MON-245 Brain Fog: An Important Cue to Neurosarcoidosis and Its Flare-Up?

Introduction: Sarcoidosis is a multisystem inflammatory disorder characterized by noncaseating granulomas in various organ systems, mainly the lung and lymphatic system. Neurosarcoidosis (NS) involving central or peripheral nervous system is uncommon and Hypothalamic-pituitary (HP) NS is rarer. Case: A 45-years-old African American man presented with a few days’ history of cognitive slowness (brain fog) and a sense of loss of direction. He was discharged a few months ago from another hospital after being admitted for shortness of breath and hypercalcemia of 13 mg/dl, which improved after hydration. CXR showed mediastinal and bilateral hilar enlargement. He was discharged home with outpatient pulmonary appointment but was readmitted to our hospital with altered mental status. Calcium level on this admission was 11.5 mg/dl. CT brain showed a sellar/suprasellar lesion, which was better visualized on MRI as enlargement and enhancement of pituitary gland, pituitary stalk, optic chiasm, left and right optic tract and nerves, and hypothalamus. He had left hemi-temporal field defect. Work up revealed inappropriately high normal 1,25 vitamin D, low PTH, PTrp and vitamin D. He has anterior hypopituitarism and mildly elevated prolactin. EBUS with mediastinal lymph node biopsy was non-diagnostic, however, excisional biopsy of mediastinal node showed non-caseating granuloma. ACE level, flow cytometry, infectious work up and serum IgG4 were normal. Discussion: NS may present as cranial nerve palsy, chronic headache with incidental HP mass and endocrine dysfunction such as diabetes insipidus, hyperprolactinemia, and anterior hypopituitarism. Visual deficits from optic atrophy or neuropathy; or change in vision from anterior uveitis are present in 41% of patients. Other non-specific presentations of NS include fatigue, cognitive difficulties (brain fog), such as impaired memory, slowed thinking, diminished attention and concentration. Hypercalcemia in sarcoidosis is due to increased intestinal absorption of calcium from increased 1,25 OH vitamin D. Though definitive diagnosis of NS is based on evidence of non-caseating granulomas from neural tissue, probable diagnosis can be made from clinical and radiologic characteristics, non-caseating granulomas at an extraneural site with no evidence of alternative disease. Steroid is the mainstay of treatment in NS and requires slow tapering. Other immunomodulators can be considered in worsening disease or patients with steroid adverse effect. Conclusion: Diagnosis of NS is challenging due to its rarity and difficult access to neural tissue for diagnosis. Though brain fog may not be specific for NS or its flare-up, additional neurological test or imaging should be considered especially in African American patients with hilar lymphadenopathy as 20% of NS patients may simply present with non-specific cognitive or behavioral complaints. ​