Chapter 130 - Pediatric Musculoskeletal Disorders and Syndromes Flashcards
Marfan’s Syndrome genetics
Autosomal DOMINANT (25% new mutations)
Fibrillin 1 defect (FBN1)
Chromosome 15q21
Marfan’s syndrome phenotype
- tall, wingspan: height >1.05
- dolichostenomelia (tall and thin, long limbs)
- arachnodactyly and joint hypermobility
Cardiac Defects: GET A CARDS CONSULT AND ECHO
- aortic root dilatation -> aortic dissection
- mitral valve prolapse
Scoliosis: difficult to brace
- dural ectasia (dilation of the dura - scalloped vertebral bodies and nerve root herniation)
- GET AN MRI
SUPERIOR lens dislocation, myopia
Acetabular protrusio, severe pes planovalgus
Ehler’s Danlos genetics
Classic form:
Autosomal DOMINANT
Col5A1, Col5A2 mutations
Type VI:
Autosomal RECESSIVE
lysyl hydroxylase mutation - key for collagen crosslinking
***severe kyphoscoliosis, globe rupture
Type IV: (vascular type)
Autosomal DOMINANT
Col3a1
arterial, intestinal, uterine rupture
Systemic JIA
Still’s disease
- rash, high fever, multiple inflamed joints
- anemia, high wbc
- serositis, heptosplenomegaly, lymphadenopathy, pericarditis
- ages 5-10, girls=boys
- least common type of JIA, with poorest prognosis
Pauciarticular JIA
most common
four or less joints involved
limp that gets better thruout day
can have LLD
large joints more common - knees/ankles
peak age 2-3
Girls 4x boys
20% have UVEITIS
- ophtho eval ever 4 months if ANA positive, 6 months if ANA Negative
Polyarticular JIA
5+ joints involved
small joints commonly affected
less frequent uveitis
girls>boys
ankylosing spondylitis
age of onset 15-35
HLA B-27
Sacroilitis, enthesopathies, bamboo spine, uveitis
Psoriatic arthritis
PENCIL IN A CUP phalangeal deformity
nail pitting
dactylitis
reactive arthritis
IMMUNE COMPLEX mediated
reaction to chlamydia, yersinia, salmonella, campylobacter, shigella
- associated with conjunctivitis and dysuria
Hypophosphatemic rickets
Most common type in the United States
X-linked dominant, impaired renal phosphate ABSORPTION
Decreased phosphate
NORMAL calcium, PTH and vitamin D
increased alkaline phosphatase
Tx: High-dose phosphate and vitamin D
Burosumab FGF-23 antibody
Vitamin D deficient rickets
NUTRITIONAL Deficiency
Decreased vitamin D, calcium, and phosphate;
increased PTH and alkaline phosphatase
Vitamin D replacement
Vitamin D dependent, type 1
Autosomal recessive
Defect in RENAL 25-hydroxyvitamin D 1-α-hydroxylase
Low calcium and phosphate
NORMAL 25-hydroxyvitamin D
very low 1,25-dihydroxyvitamin D
high alkaline phosphatase and PTH
Tx: 1,25-Dihydroxyvitamin D replacement
Hypophosphatasia
Autosomal recessive
deficient or nonfunctional alkaline phosphatase
Increased calcium and phosphate levels
very low alkaline phosphatase levels
normal PTH/vitamin D levels
early tooth loss
tx: Asfotase alfa
Genetic defect in trisomy 21
maternal duplication of chromosome 21
phenotype trisomy 21
flattened face
upward slanting eyes
epicanthal folds
SINGLE palmar crease
Congenital heart disease:
- endocardial cushion defects in 50%
duodenal atresia
hypothyroidism
hearing loss
ligamentous laxity
high incidence of leukemia/lymphoma
spine features of trisomy 21
ATLANTOAXIAL INSTABILITY
- if ADI >5 and symptomatic, or >10 and asymptomatic
scoli most common, least dangerous
spondylolisthesis
lower extremity manifestations of trisomy 21
metatrsus primus varus
pes planovalgus
hallux valgus
patellar dislocation/instability
late onset hip instability
osteogenesis imperfecta
Col1a1 and 1a2 genes
decreased number of trabeculae and decreased cortical thickness
Types: ALL are autosomal dominant (90% of patients are type I or IV)
I: least severe - quantitative disorder
II most severe - qualitative disorder
III: most severe survivable form - qualitative
IV: moderate severity normal hearing - qualitative
Spine manifestations of OI
*** type II and III (most severe forms II always lethal in childhood)
BASILAR INVAGINATION
severe scoli
Gaucher’s disease
B-glucocerebrosidase deficiency -> macrophages stuffed with glucocerebrosides
- MSK manifestations
erlenmeyer flask distal femurs
osteonecrosis of the hips/femoral condyles
cortical thinning
Caffey’s diesease
FEBRILE illness, hyperirritable
hyperostosis of infancy
average age of onset - 9weeks
self resolving, diagnosis of exclusion
kids often get NAT workup
esr and alkphos are elevated
MANDIBLE involvement is pathognomonic
forearm (ulna) next most common
VERTEBRA AND PHALANGES ARE NOT INVOLVED
