Diabetes Insipidus: A Pragmatic Approach to Management

Lithium-Induced Arginine Vasopressin Resistance (AVP-R): A Case of Chronic Exposure to Lithium

Lithium salts (lithium) is a psychotropic drug widely used as a pharmacological option in managing bipolar disorder. Regular monitoring of serum levels is necessary due to the narrow therapeutic range of lithium. Typically, the diagnosis of lithium intoxication is based on the presence of elevated plasma levels. Nevertheless, poisoning can ensue from either acute ingestion or chronic use, even in patients with normal plasma levels. The utilization of lithium has been decreasing due to its potential for multiorgan toxicity. Lithium accumulation in renal distal tubular cells is a prevalent cause of acquired arginine vasopressin resistance (AVP-R), previously known as nephrogenic diabetes insipidus (DI). Some patients might also experience neurologic persistent symptoms after plasma level normalization, a condition known as the syndrome of irreversible lithium-effectuated neurotoxicity (SILENT). We present a case report of acquired AVP-R following prolonged lithium use. This case report aims to increase awareness, particularly among those who may be unfamiliar with the use of lithium and its associated adverse reactions. In addition, it seeks to highlight the dissociation between clinical manifestations and lithium plasma levels, emphasizing the need for careful evaluation in patients receiving lithium treatment.

Evaluation and management of hypernatremia in adults: clinical perspectives

Hypernatremia is an occasionally encountered electrolyte disorder, which may lead to fatal consequences under improper management. Hypernatremia is a disorder of the homeostatic status regarding body water and sodium contents. This imbalance is the basis for the diagnostic approach to hypernatremia. We summarize the eight diagnostic steps of the traditional approach and introduce new biomarkers: exclude pseudohypernatremia, confirm glucose-corrected sodium concentrations, determine the extracellular volume status, measure urine sodium levels, measure urine volume and osmolality, check ongoing urinary electrolyte free water clearance, determine arginine vasopressin/copeptin levels, and assess other electrolyte disorders. Moreover, we suggest six steps to manage hypernatremia by replacing water deficits, ongoing water losses, and insensible water losses: identify underlying causes, distinguish between acute and chronic hypernatremia, determine the amount and rate of water administration, select the type of replacement solution, adjust the treatment schedule, and consider additional therapy for diabetes insipidus. Physicians may apply some of these steps to all patients with hypernatremia, and can also adapt the regimens for specific causes or situations.

Diabetes insipidus: A rare endocrine complication of immune check point inhibitors: A case report and literature review

Immune checkpoint inhibitors (ICIs), including anti-programmed cell death protein 1 (PD-1), anti-programmed cell death protein ligand 1 (PD-L1) and anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) monoclonal antibodies, are novel therapeutic agents widely used in numerous malignancies. They are known to cause multiple immune-related endocrine adverse events (irAEs); however, anterior pituitary hypophysitis with secondary hypopituitarism is the most frequently reported irAE, especially in patients receiving anti-CTLA-4 treatment. By contrast, posterior pituitary involvement, such as central diabetes insipidus (CDI), is relatively rare and only few case reports have been published. The present report describes the case of a 53-year-old woman with metastatic melanoma treated with nivolumab an anti-PD-L1 monoclonal antibody. At 6 months after the initiation of nivolumab treatment, the patient was diagnosed with deficiency of the corticotrope and thyreotrope axes and in the following 2 months the patient was diagnosed with progressive development of polyuria-polydipsia syndrome. The diagnosis of partial CDI was retained based on plasma and urinary osmolalities, the water deprivation test and baseline copeptin levels as well as on the absence of the bright spot in the posterior pituitary in magnetic resonance imaging. Systematic research of the literature revealed a total of 13 cases reports (including 14 patients) presenting with CDI treated with monotherapy with CTLA-4 (n=5) or PD-1/PD-L1 Abs (n=6) or combined treatments (n=3). The improved understanding of the mechanisms of ICI action along with their extensive use should contribute to the early recognition of irAE symptoms. We hypothesized that clinicians should be aware of this clinical entity and its symptoms and treat it appropriately.

Severe Hypernatremia in a Significantly Underweight Female Child

In this study, we present the case of a 5-year-old female who presented for evaluation of dehydration with labs that revealed significant hypernatremia concerning for diabetes insipidus (DI). Further evaluation revealed that she had underlying chronic malnutrition. Her diagnostic work up for DI produced some evidence consistent with DI while other data indicated otherwise, bringing up the possibility of partial DI. She was ultimately diagnosed with sporadic vasopressin release secondary to her chronic malnutrition. This case illustrates another effect chronic malnutrition can have on pediatric patients along with the importance of a broad differential for patients with severe hypernatremia.

Nephrogenic diabetes insipidus in children (Review)

Nephrogenic diabetes insipidus (NDI) is characterized by impaired urinary concentrating ability, despite normal or elevated plasma concentrations of the antidiuretic hormone, arginine vasopressin (AVP). NDI can be inherited or acquired. NDI can result from genetic abnormalities, such as mutations in the vasopressin V2 receptor (AVPR2) or the aquaporin-2 (AQP2) water channel, or acquired causes, such as chronic lithium therapy. Congenital NDI is a rare condition. Mutations in AVPR2 are responsible for approximately 90% of patients with congenital NDI, and they have an X-linked pattern of inheritance. In approximately 10% of patients, congenital NDI has an autosomal recessive or dominant pattern of inheritance with mutations in the AQP2 gene. In 2% of cases, the genetic cause is unknown. The main symptoms at presentation include growth retardation, vomiting or feeding concerns, polyuria plus polydipsia, and dehydration. Without treatment, most patients fail to grow normally, and present with associated constipation, urological complication, megacystis, trabeculated bladder, hydroureter, hydronephrosis, and mental retardation. Treatment of NDI consist of sufficient water intake, low-sodium diet, diuretic thiazide, sometimes in combination with a cyclooxygenase (COX) inhibitor (indomethacin) or nonsteroidal anti-inflammatory drugs (NSAIDs), or hydrochlorothiazide in combination with amiloride. Some authors note a generally favorable long-term outcome and an apparent loss of efficacy of medical treatment during school age.