Peds -- Msk

Front 1

1. What is the DDX of diffuse periosteal reaction in a CHILD?
2. What is Caffey's disease and what are the imaging findings?
3. Why is periosteal elevation so commonly seen in infants?

Back 1

1.
- Physiologic in the first 6 months: symmetrical; does not involve the metaphysis. Follow up films show confluence of the periosteal reaction with the existing cortex.
- Caffey's disease (AKA infantile cortical hyperostosis)
- Pachydermoperiostitis: primary HOA.
- Infection (osteomyelitis, congenital syphilis): most commonly involves the metaphysis which is a differentiating feature from normal physiologic periosteal bone formation.
- Trauma (child abuse)
- Malignancy (primary bone tumor vs. mets (NB), leukemia)
- Prostaglandin therapy: look for history of cardiac disease.
- Hypervitaminosis A
- Scurvy
2. Caffey's disease
- AKA infantile cortical hyperostosis
- Self-limited inflammatory disorder characterized by fever, irritability.
- Occurs in the first 6 months of life
- Periosteal new bone formation affects the MANDIBLE, ribs, clavicle, and ulna. Pts may have failure to thrive due to madibular pain.
- Features that allow differentiation from physiologic periosteal reaction are irregular, asymmetric periosteal reaction and presence of soft tissue swelling over the affected areas.
3. Periosteum and perichondrium are loosely attached to the diaphysis in infants. The periosteum is firmly attached to the metaphysis.

Front 2

1. What is a complication of a Salter Harris fx?
2. What modality is best in demonstrating physeal injury?

Back 2

1. Injury to the growth plate which can result in premature fusion of the physis resulting in angular deformity or leg length discrepancy.
2. MRI is better than CT. Whereas CT only shows bony trabeculae traversing the growth plate, MRI can detect both bony and fibrous physeal bridges.

Front 3

1. What are the common sites of Toddler fractures?
2. What are the imaging findings?

Back 3

1. Distal tibial shaft, calcaneus, and cuboid bones.
2. Initial radiographs are usually normal. Follow up radiographs may demonstrate sclerosis along the fracture line or periosteal reaction.

Front 4

What fractures are more specific more child abuse?

Back 4

- Transverse fx of the metaphysis/Bucket handle fractures
- Fxs of the sternum, scapula, and spinous processes.
- Skull fx
- Posterior rib fractures
- Lower extremity fxs in infants who are not of walking age (Toddler fxs seen in infants that walk).

Front 5

1. Why is the epiphysis spared in cases of osteomyelitis? What is the exception?
2. Describe how osteomyelitis occurs.
3. What are the radiographic findings of osteomyelitis?
4. How is MRI helpful in the evaluation of osteomyelitis?

Back 5

1. Osteomyelitis spares the epiphysis as the metaphyseal vessels do not cross the physis. However under 18 months of age, transphyseal arteries are present that link the two circulations.
2. Bacteria infect the marrow space resulting in increased signal intenisty within the marrow space. Intramedullary edema leads to increased intramedullary pressure and venous thrombosis. Unlike the rest of the body's tissues, bone volume does not increase with edema. Instead, the pressure drives the pus to burrow through and out of the cortex, elevating the periosteum. The elevated periosteum ossifies, forming a tunnel around the stream of pus flowing from the marrow cavity. The infection, no longer confined to the bone, may now invade soft tissues and joint spaces.
3. Radiographic bone findings for osteomyelitis are undetectable until 7-10 days after infection (30% bone loss is required for detection on radiography). Bone lucencies, cortical disruption, trabecular destruction, and periosteal new bone formation.
4. MRI is helpful in early detection of osteomyelitis, extension to soft tissues and growth plate. Infection of the physis may lead to growth arrest, hence early intervention is imperative.

Front 6

1. What is DDX of dense metaphyseal bands?
2. What is the mechanism of dense metaphyseal bands in lead poisoning?

Back 6

1.
- Normal physiologic sclerosis
- Heavy metal intoxication (lead, bismuth)
- Treated rickets
- Treated lymphoma/leukemia
- Hypervitaminosis D
- Hypothyroidism
- Hypoparathyroidism
2. Lead in the bone interferes with osteoclastic activity in the zone of provisional calcification (distal metaphysis) resulting in dense metaphysis.

