Endocrine Abstracts

Introduction/Background

Sarcoidosis is a multi-system inflammatory disease of unknown etiology, characterized by abnormal collection of inflammatory cells termed as granulomas. This disease usually involves lungs, skin, or lymph nodes, but can less commonly affect the eyes, liver, heart and brain. Neurological involvement is rare and appears in 5-10% of the cases. Neurosarcoidosis most frequently affects the cranial nerves, the hypothalamus and the pituitary gland. Hyponatremia has been found in some patients with sarcoidosis and few case reports can be found in the literature. We hereby present the case of a 52 year-old gentleman who was diagnosed with SIADH secondary to neurosarcoidosis and presented with severe symptomatic hyponatremia.

Case report

A 52-year old gentleman presented with worsening confusion, lethargy and poor sleep. He had background history of seizures previously diagnosed as epilepsy and was on different anti-epileptic medications. There were no focal signs of neurological involvement other than intermittent confusion and difficulty in organizational skills. He was found to have severe hyponatremia with concomitant serum hypo-osmolality. Anti-epileptic medications were revised in the context of SIADH, but computed tomography (CT) of thorax, abdomen and pelvis revealed mediastinal and hilar lymphadenopathy with normal liver parenchyma. His serum angiotensin converting enzyme (ACE) levels were high, however; calcium levels were within normal range. He had mild hyperprolactinemia with slightly low thyroid stimulating hormone (TSH) and oestradiol levels. Magnetic resonance imaging (MRI) of his brain revealed features consistent with neurosarcoidosis and electroencephalogram (EEG) showed epileptiform activity likely secondary to the same disease. He underwent endobronchial ultrasound biopsy of the mediastinal lymph nodes that showed non-caseating granulomas thus confirming the diagnosis of sarcoidosis.

Treatment/Outcome

Patient was started on oral steroids, tab prednisolone 1 mg/kg body weight with fluid restriction. His sodium levels started improving with improvement in his clinical symptoms. He was advised follow-up in endocrinology and neurology clinics.

Conclusion

This case report highlights that SIADH presenting with severe hyponatremia can be an initial presentation of neurosarcoidosis. Sarcoidosis should be considered in the differential diagnoses of SIADH and hyponatremia.

Keywords: hyponatremia, granuloma, sarcoidosis, inflammation.