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CMT-dos > Gigantism/Dwarfism > Flashcards

Gigantism/Dwarfism Flashcards

1
Q

Growth Hormone (GH)

general

A

Also known as somatotropin

Hormone produced by the anterior pituitary gland

Growth hormone-releasing hormone (GHRH) signals the release of GH when levels in the blood are low

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2
Q

Growth Hormone (GH)

major effects

A

Stimulates the liver to produce insulin-like growth factors (IGFs) – 4 types
Growth effects on muscle, cartilage, and bone predominantly

Adipose cells to break down stored fat - lipolysis (fuel growth)
Liver to break down glycogen into glucose - glycogenolysis (fuel growth)
Liver to produce glucose – gluconeogenesis

↑ insulin resistance in tissues – not moving glucose into cells = ↑ blood glucose levels

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3
Q

Insulin-like growth factor 1 (IGF-1)

general

A

Also known as somatomedin C

Produced by the liver in response to growth hormone in circulation

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

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4
Q

Insulin-like growth factor 1 (IGF-1)

effects

A

Promotes cellular metabolism
Prevents cell death
Increase the rate of cell division and differentiation throughout the body
Muscle growth
Stimulates amino acid uptake into the muscle cells, which helps with protein production
Growth of long bones (growth spurs in puberty)
-Acts on the epiphyseal cartilage (growth plates) of the bones
Stimulates the activity of osteoblasts in the bones
Stimulates the activity of chondrocytes in the cartilage-

might not get tested on things between - -

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5
Q

Gigantism

general

A

Abnormal linear growth due to excessive action of IGF-1 by growth hormone (GH) prior to the closure of the epiphyseal plates

Rare condition (~100 cases reported in the United States)

♂>♀

gigantism is BEFORE growth plates close

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6
Q

gigantism

caused by

A

GH overproduction due to a primarypituitary disorder:
Benign GH-producingpituitary adenoma (> 95% of cases)
Familial syndromes: multiple endocrine neoplasia types 1 or 4; McCune-Albright syndrome

GHRH overproduction inducing pituitary overproduction of GH

Ectopic GH and/or GHRH secretion from tumors of the pancreas, lungs, and/or adrenal glands

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7
Q

gigantism

clin man

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- increased sweat productions

gigantism is BEFORE growth plates close

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8
Q

Acromegaly

general

A

Abnormal growth due to an excess of growth hormone (GH) after close of the epiphyseal plates

Rare condition
Mainly develops in middle-aged adults
Mean age at diagnosis is 40-45 years
♀=♂

Progression is usually very slow
Onset to diagnosis is ~12 years

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9
Q

Acromegaly

caused by

A

GH overproduction due to a primarypituitary disorder:
Benign GH-producingpituitary adenoma
Familial syndromes: multiple endocrine neoplasia types 1 or 4; McCune-Albright syndrome

GHRH overproduction inducing pituitary overproduction of GH

Ectopic GH and/or GHRH secretion from tumors of the pancreas, lungs, and/or adrenal glands

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10
Q

acromegaly

clin man

A

Headaches and temporal hemianopia (dependent on the size of the pituitary tumor)
Large and broad hands and feet

Deep coarse voice (hypertrophy of the pharyngeal and laryngeal tissue)
Skin changes: hyperhidrosis, cystic acne, acrochordons(skin tags)

Carpal tunnel symptoms
Sleep apnea
Hypertension
Cardiomegaly
Insulin resistance → diabetes mellitus

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11
Q

acromegaly

clin feature for males and females

A

Decreased secretion of other pituitary hormones (most commonly gonadotropin)

♀ Menstrual dysfunction, hot flashes, vaginal atrophy

♂ Erectile dysfunction, loss of libido, decreased facial hair growth, small testicles

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12
Q

acromegaly

course facial changes

A

Coarse facial features
Enlargement of the eyebrows/forehead (frontal bossing)
Widening of the nose
Thickened lips
Macroglossia
Prominent jaw (prognathism and malocclusion)
Widening between the teeth

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13
Q

acromegaly/gigantism

Dx
Serum IGF-1

A

Laboratory testing to confirm the clinical diagnosis
Serum IGF-1
Increased 3-10x
Can be used to monitor response to therapy

1st step

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14
Q

acro/gigantism

Dx
oral glucose tolerance test

A

Oral glucose tolerance test/GH suppression test
Helps to determine if the pituitary is releasing too much GH
Drink a sugar drink containing 75 grams 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)

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15
Q

acromegaly/gigantism

imaging

A

MRI of the pituitary → GH-secreting pituitary adenoma (majority of cases)
Chest and abdominal CT → extra-pituitary acromegaly if the MRI of the pituitary is normal

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16
Q
A
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17
Q
A
18
Q

acro/gigantism

Surgical Tx

A

Surgical
Removal of the tumor via anendoscopic endonasaltechnique (transsphenoidal adenomectomy)
Best chance for a cure