Front 7

What is the DDX of erlenmeyer flask deformity?

Back 7

1. Anemia (Thalassemia and sickle cell disease): expansion of marrow spaces results in remodeling of bones.
2. Gaucher disease: absence of lysosomal enzyme results in accumulation of glucosylceramide which accumulates in the RES and infiltrates the marrow. Look for osteopenia, medullary expansion, and remodeling. Infiltrating cells have a similar SI to hematopoietic marrow.
3. Multiple hereditary exostoses: sessile osteochondromas result in Erlenmeyer flask deformity.
4. Fibrous dysplasia: variable density due to different degress of osseous and fibrous tissue.
5. Osteopetrosis: failure of osteoclast fxn that results in dense but fragile bones. In addition to Erlenmeyer flask deformity, look for increased bone density, bone-in-bone appearance, sandwich vertebrae.
6. Pyle disease (metaphyseal dysplasia)

Front 8

What are the imaging findings of thalassemia?

Back 8

In cases of severe anemia, there will be marrow expansion.
- Marrow hyperplasia will cause widening of the medullary cavities.
- Coarsened trabeculae and squaring of bones.
- Widening of the calvarium and hair-on-end appearance
- Erlenmeyer flask deformity
- Extramedullary hematopoiesis seen in the liver, spleen, and lymph nodes.

Front 9

What is the DDX of wormian bones?

Back 9

PORKCHOPS
P - Pyknodysostosis
O - Osteogenesis imperfecta
R - Rickets
K - Kinky hair syndrome
C - Cleidocranial dysostosis
H - Hypothyroidism / Hypophosphatasia
O - Otopalatodigital syndrome
P - Primary acroosteolysis (Hajdu-Cheney)/ Pachydermoperiostosis / Progeria
S - Syndrome of Downs

Front 10

Congenital syphilis

Back 10

- Widened metaphyses with fraying and fragmentation as the spirochetes kill the osteoblasts interfering with enchondral ossification at the gowth plate.
- Erosive changes at the medial proximal metaphysis of the tibia = Wimberger's sign.
- Diffuse periostitis
- Saber shin tibia (anterior bowing and marked thickening of the anterior cortex)

Front 11

Celery stalk appearance of metaphysis

Back 11

- longitudinally aligned linear bands of sclerosis.
- Seen in congenital infections (syphilis, CMV, rubella) and
osteopathia striata

Front 12

Vertebra plana in a child

Back 12

LCH
- usually at a single level but can be multiple.
LEUKEMIA/LYMPHOMA
- more commonly multiple
OSTEOMYELITIS:
- Bacterial infection affects the disc resulting in disc destruction and vertebral body end-plate erosions.
- TB spondylitis: results in bone destruction with relative disc preservation.
METS
- NB mets

Front 13

MSK manifestations of Down syndrome

Back 13

- Wormian bones
- Hypoplastic arch of C1
- Atlantoaxial subluxation
- Absent 12th rib
- Short tubular bones of the hands, including clinodactyly
- Wide iliac wings
- Hip dysplasia
- Patellar dislocation

Front 14

MSK manifestations of hypothyroidism

Back 14

- markedly delayed skeletal maturity
- bullet vertebrae at the thoracolumbar junction.
- fragmentation of the epiphysis

Front 15

Lucent metaphyseal bands

Back 15

LEUKEMIA
- ALL is the most common subtype
- subperiosteal infiltration of leukemic cells leas to periosteal elevation.
RICKETS
OSTEOMYELITIS
NB METS
SCURVY
- 2/2 vitamin C def
- look up "Zone of frankel" and Wimberger ring
SYPHILIS:
- bilateral upper medial tibial destruction is known as Wimberger sign (can also see destruction in this region with osteomyelitis and hyperPTH)
- Saber shin deformity refers to thickening of the anterior tibial cortex during healing.

Front 16

Fibromatosis Coli

Back 16

- Infants turn their head away from the affected side.
- 2/2 perinatal injury usually 2/2 partial muscle tear or intramuscular hematoma
- PAINLESS, palpable mass and torticollis.
- Most often present by 2 months of age and regresses spontaneously by 8 months.
- Focal thickening and fibrosis of the SCM muscle which blends with the normal muscle. Fascial planes should be intact and there should be no local invasion.
- If there is tenderness or local invasion, consider infections and tumors.