Markers of Ischemia on ECG:
🔹Peaked T waves (early)

🔹ST segment elevation (indicates transmural injury & it is diagnostic)

🔹Q waves (come later)

🔹ST segment depression (Subendocardial injury)

Categories of infarcts
♦️ ST segment elevation infarct: Transmural , include entire thickness of wall and larger.

♦️ Non-ST segment elevation infarct: Subendocardial , include one third of the wall and usually smaller.

Cardiac enzymes differentiate them❗️

Cardiac enzymes are gold standard to diagnose ischemic heart disease
▫️Troponin (I & T): most important, appear within 3-5 hr & become normal within week to two.

▫️CK-M: for recurrent infarct, appear within 4-8 hr & must be repeated every 8 hr.

Complications of acute MI:
🔺Pump failure (CHF)

🔺Arrhythmia (premature ventricular contaction , Afib, PSVT, sinus tachycardia or bradycardia, AV block)

🔺Recurrent infarction

🔺Mechanical complication like free wall rupture or rupture of inter-ventricular septum or papillary muscle.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is excess antidiuretic hormone which leads to water retention & cause: hyponatremia & volume expansion ❗️

Causes of Syndrome of inappropriate antidiuretic hormone secretion (SIADH) are:
▪️Neoplasm (tumor)

▪️CNS disorder (stroke, head trauma ,infection)

▪️Pulmonary disease (pneumonia)

▪️Ventilator with positive pressure

▪️Medication (ex morphine, oxytocin, chlorpropamide, vincristine)

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.