SBJ Flashcards
Basophilic rhomboid crystal in joint. What is it?
Calcium pyrophosphate (pseudogout)
What is actinic cheilitis
Equivalence of actinic keratosis but on the lips instead of skin (precursor lesion of squamous cell carcinoma)
Needle-shaped, strongly negatively birefringent crystals seen within and outside neutrophils from fluid aspirated from knee. What’s the composition?
Monosodium urate (gout)
GU infection 2 weeks prior. Now comes in w/ acute conjunctivitis, right knee pain, and vesicular rash on palms and soles. What’s the association?
Reactive arthritis -> assc w/ sacroiliitis in 20% of the cases
NOT syphilis. Even though syphilis presents w/ rash on palms and soles too, they’re MACULOPAPULAR or PUSTULAR rash, and the arthritis usually involves multiple joint (polyarthritis) not just one.
Injected Candida extraction 48 hrs prior and now returned w/ firm nodule. What’s the cell responsible?
Th1
This is an example of contact dermatitis, which is a DTH (type IV hypersensitivity) mediated by T cells -> calls in macrophages by interferon-g
NOT type 1
Corticosteroids administration causes false elevation of what WBC? A decrease in what WBCs?
Neutrophils (by increasing their demargination -> shed off in blood)
DONT be distracted by fever, chills, and severe fatigue after administration. They’re not trying to get at hypersensitivity rxn.
Decrease in lymphocytes, basophils, eosinophils, monocytes/macrophages
What cancer is Eaton-Lambert associated with?
Paraneoplastic syndrome of small cell lung cancer
Recurrent nonpitting edema of hands + GERD + Raynaud’s. What Ab would be positive?
Anti-centromere Ab
Pt has CREST syndrome (limited scleroderma): Calcinosis + Raynaud’s + Esophageal dysmotility (muscles replaced by fibrous scar) + Sclerodactyly (begins as nonpitting edema before progressing to tight skin) + Telangiectasia
(if diffuse scleroderma, would be anti-Scl-70 or anti-DNA topoisomerase I)
Nerve roots for musculocutaneous nerve?
C5-7
What condition is myasthenia gravis assc w/?
Thymoma or thymic hyperplasia
Myasthenia gravis doesn’t usually involve extremity weakness like lambert eaton
Different sites of injection on the leg that will risk superior gluteal nerve damage and sciatic nerve damage? Where are the safe injection sites?
Superior gluteal nerve damage: superomedial quadrant of buttock -> get Tredelenburg gait (gluteus medius weakened so the CONTRALATERAL hip drops when trying to raise the contralateral leg off the ground) and gluteus medius lurch (leans ipsilat when walking)
Sciatic nerve damage: superomedial/inferomedial/inferolateral of buttocks, posterior thigh
Safe injection sites: superolateral quadrant of buttocks, but anterolateral gluteal region is preferred (von Hochstetter triangle -> hand placed on greater trochanter, index finger on ant sup iliac spine, middle finger posteriorly)
Nerve roots for superior gluteal nerve. And what foramen does it pass thru?
L4-S1
Thru greater sciatic foramen above level of piriformis
In what context would you see calcium hydroxyapatite deposits?
Calcific tendonitis (periarticular soft tissues) -> most commonly affects rotator cuff tendons
What’s a Caisson disease?
Chronic multifocal ischemic necrosis of bone from gas emboli
What’s myoedema? And what is it characteristic of?
Focal mounding of muscle after percussion (“percussion of muscle w/ reflex hammer results in localized lump rising from the surface of skeletal muscle”)
It’s 2ndary to slow reabsorption of Ca2+ by sarcoplasmic reticulum
It’s characteristic of hypothyroid myopathy
What’s erysipelas and what one organism causes it?
Lesion in superficial skin layer -> very painful erythematous plaque w/ raised and well demarcated borders
Group A strep
What’s ecthyma gangrenosum? What organism is assc. w/ it and what pt populations are at risk?
P. aeruginosa bacteremia and septicemia -> invades perivascular areas and releases exotoxins causing vascular destruction -> insufficiency of blood flow to patches of skin -> those patches become edematous and necrose
Pt populations: neutropenic pts (immunocompromised), hospitalized, pts w/ burns and chronic indwelling catheters
How do retinoids help w/ acne? What are 2 main side effects?
Inhibits follicular epidermal keratinization -> looseing keratin plugs of comedones
Also inhibits sebum production and reduces size of sebaceous glands
Side effects: hyperTG and teratogenicity (recommend 2 forms of contraception during use + monthly pregnancy tests)
What is erythema chronicum migrans and what org is this assc. w/?
Annular erythematous rash seen in Lyme
Common peroneal n. (fx and effects of lesion)
Fx: “D”orsiflexion (“D”eep peroneal) and eversion (superficial peroneal), dorsum foot sensation
Lesion (fibular neck fracture): foot drop
Tibial n. (fx)
Fx: plantarflexion and inversion, sole of foot sensation
Injure w/ penetrating trauma to the popliteal fossa
What is cavernous hemangioma?
Soft blue, compressible mass -> can be anywhere from skin (dermis), mucosa, deep tissues, viscera
Not likely to regress spontaneously
What muscle groups have type I slow twitch red fiber predominance?
Postural muscles -> paraspinal, soleus, etc.
What does obturator externus m. do?
Externally rotates thigh
What does quadratus lumborum m. do?
