Short Stature Flashcards
(36 cards)
How do we define short stature?
Growing 2 SD below the mean (<2.3 %ile)
* Extrapolation to adults: 4’11” for women, 5’3” for men
* Varies by sex and ethnicity
What are factors that influence height?
- Social: Poor nutrition (weight percentile lower than height)
- Vitamin D deficiency: Sunlight and supplements
- Endocrine: Growth hormone deficiency, hypothyroidism
- Chronic disorders:
-Anemia, renal disease, inflammatory bowl disease (Crohns), juvenile
idiopathic arthritis, heart disease, chronic diarrhea - Genetic disorders
-Chromosomal (trisomy 21), cystic fibrosis, developmental disorders (Kabuki,
Cornelia de Lange, and a very long list of others)
What does growth arrest imply?
New onset hormone deficiency or medical disorder
How do you access bone age?
- Hand films most common
- Or, X-ray films to count growth centers from half the body—more accurate, but less used
What is the definition of a skeletal dysplasia?
- Disproportionate bones
- Short segments of limbs
- Abnormal upper:lower segment ratio
-Lower segment = long bones, upper = spine and head
-Sitting Height - Disproportionate head size in some
You have a patient with the following:
* Short stature with rhizomelia
* Macrocephaly
* Facial changes: Bossing, midface retrusion
* Exaggerated lordosis, gibbus
* Limited Extension of the arms
* Brachydactyly / trident hands
What do you suspect?
Achondroplasia
What does rhizomelia mean?
“Rhizo”= root
Shortening of the bones in the upper arms and thighs
What does “Acro” mean?
“Acro” = tip
What are complications of Achondroplasia?
- Narrow craniocervical junction can compress the spinal cord
-Hydrocephalus
-Spasticity
-Bladder/bowel disorders
-Apnea –> Death in 7.5%, untreated - Low tone and motor delay, especially with head control
- Restrictive lung disease
- Sleep apnea
- Ear infections
- Spinal complications: Kyphosis, lordosis, spinal stenosis
- Intelligence: normal, if no CNS complication
What are the Screening/interventions for Achondroplasia?
- MRI of the brain at diagnosis
- CT of the spine at diagnosis
- Sleep study at diagnosis
-May need tonsils out or CPAP - If the above abnormal, may need decompression surgery
- Orthopedic evaluation for bowing of legs
- Prevention of kyphosis through positioning and back support
What is the most common mutation causing Achondroplasia?
99% have one of two pathogenic variants in FGFR3:
* c.1138G>A p.Gly380Arg
* c.1138G>C p.Gly380Arg
What percentage of Achondroplasia is de novo?
80% de novo
What are the disorders caused by FGFR3 mutations?
- Achondroplasia
- Hypochondroplasia
- Thanatophoric dysplasia
- Crouzon
- Muenke
What is the result of Homozygous achondroplasia?
Usually causes respiratory insufficiency and neonatal death
How is Hypochondroplasia different from achondroplasia?
- Lack of rhizomelia / brachydactyly
- Craniofacial findings subtle or absent
- Head size more proportional
What is the phenotype of Hypochondroplasia?
- Other changes in FGFR3
- Milder short stature
- CNS issues more prominent
- Seizures, developmental delay
What kind of skeletal dysplasia is characterized by:
* Respiratory insufficiency
* “Telephone receiver” femurs
* Often identified by prenatal ultrasound
-“Short long bones”
Thanatophoric dysplasia
What is the phenotype of Campomelic Dysplasia “Bent limb”?
- Autosomal dominant, SOX9
- Distinctive facies
- Pierre Robin sequence with cleft palate
- Shortening and bowing of long bones, and clubfeet
- Laryngotracheomalacia with respiratory compromise—often lethal
- Ambiguous genitalia or 46,XY sex reversal
What are the characteristics shared between Osteogenesis Imperfecta Types I and IV?
- Multiple fractures, minimal trauma
-Type I often improves over time - Short stature
- Blue or gray sclerae (whites of eyes)
- Weak teeth (dentinogenesis imperfecta)
- Progressive, postpubertal hearing loss
- Loose joints
- Low bone density
- Wormian bones
- Often evaluated non-accidental trauma cases
What are the eye findings in OI Types I and IV?
- Type I: Blue sclerae, mild
- Type IV: Gray or normal sclerae, mild-moderate
What is the phenotype of OI Type II?
- Perinatal lethal. 60% die on day 1, 80% die by 1 week, survival past 1 year very rare
- Respiratory distress/insufficient aeration due to small rib cage
- Dark blue sclerae
- Extremities short, bowed
- Thin skull, wide fontanelle
- X-rays show “crumpled” long bones and multiple fractures
- More recent recessive forms
What is the phenotype of OI Type III?
- Progressive deforming
- Can have fractures from newborn handling
- Over 200 fractures in a lifetime common
- Bones progressively change even without fractures—70 to 90 degree angulation
- Short stature common
- Often require wheelchair
What are the Intervention / screening / treatment for OI?
- Orthopedic referral
- PT/OT
- If neurologic signs, CT scan for basilar impression
- Bisphosphonate infusions lead to stronger bones
-Does not decrease risk of fracture
-Now fractures occur with higher stress - Family testing/tracing
What is the phenotype of Stickler syndrome?
- Micrognathia with Pierre Robin
- High myopia – leading to retinal detachment
- Hearing Loss
- Hypermobility
- Epiphyseal dysplasia – arthritis
- Short stature
