Abstract: PUB092
A Curious Case of "Thirstless" Hypernatremia
Session Information
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Authors
- Gurumurthy, Vaishnavi, Trinitas Regional Medical Center, Elizabeth, New Jersey, United States
- Iqbal, Abiha, Trinitas Regional Medical Center, Elizabeth, New Jersey, United States
- Nadeem, Shahrukh, Trinitas Regional Medical Center, Elizabeth, New Jersey, United States
- McAnally, James F., Trinitas Regional Medical Center, Elizabeth, New Jersey, United States
Introduction
Adipsic diabetes insipidus is a rare, life-threatening condition marked by impaired thirst and reduced AVP levels, usually due to hypothalamic damage. We report a young woman with known AVP deficiency who presented with severe hypernatremia (serum osmolality 390 mOsm/kg) and complete absence of thirst for the first time. MRI brain showed no hypothalamic lesions, raising suspicion for an autoimmune process involving antibodies against vasopressin-producing cells as the underlying cause.
Case Description
A 26-year-old woman with a known history of AVP deficiency presented with right foot pain. Initial laboratory testing revealed profound hypernatremia (serum sodium 167 mmol/L) and elevated serum osmolality (390 mOsm/kg). Despite these findings, she denied any sensation of thirst. Urine studies showed an osmolality of 845 mOsm/kg, sodium 36 mmol/L, potassium 78.3 mmol/L, chloride 18 mmol/L, protein 179 mg/dL, and creatinine 218 mg/dL. On physical examination, she appeared clinically euvolemic. MRI of the brain revealed no structural abnormalities of the hypothalamus or pituitary region. There was no history of trauma, surgery, radiation, or congenital anomalies. Her desmopressin regimen was reinitiated, and she was managed with scheduled oral fluid intake. Over time, serum sodium gradually normalized; however, her adipsia persisted. She was discharged with outpatient follow-up in the endocrinology clinic.
Discussion
We report a patient with an established diagnosis of AVP deficiency who, for the first time, exhibited a complete absence of thirst on presentation—despite previous episodes of hypernatremia. Thirst is primarily regulated by osmoreceptors located in the anterior hypothalamus, particularly within the organum vasculosum of the lamina terminalis (OVLT), a circumventricular structure highly sensitive to plasma osmolality 1 . In most reported cases of adipsia, damage to this region—due to tumor, inflammation, trauma, or congenital malformation—is detectable on imaging 2 . In our patient, the absence of any radiological abnormalities raises the possibility of functional impairment of hypothalamic osmoreceptors, potentially due to an autoimmune process. Existing literature describes cases involving autoantibodies against vasopressin cells, and it has been hypothesized that molecular or receptor-level damage may impair chemoreceptor responsiveness to hypernatremia 2-4 , resulting in a dangerous dissociation between serum osmolality and thirst perception.