Endocrine Abstracts

Case History: We present a very interesting and challenging case of a 71-year-old male, with a significant medical history including Bipolar affective disorder, drug-induced parkinsonism, benign prostatic hyperplasia (BPH), and hypothyroidism. The admission was prompted by a catheter-associated urinary tract infection and subsequent hypernatremia secondary to lithium induced Diabetes Incipidus. Despite initial therapeutic interventions, such as amiloride therapy, the patient continued to manifest symptoms of polyuria and polydipsia. Sepsis and altered consciousness necessitated his transfer to a level 1 care facility. The management of fluid balance proved arduous given the intricate interplay of his comorbidities and the inherent challenges posed by lithium-induced nephrogenic DI.

Investigations: Upon admission, comprehensive investigations revealed a serum osmolality of 332 mmol and a urine osmolality of 180 mmol, indicative of nephrogenic DI. Concurrently, the patient experienced recurrent infections, further complicating the clinical scenario.

Results and Treatment: Despite the implementation of therapeutic modalities such as amiloride and thiazides aimed at managing nephrogenic DI, the patient’s polyuria persisted, necessitating a trial of Desmopressin therapy. Desmopressin demonstrated efficacy in reducing urine output. Given the persistent challenges with fluid homeostasis compounded by recurrent infections and hypernatremia, the decision was made to initiate hydration via a radiologically inserted gastrostomy (RIG) tube. This approach facilitated consistent fluid intake and yielded improvements in renal function.

Conclusions and Points for Discussion: In conclusion, the management of nephrogenic DI in this patient presented formidable challenges exacerbated by the presence of complex comorbidities, notably bipolar affective disorder. Despite diligent efforts to optimize fluid balance through interventions such as desmopressin and oral hydration, the patient’s clinical course was marked by protracted hospitalization and eventual discharge to a nursing home with comprehensive instructions for ongoing community-based management. This case underscores the critical importance of a multidisciplinary approach in navigating the intricate terrain of fluid and electrolyte imbalances, particularly in individuals grappling with psychiatric and renal comorbidities. Furthermore, it’s worth noting that individuals receiving lithium carbonate commonly develop nephrogenic DI, for which there exists no universally effective and practical treatment. However, emerging evidence suggests that large doses of desmopressin (DDAVP) may offer effective therapy with minimal adverse effects. Understanding the partial resistance to antidiuretic hormone (ADH) in most patients with nonhereditary AVP-R sheds light on the potential efficacy of supraphysiologic hormone levels in augmenting kidney response to ADH.