Musculoskeletal

Question 1

Describe the changes to bone in Rickets

Answer 1

1. Trabeculae are normal in number and size, but do not mineralize effectively
2. Rim of uncalcified osteoid is much larger than normal

Question 2

Are crystals in gout or pseudogout visible on x-ray?

Answer 2

Gout - no, they are monosodium urate crystals

Pseudogout - yes, they are calcium pyrophosphate dihydrate crystals

Question 3

What are the metabolic side effects of glucocorticoids?

Answer 3

1. hypocalcemia
2. fluid retention
3. hypokalemia
4. hyperglycemia
5. hypernatremia

Question 4

Is celecoxib a sulfa drug?

Answer 4

YES, along with:

sulfonureas, sulfamethoxazole, sulfasalazine, and thiazide diuretics, furosemide, bumetanide

Question 5

Pain at what location is pathognomonic for scaphoid fracture?

Answer 5

anatomic snuffbox – this should be fixed right away because risk of avascular necrosis

Question 6

Which lumbricals does the median nerve innervate?

Answer 6

1st and 2nd (which move the 2nd and 3rd fingers–the pointer and middle finger)

Question 7

What symptoms would be present in a common fibular nerve injury? What is another name for this nerve and how is it commonly injured?

Answer 7

Symptoms:
1. loss of sensation over dorsum of the foot (superficial fibular branch)
2. loss of dorsiflexion and toe extension (deep fibular branch)
AKA: Common peroneal nerve
Common injury: compression at the head of the fibula by bed rest, leg crossing, or hyperflexion of knee (vajrasana → “yoga foot drop”)

Question 8

What type of collagen is affected in osteogenesis imperfecta? What ocular finding is present?

Answer 8

Type I; may present with blue sclera

Question 9

Draw out the brachial plexus

Answer 9

see a picture to check

Question 10

What is tacrolimus?

Answer 10

an immunosuppresant that inhibits calcineurin-mediated transcription of IL-2

Question 11

Which levels innervate the anal wink?

Answer 11

S2-S4 via the pudenal nerve

Question 12

What are the markers of osteoblast and osteoclast activity?

Answer 12

Osteoblast:
- bone specific alkaline phosphatase
Osteoclast:
- TRAP, urinary hydroxyproline, urinary deoxydyridinoline (most reliable)

Question 13

Which gout drug has GI side effects such as nausea, vomiting, and diarrhea? What is its mechanism of action? Is it used for acute or chronic gout?

Answer 13

Colchicine; microtubule polymerization inhibitor; both

Question 14

When overactive, this enzyme can lead to gout

Answer 14

PRPP (5’-phosphoribosyl-1’-pyrophosphate; increases purine production → uric acid)

Question 15

What immune cell mediates the inflammation in gout?

Answer 15

neutrophils (they try to eat the crystals → release cytokines to recruit more neutrophils and cause inflammation)

Question 16

What are the findings in alkaptonuria? What enzyme is deficient?

Answer 16

1. Dark connective tissue (e.g. helix of ears)
2. Brown pigmented sclerae
3. Urine turns black on prolonged exposure to air
4. Arthralgias (homogentisic acid damage to cartilage)
   Deficiency = homogentisate oxidase
   Pathway = Tyrosine → Fumarate

Question 17

What are the top 2 causes of osteomyelitis in SS patients?

Answer 17

1. Salmonella - most common

2. E. coli

Question 18

What is Ecthyma gangrenosum?

Answer 18

a rapidly progressive necrotic cutaneous infection caused by Pseudomonas in immunocompromised patients

Question 19

Key differences b/w polymyalgia rheumatica and fibromyalgia?

Answer 19

1. Age: PMR is more common in ♀ > 50 vs. FM in F8 20 - 50
2. Symptoms: PMR has fever and weight loss, FM has point tenderness
3. Labs: PMR will have ↑ ESR, CRP, (normal CK)
4. Treatment: PMR: low-dose corticosteroids vs. FM: exercise, antidepressants, anticonvulsants

Question 20

Inheritance of achondroplasia?

Answer 20

AD

Question 21

What is a common manifestation of sickle cell disease painful crisis in children?

Answer 21

Dactylitis (painful hand swelling)

Question 22

How does Paget’s disease start?

Answer 22

↑ osteoclast activity

4 stages: lytic, mixed, sclerotic, quiescent

Question 23

Intracellular levels of what substance activates the breakdown of glycogen?

Answer 23

Ca2+

Question 24

What is a central joint that can be affected in reactive arthritis?

Answer 24

sacroiliac joint (20% of cases) → sacroiliits

Question 25

What are the symptoms of polymyositis? Pathophys?

Answer 25

Progressive symmetric proximal muscle weakness; muscle damage → overexpression of MHC I on sarcolemma → CD8+ T cell infiltration → further damage

Question 26

What is etanercept? What do you have to check before using it?

Answer 26

TNF-α inhibitor; See if patient has TB b/c this class of drugs predispose to infection

Question 27

What are some prominent features of congenital hypothyroidism?

Answer 27

``` Pot-bellied Pale Puffy-faced (course facial features) Protruding umbilicus Protuberant tongue Poor brain development Pooped (lethargy, floppy) Poor feeding ```

Question 28

What is Hirschsprung disease?

Answer 28

abnormal migration of neural crest cells into rectosigmoid colon → absence of ganglion cells in wall → abdominal distention, bilious emesis, failure to pass meconium

Question 29

What viral infection can closely mimic rheumatoid arthritis? How can you tell the difference?

Answer 29

Parvovirus; it will self-resolve

Question 30

What are the symptoms of scurvy? Who might get it?

Answer 30

Swollen gums, bruising, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, "corkscrew" hair People on "Tea and Toast" diet, homeless, alcoholics, drug users

Question 31

Where is collagen (proline and lysine residues) hydroxylated by vitamin C?

Answer 31

RER

Question 32

What is the most commonly injured structure in rotator cuff syndrome? How do you test for it?

Answer 32

Supraspinatus tendon because it gets impinged b/w acromion and head of humerus; "empty can" test is 90% specific (abduct arms 90 degrees, flex 30 degrees, point thumbs toward floor)

Question 33

What two signals produced by osteoblasts promote osteoclastic differentiation?

Answer 33

1. Macrophage CSF | 2. RANK-L

Question 34

What kind of hypersensitivity is MG?

Answer 34

II

Question 35

What protein is defective in Marfan's? What is its function?

Answer 35

Fibrillin-1 - a component of microfibrils that forms a sheath around elastin

Question 36

Contrast the functions of golgi tendon organ and extrafusal fibers in the mm.

Answer 36

Golgi: senses when too much stretch → reflex relax Muscle spindle (aka intrafusal fibers): mm. contracts to resist stretch Note that golgi is in series and muscle spindle is parallel to muscle fibers

Question 37

What nerve passes through the obturator foramen? What action do the innervated muscles perform?

Answer 37

Obturator nerve → thigh adduction

Question 38

What two muscles does the median nerve pass between in the arm?

Answer 38

flexor digitorum superficialis and flexor digitorum profundus

Question 39

Injury to this nerve and muscle causes a winged scapula

Answer 39

long thoracic nerve to serratus anterior

Question 40

Does the PCL attach medially or laterally to the midline on the femur? What about the ACL?

Answer 40

PCL: medially ACL: laterally

Question 41

Why is there hypercalcemia in sarcoidosis?

Answer 41

Activated T cells secrete IFN-gamma → ↑ 1α-hydroxylase in Mø → ↑ vit D → ↑ absorption of Ca2+ from GI and kidneys