3. Posterior_Pituitary_Flashcards
What is SIADH?
Syndrome of Inappropriate Anti-Diuretic Hormone, characterized by excessive ADH secretion.
What is the main result of SIADH?
Water retention leading to dilutional hyponatremia.
What are the symptoms of SIADH?
Lethargy, confusion, cerebral edema, muscle cramps, decreased urine output, and weight gain without edema.
What are the diagnostic findings in SIADH?
Low serum sodium, low serum osmolality, high urine osmolality.
What are the treatment options for SIADH?
Fluid restriction, hypertonic fluids, demeclocycline, and vasopressin antagonists (e.g., Conivaptan, Tolvaptan).
What is Diabetes Insipidus (DI)?
A disorder caused by ADH deficiency (central DI) or renal insensitivity to ADH (nephrogenic DI), leading to excessive water loss.
What are the signs and symptoms of DI?
Polyuria (>3 liters/day), polydipsia, weight loss, dry skin, hypotension, and dehydration.
What are the diagnostic findings in DI?
High serum sodium, high serum osmolality, and low urine osmolality.
What test distinguishes between central and nephrogenic DI?
Vasopressin response test. Improvement indicates central DI; no response suggests nephrogenic DI.
What is the treatment for central DI?
Desmopressin (ADH replacement).
What is the treatment for nephrogenic DI?
Thiazide diuretics, low sodium diet, and indomethacin.
What is the main difference in ADH levels between SIADH and DI?
ADH is high in SIADH and low (or ineffective) in DI.
What is the urine output like in SIADH versus DI?
Decreased in SIADH and increased in DI.
What are the serum sodium levels in SIADH versus DI?
Low in SIADH and high in DI.
What are the urine osmolality levels in SIADH versus DI?
High in SIADH and low in DI.
