Basic Science

Question 1

FRAX score calculates the clinical risk of fracture using

Answer 1

bone mineral density of the femoral neck, BMI, current smoking activity, history of parental hip fracture, and prior personal history of fracture before age 50.

Question 2

PHEX

Answer 2

responsible for X-linked hypophosphatemic rickets

Question 3

CLCN7 and TC1RG1

Answer 3

mutations cause osteopetrosis

Question 4

BMP signaling mech

Answer 4

binds serine/threonin kinase receptor then triggers SMAD which upreg transcription

Question 5

MRSA resistance mech

Answer 5

mutation mecA encoding an altered penicillin binding protein

Question 6

Beta-lactam antibiotics

Answer 6

Penicillin, Cephalosporins inhibit bacterial peptidoglycan synthesis = bac cell wall synthesis

Question 7

Aminoglycosides

Answer 7

Gentamycin, Tobramycin inhibit protein synthesis (via binding to cytoplasmic ribosomal RNA)

Question 8

Clindamycin and Macrolides

Answer 8

Clindamycin, Erythromycin, Clarithromycin, Azithromycin inhibit the dissociation of peptidyl-transfer RNA from ribosomes during translocation (they don’t ask about this one a lot)

Question 9

Tetracyclines

Answer 9

inhibit protein synthesis

Question 10

Glycopeptides

Answer 10

Vancomycin, Teicoplanin interfere with the insertion of glycan subunits into the cell wall

Question 11

Rifampin

Answer 11

inhibits RNA synthesis (you can remember that because they both start with the letter “R”)

Question 12

Quinolones

Answer 12

Ciprofloxacin, Levofloxacin, Ofloxacin inhibit DNA gyrase - they ask a lot about this one

Question 13

Oxazolidinones

Answer 13

Linezolid inhibits protein synthesis by blocking formation of the 70S ribosomal translation complex . Ribosomal activity- Linezolid can cause serotonin syndrome (abdominal pain, headache, diarrhea, and clonus, unresponsive pupillary reaction, tachycardia, hypertension, tremor, and clonus.) Give Benzo to decrease reaction

Question 14

Steroids in spinal cord injury have been shown to do what with regard to edema and hemmorhage?

Answer 14

just prevent exent of hemmorahge, not correlated with outcome. no effect on edema

Question 15

Wheelchair Spinal cord injury: C4,5,6,7

Answer 15

C4 injury needs puffer control; C5 can use hand controls; C6 can use a manual wheelchair and sliding board transfers; C7 allows independent transfers

Question 16

Asia Scale

Answer 16

ASIA A: complete spinal cord injuries. ASIA B: are incomplete injuries and have preserved sensory but no motor function. ASIA C: are incomplete injuries characterized by greater than half of the key muscle groups below the neurological level with muscle grade less than 3. ASIA D: are incomplete injuries characterized by at least half of the key muscle groups below the neurological level with muscle grade greater than 3. ASIA E: implies normal motor and sensory function.. E has Everything

Question 17

malignant peripheral nerve sheath tumor

Answer 17

4% incedence with NF-1 (AD). spindle cell, stains with S100. Tx wide resection +radiation

Question 18

TGF-β1 and muscle injury

Answer 18

causes fibrosis

Question 19

MOM THA cause of pseudotumor

Answer 19

MOM THA: pseudotumors occur more often with increased wear attributable to edge loading. Not lymphocyte activity to metal

Question 20

Rickets effect what zone

Answer 20

Rickets: Due to defective mineralization in zone of provisional calcification. Xrays: Increased physeal width, metaphyseal cupping, bowing. First line deformity treatment- medical (improves physes & alignment)

Question 21

Familial Hypophosphatemic or Vit D resistant Rickets

Answer 21

Also known as “Vitamin D- resistant” rickets or phosphate diabetes. Due to impaired renal tubular phosphate absorption. X linked dominant (usually, also AR, AD). Treat with vit D(1,25 dihydroxy vitamin D3 (calcitriol)) & phosphate

Question 22

Hypophosphatasia Rickets

Answer 22

Autosomal recessive. Due to defect in alkaline phosphatase. Labs- low alkaline phosphatase and high urinary phosphoethanolamine

Question 23

Nutritional/Vit D deficient

Answer 23

Occurs in premies, exclusively breast-fed, intestinal malabsorption. Genu varum, hypotonia, height< 5th percentile. RX with vit D (5000 IU daily)

Question 24

T-score

Answer 24

T-scores are defined as standard deviations from normal peak bone mass (young adults). Osteoporosis is defined as a T-score of -2.5 or below as defined by the WHO, and osteopenia is defined as a T-score between -1.0 and -2.5

Question 25

Z-score

Answer 25

Z-scores compare bone density of the same age and size. Z-scores are not used to stratify patients into categories of “osteopenia” or “osteoporosis” in elderly patients. They are used to aid in the diagnosis of metabolic bone disease in young patients.

Question 26

Osteoconductive mechanism

Answer 26

Osteoconductive bone graft material is described as the scaffold that allows new bone growth. This new bone is created via sprouting capillaries, perivascular tissue, and osteoprogenitor cells on the three-dimensional graft structure, permitting creeping substitution, which allows for graft incorporation.

Question 27

Rickets Labs values