A Case of Central Diabetes Insipidus Secondary to Neurosarcoidosis

We present a case of central diabetes insipidus (DI) secondary to neurosarcoidosis. The path to final diagnosis was challenging. Along with reporting the case, we review the available medical literature relating to neurosarcoidosis and central diabetes insipidus in this case report. Patient is a 56-year-old female with notable history of rheumatoid arthritis, anxiety, asthma, hypertension, spinal stenosis, and seizures of unknown etiology who presented to the emergency department for worsening headache for one week. She also endorsed decreased vision, photophobia, nausea, vomiting, gait abnormality, polyuria, and polydipsia over the past three months. Physical exam and neurological exam were unremarkable. Labs on presentation were notable for hypernatremia, increased serum osmolality and urine output of 5 L/day. Given her persistent headache and history of seizure, she underwent a CT head without contrast which showed a posterior suprasellar soft tissue fullness measuring 6 mm in the hypothalamic region. She then had additional imaging studies of the brain including MRI brain w/wo contrast and MRI pituitary w/wo contrast. MRI of the brain showed enlarged optic chiasm with increased T2 signal involving the proximal optic nerves and bilateral optic tracts, no brain parenchymal lesions to suggest multiple sclerosis. MRI of the pituitary w/wo contrast showed suprasellar mass arising from either the hypothalamus or less likely the chiasm which was concerning for high-grade glioma initially. Lumbar puncture was done that showed lymphocytic pleocytosis. Patient underwent right supraorbital craniotomy for biopsy of the suprasellar lesion. Surgical pathology showed noncaseating granulomatous inflammation most consistent with neuro-sarcoidosis. The diagnosis of neurosarcoidosis was made and patient was started on high dose steroids. Although central DI can be seen as a post-op complication, in our case, based on the clinical presentation, labs and imaging, there was concern of central DI on initial presentation. Patient was started on desmopressin 50 mg twice a day which resulted in marked improvement in urine output, serum sodium, and osmolality. Although it is rare to have nervous system involvement of sarcoidosis, symptoms of central diabetes insipidus could represent the first clinical manifestations of neurosarcoidosis. Proper treatment should be initiated in a timely fashion to avoid complications such as hydrocephalus.