Adipsic Diabetes Insipidus-The Challenging Combination of Polyuria and Adipsia: A Case Report and Review of Literature

When Thirst Ceases to Exist: A Case Report and Literature Review of Adipsic Diabetes Insipidus Following Coil Embolization of a Ruptured Anterior Communicating Artery Aneurysm

Diabetes insipidus is a condition characterized by inappropriately dilute urine in the setting of serum hyperosmolality. The two predominant subtypes include central (from lack of vasopressin production) and nephrogenic diabetes insipidus (from renal resistance to circulating vasopressin). A common manifestation is the significant pursuant thirst from excessive polyuria. We present a case report and literature review of an infrequent variation of central diabetes insipidus known as adipsic (hypothalamic) diabetes insipidus, characterized by the absence of thirst, secondary to coiling of a ruptured anterior communicating artery aneurysm. Due to the loss of thirst, patients are at a heightened risk for hypernatremia and complications secondary to dehydration. Our patient's course was complicated by recurrent polyuria and hypernatremia, requiring a fixed-dose desmopressin regimen. On follow-up, only partial thirst sensation was restored. We provide a literature review to compare our case report to the scant literature available to broaden the awareness of this infrequent, perilous, manifestation.

Persistent hypernatremia secondary to adipsic central diabetes insipidus in a patient with herpes-induced meningoencephalitis and COVID-19 infection: a case report

Central diabetes insipidus (CDI) typically manifests as a polyuria-polydipsia syndrome, in which normonatremia is generally maintained through the polydipsia. A 53-year-old woman presented with diabetic ketosis and hyperosmolar hyperglycemic syndrome. Her medical history included herpes meningoencephalitis, which was associated with confusion and amnesia. On physical examination, she was apyretic, confused, and had signs of extracellular dehydration. Her capillary glucose concentration was high and her urine was positive for ketones. Laboratory investigations revealed severe hyperglycemia, hypernatremia (plasma hyperosmolarity of 393.6 mOsm/L), and mild acute renal failure. In addition, she had a paucisymptomatic COVID-19 infection. Intravenous rehydration with isotonic saline solution and insulin therapy were effective at controlling the ketosis and ameliorating the hyperglycemia, but failed to normalize the hypernatremia and hyperosmolarity. She was not thirsty and had a urine output of 1 L/day, with urinary hypotonicity. Desmopressin administration reduced the hypernatremia and hyperosmolarity to within their normal ranges, and the patient's urinary osmolarity increased to 743 mOsm/L. Therefore, adipsic CDI was diagnosed. Endocrine investigations revealed isolated central hypothyroidism. The results of pituitary magnetic resonance imaging were normal. Thus, patients with impaired thirst may have an atypical presentation of CDI. In addition, the diagnosis of adipsic CDI is particularly challenging.

Clinical Characteristics of Adipsic Diabetes Insipidus

OBJECTIVE

Adipsic diabetes insipidus (ADI) is a life-threatening disease. It is characterized by arginine vasopressin deficiency and thirst absence. Data about clinical characteristics of ADI were scarce. This study investigated the clinical features of hospitalized ADI patients.

METHODS

A retrospective study was conducted of hospitalized ADI patients admitted to the Endocrinology Department of Huashan Hospital between January 2014 and December 2021, and compared with central diabetes insipidus (CDI) patients with normal thirst.

RESULTS

During the study period, there were a total of 507 hospitalized CDI patients, among which 50 cases were ADI, accounting for 9.9%. Forty percent of ADI patients were admitted due to hypernatremia, but there were no admissions due to hypernatremia in the control group. The lesions of ADI patients were more likely to be located in the suprasellar area (100% vs 66%, P < .05). Higher prevalence of hypothalamic dysfunction (76% vs 8%, P < .001), central hypothyroidism (100% vs 90%, P = .031), hyperglycemia (66% vs 32%, P < .001), dyslipidemia (92% vs 71%, P = .006), and hyperuricemia (64% vs 37%, P = .003) was found in the ADI group than in the control group. The proportions of hypernatremia were higher in the ADI group both at admission and at discharge (90% vs 8%, 68% vs 8%, respectively, both with P < .001), contributing to higher prevalence of complications, such as renal insufficiency, venous thrombosis, and infection.

CONCLUSION

ADI patients were found with higher prevalence of hypernatremia, hypopituitarism, hypothalamic dysfunction, metabolic disorders, and complications, posing a great challenge for comprehensive management.

