Central adrenal insufficiency and diabetes insipidus misdiagnosed as severe depression

Adrenal Failure: An Evidence-Based Diagnostic Approach

The diagnosis of adrenal insufficiency (AI) requires a high index of suspicion, detailed clinical assessment including detailed drug history, and appropriate laboratory evaluation. The clinical characteristics of adrenal insufficiency vary according to the cause, and the presentation may be myriad, e.g. insidious onset to a catastrophic adrenal crisis presenting with circulatory shock and coma. Secondary adrenal insufficiency (SAI) often presents with only glucocorticoid deficiency because aldosterone production, which is controlled by the renin angiotensin system, is usually intact, and rarely presents with an adrenal crisis. Measurements of the basal serum cortisol at 8 am (<140 nmol/L or 5 mcg/dL) coupled with adrenocorticotrophin (ACTH) remain the initial tests of choice. The cosyntropin stimulation (short synacthen) test is used for the confirmation of the diagnosis. Newer highly specific cortisol assays have reduced the cut-off points for cortisol in the diagnosis of AI. The salivary cortisol test is increasingly being used in conditions associated with abnormal cortisol binding globulin (CBG) levels such as pregnancy. Children and infants require lower doses of cosyntropin for testing. 21-hydoxylase antibodies are routinely evaluated to rule out autoimmunity, the absence of which would require secondary causes of adrenal insufficiency to be ruled out. Testing the hypothalamic-pituitary-adrenal (HPA) axis, imaging, and ruling out systemic causes are necessary for the diagnosis of AI. Cancer treatment with immune checkpoint inhibitors (ICI) is an emerging cause of both primary AI and SAI and requires close follow up. Several antibodies are being implicated, but more clarity is required. We update the diagnostic evaluation of AI in this evidence-based review.

Central diabetes insipidus unmasked by corticosteroid therapy for cerebral metastases: beware the case with pituitary involvement and hypopituitarism

Patients with intra-cerebral metastases often receive glucocorticoids, particularly in the presence of peri-lesional vasogenic cerebral oedema. We present a case of presumptive lung carcinoma with cerebral metastases where central diabetes insipidus was unmasked after glucocorticoid administration and correction of undiagnosed central hypocortisolism.

Neurosarcoidosis-associated central diabetes insipidus masked by adrenal insufficiency

Central diabetes insipidus (CDI) is an infrequent complication of neurosarcoidosis (NS). Its presentation may be masked by adrenal insufficiency (AI) and uncovered by subsequent steroid replacement. A 45-year-old woman with a history of NS presented 2 weeks after abrupt cessation of prednisone with nausea, vomiting, decreased oral intake and confusion. She was diagnosed with secondary AI and intravenous hydrocortisone was promptly begun. Over the next few days, however, the patient developed severe thirst and polyuria exceeding 6 L of urine per day, accompanied by hypernatraemia and hypo-osmolar urine. She was presumed to have CDI due to NS, and intranasal desmopressin was administered. This eventually normalised her urine output and serum sodium. The patient was discharged improved on intranasal desmopressin and oral prednisone. AI may mask the manifestation of CDI because low serum cortisol impairs renal-free water clearance. Steroid replacement reverses this process and unmasks an underlying CDI.