Hypodipsic-hypernatremia syndrome in an adult with polycythemia: a case report

Hypodipsic hypernatremia after long-standing polydipsia in a cat with suspect neonatal head trauma

A 16-month-old neutered male domestic shorthair cat weighing 2.7 kg was referred for further evaluation of acute generalized muscle weakness and paraparesis after a long-standing history of polyuria-polydipsia. The diagnosis of hypodipsic/adipsic hypernatremia relied on the key findings of absent spontaneous drinking despite hypernatremia and a hyperosmolar state (444.8 mOsm/kg, reference interval 280 to 310 mOsm/kg). Brain MRI revealed severe multifocal anatomic anomalies of the rostral calvarium and the forebrain, suggestive of encephaloclastic porencephaly. Involvement of the thalamic and hypothalamic regions could have been responsible for the cat's adipsic hypernatremia. The unique aspects of this case were the rare description of central nervous system disease leading to hypodipsia, and the history of chronic polydipsia before the acute onset of hypodipsia. Key clinical message: Multifocal abnormalities of the forebrain can present with polyuria-polydipsia syndrome, hypodipsia/adipsia, or both, depending on the stage of the disease. This likely happens when the hypothalamic and thalamic regions are affected, since they regulate antidiuretic hormone release and thirst, respectively.

Recurrent Adipsic Hypernatremia in a Fully Independent Non-psychiatric Patient With Multiple Congenital Anomalies: A Case Report

Osmoregulation is a fundamental process of homeostasis that maintains metabolic and biochemical reactions, thermoregulation, and fluid-electrolytes balance. Fluid-electrolytes imbalance leads to various clinical manifestations ranging from mild weakness to severe neurological dysfunction. Adipsic hypernatremia is an exceedingly rare life-threatening condition characterized by defective osmoregulatory mechanisms. It is more often reported in patients with severe untreated psychiatric disorders for unknown etiologies, but it may result from congenital or acquired hypothalamic lesions in the form of stroke, neoplastic infiltration, trauma, or infection. Herein we report an unusual case of isolated hypernatremia in a fully independent non-psychiatric 27-year-old diabetic male with spina bifida, repaired cleft palate, and mild caudal regression syndrome.

Psychogenic Adipsia Presenting as Recurrent Functional Vomiting and Hypernatremia

Hypernatremia is caused by a disproportionate balance of inadequate free water relative to sodium level. Frequent causes of hypernatremia include renal or gastrointestinal fluid loss, hypothalamic injury, and endocrine abnormalities. The authors describe a rare case of hypernatremia that manifested secondary to psychogenic adipsia in a 46-year-old woman presenting with intractable vomiting. Her presenting symptoms and laboratory abnormalities resolved after treatment was initiated for major depression. This case highlights the need for a holistic approach when confronted with a case of unexplained hypernatremia.