Diabetes Insipidus (DI) Causes Diagnosis and Treatment

Diabetes insipidus (DI) Disorders of Neurohypophysis 

The neurohypophysis or posterior pituitary gland is made up of nerve tissues originating in su­praoptic and paraventricular nuclei of hypothala­mus.

  • It produces 2 hormones:
  • 1. AVP or arginine vasopressin, also known as antidiuretic hormone (ADH).
  • 2. Oxytocin
  • AVP acts on renal tubules to absorb the water back into the circulation helping to reduce the water loss and concentrating the urine.
  • AVP deficiency causes diabetes insipidus.


Diabetes insipidus (DI) —

  • It is a disease of ‘Posterior pituitary insufficiency or AVP deficiency in which large amounts of dilute urine are passed.
  • inadequate secretion of or insensitivity to vasopressin (ADH) leading to hypotonic polyuria.
  • In excessive AVP secretion, there is decreased urine output and hyponatraemia, especially if water intake is not reduced. This is called inappropriate ADH syndrome or inappropriate AVP production.
  • In DI there is urine output more than 50 mljkg in 24 hours and osmolarity is <300 mosmol / L.
  • There is polyuria, urinary frequency, nocturia, fatigue, .­somnolence (sleepiness), thirst, polydipsia.
Diabetes Insipidus Risk Factors
  • Diabetes insipidus may be part of the paraneoplastic syndrome associated with small cell bronchocarcinoma.
  • Intracranial neoplasm
  • Patients using  lithium
  • Following surgery
  • Head trauma

Causes of Diabetes insipidus (DI) are:

  • · Head trauma
  • · Chronic meningitis
  • · SLE (Systemic lupus erythematosus)
  • · Snake venom
  • · Craniopharyngioma
  • · Pituitary adenoma
  • · Metastatic tumors
  • · Pregnancy
  • · Sheehan’s syndrome (post partum pituitary apo­plexy)
  • · Drugs like lithium, amphotericin B, aminoglycosides, rifampin
  • Psychogenic Tubercular meningitis Multiple sclerosis

Diabetes insipidus (DI) Diagnosis —

  • Initial Lab Tests

    • Plasma vasopressin or urinary vasopressin following osmotic stimulus, such as fluid restriction or administration of hypertonic saline
    • Urinary glucose: Rule out diabetes mellitus.
    • Normal:
      • Water restriction causes a rise in plasma osmolality andtn0[10] ADH secretion. This leads to tn0[11] water reabsorption in the collecting ducts. Urine is concentrated (urine osmolality >600 mosmol/kg)
    • Diabetes insipidus:
      • Lack of ADH activity means that urine is unable to be concentrated by the collecting ducts (urine osmolality <400 mosmol/kg).
  • Blood test :

    • U&E and Ca2+ (Na+may be rise secondary to dehydration,tn0 K+ or tn0[1] Ca2+ as the aetiological factor). tn0[2] Plasma osmolality. tn0[3] Urine osmolality.

Treatment of Diabetes insipidus (DI)

  • Treatment is DDAVP – a synthetic analog of AVP.
  • It increases the urine concentration, and de­creases t~e urine flow.
  • Other drugs are chlorpropamide (antidiabetic drug).
  • Patient counselling helps in psychogenic poly­dipsia.
  • Therapy depends on type of DI.
    • ›Orally available as 0.1- to 0.2-mg tablets
    • ›Intranasally 0.2–0.6 mg at bedtime
    • ›Desmopressin (DDAVP) a derivative of vasopressin, available PO, nasal spray, and parenterally
  • Central DI:
    • ›Correct water deficits.
    • ›Reduce excessive urinary water loss.
  • Symptomatic nephrogenic DI:
    • Amiloride can be added to HCTZ for the added effect.
    • Hydrochlorothiazide 25 mg once or twice a day
    • Thiazide diuretic with amiloride
  • Contraindications Diabetes insipidus (DI):
    • Use desmopressin with caution in the immediate postop period for intracranial lesions because of possible cerebral edema.
  • Precautions Diabetes insipidus (DI):
    • An overdose of desmopressin may produce water intoxication and hyponatremia in patients with excessive water intake.
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