MSK Pt 2 Flashcards
What are 4 types of skeletal dysplasia? Which one is most common lethal? Which one is not?
Thanatophoric dysplasia (most common lethal)
achondrogenesis
ostegenesis imperfecta
achondroplasia (most common nonlethal)
_______________, ______________, and ________________ dwarfism are caused by the different mutations in the fibroblast growth factor receptor 3 gene
achondroplasia, hypochondroplasia, and thanotophoric
Achondroplasia:
most common nonlethal
autosomal dominant
What can we see with achondroplasia? (9)
rhizomelic shortening mild limb bowing exaggerated lumbar lordosis macrocephaly trident hands frontal bossing mid face hypoplasia flattened nasal bridge broad mandible
Which type of SD is lethal within the first 2yrs of life?
homozygous achrondroplasia
Heterozygous achondroplasia:
compatible with normal life + intellectual development rhizomelic shortening large head + prominent forehead flattened nasal bridge spinal kyphosis or lordosis varus or valgus deformities ear infections sleep apnea hydrocephalus
What is spinal kyphosis vs. lordosis
kyphosis- convex curvature (hunchback looking spine)
lordosis- concave curvature (sticking butt out like a try hard looking spine)
What is varus and vagus deformities
varus- bowlegged
valgus- knock knee
What GA can we see the shortened limbs/disparity between head size and FL?
21-27 wks
What do we see with heterozygous achondroplasia?
macrocephaly kyphoscoliosis thoracic dysplasia polyhydramnios micromelia
What do we see with thanatophoric dwarfism?
extremely short limbs extra skin folds narrow chest short ribs underdeveloped lungs enlarged head w/ large forehead prominent, wide shaped eyes
What are the 2 types thanatophoric dwarfism?
Type I- distinguished by the presence of curved thigh bones and flattened bones of the spine (platyspondyly)
Type II- straight thigh bones and a moderate to severe skull abnormality (cloverleaf skull)
What do we see with thanatophoric dysplasia:
severe micromelia severe thoracic dysplasia polyhydramnios cloverleaf skull also: ventriculomegaly, macrocranium, cerebellar hypoplasia, prominent forehead, saddle nose, hypertelorism, short ribs, platyspondyly, bowed legs
What is platyspondyly
radiographic feature and refers to flattened vertebral bodies throughout the axial skeleton
most common spinal abnormality in the axial skeleton
What’s a sign of thanatophoric dysplasia? (this was on a slide by itself so ?important)
significant narrowing of the chest and prominent abdomen
Achondrogenesis:
2nd most common lethal skeletal dysplasia, most severe degree of limb shortening
trident fingers and frontal bossing
Achondrogenesis type I vs. type II
type I- inherited autosomal recessive
most severe form. Characterized by: inadequate ossification of the skull, spine + pelvis, extensive shortening of tubular bones, multiple rib fractures
type II- various degrees of calcifications of the pelvis, skull, and spine. Without rib fractures. Mostly sporadic (new autosomal dominant mutations)
What are the characteristics of achondrogenesis type I (9):
autosomal recessive severe micromelia thoracic dysplasia short ribs with multiple fractures short trunk macrocrania focal bone hypomineralization, especially of the spine calvarium demineralized polyhydramnios
What are the characteristics of achondrogenesis type II (5):
autosomal dominant
lack of mineralization to vertebral bodies, sacrum and ischium
enlarged calvarium w/ normal ossification
shortening of ribs
absence of fractures
What is a useful measurement when looking for achondrogenesis?