Patients with incomplete remission following surgery:
Medication

19
Q

acro/gigantism

medication tx

A

Medication
Dopamine agonists (bromocriptine)
Helps to lower levels of GH and IGF-1
GH-receptor-antagonists (pegvisomant)
Normalize the elevated IGF-1 levels
Somatostatin analogs (octreotide)
Reduce growth hormone production

20
Q

acro/gigantism

Radiation therapy

A

Reduce the size of the tumor
Risk of possible damage to other normal pituitary cells

21
Q

acro/gigantism

Complications of disease

A

Hypertension
Heart problems (cardiomyopathy) → referral to cardiology
Type 2 diabetes
Thyroid goiter
Increased risk of developing colon cancer and thyroid cancer
Colonoscopy screening every 3-5 years
Yearly examination of the thyroid gland → thyroid US if any masses or enlargement is detected

22
Q
A
23
Q
A
24
Q

Dwarfism

general

A

Medical term for short stature
Short stature: height-vertex below 2SD or in the 3rd percentile for a given age and sex
Generally defined as an adult height of 4 feet 10 inches (147 centimeters) or less
Results from a medical condition or genetics
Affects 2.5% of the U.S. population

400 types of dwarfism

25
Q

dwarfism

2 types

A

Categorized into 2 types:
Disproportionate: often present at birth or in early infancy
Proportionate: not immediately apparent

26
Q

proportionate is a GH deficiency

A
27
Q

dwarfism

Familial Short Stature (FSS)

A

Low-normal height velocity throughout life
Matches parental height (child is short like their parents)

28
Q

dwarfism

Constitutional delay of growth and puberty (CDGP):

A

Short height in childhood, but attainment of target height in adulthood; “late bloomer”

29
Q

dwarfism

Idiopathic Short Stature (ISS):

A

Short stature when no other etiology (endocrine/metabolic) can be determined

Dx of exclusion

30
Q

dwarfism

Endocrine disorder etiologies

A

Growth hormone deficiency (GHD) or growth hormone insensitivity

31
Q

dwarfism

Bone disease etiologies

A

Achondroplasia - 90% of cases of dwarfism
Autosomal dominant genetic condition in which there is inhibition of chondrocyte proliferation → impairment of endochondral bone formation

Spondyloepiphyseal dysplasia:
Primarily involves the vertebrae and the proximal epiphyseal centers

32
Q

dwarfism

systemic disease etiology

A

Systemic diseases → secondary effect on growth

Undernutrition, juvenile idiopathic arthritis, inflammatory bowel disease (IBD), celiac disease, chronic kidney disease (CKD), pulmonary/cardiac/immunologic/metabolic diseases, cancers, and glucocorticoid therapy

33
Q

dwarfism

Growth hormone deficiency

A

Proportionate

Pituitary gland fails to produce an adequate supply of growth hormone
Can be congenital or acquired

Signs include:
Height below the 3rd percentile on standard pediatric growth charts
Growth rate slower than expected for age
Delayed or no sexual development during the teen years

Features:
Head, trunk, and limbs are all proportionately small
Poor development of organs

34
Q

Achondroplasia

clinical features

disproportionate

A

Most common form
Clinical Features:
An average-size trunk
Short arms and legs, particularly noticeable in the upper arms and thighs
Short fingers, often with a wide separation between the middle and ring fingers (trident hand)
Limited mobility at the elbows
A disproportionately large head, with a prominent forehead and a flattened bridge of the nose
Progressive development of bowed legs
Protruding jaw sometimes with poor dental structure
Progressive exaggeration of lumbar lordosis
Decrease in muscle tone (hypotonia) and loose joints

35
Q
A

Achondroplasia

36
Q

dwarfism

Dx

A

Disproportionate dwarfism may be suspected during a prenatal ultrasound (very short limbs disproportionate to the trunk) → genetic testing by chorionic villus sampling (CVS) or amniocentesis

37
Q

dwarfism

Growth curves

A

Growth pattern documented on appropriate age andsex growth curve

Birth–48 months:
Length-for-age and weight-for-age
Head circumference-for-age and weight-for-length

Ages 2–20 years:
Stature-for-age and weight-for-age
BMI-for-age

Accurate measurement of child < 24 months is supine
Only children with height < 2 standard deviations require further evaluation

38
Q
A
39
Q

dwarfism

Dx
Bone age with ahand x-ray

A

X-ray performed in standardized manner and compared to reference

40
Q

dwarfism

labs

A

CBC with diff – anemia and chronic illness
ESR – chronic inflammatory illness (IBS)
Thyroid studies
CMP – renal and liver diseases
Antibody testing – IgA for celiac disease
IGF-1 – GH deficiency
Sweat chloride – cystic fibrosis
Pre-albumin and albumin – malnutrition

41
Q

dwarfism

Tx

A

Constitutional growth delay and familial short stature do not require treatment

Growth hormone deficiency
GH replacement therapy indicated in:
Current height below -2.25 standard deviations ofthe mean
Epiphyses not closed
Recombinant human growth hormone (rhGH)
Daily or sustained-release formulations
Growth response is greater when rhGH is initiated at younger versus older age

42
Q

Achondroplasia

Tx

A

No specific treatment
Interventions for complications as they occur

CMT-dos (95 decks)

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