pituitry disorders

Question 1

what is gigantism

Answer 1

abnormal linear growth during childhood due to growth hormone excess while the epiphyseal growth plates are still open.

Question 2

rf

Answer 2

associated with an ↑ incidence of pituitary tumors

Multiple endocrine neoplasia (MEN) type I
McCune-Albright syndrome

Neurofibromatosis

Question 3

PP of gigantism

Answer 3

↑ growth hormone (GH) secretion from the anterior pituitary
→ GH induces IGF-1 synthesis
→ IGF-1 stimulates cell growth and proliferation and inhibits apoptosis

GHRH secretion from the hypothalamus (i.e., tumors)

increased IGF-1 binfing protein which increases IGF-1 half life

Question 4

sx

Answer 4

Tall

↑ Growth of distal limbs (i.e., hands, feet, fingers, toes)

macroencephaly

Coarse facial features

frontal bossing (rihanna bosses fenty)

tumor mass sx
blurred vision, headache

Question 5

dg

Answer 5

elevated IGF-1

elevated GH w/ OGTT shows pituitary causes

MRI

Question 6

rx

Answer 6

transphenpoidal adeneectomy

somatostatin analog (ocreotide/ lanreotide)

Question 7

complications

Answer 7

carpal tunnel

CDV
LFH, HF, Aneurysm

Question 8

diabetes insipidus

Answer 8

secretion of or response to the vasopressin(ADH) is impaired, resulting in the production of very large quantities of dilute urine, (polyuria) often with dehydration and insatiable thirst.(polydipsia)

Question 9

class of DI

Answer 9

Central diabetes insipidus (CDI) (most common form)

• lack of hypothalamal synthesis of ADH
• lack of ADH secretion from post pituitary

Nephrogenic diabetes insipidus (NDI) (rare)
-defective ADH receptors in the distal tubules and collecting ducts

Question 10

causes of CDI

Answer 10

Primary defect in hypothal/ pituitary (1/3 cases)

secondaary 2/3

• cranial tumors/ metastasis
• post op removal of adenoma
• pituitaru ischemia in sheehan syndrome and meningitis

Question 11

causes of NDI

Answer 11

hereditary defects ofdistal tubules & collecting duccts

acquired

• lithium medication
• hypokalemia
• hypercalcemia
• polycystic kidney disease

Question 12

sx

Answer 12

Polyuria with dilute urine

Nocturia → Restless sleep, daytime sleepiness

Polydipsia

dehydration w/ altered mental status

Question 13

dg

Answer 13

plasma & urine osmalality test

• mild hyponatremia
• high/normal plasma osmolality
• low urine osmolality

water deprivation test

• plasma osmolality increases
• urirne osmolality stays the same

desmopressin administration test (dx CDI vs NDI)

CDI:

• plasma osmolality becomes normal
• urine osmolality increases

NDI:

• plasma osmolality stays high
• urine osmolality stays low

Question 14

describe water deprivation test

Answer 14

obtain baseline labs

pt doesnt drink for 2-3 hrs

test urine vol and osmolaltiy every hour

test plasma osmolality every 2hrs

continue until
-urine osmolality becomes normal RULES OUT DI as ADH release and effect on kidneys both func = primamry polydipsia

-no change in urine osmolality while plasma osmolality rises

plasma osmolality

if no change in urine and plasma osmolality increases apply desmopressin (synthetic ADH)
to dx betwen CDI vs NDI
monitor urine osmalilty every 30 mins for 2 hours

Question 15

how does desmopressin dx between CDI & NDI

Answer 15

CDI: Urine osmolality rises after desmopressin administration (renal ADH receptors are intact).

NDI: Urine osmolality remains low after desmopressin administration (defective renal ADH receptors).

Question 16

dx of DI

Answer 16

DB mellitus

beer ppotomani (excess beer intake causing hyponatremia)

Question 17

rx

Answer 17

CDI
-desmopressin (can cause hyponatremia)

NDI

• thiazide diuretics
• AMILORIDE for lithuim induced