Cerebral fat embolism syndrome mimicking thrombotic thrombocytopenic purpura in a patient with hemoglobin SC disease

Fat Embolism Syndrome Mimicking Thrombotic Thrombocytopenic Purpura in a Patient With Hemoglobin S/Beta-Thalassemia

Thrombotic microangiopathies cause ischemic organ damage and require urgent management for a favorable prognosis. Fat embolism syndrome from bone marrow necrosis is a rare and unique pathology that carries a high mortality rate. It can mimic thrombotic microangiopathies such as thrombotic thrombocytopenic purpura (TTP). Herein, we present a patient with sickle cell-beta-thalassemia who initially presented with a vaso-occlusive crisis, lab evidence of hemolysis, schistocytes and thrombocytopenia who developed acute encephalopathy with respiratory distress, consistent with TTP. She was found to have multiple infarcts in the brain. She was intubated and underwent plasma and red cell exchange. Bone marrow biopsy confirmed marrow necrosis from her vaso-occlusive crisis and subsequently, fat embolism syndrome. Here, we discuss the complex presentation and the complications of fat embolism from bone marrow necrosis and how it can mimic TTP.

A Rare Case of Progressive Encephalopathy in a Sickle Cell Trait Patient: A Case Report

Fat embolism syndrome (FES) is one of the underdiagnosed and underrecognized complications that can happen in multiple medical and surgical conditions. FES can manifest in a broad spectrum of signs and symptoms and affect multiple organ systems in the human body. One of the most commonly involved is the central nervous system (CNS), mainly the brain, which can be involved in different ways, and the presenting symptoms can vary in type and severity. One of the most common causes of FES is trauma, mainly a long bone fracture or any orthopedic injury. However, one of the rare causes of FES is sickle cell disease (SCD) and thalassemia. Generalized and vague presenting symptoms, the rarity of FES, and the absence of well-defined diagnostic criteria make it a challenging diagnosis for healthcare practitioners. FES diagnosis is usually made after having a high index of suspicion in patients with underlying risk factors that can precipitate and contribute to the pathophysiology of FES. Moreover, the diagnosis is usually reached after excluding other more common and treatable conditions.

Rare, fatal pulmonary fat embolism after acupuncture therapy: A case report and literature review

BACKGROUND

Death from nontraumatic pulmonary fat embolism associated with minor soft tissue contusion, surgery, cancer chemotherapy, hematologic disorders and so on has been reported. Patients often present with atypical manifestations and rapid deterioration, making diagnosis and treatment difficult. However, there are no reported cases of death from pulmonary fat embolism after acupuncture therapy. This case emphasizes that the stress induced by acupuncture therapy, a mild soft tissue injury, plays an important role in pulmonary fat embolism. In addition, it suggests that in such cases, pulmonary fat embolism as a complication of acupuncture therapy needs to be taken seriously, and autopsy should be used to identify the source of fat emboli.

CASE PRESENTATION

The patient was 72 years old female and experienced dizziness and fatigue after silver-needle acupuncture therapy. She experienced a significant drop in blood pressure and died 2 h later despite treatment and resuscitation. A systemic autopsy and histopathology examination (H&E and Sudan Ⅲ staining) were performed. More than 30 pinholes were observed in the lower back skin. Focal hemorrhages were seen surrounding the pinholes in the subcutaneous fatty tissue. Microscopically, numerous fat emboli were observed in the interstitial pulmonary arteries and alveolar wall capillaries, in addition to the vessels of the heart, liver, spleen and thyroid gland. The lungs showed congestion and edema. The cause of death was identified as pulmonary fat embolism.

CONCLUSION

This article suggests that high vigilance for risk factors and the complication of pulmonary fat embolism following silver-needle acupuncture therapy should be exercised. In postmortem examinations, it should be pay attention that the peripheral arterial system and the venous system draining from non-injured sites should be examined for the formation of fat emboli, which can help distinguish posttraumatic and nontraumatic pulmonary fat embolism.

Pitfalls in Diagnosing Thrombotic Thrombocytopenic Purpura in Sickle Cell Disease

Thrombotic thrombocytopenia purpura is characterised by microangiopathic haemolytic anaemia and red cell fragmentation on the peripheral smear, neurological involvement and thrombocytopenia. Diagnosis in the context of sickle cell disease can be challenging due to the inherent haemolytic state and the multitude of other associated complications of the latter. Specifically, fat embolism syndrome characterised by respiratory failure, neurological impairment and thrombocytopenia can be misdiagnosed this way. Confirmation of a diagnosis of thrombotic thrombocytopenic purpura requires demonstration of very low levels (<10%) of the metalloproteinase ADAMTS13 which in fat embolism syndrome is normal. Existing scoring systems used to estimate the pre-test probability for thrombotic thrombocytopenic purpura cannot be applied in patients with sickle cell disease due to the chronic underlying haemolysis. Here, we analyse the diagnostic approach in published cases of thrombotic thrombocytopenic purpura affecting patients with sickle-cell disease. The vast majority of cases were characterised by severe respiratory failure before any other manifestation, a feature of fat embolism syndrome but not of thrombotic thrombocytopenic purpura, and all received red cell transfusion prior to receiving therapeutic plasma exchange. Despite the potential overestimation of the pre-test probability using the existing scoring systems, a large number of cases still scored low. There were no cases with documented low ADAMTS13. In the majority this was not tested, while in the 3 cases that ADAMTS13 was tested, levels were normal. Our review suggests that due to many overlapping clinical and laboratory features thrombotic thrombocytopenic purpura may be erroneously diagnosed in sickle cell disease instead of other complications such as fat embolism syndrome and confirmation with ADAMTS13 testing is essential.

