Msk Usmle Step 1

Front 1

What type of ossification is not affected in Achrondroplasia?

Back 1

Membranous ossification (so they have a normal head size)

Front 2

Genetics involved in Achondroplasia?

Back 2

AD, mutation in fibroblast growth factor receptor gene. Activates it so it inhibits chondrocyte proliferation

Front 3

Main type of bone that is reduced in osteoporosis?

Back 3

-trabecular (spongy bone)
-normal bone mineralization

Front 4

Secondary causes of osteoporosis?

Back 4

increased cortisol, heparin, hypogonadism, space travel

Front 5

defect in osteoporosis?

Back 5

increased osteoclasts, decreased osteocbasts. Estrogen inhibits production of osteoclasts and enhances osteoblasts

Front 6

MC type of fracture in osteoporosis?

Back 6

vertebral fracture

Front 7

TX of osteoporosis?

Back 7

estrogen, calcitonin (inhibits osteoclasts, bisphosphonates or pulsatile PTH for severe cases.

Front 8

What is contraindicated in osteoporosis?

Back 8

Glucoccorticioids are c/I

Front 9

what is the bone defect due to in osteopetrosis?

Back 9

osteoclasts

Front 10

T,F alkaline phosphatase is normal in osteopetrosis?

Back 10

T

Front 11

Genetic deficiency in osteopetrosis

Back 11

carbonic anhydrase II

Front 12

Clinical findings of osteopetrosis?

Back 12

-anemia, thrombocytopenia, infection (decreased marrow)
-hearing and visual loss (cranial nerve impingement)

Front 13

Osteomalacia/ rickets

Back 13

-Defective mineralization/calcification of osteoid (organic bone matrix)
-fractures and bone pain

Front 14

What causes osteitis fibrosa cystica?

Back 14

-hyper-PTH
-cystic spaces are lined by osteoclasts filled with fibrous stroma and sometimes blood

Front 15

Labs of osteitis fibrosa cystica?

Back 15

-High calcium, low phosphorus, and high ALP

Front 16

Clinical sx of osteitis fibrosa cystica?

Back 16

-Brown tumors
-Bone lesions
-commonly involves jaw

Front 17

Common age of Paget's?

Back 17

men > 50

Front 18

Where does paget's target?

Back 18

Skull, pelvis femur

Front 19

What causes Paget's?

Back 19

abnormal bone architecture caused by increase in both osteoblastic and osteoclastic activity. Possibly paramyxovirus

Front 20

Lab values of Pagets?

Back 20

-Calcium, phosphorus and PTH levels are normal
-Increased ALP

Front 21

early phase and late phase of pagets?

Back 21

in early phase osteoclasts are increased = lytic lesions
-in late phase osteoblasts are increased

Front 22

clinical findings?

Back 22

-bone pain
-headaches (increased hat size)
-hearing loss (auditory narrowing of foramen)
-high output heart failure (increase in AV shunts
-can lead to osteogenic sarcoma

Front 23

describe the bone in pagets?

Back 23

-weak, thick vascular
-mosaic bone pattern
-long bone chalk-stick fractures

Front 24

What causes Polyostotic fibrous dysplasia?

Back 24

-Bone is replaced by fibroblasts, collagen, and irregular bony trabeculae.
-defect in osteoblastic differentiation and maturation
-defects in forming mesenchyme.
-Replacement of medullary bone by fibrous tissue with cyst formation

Front 25

McCune-Albright sydrome

Back 25

form of polyostotic fibrous dysplasia chracterized by multiple unilateral bone lesions associated with endocrine abnormalities (precocious puperty)
-unilateral pigmented skin lesions (cafe-au-lait spots)

Front 26

treatment of Polyostotic fibrous dysplasia?

Back 26

surgery

Front 27

MC location for Polyostotic fibrous dysplasia?

Back 27

ribs

Front 28

complications of Polyostotic fibrous dysplasia?

