Super-refractory nonconvulsive status epilepticus secondary to fat embolism: A clinical, electrophysiological, and pathological study

Microbleeds show a characteristic distribution in cerebral fat embolism

This systematic review aims to test the hypothesis that microbleeds detected by MRI are common and show a characteristic pattern in cerebral fat embolism (CFE). Eighty-four papers involving 140 CFE patients were eligible for this review based on a systematic literature search up to 31 January 2020. An additional case was added from hospital records. Patient data were individually scrutinised to extract epidemiological, clinical and imaging variables. Characteristic CFE microbleed pattern resembling a "walnut kernel" was defined as punctuate hypointensities of monotonous size, diffusely located in the subcortical white matter, the internal capsule and the corpus callosum, with mostly spared corona radiata and non-subcortical centrum semiovale, detected by susceptibility- or T2* weighted imaging. The presence rate of this pattern and other, previously described MRI markers of CFE such as the starfield pattern and further diffusion abnormalities were recorded and statistically compared. The presence rate of microbleeds of any pattern, the "walnut kernel microbleed pattern", diffusion abnormality of any pattern, the starfield pattern, and cytotoxic edema in the corpus callosum was found to be 98.11%, 89.74%, 97.64%, 68.5%, and 77.27% respectively. The presence rate between the walnut kernel and the starfield pattern was significantly (p < 0.05) different. Microbleeds are common and mostly occur in a characteristic pattern resembling a "walnut kernel" in the CFE MRI literature. Microbleeds of this pattern in SWI or T2* MRI, along with the starfield pattern in diffusion imaging appear to be the most important imaging markers of CFE and may aid the diagnosis in clinically equivocal cases.

Fat Embolism Syndrome - A Qualitative Review of its Incidence, Presentation, Pathogenesis and Management

Fat Embolism Syndrome (FES) is a poorly defined clinical phenomenon which has been attributed to fat emboli entering the circulation. It is common, and its clinical presentation may be either subtle or dramatic and life threatening. This is a review of the history, causes, pathophysiology, presentation, diagnosis and management of FES. FES mostly occurs secondary to orthopaedic trauma; it is less frequently associated with other traumatic and atraumatic conditions. There is no single test for diagnosing FES. Diagnosis of FES is often missed due to its subclinical presentation and/or confounding injuries in more severely injured patients. FES is most frequently diagnosed using the Gurd and Wilson criteria, like its rivals it is not clinically validated. Although FES is a multi-system condition, its effects in the lung, brain, cardiovascular system and skin cause most morbidity. FES is mostly a self-limiting condition and treatment is supportive in nature. Many treatments have been trialled, most notably corticosteroids and heparin, however no validated treatment has been established.

Extremely Acute-Onset Cerebral Fat Embolism

Cerebral fat embolism (CFE) causes the neurological involvement observed in fat embolism syndrome, which is a post-traumatic complication seen mostly after long bone fractures and usually presents 24–72 h after the injury. An early 80s female who sustained an isolated traumatic fracture of the left distal femur without dislocation was alert on admission but fell into a coma 55 min after the injury. Brain computed tomography showed no abnormalities. Brain magnetic resonance imaging was performed approximately 5 h after the accident, and diffusion-weighted images revealed hyperintense, dot-like lesions disseminated in a “starfield” pattern in the brain. The patient was diagnosed with CFE and admitted to the intensive care unit. The day after the injury, the patient developed petechiae on the palpebral conjunctiva and was still comatose 4 months after the trauma. The current patient developing CFE in less than 1 h after a traumatic injury illustrates that CFE should be considered in patients with sudden deterioration of consciousness within 1 h after long bone fractures.

Use of Newer Anticonvulsants for the Treatment of Status Epilepticus

Status epilepticus (SE) has a high mortality rate and is one of the most common neurologic emergencies. Fast progression of this neurologic emergency and lack of response to traditional antiepileptic drugs (AEDs) in most cases has challenged clinicians to use new agents. This article evaluates the efficacy and safety of AEDs released to the market after 2000 for SE, refractory status epilepticus (RSE), and super-refractory status epilepticus (SRSE). The PubMed database was searched for clinical trials published between January 2000 and July 2018 using the search terms status epilepticus, refractory status epilepticus, super refractory status epilepticus, brivaracetam, clobazam, cannabidiol, eslicarbazepine, lacosamide, perampanel, rufinamide, stiripentol, and zonisamide. Trials that evaluated these agents in adults with SE, RSE, and SRSE were included. Brivaracetam use was identified in two retrospective reviews with success rates of 27% and 57%. One unsuccessful case report of cannabidiol use in SE was found. Four clobazam studies were identified in SE and RSE with success rates ranging from 25-100%. No evidence for the use of eslicarbazepine and zonisamide was found. Using the search terms for lacosamide identified 38 articles: 1 systematic review, 5 prospective studies, 15 retrospective reviews, and 17 case reports. Success rates and dosing varied, but studies that included focal or partial types of SE showed higher success rates. Five articles were identified regarding perampanel use in this setting. Three were retrospective reviews with success rates ranging from 17-60%, and two were case reports. Only one case report regarding the use of rufinamide was found; rufinamide titrated up to 4.4 mg/day allowed discontinuation of barbiturate and clobazam. One case report and two case series of stiripentol were found with reported efficacy between 60% and 100% in SRSE. Evidence is currently insufficient to support the use of these agents in this setting.

