UWorld-Musculoskeletal Flashcards
comedonal and inflammatory nodular eruptions (acne) can be caused by what substances
methyltestosterone (anabolic steroids), epidermal growth factor receptor inhibitors, and lithium
what conditions does chewing tobacco predispose to
dental carries, gingivitis, oral leukoplakia, oral cancer
how do anabolic steroids cause acne
anabolic steroids (methyltestosterone) causes epidermal hyperproliferation and sebum overproduction
verruca vulgaris is caused by what strains of what pathogen
HPV strains 1-4
a patient with migratory joint pain, a malar rash and generalized LAD has a disease that can involve defective Fas receptor; what does this receptor do
Fas receptor, when bound to Fas ligand causes apoptosis
an increase in PRPP synthetase activity could cause what condition
hyperuricemia leading to gout
which kind of cell is most responsible for the pain and swelling seen in gout
neutrophils
a patient with pain shooting down the posterior thigh and posterior leg likely has what condition?
what are the possible nerve roots involved and which nerve root would cause impaired ankle jerk reflex?
sciatica;
sciatica is caused by impingement of the sciatic nerve
S1 is responsible for ankle jerk reflex (plantar flexion)
osteocytes are connected to each other by what kind of intercellular connector
gap junctions
a baby with lethargy, poor feeding, jaundice, constipation, muscle hypotonia, macroglossia and umbilical hernia
congenital hypothyroidism
what respiratory complication is seen in ankylosing spondylitis and why;
what must you monitor in these patients regarding this complication
enthesitis (inflammation of tendon insertion) causes pain upon respiration at the costovertebral and costosternal angles leading to hypoventilation so chest expansion must be monitored in these patients
what does osteoprotegerin (OPG) do and where does it come from
OPG is secreted by osteoblasts as a decoy for RANK receptor;
OPG binds RANK ligand, preventing it from binding the receptor on osteoclasts and thereby inhibiting bone resorption
late separation of the umbilical cord suggests what condition;
what’s the defect
leukocyte adhesion deficiency;
caused by deficient CD18, which is needed for formation of integrins
the cell is permeable to what two ions
K+ and slightly permeable to Na+
how do you differentiate between septic arthritis and gout/pseudogout for an acute monoarticular arthritis
WBC > 20,000 is septic arthritis
WBC < 20,000 is gout/pseudogout
hematogenous osteomyelitis tends to occur in what population?
what part of the bone?
children (often boys);
long bone metaphysis
what is the cause of myasthenia gravis
autoantibodies to post-synaptic nicotinic ACh receptors which bind and cause internalization and complement-mediated degradation of the receptors
what happens at the pre-synaptic membrane vs. the post-synaptic membrane in myasthenia gravis
pre-synaptic membrane is unaffected (ACh concentration is normal)
post-synaptic nicotinic ion channels don’t open –> reduced end plate potential
which muscles are most commonly affected by myasthenia gravis
muscles innervated by cranial motor nuclei (facial, ocular, hypoglossal, masticatory muscles)
probenecid and sulfinpyrazone treat what condition
they are uricosuric drugs that are used for long-term management of gout
name a diuretic that increases serum Ca2+
name a diuretic that decreases serum Ca2+
hydrochlorothiazide increases DCT reabsorption of Ca2+
furosemide causes Ca2+ wasting
Grotton papules (red/violaceous, flat-topped papules over bony prominences) and heliotrope rash (red/violaceous, edematous eruption on upper eyelids or periorbital skin) suggests what condition
dermatomyositis (also associated with proximal muscle weakness and anti-Jo1 antibodies, which are a specific marker)
keratoderma blenorrhagicum (vesiculo-pustular desquamating rash of yellow/brown appearance) and sacroilitis are common, but not pathognomonic features of
reactive arthritis
common cause of demineralized bone (osteoid)
vitamin D deficiency
anti-DNA topoisomerase I antibodies are specific for
systemic sclerosis (aka diffuse scleroderma)
side effects of colchicine
nausea, abdominal pain, diarrhea
what is haptoglobin and what does an abnormal value tell you
haptoglobin binds free hemoglobin to prevent its renal excretion;
in intravascular hemolysis haptoglobin-hemoglobin complexes will be hepatically cleared –> lower haptoglobin levels
in extravascular hemolysis the macrophages clear the hemoglobin in the cells they destroy so haptoglobin remains unchanged
name the most common injury in young children
radial head subluxation (nursemaid’s elbow), which involves displacement of the annular ligament that normally holds the radius in place
list the three parts of the “female athelete triad” associated with anorexia nervosa
eating disorder, amenorrhea, osteoporosis
prolonged kneeling causes injury to which bursa
prepatellar bursitis (“housemaids knee”)
