There are two types of diabetes insipidus:
▪️Central: which due to low ADH.

▪️Nephrogenic: when ADH is normal but tubules can not respond to it.

Polyuria is hallmark of diabetes insipidus (urine is 5- 15 L daily & colorless) 📍

Other presentations of diabetes insipidus are:
⭕️ Polydipsia “excessive thirst to compensate water loss”

⭕️ Hypernatremia “mild unless thirst center are impaired”

Diagnosis of diabetes insipidus :
▪️ Urine which shows low specific gravity & osmolality.

▪️ When plasma osmolality exceed 280 mOsm/kg.

▪️ A dehydration test “stop fluid & measure urine osmolality every hour”

A dehydration test result:
⭕️ Increase in urine osmolality with dehydration (>280 mOsm/kg) can be normal or psychogenic DI.

⭕️No responce to dehydration but respond to ADH: Central DI.

⭕️No responce to both dehydration & ADH: Nephrogenic DI.

Causes of diabetes insipidus:
▫️ Wolfram syndrome

▫️ Idiopathic

▫️ Tumors [ex. Craniopharyngioma, Lymphoma/leukaemia]

▫️ Infection [TB ,meningitis ,cerebral abscess]

▫️ Sarcoidosis

Desmopressin (DDAVP) is the primary therapy for central diabetes insipidus❗️

USMLE Immunology 1: Innate and Adaptive Immune System, T Cell Activation https://youtu.be/3maP0hZjE3E via @YouTube

A great introduction to the immune system