Back 28

pathologic fractures, osteogenic sarcoma, fibrosarcoma

Front 29

osteoma

Back 29

-benign
-a/w gardner's
-new piece of bone grows on another piece of bone, often in the skull
(OMAR was a gardner with strange facial bones. New plants would grow on top of other plants in the garden)

Front 30

Osteoid osteoma

Back 30

-interlacing trabeculae of woven bone surrounded by osteoblasts
-<cm
-proximal tibia and femur
-mc in men <25 yrs
(Jr. Omar was <25, and was a weaver who was growing quickly, esp in his legs)

Front 31

Osteoblastoma

Back 31

-benign
-Same morphologically as osteoid sarcoma but larger and found in vertebral column
"One day Omar blasted off in a rocket and landed on his vertebrae"

Front 32

Giant cell tumor (osteoclastoma)

Back 32

-Epiphyseal end of long bones
-20-40 yrs (f)
-aggresive benign
-distal femur, proximal tibial (knee)
- double bubble or soap bubble
-spindle-shaped cells with multinucleated giant cells
"The 20-40 yr old giant was long and aggressive. She loved to blow bubbles but one day she clashed with other multi-giants and fell into a spindle-shaped tree with her knee"

Front 33

Osteochondroma

Back 33

-MC bengin bone tumor
-Mature bone with cartilaginous cap.
-usually in men <25
-Originates from metaphysis
-Maligant transformation is rare

Front 34

Enchondroma

Back 34

-benign cartlaginous neoplasm found in intramedullary bone
-usually distal extremities (vs chondrosarcoma)
-small tubular bones in hands and feet
"Edward has small hands and feet and drove a medium car. He was bengin"

Front 35

Osteosarcoma

Back 35

-2nd mc primary malignant tumor of bone (after multiple myeloma)
-men 10-20 yrs
-metaphysis of long bones in knee
-Codman's triangle or sunburst pattern (from elevation of periosteum) on x-ray
-poor prognosis

-

Front 36

Predisposing factors to osteosarcoma?

Back 36

-pagets
-bone infarcts
-radiation
-familial retinoblastoma

Front 37

ewing's sarcoma

Back 37

-anaplastic small blue cell malignant tumor
-boys ,15
-extremely agressive with early mets but responsive to chemotherapy
-Onion-skin appearance in bone
-diaphysis of long bones, pelvis scapula and ribs
-11;22

"ewing was a mean aggresive little boy who would draw blue dots all over evryone. He was long and his breath smelled like onions. He would beat people up in the pelvis, scapula and ribs"

Front 38

Chondrosarcoma

Back 38

-Malignant cartilaginous tumor
-men 30-60
-pelvis, spine, scapula, humerus, tibia or femur
-Expansile glistening mass within medullary cavity

Front 39

classic triad of sjogren's syndrome

Back 39

1. Xerophthalmia (dry eyes, conjunctivitis)
2. Xerostomia (dry mouth dysphagia
3. Arthritis
-also parotid enlargment (destruction of minor salivary glands and lacrimal glands, autoimmune)

Front 40

sicca syndrome

Back 40

-sjogren's syndrome
-dry eyes, dry mouth, nasal and vaginal dryness, chronic bronchitis, reflux esophagitis.
-no arthritis

Front 41

autoantibodies in sjogren's

Back 41

-ribonucleoprotein antigens, SS-A (Ro), SS-B (La)
-serum ANA
-RF
-lipid biopsy confirms

Front 42

TX for sjogrens syndrome?

Back 42

muscarinic agonist

Front 43

What can cause gout?

Back 43

-lesch-nyhan syndrome
-prpp excess
-decrease excretion of uric acid (thiazide diuretics)
-increased cell turnover (von Gierke's dz
-90% due to underexcretion
-10% due to overproduction

Front 44

cystals in gout?

Back 44

monosodium urate crystals

Front 45

cyrstals in pseudogout?

Back 45

calcium pyrophosphate

Front 46

SLE

Back 46

IM DAMN SHAPR
-Immunoglobulins
(ant-dsDNA, ant-Sm, antiphospholipids)
-Malar rash
-discoid rash
-antinuclear antibody
-Mucositis (oropharyngeal ulcers)
-Neurologic disorders
-Serositis (pleuritis, pericarditis)
-Hematologic disorders
-Arthritis
-Renal disroders
-Photosensitivity

Front 47

Why do you get a false positive on syphilis test in SLE?

