Describe an unusual presentation of X-linked adrenoleukodystrophy (ALD) with cerebral edema and increase the awareness of brain edema and intracranial hypertension as a possible first sign of the disease.  

X-linked adrenoleukodystrophy (ALD) is a peroxisomal disorder with highly variable disease manifestations and disease severity. Here we describe a clinical case of a previously healthy teenager that presented to the hospital with acute vomiting, decreased mental status and possible seizures as a first manifestation of ALD. 

A previously healthy 18-year-old male presented with new onset headache, emesis, decreased mental status and possible seizures. Initial head CT showed brain edema with transtentorial herniation. Patient required intubation and admission to the neuro-ICU. He was empirically covered for viral and bacterial meningitis. Lumbar puncture showed intracranial hypertension with opening pressure of 35 cm of water. CSF analysis was normal. CT head venogram showed no evidence of cerebral venous thrombosis. EEG revealed severe diffuse encephalopathy without epileptiform activity. Patient received supportive treatment. Brain MRI later showed resolved brain edema and was overall normal. Given history of febrile seizures and unknown cause for brain edema, emergency whole genome sequencing was performed and showed a variant of unknow significance in the ABCD1 gene. ACTH was critically elevated, and patient was diagnosed with adrenal insufficiency. Very long fatty acid profile showed elevation of C26:0 with increased C26/C22 and C24/C22 ratios. Patient was diagnosed with X-linked ALD. He was treated for adrenal insufficiency and remains asymptomatic at 6 months follow up. 

X-linked adrenoleukodystrophy should be considered for a possible diagnosis of a male young patient with cerebral edema of unknown etiology. Cerebral edema in this context could be reversible and associated with excellent outcome. The mechanism of cerebral edema is unclear and may be related to glucocorticoid deficiency.