Diabetes insipidus Diabetes insipidus (DI) refers to a group of syndromes characterized by varying degrees of deficiency in vasopressin or reduced sensitivity of the kidneys to vasopressin due to various reasons, leading to functional impairment of water reabsorption in the renal tubules. The former is known as central diabetes insipidus, while the latter is referred to as nephrogenic diabetes insipidus. Additionally, gestational diabetes insipidus occurs during late pregnancy and the short period after childbirth. Clinical features of this condition include polyuria, restlessness, extreme thirst, increased fluid intake, low urine specific gravity, and hypotonic urine.

Diabetes insipidus (DI) refers to a group of syndromes caused by varying degrees of deficiency in vasopressin or decreased sensitivity of the kidneys to vasopressin due to various reasons, leading to functional impairment of water reabsorption in the renal tubules. The former is known as central diabetes insipidus, while the latter is referred to as nephrogenic diabetes insipidus. Additionally, gestational diabetes insipidus occurs during late pregnancy and shortly after childbirth. The clinical features of this condition include polyuria, restlessness, extreme thirst, excessive water intake, low urine specific gravity, and hypotonic urine.

Central diabetes insipidus

Central diabetes insipidus is caused by various factors affecting the synthesis, transport, storage, and release of vasopressin. It can be categorized as acquired central diabetes insipidus, hereditary central diabetes insipidus, and idiopathic central diabetes insipidus.

Acquired (secondary) central diabetes insipidus: Approximately 50% of patients develop this condition due to tumors in the hypothalamic-pituitary region and nearby areas, such as craniopharyngioma, pineal gland tumors, tumors of the third ventricle, metastatic tumors, and granulomatous diseases such as Langerhans cell histiocytosis. Around 10% of cases are attributed to head trauma (severe head injury, surgery in the pituitary-hypothalamic region). Additionally, a small number of cases result from infectious diseases of the brain (meningitis, tuberculosis, syphilis), sarcoidosis or other granulomatous lesions, vascular disorders, and so on.

Hereditary central diabetes insipidus: A small percentage of cases have a family history and show autosomal dominant inheritance, caused by mutations in the arginine vasopressin-neurophysin II (AVP-NPII) gene. Additionally, there are cases of autosomal recessive hereditary, X-linked recessive hereditary diabetes insipidus, and Wolfram syndrome, although these are extremely rare.

Idiopathic central diabetes insipidus: Accounts for approximately 30% of cases, and no identifiable cause is found in clinical examinations. Research suggests a possible association with autoantibodies.

Nephrogenic diabetes insipidus

Nephrogenic diabetes insipidus can be classified as congenital nephrogenic diabetes insipidus and acquired nephrogenic diabetes insipidus:

Congenital nephrogenic diabetes insipidus: Caused by mutations in the vasopressin V2 receptor gene or aquaporin-2 gene.

Acquired nephrogenic diabetes insipidus: Resulting from factors such as medications (lithium preparations), hypercalcemia, and prolonged severe hypokalemia.

Furthermore, various kidney diseases, including relief of bilateral urinary obstruction, sickle cell disease, autosomal dominant polycystic kidney disease and medullary cystic kidney disease, renal amyloidosis, and Sjögren's syndrome, can lead to nephrogenic diabetes insipidus.

Gestational diabetes insipidus

Gestational diabetes insipidus occurs due to the placental production of N-terminal peptide enzyme (AVPase), which accelerates the degradation of vasopressin, leading to vasopressin deficiency. Symptoms appear during pregnancy and often subside several weeks after delivery.

The typical symptoms of diabetes insipidus include extreme thirst and excessive urination, often accompanied by hypotonic polyuria.

Depending on the severity of the condition, the 24-hour urine output of patients with diabetes insipidus can reach 4-10 liters, generally not exceeding 18 liters. Some patients with partial diabetes insipidus may experience milder symptoms, with a 24-hour urine output of only 2.5-5 liters. The urine color of patients is pale, with a urine specific gravity usually below 1.005, and urine osmolality typically ranging from 50-200 mOsm/(kg·H2O). Due to hypotonic polyuria, the thirst center in the hypothalamus is stimulated, leading to restlessness and extreme thirst, resulting in excessive water intake and a preference for cold drinks.

Children with diabetes insipidus also exhibit extreme thirst, excessive urination, equivalent intake and output of fluids, and pale, watery urine. If water intake is restricted, it can lead to dehydration, vomiting, constipation, fever, agitation, irritability, emotional instability, growth retardation, and even coma and death, requiring attention from parents. With adequate water intake, the general condition of the child can be normal, with no obvious signs.

Due to the presence of polyuria, sleep may be affected at night, leading to daytime fatigue. It is important to create a quiet and comfortable sleep environment to facilitate rest for the patient.

In cases of extreme thirst and excessive urination, appropriate drinking water should be provided, while avoiding excessive water intake.

For cases of restlessness, moderate exercise can be beneficial in maintaining good emotional well-being, and psychological counseling may be necessary when needed.

Exercise: Patients may experience restlessness, and moderate exercise can help alleviate this and maintain good emotional well-being.

Diet: Adjust sodium intake as per medical advice and ensure adequate nutritional intake.