Diabetes Insipidus

Definition

• Diabetes insipidus (DI) is caused by decreased secretion or action of arginine vasopressin (AVP), resulting in the production of abnormally large volumes of dilute urine.
  • 24-hour urine volume is > 50 mL/kg body weight.
  • Urine osmolarity is <>
• Neurohypophyseal DI is caused by deficient AVP secretion from the neurohypophysis (posterior pituitary).
• Nephrogenic DI is caused by defective AVP action to reabsorb water via the renal collecting tubules.

Causes of Diabetes Insipidus

Pituitary diabetes insipidus

• Acquired

Head trauma (closed and penetrating)

Neoplasms

• Primary

Craniopharyngioma

Pituitary adenoma (suprasellar)

Dysgerminoma

Meningioma

• Metastatic (lung, breast)

• Hematologic (lymphoma, leukemia)

Granulomas

Neurosarcoid

Histiocytosis

Xanthoma disseminatum

• Infectious

Chronic meningitis

Viral encephalitis

Toxoplasmosis

• Inflammatory

Lymphocytic infundibuloneurohypophysitis

Wegener's granulomatosis

Lupus erythematosus

Scleroderma

• Chemical toxins

Tetrodotoxin

Snake venom

Vascular

Sheehan's syndrome

Aneurysm (internal carotid)

Aortocoronary bypass

Hypoxic encephalopathy

Pregnancy (vasopressinase)

• Idiopathic

Congenital malformations

Septooptic dysplasia

Midline craniofacial defects

Holoprosencephaly

Hypogenesis, ectopia of pituitary

• Genetic

Autosomal dominant (AVP-neurophysin gene)

Autosomal recessive (AVP-neurophysin gene)

Autosomal recessive-Wolfram-(4p - WFS 1 gene)

X-linked recessive (Xq28)

Deletion chromosome 7q

Nephrogenic diabetes insipidus

Acquired

Drugs

Lithium

Demeclocycline

Methoxyflurane

Amphotericin B

Aminoglycosides

Cisplatin

Rifampin

Foscarnet

Metabolic

Hypercalcemia, hypercalciuria

Hypokalemia

Obstruction (ureter or urethra)

Vascular

Sickle cell disease and trait

Ischemia (acute tubular necrosis)

Granulomas

Neurosarcoid

Neoplasms

Sarcoma

Infiltration

Amyloidosis

Pregnancy

Idiopathic

Genetic

X-linked recessive (AVP receptor-2 gene)

Autosomal recessive (aquaporin-2 gene)

Autosomal dominant (aquaporin-2 gene)

Primary polydipsia

Acquired

Psychogenic

Schizophrenia

Obsessive-compulsive disorder

Dipsogenic (abnormal thirst)

Granulomas

Neurosarcoid

Infectious

Tuberculous meningitis

Head trauma (closed and penetrating)

Demyelination

Multiple sclerosis

Drugs

Lithium

Carbamazepine

Idiopathic

Iatrogenic

Category: Medicine Notes