MSK Flashcards
A lateral blow to the knee causes the “unhappy triad” injury. What makes up the triad?
LAMe
LAME
Lateral meniscus
MCL
ACL
Dislocation of which wrist bone can cause median nerve compression?
Lunate
Which 2 nerves come off the posterior cord of the brachial plexus?
Axillary and radial (i.e. extensors)
Trauma to which wrist bone can damage the ulnar nerve?
Hamate (specifically the hook)
“Pope’s blessing” claw = _____ nerve damage.
Ulnar
What nerve innervates the thenar muscles?
Median
Which muscles are responsible for the clawing defects seen in ulnar and median nerve lesions?
Lumbricals
Flex at MCP, extend at PIP and DIP
What is the MOA of etanercept, a drug used to treat moderate-to-severe RA in patients who have failed methotrexate alone?
A decoy TNF-alpha that binds to the Fc component of IgG to reduce the biological activity of TNF-alpha
What is McCune-Albright syndrome and how does it present?
Mutation in GNAS gene -> constant G protein activation -> hormone overproduction
Peripheral precocious puberty
Irregular cafe-au-lait macules
Polyostotic fibrous dyslplasia
What is Legg-Calve-Perthes disease?
A disease of young children that results in isolated idiopathic osteonecrosis of the hip.
Which band does not get smaller in muscle contraction?
A band
“HIZ shrinkage”
Which autoimmune marker is seen in primary biliary cirrhosis?
Anti-mitochondrial antibodies
Which artery is at risk from a femoral neck fracture?
Medial circumflex
Anti-Jo antibodies are Abs against what exactly?
(seein in polymyositis!)
Against histidyl-trna-synthetase
What are the treatments for ACUTE gouty arthritis and what is the MOA?
NSAIDs are fine in most patients but if not (i.e. renal failure, PUD)…Colchicine:
Anti-inflammatory that binds intracellular tubulin preventing tubulin polymerization into microtubules -> impaired leukocyte migration and phagoyctosis -> reduced inflammation
Can cause n/v/d
What drug is contraindicated/needs to be monitored with allopurinol (xanthine oxidase inhibitor) use?
Azathioprine
Longterm treatment for gout?
Allopurinol (xanthine oxidase inhibitor) to decrease uric acid production
In addition to spinal problems, what other symptoms can ankylosing spondylitis patients present with?
Chronic hypoventilation
Ascending aortitis -> aortic insufficiency
Anterior uveitis
Back pain relieved by walking up hill or leaning on a stroller/shopping cart = ?
Spinal stenosis, usually caused by degenerative arthritis of the spine
This leads to hypertrophy of the ligamentum flavum along the posterior aspect of the spinal canal
What crystal accumulates in pseudogout? How will patients present?
Calcium pyrophosphate
Present with acute mono or oligo arthritis (often knee) characterized by pain, swelling, erythema, and warmth.
Synovial fluid will show blue pos birefringent crystals, rhomboid shaped + neutrophils
Achondroplasia is one of the few diseases whose incidence increases with ________.
Increasing paternal age
Osteopetrosis is due to a gene defect in which enzyme?
Carbonic anhydrase II which impairs the ability of osteoclasts to generate an acidic enough environment for bone resorption.
What is osteopetrosis?
Failure of normal bone resorption due to defective osteoclasts -> thickened, dense bones prone to fracture. Specifically you’ll get overgrowth of cortical bone and filling of marrow space.
Mosaic bone, long bone “chalk stick fracture”, elevated Alk phos = ?
Paget’s disease of the bone
What are the causes of death in Paget’s disease of the bone?
AV shunt formation through bone
Osteogenic sarcoma
Which primary bone tumor is unique in that it tends to occur in slightly older populations (20-40 years)
Giant cell tumor
Multinculeated giant cells
Spindle shapes
Also more common in women
What are osteochondromas?
Most common benign bone tumor - occurs in the metaphysis of bones
Most common in men <25 years
Where are osteosarcomas found? What is the age distribution?
Metaphysis of long bones
Codman’s triangle/sunburst appearance due to lifting off of the periosteum
Bimodal age distribution:
peaks at 10-20 years and 65+
What are predisposing factors to osteosarcoma?
Paget’s disease
Bone infarct
Radiation
Retinoblastoma
Osteophytes (bone spurs) occur in ___arthritis.
Osteoarthritis
DIP pain = ____arthritis.
osteoarthritis
Pannus formation = ____arthritis
Rheumatoid
What crystals are formed in gout?
Monosodium urate - negatively birefringent - yellow - needle shaped
Which arthritis is associated with hemochromatosis?
Pseudogout
Although you need to check crystals to be definitive, what is one indication that you might be seeing pseudogout instead of gout?
Larger joints (e.g. knee) more associated with pseudogout
Polymyalgia rheumatica (joint pain without weakness) is often associated with what disease?
Temporal giant cell arteritis
Polymyositis = proximal muscle ______ but NOT _____.
Weakness but not pain
CD_+ T cells = polymyositis
CD_+ T cells = dermatomyositis
4+ = polymyositis 8+ = dermatomyositis
What is Paget’s disease of the bone?
Localized disorder of bone remodeling caused by increased osteoclastic activity followed by increased osteoblastic activity that forms poor-quality bone -> mosaic pattern of woven lamellar bone.
Which spinal consequence can be seen in RA?
Cervical subluxation
What lab findings will you see in RA?
Positive rheumatoid factor
Anti-citrullinated (CCP) antibodies
What part of the bone does hematogenous osteomyelitis affect?
Metaphysis of long bones
In acanthosis, which layer is thickened?
Spinosum
Which arthritis looks like a “pencil in cup deformity” on xr?
Psoriatic arthritis
Lichen in planus is associated with hepatitis ___.
C
In which skin lesion do you see parakeratosis?
Psoriasis
Which skin cancer is associated with BRAF V600 mutation?
Melanoma
Which skin abnormality can be seen with PBC?
Xanthelasma (excess cholesterol!)
Round papules that evolve into target lesions with a dusky central area = ?
Erythema multiforme
Junctional nevus vs compound nevus.
Junctional nevus is aj nest at the dermoepidermal unction only. Compound nevi have discrete epidermal AND dermal involvement
A curious treatment for psoriasis is with Vitamin ___ analogs such as:
D analogs
calcipotriene (calcipotriol)
May work by inhibiting T cell proliferation and other inflammatory mediators
What are the most serious side effects of bisphosphanates?
corrosive esophagitis and osteonecrosis of the jaw
