Diabetes insipidus

• Diabetes Insipidus is a disorder characterised by an inability to concentrate urine, leading to polyuria and polydipsia.
• Caused by either a deficiency of antidiuretic hormone (ADH) or a renal insensitivity to ADH.
• Divided into central (neurogenic) and nephrogenic types.

• Central DI is more common than nephrogenic DI.
• Affects males and females equally.
• Can occur at any age, but central DI often presents in childhood or young adulthood.
• Nephrogenic DI can be congenital or acquired.
• Rare condition overall.

Lack of ADH action leads to inability of kidneys to concentrate urine, resulting in excessive water loss and dehydration.

• Central DI: Caused by damage to the hypothalamus or pituitary gland, leading to ADH deficiency.
• Nephrogenic DI: Caused by renal insensitivity to ADH, often due to genetic mutations or drugs (e.g. lithium).
• Other causes include head trauma, tumours, infections, and autoimmune conditions.

• Polyuria (excessive urination).
• Polydipsia (excessive thirst).
• Nocturia (waking up at night to urinate).
• Dehydration.
• Fatigue.
• Headache.
• Dry skin and mucous membranes.

• Signs of dehydration (e.g., dry mucous membranes, reduced skin turgor).
• Hypotension.
• Tachycardia.
• Hypernatraemia (if fluid intake is inadequate).
• Low urine osmolality.
• High serum osmolality.
• Large volumes of dilute urine.

• Water deprivation test (to differentiate between central and nephrogenic DI).
• Desmopressin (DDAVP) test.
• Serum electrolytes and osmolality.
• Urine osmolality.
• MRI of the brain (to identify pituitary or hypothalamic pathology).
• Genetic testing (if congenital nephrogenic DI is suspected).
• 24-hour urine volume measurement.

• Central DI: Desmopressin (DDAVP) replacement therapy.
• Nephrogenic DI: Thiazide diuretics, low-salt diet, and NSAIDs.
• Adequate hydration to prevent dehydration.
• Monitor serum sodium and osmolality regularly.
• Treat underlying cause if identified (e.g. tumour removal).
• Patient education on condition management and emergency measures.

• Dehydration and electrolyte imbalances.
• Hypernatraemia.
• Hypotension.
• Kidney damage (if chronic and untreated).
• Severe dehydration can lead to shock.
• Increased risk of urinary tract infections.
• In rare cases, death if not managed appropriately.

• With proper treatment, patients can lead normal lives.
• Lifelong treatment is often necessary for central DI.
• Prognosis for nephrogenic DI depends on the underlying cause.
• Regular monitoring and patient compliance with therapy are crucial.
• Patient education on fluid management and medication use is essential.
• Complications can be minimised with appropriate treatment.

• Diabetes insipidus is characterised by polyuria and polydipsia due to ADH deficiency or insensitivity.
• Differentiation between central and nephrogenic DI is essential for appropriate management.
• Management includes hormone replacement, lifestyle changes, and treatment of underlying causes.
• Regular monitoring and patient education are critical to prevent complications.
• With proper management, patients can lead normal lives.