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42. Diabetes Insipidus in Children
1. Bugubaeva Makhabat Mitalipovna
2. Mohammed Sidan Sadique
(1. HOD Clinical Disciplines-2, Associate Professor, International Medical Faculty, Osh State University, Osh, Kyrgyzstan.
2. Student, International Medical Faculty, Osh State University, Osh, Kyrgyzstan.)
Abstract
Diabetes Insipidus (DI) in children is a rare but significant endocrine disorder characterized by the excretion of abnormally large volumes of dilute urine and excessive thirst. The condition results from either a deficiency of antidiuretic hormone (ADH, vasopressin) or the kidney’s inability to respond to it. This review provides a comprehensive overview of the types, causes, clinical presentation, diagnostic methods, treatment strategies, and prognosis of diabetes insipidus in the pediatric population. Early recognition and proper management are crucial to prevent dehydration, growth retardation and other major long-term complications.
Introduction
Diabetes insipidus (DI) is a disorder of water balance characterized by the inability of the kidneys to concentrate urine, resulting in polyuria and polydipsia. It differs fundamentally from diabetes mellitus, as it is unrelated to insulin or blood glucose metabolism. The global incidence of DI in children is approximately 1 in 25,000, with central (neurogenic) DI being the most common type. Early diagnosis in childhood is essential to prevent dehydration and physical and cognitive developmental delays (Mayo Clinic, 2024).
Classification and Pathophysiology
Diabetes insipidus is broadly classified into four types based on the underlying mechanism:
1. Central (Neurogenic) DI – caused by a deficiency in the synthesis or secretion of antidiuretic hormone (ADH) from the hypothalamus or posterior pituitary gland.
2. Nephrogenic DI – results from renal insensitivity to ADH despite adequate or elevated levels of the hormone.
3. Dipsogenic (Primary Polydipsia) – caused by excessive fluid intake due to a defect in the thirst mechanism located in the hypothalamus.
4. Gestational DI – rare in children, but seen in pregnancy due to placental vasopressinase activity degrading ADH.
Pathophysiologically, ADH acts on the collecting ducts of the kidney to increase water reabsorption. In central DI, there is inadequate ADH secretion, while in nephrogenic DI, the collecting ducts fail to respond appropriately, leading to massive loss of free water and hypernatremia.
Etiology and Risk Factors
The causes of diabetes insipidus in children vary depending on its type:
- Central DI: Common causes may include genetic mutations (AVP-NPII gene), traumatic brain injury, neurosurgery, central nervous system tumors (such as craniopharyngioma), infections (meningitis, encephalitis), or autoimmune destruction of ADH-producing cells.
- Nephrogenic DI: Usually results from certain mutations in the AVPR2 gene (X-linked recessive) or AQP2 gene (autosomal). Secondary causes may include chronic kidney disease, hypercalcemia, hypokalemia, or exposure to nephrotoxic agents such as lithium.
- Dipsogenic DI: May arise from certain psychiatric disorders or hypothalamic dysfunction affecting thirst regulation.
Risk factors may include a family history of endocrine disorders, CNS infections, and prior cranial surgery or irradiation.
Clinical Features
The hallmark symptoms of DI are polyuria and polydipsia. Affected children may excrete 5–10 liters of urine per day depending on age and water intake. Infants often present with irritability, poor feeding, vomiting, fever, and failure to thrive on their daily lives. Older children exhibit nocturia, enuresis, dehydration, and preference for cold water. Severe dehydration can lead to hypernatremia, lethargy, seizures, and, in extreme cases, coma.
Diagnosis
Diagnosis of diabetes insipidus in children requires a combination of clinical assessment, laboratory evaluation, and imaging studies. Key diagnostic steps may include:
- Measurement of urine output and osmolality (low in DI, typically <300 mOsm/kg).
- Serum sodium and osmolality (usually elevated).
- Water deprivation test to distinguish between central, nephrogenic, and primary polydipsia.
- Desmopressin (DDAVP) response test: Improvement in urine concentration after DDAVP indicates central DI, whereas no response suggests nephrogenic DI.
- MRI of the brain and pituitary gland to assess hypothalamic or pituitary lesions.
Differential Diagnosis
Differential diagnoses may include uncontrolled diabetes mellitus, psychogenic polydipsia, chronic renal failure, hypercalcemia, and hypokalemia. Distinguishing features are the absence of glucosuria and hyperglycemia in DI, as well as persistently low urine osmolality despite dehydration in the patient.
Treatment and Management
The primary goal of treatment is to prevent dehydration and maintain normal fluid and electrolyte balance in the body.
- Central DI: Desmopressin (DDAVP), a synthetic analog of vasopressin, is the drug of choice. It can be administered intranasally, orally, or parenterally. Regular monitoring of serum sodium is essential to avoid water intoxication.
- Nephrogenic DI: Management may include low-salt and low-protein diet, thiazide diuretics (e.g., hydrochlorothiazide), and nonsteroidal anti-inflammatory drugs (e.g., indomethacin) to reduce urine output. Adequate water intake must be ensured.
- Dipsogenic DI: Behavioral and psychiatric therapy may be indicated in psychogenic cases.
Children with secondary DI due to tumors or infections should receive treatment directed at the underlying cause.
Complications and Prognosis
Without appropriate management, diabetes insipidus can cause severe dehydration, electrolyte imbalances, growth failure, and cognitive developmental delay. Long-term use of DDAVP generally provides good control and allows normal growth and cognitive development. Prognosis is excellent for idiopathic or genetic forms when diagnosed early and managed properly.
Prevention and Follow-up
Prevention strategies include avoiding nephrotoxic drugs in at-risk children, early identification of familial cases, and regular monitoring of children with hypothalamic or pituitary lesions. Follow-up care should include growth tracking, physical and cognitive developmental assessment, and periodic evaluation of serum electrolytes and renal function.
Conclusion
Diabetes insipidus in children, though rare, can lead to life-threatening dehydration if it goes undiagnosed. Early recognition, accurate differentiation between central and nephrogenic forms, and tailored therapy with desmopressin or supportive measures are vital for favorable outcomes. Continuous follow-up and family education will play crucial role in ensuring optimal growth and quality of life for the affected children.
References
1. Mayo Clinic. (2024). Diabetes insipidus - Symptoms and causes. https://www.mayoclinic.org/
2. National Institutes of Health (NIH). (2023). Diabetes Insipidus Overview. https://www.niddk.nih.gov/
3. Verbalis, J. G., et al. (2023). Disorders of water balance in children. Pediatric Nephrology, 38(5), 1187–1204.
4. Bichet, D. G. (2024). Central and nephrogenic diabetes insipidus. New England Journal of Medicine, 390(2), 145–158.
5. World Health Organization (WHO). (2024). Pediatric Endocrine Disorders: Global Overview. https://www.who.int/
