Syndrome of Inappropriate Antidiuretic Hormone Release as the Initial Presentation of Adenocarcinoma of the Colon

Abstract

Syndrome of inappropriate antidiuretic hormone release (SIADH) is a condition defined by the unsuppressed release of antidiuretic hormone (ADH) from the pituitary gland or nonpituitary sources or its continued action on vasopressin receptors. Of the many causes of SIADH, an important one includes tumours that secrete ADH. We describe a rare case of a patient with colonic adenocarcinoma presenting initially as SIADH. A 60-year-old man presented with confusion and vomiting. Over the previous month he had fatigue and loss of weight. Baseline investigations showed a low serum sodium level of 108mmol/l. He was euvolaemic on examination and fulfilled the criteria for SIADH. Further evaluation and imaging tests revealed that the patient had adenocarcinoma of the colon. It is remarkable that our patient did not present with any of the cardinal symptoms/signs suggestive of colorectal carcinoma including haematochezia, change in bowel habits or iron-deficiency anaemia. Initial therapy with hypertonic saline, fluid restriction and salt diet for management of SIADH was unsuccessful. Tolvaptan was added to the treatment regimen and the patient improved dramatically. Oncology consultation was initiated, and chemotherapy for the carcinoma was planned.

dDAVP Downregulates the AQP3-Mediated Glycerol Transport via V1aR in Human Colon HCT8 Cells

“…Abnormal release of AVP from the pituitary gland or nonpituitary sources causes the syndrome of inappropriate antidiuretic hormone secretion (SIADH), a condition characterized by water body deregulation and hyponatremia. SIADH has been associated with some forms of cancers including head and neck cancers, olfactory neuroblastomas, pancreatic neuroendocrine tumors, lymphoma, breast and colon cancers (Cabrijan et al, 1985;Gupta et al, 1986;Jayadeep et al, 2020;Navarro-Almenzar and Perianes, 2020;Li et al, 2021;Yasir and Mechanic, 2022). Importantly, several types of cancers express vasopressin receptors (VRs) that cause contrasting responses depending on receptor subtypes, their relative expression, and signaling (North et al, 1999;North, 2000;Heasley, 2001).…”