An unusual case of type I hyperlipidemia - infant with acute encephalopathy, bulging fontanel, vomiting and pink blood: a case report

Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder with heterogeneous presentation, where acute encephalopathy is rarely described in literature. Therefore, initial neurologic symptoms could make the diagnosis and treatment challenging.

Case presentation: A four-month-old male infant presented with acute encephalopathy, vomiting, bulging fontanel, decreased appetite and failure to thrive. He had extremely lipemic serum and anemia. Intracranial computed tomography (CT) revealed lipid collection which was suspected to be epidermoid cyst, and also lipid deposits with extra-axial and intravascular location. This was initially described as a ruptured intracranial epidermoid cyst with dissemination of lipid content, including intravascular dissemination. Together with clinical signs of raised intracranial pressure it was discussed whether the cyst should be surgically removed. Since the blood sample appearence was milky and the child was rather stable, surgery wasn't performed and the treatment with exchange transfusion (ET) was started immediately. Only after ET it was possible to obtain laboratory results including lipid status (triglycerides were 106.8 mmol/l). At that point we suspected that the underlining cause is a genetic disease. Three cycles of plasmapheresis followed ET, after which symptoms resolved almost completely, despite remaining lipid deposits on brain CT scan and brain ultrasound, with some signs of regression. After these repeated imaging studies, it was concluded that the 'cyst' was actually the largest brain lipid collection. The definitive genetic diagnosis confirmed FCS. A short course of insulin, antioxidants and fibrates was initially given, but discontinued after the diagnosis confirmation due to lack of supporting data in the literature. Effective and the only maintenance treatment was the diet consisting of formula low in fat and high in medium-chain triglycerides. On the discharge the infant's neurological status, except mild hypotonia, was normal, he was thriving well, had good appetite and no anemia.

Conclusions: This is a rare case of FCS presenting with neurological symptoms that mimicked the clinical picture of ruptured intracranial epidermoid cyst, which was initially the differential diagnosis of this case. Initial interpretation of imaging studies didn't delay treatment. With the right treatment, the symptoms of the disease could be reversible with satisfactory outcome.