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Diabetes insipidus (DI) Disorders of Neurohypophysis
The neurohypophysis or posterior pituitaryAldosteronism Clinical features Causes and Treatment. Read more ... » gland is made up of nerve tissues originating in supraoptic and paraventricular nuclei of hypothalamus.
- It produces 2 hormones:
- 1. AVPSIADH or Syndrome of inappropriate ADH (AVP). Read more ... » or arginine vasopressin, also known as antidiuretic hormoneAnterior Pituitary Hormones and Disorders. Read more ... » (ADH).
- 2. Oxytocin
- AVP acts on renalDiabetic Nephropathy and Renal complications of DM (Diabetes Mellitus). Read more ... » tubules to absorb the water back into the circulation helping to reduce the water loss and concentrating the urine.
- AVP deficiency causesHow to Manage Hay Fever at Home. Read more ... » diabetes insipidusDiabetic Nephropathy and Renal complications of DM (Diabetes Mellitus). Read more ... ».
Diabetes insipidus (DI) –
- It is a diseaseHow to Manage Hay Fever at Home. Read more ... » 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 ADHSIADH or Syndrome of inappropriate ADH (AVP). Read more ... » syndromeMetabolic,Insulin Resistance Syndrome X Causes Symptoms. Read more ... » 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, fatigueFatigue diagnosis medicine and treatment. Read more ... », .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
- · ChronicChronic Hepatitis Classification viral hepatitis Clinical features and Treatment. Read more ... » 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 glucoseGlycogen Storage Diseases von Gierke disease, Andersen's disease, McArdle's disease. Read more ... »: Rule out diabetes mellitusOphthalmologic Complications of DM (Diabetes Mellitus). Read more ... ».
- Water restriction causes a rise in plasma osmolalityHow to Maintain Fluid & Electrolytes balance. Read more ... » and ADH secretion. This leads to 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 :
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 drugHow to Manage Hay Fever at Home. Read more ... »).
- 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.