Coma secondary to cerebral fat embolism syndrome due to sickle cell disease fully recovering following red cell exchange transfusion

A 51-year-old woman known for sickle cell disease presented with 2 weeks of headache and bilateral lower limb pain. During admission, she suffered from multiple generalised tonic-clonic seizures but had an unremarkable CT of the brain. Incidentally, she had worsening baseline renal function. She was admitted to the intensive care unit with an acute confusional state. A bedside electroencephalogram showed triphasic waves and diffuse slow activity suggestive of encephalopathy with no epileptiform discharges. She remained obtunded despite appropriate medical therapy of hydration, antiepileptic and pain control. Lumbar puncture failed to identify an infectious cause. An urgent MRI of the brain was done and revealed features compatible with fat embolism syndrome (FES). Her haemoglobin S was 84.2%. Urgent red cell exchange transfusion was done, and within 3 days she fully regained her orientation and motor function. This represents the first case of such profound obtundation due to FES with a complete response to exchange transfusion.

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.

Nontraumatic Multiple-Organ Fat Embolism: An Autopsy Case and Review of Literature

The patient was an 88-year-old woman with a 10-year history of hypertension. She was suspected to have been hit by a car. At the time of the event, she was conscious and able to stand on her own and had no obvious injuries. She was sent home, but she lapsed into unconsciousness and was nonresponsive after 2 hours. She was sent to the hospital, and her heartbeat and breathing stopped. After half an hour of rescue attempts, her heartbeat did not recover, and she was declared dead. During the autopsy, a small subcutaneous hemorrhage was observed below the right knee joint. No obvious internal organ injuries or bone fractures were observed. The deceased also had mild atherosclerosis in the coronary arteries and an old cerebral infarction in the right cerebellum. The tissue histopathological tests showed distinct fat embolism in multiple organs, including the brain, lungs, kidneys, liver, and pancreas. A postmortem blood biochemistry test of the heart blood showed that the levels of low-density lipoprotein, cholesterol, triglycerides, and free fatty acids in the blood were increased, and the level of C-reactive protein was elevated. According to the autopsy results, the direct cause of death was multiorgan fat embolism. This case suggests that aging, hypertension, and hyperlipidemia may be risk factors for nontraumatic fat embolism under stressful conditions.

Fat Embolism Syndrome in Sickle Cell Disease

Fat embolism syndrome is a devastating complication of sickle cell disease resulting from extensive bone marrow necrosis and associated with high mortality rates, while survivors often suffer severe neurological sequelae. Despite that, the syndrome remains under-recognised and under-diagnosed. Paradoxically, it affects exclusively patients with mild forms of sickle cell disease, predominantly HbSC and HbSβ⁺. A significant number of cases occur in the context of human parvovirus B19 infection. We provide here a brief summary of the existing literature and describe our experience treating 8 patients in our institution. One patient had HbSS, 6 HbSC and 1 HbSβ⁺. All patients developed type I respiratory failure and neurological involvement either at presentation or within the first 72 h. The most striking laboratory abnormality was a 100-fold increase of the serum ferritin from baseline. Seven patients received emergency red cell exchange and 1 simple transfusion. Two patients (25%) died, 2 patients (25%) suffered severe neurological impairment and 1 (12%) mild neurological impairment on discharge, while 3 (38%) patients made a complete recovery. With long-term follow-up, 1 patient with severe neurological impairment and one patient with mild neurological impairment made dramatic improvements, making the long-term complete recovery or near complete recovery rate 63%. Immediate red cell exchange transfusion can be lifesaving and should be instituted as soon as the syndrome is suspected. However, as the outcomes remain unsatisfactory despite the increasing use of red cell exchange, we suggest additional therapeutic measures such as therapeutic plasma exchange and pre-emptive transfusion for high risk patients.

Neurologic recovery in systemic nontraumatic fat embolism syndrome in an elderly patient with hemoglobin SC disease: A case report

Cerebral fat embolism syndrome is an under-recognized yet well-known complication of bone marrow necrosis occurring in patients with sickle cell disease. We highlight a case manifested by multisystem organ failure in an elderly patient who attained neurologic recovery with prompt initiation of hematology consultation, RBC exchange, and supportive measures.

Posttraumatic subarachnoid fat embolism: Case presentation and literature review

Fat embolism in the subarachnoid space has a unique pathophysiology and clinical picture when compared to fat embolism syndrome. Lipid deposits in the subarachnoid space-most commonly the sequela of dermoid rupture in the neuraxis-can cause an inflammatory reaction leading to irritation of nearby neurovascular structures. Herein, we report the only case in the United States, to our knowledge, of a patient diagnosed with subarachnoid fat emboli secondary to sacral fracture who initially presented with a normal head CT and subsequently developed visual changes.

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.

An autopsy case of non-traumatic fat embolism syndrome

Fat embolism syndrome (FES) occurs after long bone fractures and the symptoms appear 24-72 h after the initial trauma. Fat emboli can affect both the pulmonary and systemic circulation. Apart from the most common type of FES that originates from bone fracture, non-traumatic FES has been also reported. We have experienced an autopsy case of non-traumatic FES. An 81-year-old man with hepatocellular carcinoma associated with alcoholic liver cirrhosis suddenly lost consciousness before transcatheter arterial chemoembolization treatment for his disease and died 5 h after the episode. At autopsy, numerous fat droplets were detected in the alveolar capillaries of the lung and glomerular capillaries of the kidney. Lipid analysis of lung autopsy specimens by thin-layer chromatography showed that the emboli were composed mainly of tristearin. Free fatty acids (FFA) has been considered to be the main component of fat emboli and can be a cause of acute respiratory distress syndrome (ARDS). However, in the present case, the lung specimen contained tristearin and ARDS did not occur. This is the first report of non-traumatic FES in which lipid analysis of human autopsy specimens has been conducted.