Autoimmunity Related to Adipsic Hypernatremia and ROHHAD Syndrome

Specific antibody responses to subfornical organs, including Na_x antibody, have been reported in patients with adipsic hypernatremia of unknown etiology who do not have structural lesions in the hypothalamic–pituitary gland. The subfornical organ, also referred to as the window of the brain, is a sensing site that monitors sodium and osmotic pressure levels. On the other hand, ROHHAD syndrome is a rare disease for which the etiology of the hypothalamic disorder is unknown, and there have been some reports in recent years describing its association with autoimmune mechanisms. In addition, abnormal Na levels, including hypernatremia, are likely to occur in this syndrome. When comparing the clinical features of adipsic hypernatremia due to autoimmune mechanisms and ROHHAD syndrome, there are similar hypothalamic–pituitary dysfunction symptoms in addition to abnormal Na levels. Since clinical diagnoses of autoimmunological adipsic hypernatremia and ROHAD syndrome might overlap, we need to understand the essential etiology and carry out precise assessments to accurately diagnose patients and provide effective treatment. In this review, I review the literature on the autoimmune mechanism reported in recent years and describe the findings obtained so far and future directions.

Approach to the Pediatric Patient: Central Diabetes Insipidus

Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of disorders affecting the hypothalamic-posterior pituitary network. The differential diagnosis is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies, and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating congenital or acquired cerebral and pituitary stalk lesions. Pituitary stalk size at presentation could be normal, but it may change over time, depending on the underlying condition, while other brain areas or organs may become involved during follow-up. Early diagnosis and treatment are crucial to avoid central nervous system damage and germ cell tumor dissemination and to minimize complications of multiple pituitary hormone defects. We provide a practical update on the diagnosis and management of patients with CDI and highlight several pitfalls that may complicate the differential diagnosis of conditions presenting with polyuria and polydipsia. The need for a careful and close follow-up of patients with apparently idiopathic CDI is particularly emphasized because the underlying condition may be recognized over time. The clinical scenario that we outline at the beginning of this article represents the basis for the discussion about how the etiological diagnosis of CDI can be overlooked and demonstrates how a water intake and urine output improvement can be a sign of progressive damage of both hypothalamus and anterior pituitary gland with associated pituitary hormonal deficiencies.

Metabolic syndrome as a common comorbidity in adults with hypothalamic dysfunction

OBJECTIVE

Hypothalamic dysfunction (HD) results in various endocrine disorders and is associated with an increased risk of metabolic comorbidities. This study aimed to analyze the clinical characteristics and metabolic abnormalities of adults with HD of various causes.

METHODS

This study retrospectively reviewed adults with HD treated at our center between August 1989 and October 2020. Metabolic characteristics of patients were compared to those of age-, sex-matched lean, and body mass index (BMI)-matched controls.

RESULTS

Temperature dysregulation (61.0%) was the most common hypothalamic physiological dysfunction. At least one anterior pituitary hormone deficiency was observed in 50 patients (84.7%), with hypogonadotropic hypogonadism being the most frequently observed. Metabolic syndrome was confirmed in 31 patients (52.5%) and was significantly more prevalent in those with panhypopituitarism or overweight/obesity. Metabolic syndrome (MetS) was significantly more common in patients with HD than in both lean and BMI-matched controls (P < 0.001 and P = 0.030, respectively). Considering the components of MetS, elevated fasting glucose levels were significantly more common in patients with HD than in BMI-matched controls (P = 0.029). Overweight/obesity and panhypopituitarism were significant risk factors for MetS in the multivariate analysis on patients with HD. Moreover, in the multivariate analysis on patients and BMI-matched control, HD was a significant risk factor of MetS (P=0.035, OR 2.919) after adjusted for age, sex and BMI.

CONCLUSIONS

Temperature dysregulation and hypogonadotropic hypogonadism are the most common physiological and endocrine dysfunctions, respectively. MetS and unfavorable metabolic profiles were prevalent in adults with HD. HD was a significant risk factor of MetS after adjusted for BMI.

Analysis of water and electrolyte imbalance in a patient with adipsic hypernatremia associated with subfornical organ-targeting antibody

Patients with adipsic hypernatremia present with chronic hypernatremia because of defects in thirst sensation and dysregulated salt appetite, without demonstrable hypothalamic structural lesions. The involvement of autoantibodies directed against the sodium channel, Na_x in the subfornical organ (SFO) has recently been reported. However, the pathophysiology of water and electrolyte imbalance underlying the disease has yet to be elucidated. We describe the case of a 5-year-old boy who complained of headaches and vomiting that gradually worsened. Brain magnetic resonance imaging detected no abnormal lesions. Blood laboratory testing revealed a serum sodium (Na) concentration of 152 mmol/L and a serum osmolarity of 312 mOsm/L. His body weight had slightly decreased, and his thirst sensation was absent. His plasma vasopressin concentration was 0.9 pg/mL, despite the high serum osmolarity. He was encouraged to drink water, and oral 1-deamino-8-D-arginine-vasopressin was administered. When serum sodium concentrations were normalized, plasma vasopressin concentrations were apparently normal and ranged from 0.8 to 2.0 pg/mL. He did not present with polyuria at any time. Immunohistochemical study using mouse brain sections and the patient's serum revealed the deposition of human immunoglobulin G (IgG) antibody in the mouse SFO. In conclusion, our observations suggested that water and electrolyte imbalance in adipsic hypernatremia is characterized by a certain amount of vasopressin release regardless of serum sodium concentrations with no response to hyperosmolarity.