FL to BPD
often below 5th percentile
Hypophospatasia is an inherited condition that affects:
bones + teeth
Infants with hypophosphatasia are born with:
short limbs, an abnormally shaped chest and soft skull bones
spine is usually hypomineralized whereas with osteogenesis type II, the spine is not affect
What two conditions are most commonly associated with hypomineralization of the spine?
achondrogenesis type I and hypophosphatasia
skull is not affected with achondrogenesis type I
Osteogenesis imperfecta:
congenital bone disorder characterized by brittle bones that are prone to fracture
What are the two types of osteogenesis imperfecta:
Type 1- blue sclera, hyperlaxity of ligaments and skin. Hearing impairment. No prenatal deformities
Type 2- lethal, no ossification of the skull, beaded ribs, shortened and crumpled long bones, multiple fractures, thorax short but not narrow
What condition is most commonly associated with fetal fractures?
osteogenesis imperfecta
Caudal regression syndrome:
impairment of the development of the lower half of the body–lower back/limbs/GU and GI tract
bones of lower spine are frequently misshapen or missing (same with corresponding spinal cord)
incomplete closure of spine
breathing problems
There’s a lot of shit on this PPT
too much info for these cards
What are the genital abnormalities seen in females + males with caudal regression?
males- urethral opening on underside of penis (hypospadia) + cryptorchidism
females- rectovaginal fistula
*both can lack genitalia all together in severe cases
What are the GI abnormalities seen with caudal regression?
malrotation of large intestine
imperforated anus
inguinal hernias
What are the urinary abnormalities seen with caudal regression?
unilateral renal agenesis
horseshoe kidney
ureteral duplication
bladder exstrophy
What is sirenomelia?
legs are fused together
usually fatal bc of abnormal kidney + bladder developmet
What causes sirenomelia?
failure of a normal vascular supply from lower aorta in utero
Amniotic band syndrome:
spectrum of abnormalities which results from entrapment of various fetal parts from a disrupted amnion
Radial ray anomaly:
large spectrum of upper limb anomalies which range from partial to complete deficiency of the radius w/ or w/o accompanying deficiency of the thumb
Polydactyly:
foot/hand w/ more than 5 digits
a/w tri-13, Meckel Gruber Syndrome (encephalocele, polydactyly + renal cystic dysplasia)
Clinodactyly is what? What is it most a/w?
inward curvature of 5th digit of the hand due to hypoplasia of the mid phalanx
tri-21 - 61%
Persistently clenched hand with overlapping fingers is a/w?
aneuploidic: tri-18 (edwards syndrome) tri-13 (patau syndrome) non-aneuploidic: Pena-Shokei syndrome Smith-Lemli-Opitz syndrome
What is Pena-Shokeir syndrome?
autosomal recessive non aneuploidic condition with some clinical features similar to tri18. Lethal
What is Smith-Lemli-Opitz syndrome?
lack of cholesterol production as well as build up of potentially toxic by-products of cholesterol production which accumulates in the blood and other tissues
Trident fingers:
short stubby fingers with a separation b/w middle and ring fingers
a/w various chondrodysplasias
Syndactyly:
congenital fusion of 2 or more digits. Can be soft tissue or bone
tends to affect 3rd + 4th digits
Clubfoot:
abnormal deviation of the foot in relation to the tib + fib
majority of the cases the sole is turned medially
mostly isolated
can be caused by abnormal bone formation, spina bifida + muscular defects
Rocker bottom feet:
convex curvature of the pedal arch (like a rocking chair) + is most commonly a/w tri-18
Sandal foot:
increase in space b/w great toe and second toe
can be normal, but also a soft marker
a/w tri21
Which form of achondroplasia is incompatible with normal life?
heterozygous
Which type of thanatophoric dysplasia is distinguished by curved femurs and a flattened spinal column?
type I
What condition is likely indicated if you find fractured bones and a region of irregular thickening at the area of the fracture?
hypophosphatasia
Which type of skeletal dysplasia has the most severe degree of limb shortening?
achondrogenesis
What skeletal disorder is sometimes referred to as “brittle bone disease/syndrome”?
osteogenesis imperfecta
Misshapen lower spinal vertebrae and absent spinal cord below L2 would be characteristic of what condition?
caudal regression
