A Case of Neurosarcoidosis-Induced Syndrome of Inappropriate Secretion of Antidiuretic Hormone Diagnosed with Neuroendoscopy

Abstract

We treated a patient with neurosarcoidosis, which caused the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), in whom diagnosis was performed using neuroendoscopy. The patient was a 56-year-old female who was hospitalized for hyponatremia and diagnosed with SIADH based on a detailed examination. During the course, she developed impaired consciousness due to acute hydrocephalus, which improved after ventricular drainage. Head magnetic resonance imaging (MRI) confirmed nodular lesions at the floor of the third ventricle and the cerebral aqueduct. Neuroendoscopic biopsy led to the diagnosis of neurosarcoidosis. Her hyponatremia improved after steroid therapy. Neurosarcoidosis can cause SIADH, and complication of hydrocephalus may lead to a poor prognosis. Neuroendoscopy appears to be effective for the diagnosis of neurosarcoidosis with hydrocephalus and helps in deciding the treatment modality.

Hypothalamic-Pituitary Axis Dysfunction, Central Diabetes Insipidus, and Syndrome of Inappropriate Antidiuretic Hormone Secretion as the First Clinical Presentation of Neurosarcoidosis: Why Early Diagnosis and Treatment is Important?

“…Following nodular lesions discovered on MRI of the brain, neuroendoscopic evaluation and biopsy were ordered. The finding of non-caseating granulomas led to the final diagnosis of isolated neurosarcoidosis [15]. This study demonstrates how helpful neuroendoscopy can be in diagnosing and treating neurosarcoidosis-induced SIADH with concomitant hydrocephalus.…”

“…In all previously reported studies, a history of additional symptoms like erythema nodosum, uveitis, cough, and dyspnea, led to a more detailed investigation to determine the primary cause of SIADH [42,43]. MRI findings of the central nervous system included thickening of the floor of the third ventricle and meningeal enhancement [15,42]. Nevertheless, in one reported case, a patient diagnosed with SIADH and subsequently with hydrocephalus had no other symptoms associated with sarcoidosis.…”

“…The significant limitation of this study is that it included only four patients. Published cases over the last several years show that the initial manifestations of sarcoidosis may be panhypopituitarism, hyperprolactinemia, hypogonadotropic hypogonadism, thyrotropin dysfunction and amenorrhoea, hypothermia, syndrome of inappropriate antidiuretic hormone secretion (SIADH), and central diabetes insipidus (DI) [9,10,[12][13][14][15][16]. The diagnosis of neurosarcoidosis was delayed in a substantial number of cases.…”

“…The etiology of SIADH can include the ectopic release of ADH, adverse effects of different drugs, or various central nervous system disorders like infections, trauma, and neoplasia [39,40]. Interestingly, neurosarcoidosis, despite more frequently inducing deficiency of ADH, can also be a reason behind the excess production of ADH [15,[41][42][43]. Up to date, we were able to find only four studies in the literature describing sarcoidosis as a definitive cause of SIADH ( Table 2).…”

“…Inappropriate ADH secretion in a patient with systemic sarcoidosis [41] 1992 No SIADH as presenting feature in a male with coexisting sarcoidosis and systemic lupus [42] 2013 No A rare presentation of sarcoidosis with SIADH: a case report [43] 2016 No A case of neurosarcoidosis-induced syndrome of inappropriate secretion of ADH diagnosed with neuroendoscopy [15] 2018 No…”