DWARFISM

Question 1

what is dwarfism?

Answer 1

short stature
height-vertex below 2SD or in 3rd percentile for given age and sex
generally- adult height of 4 foot 10 in (147 cm) or less

Question 2

what does dwarfism result from?

Answer 2

medical condition or genetics

Question 3

what 2 categories is dwarfism put into?

Answer 3

disproportionate- present at birth or in early infancy; most common type is achondroplasia -> normal size torso and short limbs
proportionate- not immediately apparent; d/t growth hormone deficiency-> pt smaller than average all over

Question 4

what is the etiology of dwarfism?

four bullet points

Answer 4

1. familial short stature (FSS)
   - low-normal height velocity throughout life
   - matches parental height (child is short like their parents
2. constitutional delay of growth and puberty
   - short height in childhood, but attainment of target height in adulthood; “late bloomer”
3. idiopathic short stature (ISS)
   - short stature with no other etiology (endocrine/metabolic) can be determined
4. endocrine disorders
   - growth hormone deficiency (GHD) or growth hormone insensitivity

Question 5

bone disease etiology of dwarfism?

Answer 5

1. achondroplasia- 90% dwarfism- auto dom where theres inhibition of chondrocyte proliferation -> impairment of endochondral bone formation
2. spondyloepiphyseal dysplasia: primarily involves vertebrae and proximal epiphyseal centers

Question 6

systemic disease etiology of dwarfism?

Answer 6

systemic dz has 2ndary effect on growth

• undernutrition, juvenile idiopathic arthritis, IBD, celiacs, CKD, pulm/cardiac/immunologic/metabolic dz, cancers, glucocorticoid therapy

Question 7

what is proportionate GH deficiency exactly?

Answer 7

pituitary gland fails to produce adequate supply of growth hormone
-can be congenital or acquired

Question 8

what are signs of proportionate GH deficiency?

Answer 8

1. height below 3rd precentile on standard pediatric growth charts
2. growth rate slower than expected for age
3. delayed or no sexual development during teen years

Question 9

what are features of proportionate GH deficiency?

Answer 9

head, trunk. and limbs are all proportionately small
poor development of organs

Question 10

which of these is most common form of dwarfism?

Answer 10

achondroplasia

Question 11

what are the clinical features of the body in achondroplasia?

Answer 11

average sized trunk
short arms and legs, particularly noticeable in upper arms and thighs
short fingers, often with wide separation between middle and ring fingers (trident hand)
limited mobility at elbows

Question 12

what are the clinical features of the head in achondroplasia?

Answer 12

disproportionately large head with prominent forehead and flattened bridge of nose

Question 13

what is a very specific but important characteristic of the legs in achondroplasia?

Answer 13

progressive development of bowlegs

Question 14

what are the last 3 miscellaneous clinical features of achondroplasia?

Answer 14

protruding jaw (sometimes poor dental structure), progressive exaggeration of lumbar lordosis, decrease in muscle tone (hypotonia) and loose joints

Question 15

when can disproportionate dwarfism be suspected?

Answer 15

during a prenatal US where very short limbs disproportionate to the trunk can be seen

in this case you then go on to genetically test by chorionic villus (cvs) sampling or amniocentesis

Question 16

what is an important way to diagnose dwarfism other than prenatal US and all that comes with it?

Answer 16

growth curves: they are growth patterns documented on appropriate age and sex growth curve

Question 17

at birth-36 months what will you look for on growth curve?

Answer 17

1. length-for-age and weight-for-age
2. head circumference-for-age and weight-for-length

Question 18

at ages 2-20 years what do you look for on growth curve?

Answer 18

1. stature-for-age and weight-for age
2. BMI-for-age

Question 19

how is accurate measurement of child <24 months conducted?

Answer 19

supine

Question 20

only children with ____ requires further evaluation.

Answer 20

height <2 SD

Question 21

what is the boys calculation?

Answer 21

(fathers height (cm)+ moms height (cm) +13 cm)/2

Question 22

whats the girls calculation?

Answer 22

(fathers height (cm)+ moms height (cm) -13 cm)/2

Question 23

what is an important method of diagnosis for dwarfism regarding xray?

Answer 23

bone age with a hand x-ray
- x-ray performed in standardized manner and compared to reference

Question 24

what labs should be drawn in dwarfism?

Answer 24

1. cbc w/ diff- anemia and chronic illness
2. ESR- chronic inflammatory diseases (ibs)
3. thyroid studies
4. CMP- renal and liver diseases
5. ab testing - igA for celiacs
6. IGF-1- GH Deficiency
7. sweat chloride- CF
8. pre-albumin and albumin- malnutrition

Question 25

what does not require treatment?

Answer 25

constitutional growth delay and familial short stature

Question 26

in growth hormone deficiency what is the management?

Answer 26

GH replacement therapy indicated in:
1. current height below -2.25 SD of mean
2. epiphyses not closed
- (rhGH) recombinant human growth hormone
>daily or sustained-release formulations
> growth response is greater when rhGH is
initiated at younger vs. older age

Question 27

achondroplasia management:

Answer 27

no specific treatment
interventions for complications as they occur
genetic counseling