Hypothalamus and Pituitary (Correa) Flashcards
Which test allows you to make the diagnosis of diabetes insipidus?
Fluid deprivation test
Which test allows you to differentiate between central and nephrogenic diabetes insipidus?
Desmopressin (ADH) Stimulation test
If central: urine will become more concentrated
If nephrogenic: no change, dilute urine
Central Diabetes insipidus: treatments (3)
- Desmopressin (DDAVP) (synthetic ADH)
- Carbamazepine
- Chlorpropamide
oral, or nasal forms
Nephrogenic Diabetes insipidus: Tx
- Thiazide diuretic (HCTZ)
2. Low salt diet
Name some potential causes of nephrogenic diabetes insipidus
- Lithium**
- Hypercalcemia*
- Hypokalemia
What is the clinical hallmark of SIADH?
hyponatremia (<135meq) and no evidence of excess water (euvolemic)
Also, increased sodium in the urine
SIADH treatment
-restrict fluid (<800ml-1 liter a day)**
if severe: give hypertonic saline and furosemide
SIADH: diagnosis
- low serum osmolarity
- High urine osmolarity
In a patient you are suspicious may have hyperprolactinemia what do you need to rule out?
- Pregnancy
2. Hypothyroidism (because TRH increase can cause increased prolactin)
What is the best initial test for a patient with galactorrhea and amenorrhea, and infertility?
Basal/Fasting prolactin level
Name some drugs that can cause high prolactin?
- Dopamine antagonists
- Methyldopa
- Opioids
- H2-blockers
- Verapamil
In pregnancy which is the preferred dopamine agonist
bromocriptine
Discuss the secretion of GH
- pulsatile (undetectable between pulses)
- peak within an hour of start of deep sleep
How is Acromegaly diagnosed?
Insulin-like Growth factor is elevated
Confirm dx with oral glucose suppression test (GH will still be elevated)
What diagnostic test is the gold standard in confirming GH deficiency in a child with short stature?
GH stimulation test: give insulin and measure serum glucose and serum GH. (normal test: giving insulin should make GH increase)
(do this if you find IGF-1 to be low)
