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ENDOCRINE > GIGANTISM AND ACROMEGALY > Flashcards

GIGANTISM AND ACROMEGALY Flashcards

1
Q

what is growth hormone also known as?

A

somatotropin

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2
Q

what is growth hormone produced by?

A

anterior pituitary gland

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3
Q

what does GHRH signal?

A

it signals the release of GH when blood levels are low

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4
Q

what does GH stimulate the liver to produce?

A

insulin-like growth factor (IGF’S) -4 types

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5
Q

what are the growth effects of IGF’s on?

A

muscle, cartilage, bone

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6
Q

what does GH stimulate adipose cells to do?

A

break down stored fat- lipolysis

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7
Q

what 2 things does GH stimulate the liver to do regardless of IGF’s?

A
  1. liver to break down glycogen into glucose- glycogenolysis
  2. liver to produce glucose- gluconeogenesis
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8
Q

what did GH stimulate insulin to do?

A

increase insulin resistance in tissues- not moving glucose into cells = increased blood glucose levels

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9
Q

what is IGF-1 also known as?

A

somatomedin C

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10
Q

What is IGF-1 produced by?

A

produced by liver in response to growth hormone in circulation

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11
Q

What does IGF-1 bind to?

A

binds to IGF-1 receptors and insulin receptors to produce multiple effects

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12
Q

what are the effects of IGF-1?

A
  1. PROMOTES CELLULAR METABOLISM
  2. prevents cell death
  3. increase the rate of cell division and differentiation throughout body
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13
Q

what is IGF-1 effect on muscle growth?

A

stimulates amino acid uptake into muscle cells, which helps w/ protein production

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14
Q

what is IGF-1 effect on growth of long bones (growth spurs in puberty)?

A
  1. acts on epiphyseal cartilage (growth plates) of bones
  2. stimulates activity of osteoblasts in bones
  3. stimulates activity of chondrocytes in cartilage
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15
Q

what is gigantism?

A

abnormal linear growth d/t excessive action of IGF-1 by growth hormone prior to closure of epiphyseal plates
rare condition (about 100 cases reported in US)

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16
Q

is gigantism seen more in men or women?

A

men

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17
Q

what is gigantism caused by?

three things

A
  1. GH overproduction d/t primary disorder
  2. GHRH overproduction inducing pituitary overproduction of GH
  3. ectopic GH and/or GHRH secretion from tumors of the pancreas, lungs, and/or adrenal glands
18
Q

what are the 2 different types of primary gigantism?

A

GH overproduction d/t PRIMARY DISORDER
- benign GH-producing pituitary adenoma (>95% cases)
- familial syndromes: multiple endocrine neoplasia types 1 or 4; McCune-Albright syndrome

19
Q

what are the clinical features of gigantism?

A
  • rapid and excessive height growth (long bones) and weight gain
    - patients commonly >6’6” tall
  • large hands and feet
  • macrocephaly
  • coarse facial features (frontal bossing and prominent jaw)
  • hyperhidrosis
20
Q

what is acromegaly?

A

abnormal growth d/t excess of growth hormone after close of the epiphyseal plates
rare condition

21
Q

what age and gender does acromegaly occur?

A

develops in middle-aged adults
mean age at dx: 40-45 y/o
WOMEN OVER MEN

22
Q

how does acromegaly progress?

A

very slowwww. onset to dx: roughly 12 years

23
Q

what is acromegaly caused by?

A
  1. GH overproduction d/t PRIMARY DISORDER
    - benign GH-producing pituitary adenoma
    - familial syndromes: multiple endocrine neoplasia types 1 or 4; McCune-Albright syndrome
  2. GHRH overproduction inducing pituitary overproduction of GH
  3. Ectopic GH and/or GHRH secretion from tumors of pancreas, lungs, and/or adrenal glands
24
Q

what is a clinical feature that occurs to the skin in acromegaly?

A

hyperhidrosis, cystic acne, acrochordons

25
Q

what happens to the voice in acromegaly and why?

A

deep coarse voice due to the hypertrophy of pharyngeal and laryngeal tissue

26
Q

what are some coarse facial features of acromegaly?

A
  1. enlargement of eyebrows/ forehead -> frontal bossing
  2. widening of nose
  3. thickened lips
27
Q

what happens to the hands and feet in acromegaly?

A

large and broad hands and feet

28
Q

what clinical feature of acromegaly happens to the head?

A

headaches and temporal hemianopia (dependent on size of pituitary tumor)

29
Q

what are some other important clinical features other than the ones already stated?

A

macroglossia, prominent jaw (prognathism and malocclusion), widening between teeth, carpal tunnel, sleep apnea, HTN, cardiomegaly, insulin resistance leading to diabetes mellitus

30
Q

what is a clinical feature of acromegaly pertaining to other hormones?

A

decrease in secretion of other pituitary hormones - most commonly GONADOTROPIN

31
Q

whats a clinical feature of acromegaly in females?

A

menstrual dysfxn, hot flashes, vaginal atrophy

32
Q

whats a clinical feature of acromegaly in males?

A

ED, libido loss, decreased facial hair growth, small testicles

33
Q

what laboratory testing is first line in confirming acromegaly?

A

serum IGF-1 because it is increased in 3-10x

it can be also used to monitor response to therapy

34
Q

what is another testing method other than IGF-1 that can be used to dx acromegaly?

A

oral glucose test/GH suppression test

35
Q

what does the oral glucose test do?

A

helps determine if pituitary is releasing too much GH

36
Q

how is the oral glucose test performed?

A

drink a sugar drink of 75 g of glucose
measure serum GH before and after 2 hours
>1 ng/mL is abnormal -> normally with an increase in blood glucose, growth hormone is suppressed (LOW GH LEVEL)

37
Q

what is the first step in imaging for acromegaly dx?

A

MRI of pituitary-> GH- secreting pituitary adenoma (majority of cases)

38
Q

what is the second method of imaging in acromegaly dx if MRI normal?

A

chest and abdominal CT -> extra-pituitary acromegaly if MRI of pituitary is normal

39
Q

what is the surgical treatment option for acromegaly?

A

removal of tumor via endoscopic endonasal technique (transsphenoidal adenectomy)
- best chance for a cure

40
Q

what happens with incomplete remission following surgery?

A

MEDICATIONS:
1. dopamine agonists (bromocriptine) -helps to lower levels of GH and IGF-1
2. GH-receptor- antagonists (pegvisomant) -normalize elevated IGF-1levels
3. somatostatin analogs (octreotide) -reduce growth hormone production

41
Q

what is the goals/risks of radiation therapy in acromegaly cases?

A

goal: reduce tumor size
risk: possible damage to other normal pituitary cells

42
Q

complications of acromegaly:

A

HTN
heart problems (cardiomyoptahy)-> referral to cardiology
T2 diabetes
thyroid goiter
increased risk of developing colon cancer and thyroid cancer
- colonoscopy screening every 3-5 years
- yearly exam of thyroid gland-> thyroid US if any masses or enlargement is detected

ENDOCRINE (18 decks)

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