and decreased right ventricular systolic function on the apical 4-chamber view.

The neurological dysfunction observed in FES is common, but it is rarely associated with coma. Occasionally, CT scans of the brain may demonstrate findings of FES, but in most cases CT scanning is not explanatory, as was true in this patient. Given the disproportionate encephalopathy, the presence of coma in this patient is not fully or easily explained by the FES. This raises the possibility that further workup for impaired consciousness may be indicated. In the setting of the ICU, EEG has been proposed as an important diagnostic tool in the evaluation of impaired consciousness. While substantial debates appropriately quibble over the formal diagnostic criteria for NCSE, a substantial number of ICU patients with coma of unknown cause have NCSE. NCSE can complicate a wide range of brain injuries, including FES and shock. While no randomized controlled trials have administered placebo to patients in NCSE, this probably reflects ethical consensus rather than an important gap in scientific knowledge. It is widely considered appropriate to treat NCSE when it is present, given known neurotoxicities of status epilepticus. EEG to exclude NCSE is therefore the best answer, as it will allow establishment of the diagnosis of NCSE, as well as subsequent treatment (choice B is correct).

There is no specific treatment for FES, so although hemodialysis to remove bone marrow particles seems relevant to the actual diagnosis, dialysis cannot achieve the stated goal (choice A is incorrect). While the patient is at risk for low-flow brain injury from her hemodynamic embarrassment related to right heart failure, there is no immediate change in treatment associated with the diagnosis (choice C is incorrect). Modafinil has been associated with some synchronization of circadian rhythms but is something that would be undertaken only after establishment of a diagnosis as part of a rehabilitation plan (choice D is incorrect).1234

Footnotes

  1. SEEK Questionnaires ↩

  2. Kinney MO, Kaplan PW. An update on the recognition and treatment of non-convulsive status epilepticus in the intensive care unit. Expert Rev Neurother. 2017;17(10):987-1002. PubMed ↩

  3. Morales-Vidal SG. Neurologic complications of fat embolism syndrome. Curr Neurol Neurosci Rep. 2019;19(3):14. PubMed ↩

  4. Sutter R, Semmlack S, Kaplan PW. Nonconvulsive status epilepticus in adults - insights into the invisible. Nat Rev Neurol. 2016;12(5):281-293. PubMed ↩