From the diagnosis to the therapeutic management: cerebral fat embolism, a clinical challenge

Cerebral fat embolism (CFE) is an uncommon incomplete type of fat embolism syndrome (FES), characterized by purely cerebral involvement. It usually occurs 12-72 hours after the initial trigger, mainly represented by closed, long-bone multiple fractures of the lower extremities. Neurological manifestations are mainly characterized by headache, confusion, seizures, focal deficit, and alteration of the consciousness state up to coma onset. It represents a diagnostic challenge, above all when secondary to uncommon nontraumatic causes, because neurological signs and symptoms are variable and nonspecific, not satisfying the Gurd and Wilson's criteria, the diagnostic features most widely used today for FES diagnosis. Neuroimaging (mainly MRI, but in some cases, brain computed tomography too) can hasten the diagnosis, avoiding other unnecessary investigations and treatment. Usually self-limiting, CFE may sometimes be fatal. Treatment is to date mainly supportive and prophylactic strategies are considered an important tool to decrease the development of fat embolism and, consequently, the rate of CFE.

Fat Embolism and Nonconvulsive Status Epilepticus

Fat embolism syndrome (FES) typically occurs following orthopedic trauma and may present with altered mental status and even coma. Nonconvulsive status epilepticus is an electroclinical state associated with an altered level of consciousness but lacking convulsive motor activity and has been reported in fat embolism. The diagnosis is clinical and is treated with supportive care, antiepileptic therapy, and sedation. A 56-year-old male presented with altered mental status following internal fixation for an acute right femur fracture due to a motor vehicle accident 24 hours earlier. Continued neuromonitoring revealed nonconvulsive status epilepticus. Magnetic resonance imaging of the brain showed multiple bilateral acute cerebral infarcts with a specific pattern favoring the diagnosis of fat embolism syndrome. He was found to have a significant right to left intracardiac shunt on a transesophageal echocardiogram. He improved substantially over time with supportive therapy, was successfully extubated on day 6, and discharged to inpatient rehabilitation on postoperative day 15. Fat embolisms can result in a wide range of neurologic manifestations. Nonrefractory nonconvulsive status epilepticus that responds to antiepileptic drugs, sedation, and supportive therapy can have a favorable outcome. A high index of suspicion and early recognition reduces the chances of unnecessary interventions and may improve survival.

Unexpected good outcome in severe cerebral fat embolism syndrome

In this case study, we report the longitudinal and multimodal follow-up of a catastrophic initial presentation of cerebral fat embolism syndrome. We show that despite the initial severity, the cognitive outcome was ultimately very good but with a highly nonlinear time-course and prolonged loss of consciousness (more than 2 months). Repeated clinical assessments and brain-imaging techniques (electroencephalography, event-related potential, ¹⁸-Fluoro-Deoxy-Glucose-PET and magnetic resonance imaging) allowed us to monitor and anticipate this dynamic, providing relevant information to guide decision making in front of withdrawal of life-sustaining therapy discussions. This case illustrates the value of multimodal functional imaging in devastating brain injuries.

Perioperative management of massive fat embolism syndrome presenting as refractory status epilepticus

Fat embolism syndrome (FES) most commonly can occur after trauma in patients with long bone fractures. While the majority of FES cases present as a mild decrease in mental status, some may manifest as seizure activity. We describe a case of a young patient with traumatic fractures who developed FES leading to refractory status epilepticus and simultaneously required damage controlled orthopedic surgery. The role of imaging modalities including magnetic resonance imaging, transcranial Doppler, and transesophageal echocardiography in diagnosis is discussed, and a multidisciplinary approach to successful perioperative management is described.

Lacosamide in status epilepticus: Systematic review of current evidence

OBJECTIVE

The intravenous formulation of lacosamide (LCM) and its good overall tolerability and safety favor the use in status epilepticus (SE). The aim of this systematic review was to identify and evaluate studies reporting on the use of LCM in SE.

METHODS

We performed a systematic literature search of electronic databases using a combined search strategy from 2008 until October 2016. Using a standardized assessment form, information on the study design, methodologic framework, data sources, efficacy, and adverse events attributed to LCM were extracted from each publication and systematically reported.

RESULTS

In total, 522 SE episodes (51.7% female) in 486 adults and 36 children and adolescents were evaluated with an overall LCM efficacy of 57%. Efficacy was comparable between use in nonconvulsive (57%; 82/145) and generalized-convulsive (61%; 30/49; p = 0.68) SE, whereas overall success rate was better in focal motor SE (92%; 34/39, p = 0.013; p < 0.001). The efficacy with later positioning of LCM decreased from 100% to 20%. The main adverse events during treatment of SE are dizziness, abnormal vision, diplopia, and ataxia. Overall, lacosamide is well tolerated and has no clinically relevant drug-drug interactions.

SIGNIFICANCE

The available data regarding the use of LCM in SE are promising, with a success rate of 57%. The strength of LCM is the lack of interaction potential and the option for intravenous use in emergency situations requiring rapid uptitration.