Back 47

-antiphospholipid antibodies cross react with cardiolpin use

Front 48

Positive antinuclear antibody diseases

Back 48

-SLE
-Sjogrens (sicca)
-scleroderma
-polymyotositis
-rhematoid arthritis
-juvenile arthritis
-mixed connective tissue disorders

Front 49

Sarcoidosis

Back 49

GRAIN
Gammaglobinemia
Rheumatoid arthritis
ACE increase
Interstitial fibrosis
Noncaseating granulomas

Front 50

Manifestations of Sarcoidosis?

Back 50

-African American female
-Restrictive lung dz
-non-caseating granulomas
-b/l hilar lymphadenopathy
-erythema nodosum
-Bell's palsy
-epithelial granulomas (schauman and asteroid bodies)
-uveoparotitis
-hypercalcemia

Front 51

Clinical presentation of Sarcoidosis

Back 51

#1 symptom = dyspnea
-blurry vision

Front 52

tx of sarcoidosis?

Back 52

steroids

Front 53

Clnical presentation of Polymyalgia rheumatica

Back 53

-Pain and stiffness in shoulders and hips
-fever, malaise and weight los
-NO MUSCULAR WEAKNESS
-pt >50
-a/w temporal (giant cell) arteritis)

Front 54

Lab values of Polymyalgia rheumatica and tx?

Back 54

labs: increased ESR, normal CK
tx: prednisone

Front 55

What causes Polymyositis

Back 55

-CD T cell-induced injury to myofibers.
-autoimmune
-inflammatory myopathy and cutaneous involvement

Front 56

Clinical presentation of Polymyositis

Back 56

-progressive symmetric proximal muscle weakness
-most often shoulders
-does not involve rash
-pts have difficulty climbing the stairs, rising from a seating position and combing their hair

Front 57

labs for polymyositis and dermatomyositis

Back 57

-increased CK
-increased aldolase
-poitive ANA and anti-jo-1

Front 58

tx for polymyositis and dermatomyositis

Back 58

steroids

Front 59

dermatomyositis

Back 59

-similar to PM (m weakness) but involved malar rash, helitrope rash, shawl and face rash, Grottron's papules (purple papules over hand, mahcanics hand)
-increased risk of maliganancy

Front 60

Clinical symtoms of Myasthenia gravis?

Back 60

-ptosis, diplopia general weakness
-a/w thyoma
-sx worse with muscle use
-reversal of symptoms with AChE inhibitors

Front 61

Tensilon test

Back 61

used in Myasthenia gravis,
infustion of short-acting cholines
-if it works = myasthenia gravis
-if it doesn't = cholinergic crisis

Front 62

What causes Myasthenia Gravis

Back 62

MC NMJ disorder
-autoantibodies to postsynaptic AChR

Front 63

What causes Lambert-Eaton syndrome?

Back 63

Autoantibodies to presynaptic Ca2+ channels result in decrease in ACh release leading to proximal muscle weakness.
-symptoms improve with muscle use
-no reversal of symptoms with AChe inhibitors alone

Front 64

Clinical presentation of Lamber-Eaton?

Back 64

Proximal muscle weakness
-extra-ocular muscles are spared
-hyporeflexia, areflexia
-gait alteration
-dysphagia, dysarthia

Front 65

What is Lamber eaton?

Back 65

paraneoplastic diseases (small cell lung cancer)

Front 66

Clinical presentation of Scleroderma

Back 66

-Excessive fibrosis and collagen deposits throughout the body.
-puffy and taut skin with absence of wrinkles
-Also sclerosis of renal, pulmonary, cardiovascular, and GI systems

Front 67

Diffuse scleroderma

Back 67

-widespread skin involvement, rapid progression, early visceral involvement
-A/w anti-Scl-70 antibody (anti-DNA topoisomerase I antibody)

Front 68

CREST syndrome

Back 68

Calcinosis
Raynaud's phenomenon
Esophageal dysmotility
Sclerodactyly
Telangectasia
-limited skin involvement, often confined to fingers and face. More benign clincical course
-a/w anitcentromere antibody (C for CREST)