Most important clinical features of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is hyponatremia whether acute which is less than 48 hr or chronic (more than 48 hr) ❗️

Diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH)is by
🔺Exclusion of other causes of hyponatremia
🔺Looking at the labs (low serum uric acid, bun, creatinine)

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH)’s Treatment is:
▪️If asymptomatic: correct the cause.
Not known then water restriction is most important.
▪️For symptomatic patient:
Must restrict water & may give isotonic saline.

Pituitary adenoma’s most common type is prolactinoma” a benign noncancerous tumor of the pituitary gland that produces prolactin” & usually cause hyperprolactinemia❗️

Other causes of hyperprolactinemia are:
🔺Pregnancy

🔺Renal failure

🔺hypothyroidism

🔺Medication like (psychotic medication, H2 antagonist, metoclopramide, verpamil, estrogen)

Clinical features of hyperprolactinemia in men:
▫️ Hypogonadism

▫️Decrease libido

▫️Infertility

▫️Visual field defect

Clinical features of hyperprolactinemia in women:
◾️Premenopausal:

▫️Menstrual irregularities

▫️Oligomenorrhea or amenorrhea

▫️Infertility

▫️Decrease libido

◾️Postmenopausal

▫️Visual defect & headache

Diagnosis of hyperprolactinemia:
▪️Elevated serum prolactin

▪️Rule out pregnancy & p. hypothyroidism (TSH level)

▪️CT or MRI to rule out mass

Diabetes Insipidus is disorder of ineffective ADH resulting in excretion of large volumes of dilute urine ❗️

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