Ch. 26 Fractures, Infections, Metabolic, Rickets

Question 1

Inadequate mineralization of newly formed bone due to an abnormality in vitamin D metabolism, phosphate deficiency, or defects in mineralization itself which causes thicker than normal osteoid on the bony trabeculae. Results in? What are some signs of the childhood form?
Causes of vitamin D deficiency?
Causes of phosphate deficiency?
What is the pseudofractures syndrome associated?

Answer 1

Osteomalacia/Rickets: Weak bone with increased risk for fracture
Rickets signs: frontal bossing, rachitic rosary, bowing of legs, pigeon breast deformity (pectus carnatum)
Vit D: decreased sun exposure, poor diet, malabsorption (intestine damage), renal/liver damage; enzyme/receptor deficit (Type 1: 1a-hydroxylase defect; Type 2: vitamin D insensitivity)
Phos: Mutations in PHEX (breaks down FGF23) leading to high FGF23 that causes phosphate wasting, fanconi syndrome
Fractures: Milkman-Looser syndrome

Question 2

Metabolic bone disease characterized by diffuse skeletal lesions and fractures in weight bearing areas (hip and distal radius/Colles fracture most common) in which remaining bone mineralization is normal with Alk phos, Ca, Phosphate, and PTH all being normal as well.
Describe the two types of this disease.
What are some other risk factors?
Common sign in elderly?
Treatment?

Answer 2

Osteoporosis (porous bone)
Type 1: Estrogen withdrawl: increased osteoclast activity
Type 2: Aging: decreased osteoblast activity
***Risk: smoking, Vit D deficiency, low body mass, Hyperthyroid/parathyroid, hypogonadism, sedentary lifestyle, hematologic malignancies, GLUCOCORTICOID THERAPY
Sign: Patient becomes shorter, kyphosis/Dowager’s Hump
Rx: Bisphosphonates, Vit D and calcium

Question 3

Large, phagocytic cells with pale, eosinophilic cytoplasm and convoluted or grooved nuclei. “Birbeck granules”
Subtypes
1. Radiolucent lesions of the skull, diabetes insipidus, exophalmos, age 2-5
2. Hepatosplenomegaly, lymphadenopathy, anemia, leukopenia, thrombocytopenia, failure to thrive, cachectic, progressive bone lesions and pulmonary infiltration that can cause death
3. Self limiting, one or two lytic areas in bone

Answer 3

Langerhans Cell Histiocytosis

1. Hand-Schuller-Christian (May need radiation, DI seesm to be irreversible)
2. Letterer-Siwe (aggressive chemo)
3. Eosinophilic Granuloma

Other Rx: corticosteroids, cyclophosphamide, basically suppress that crazy immune system

Question 4

Bone infection (aka?)…

1. …leading to resorption of bony trabeculae of the vertebrate and extrusion of the intervertebral disk
2. …most common in sickle cell disease
3. …important in diabetic or IV drug user
4. …due to CAT/dog bite
5. …causing excess reactive bone formation leading to deformed and short bone in the congenital version and SABER SHINS/SADDLE NOSE in the acquired adult version
6. …most common overall

Answer 4

Osteomyelitis

1. Tuberculosis/Pott Disease
2. Samonella
3. Pseudomonas
4. Pasteurella
5. Syphilis
6. Staph followed by Strep

Question 5

Most common site of origination by hematogenous osteomyelitis?
Which is more common in the US, hematogenous or direct infection?
Clinical signs?
VOCAB!
Cloaca:
Sequestrum:
Brodie abscess:
Involucrum:

Answer 5

Metaphysis (knee ankle hip)
Direct
Cloaca: hole formed in bone during formation of draining sinus
Clinical signs: Bone pain with fever and leukocytosis; x-ray shows lytic focus surrounded by sclerosis
Sequestrum: fragment of necrotic bone that is embedded in the pus
Brodie abscess: consists of reactive bone from the periosteum and the endosteum, which surrounds and contains the infection
Involucrum: lesion in which periosteal new bone formation forms a sheath around the necrotic sequestrum (may exist for years before seeking medical help)

Question 6

Describe the process of a bone infection

Complications of bone infection?

Answer 6

Microabscess->Expansion of abscess leads to woven bone formation to surround it->abscess expands through cortex into subperiosteal tissue, SHEARS OFF PERFORATING ARTERIES->NECROSIS OF THE CORTEX->Abscess extends into joint space/epiphysis and forms draining sinus
(Sequestrum=dead bone; Involucrum: surrounding viable bone)
Complication: Septicemia, Acute bacterial arthritis, pathologic fractures, SQUAMOUS CELL CARCINOMA, amyloidosis, chronic osteomyelitis (usually requires amputation)

Question 7

Benign condition mimicking a malignant neoplasm causing heterotopic ossification typically following blunt trauma to muscle and soft tissue. What differentiates it from neoplasm

Metastatic vs dystrophic calcification:

What do we call bone formation outside the skeletal system

Answer 7

Myositis Ossificans
Peripheral maturity with central immaturity (zonation effect)

Metastatic: hypercalcemic vs hyperphosphatemic condition
Dystrophic: due to abnormal or damaged soft tissue, seen in tumors, degenerative disease (arteriolarsclerosis), or trauma

Heterotopic ossification

Question 8

Intramembranous bone formation in response to stress. Characteristic patterns include onionskin pattern and sunburst pattern

Answer 8

Reactive Bone formation

Question 9

Death of bone and marrow in absence of infection, commonly caused by trauma, thrombi, emboli, and corticosteroid use.
What do we call this disease in children which commonly affects the femoral head and leads to severe osteoarthritis?

Answer 9

Avascular osteonecrosis

Legg-Calve-Perthes disease

Question 10

This process involves and inflammatory phase with neovascularization and blood clot formation followed by the reparative phase with woven bone and a CALLUS of cartilage formation. The last phase is called the remodeling phase in which the callus has sealed the injury and reorganization occurs. Name that process.
What can occur if this process is not allowed to occur?

Answer 10

The process described was that of a healing fracture of a bone

A nonunion can lead to a pseudoarthrosis in which joint like tissue is formed at a site of injury due to failed healing and constant movement