Extension and lateral flexion of vertebral column
What does rectus femoris m. (and other quadriceps m.) do?
Extends knee and flexes thigh
Differences in Ab for drug-induced lupus and SLE?
Drug induced: positive ANA and histone Ab
SLE: positive dsDNA and ANA Ab
Where’s the receptor for PTH and what’s the effect?
OsteoBLAST
Effect: increase production of RANKL and M-CSF -> go to affect osteoblasts
Fracture of midshaft of humerus will affect what nerve and what artery?
Radial n.
Deep brachial artery (coursing w/ radial n.) -> divides into radial collateral ar. and middle collateral ar. just distal to midshaft
Which drug provides the most rapid relief of RA sx? Which drugs are used long-term?
Corticosteroids provide the most rapid relief so start that first (inhibits phospholipase A2 -> decreases prostaglandins and leukotrienes)
Methotrexate is the drug that’s used long term -> DMA (disease-modifying agent) that takes weeks to take effect
What 2 nerves are injured if can’t abduct fingers?
Recurrent branch of median n.
Deep branch of ulnar n.
What nerve is injured if can’t adduct thumb? Can’t oppose thumb?
Can’t adduct thumb: deep branch of ulnar n.
Can’t oppose thumb: median n.
3 diseases of the skin involving dermal-epidermal areas?
Bullous pemphigoid -> Ab against hemidesmosomes at BM
Junctional epidermolysis bullosa -> Ab against collagen type VII at dermoepidermal jx
Dermatitis herpitiformis -> IgA at upper papillary DERMIS
What is osteitis fibrosa cystica?
High bone turnover 2ndary to hyperparathyroidism
What is a triad in skeletal muscle composed of? Where is the triad?
One T-tubule
Two terminal cysterns
Triad is at the jx of A band and I band
What would happen if you don’t have T tubules in some skeletal muscles?
Uncoordinated contraction of myofibrils
Dx of “poor contractile force on repeated muscle stimulation” or “decreased compound muscle potential amplitude” or “reduced motor end-plate potential”?
Myasthenia gravis -> your problem is Ab binding to receptors -> receptor internalization and degradation -> damage to motor end-plate from complement fixation ->
Decreased compound muscle potential amplitude is NOT the same thing as AP amplitude, which is not affected (determined by the properties of cell membrane)
Synaptic conc of ACh and absolute refractory period are NOT affected
1st and 2nd line drugs for acute gouty arthritis?
1st line: NSAIDs
2nd line: cochicine
1st line if renal dysfx or elderly (so can’t use NSAIDs and colchicine): glucocorticoids
Linear streaks of papules, vesicles, bullae that are intensely pruritic after wilderness exposure. What hypersensitivity rxn?
Think poison ivy dermatitis -> urushiol attached to hapten protein acting as Ag
This is type 4 -> called delayed type, but it’s not really that delayed for poison ivy because it produces urushiol, which is able to creates elicitation phase even w/ first exposure - other things usually need sensitization phase first)
Primarily mediated by CD8+ T cells! (unlike other contact dermatitis DTH like candida which is mediated by CD4+ and macrophages)
What’s the assc. when you have diminished transfer of melanin to keratinocytes?
Postinflammatory hypopigmentation
What is the process leading to cafe au lait spots?
Increased melanosome aggregates w/in melanocyte cytoplasm
What’s the pathogenesis of lentigo?
Benign linear (not nested) melanocytic hyperplasia
2 Ab assc. w/ RA
Anti-CCP: more specific (citrullination converts arginine residue in proteins like vimentin to citrulline)
RF (anti Fc portion of IgG): less specific
What will you find on bx of urticaria?
Superficial DERMAL edema (collagen bundles are parted) and lymphatic channel dilation -> might see mild mononuclear&eosinophil infiltrates around dermal venules
NOTHING wrong on epidermis
What’s acanthosis and what’s the disease assc?
Acanthosis = increased thickness in stratum spinosum
Seen in psoriasis
Disease conditions assc. w/ acantholysis?
Eczematous dermatitis among others
What’s dyskeratosis and what condition do you find this in?
Abnormal premature keratinization of individual keratinocytes -> strongly eosinophilic and might have small basophilic nuclear remnant
See this in squamous cell carcinoma
What is spongiosis and what’s the disease assc.?
Increase in width of spaces bet. cells
Assc. w/ eczematous dermatitis (incl contact dermatitis)
What org is responsible for granuloma inguinale?
Klebsiella granulomatis
Swelling, ulcers, abscesses, fistulas
See cells w/ Donovan bodies (rod-shaped intracytoplasmic inclusions)
Differences in skin lesions during different stages of syphilis?
Primary: chancre (painless ulceration)
2ndary: macular rash incl. palms and soles, condyloma lata (Lata for syphiLis, don’t confuse w/ accuminatum which is HPV)
Tertiary (w/ neurological involvement and VLDR+ CSF now): gummas (painless then ulcerates, can happen anywhere from skin to w/in other organs)
Differences bet. Duchenne muscular dystrophy and myotonic dystrophy?
Necrosis of muscle fibers and fibrofatty replacement are NOT common in myotonic dystrophy
Sx of ion channel myopathies? What do you see under microscope?
Myotonia and episodes of hypotonic paralysis, usually assc. w/ exercise
PAS+ intracytoplasmic vacuoles
No muscle atrophy
AA pt w/ repeated episodes of intense pain over right thigh. Culture grows nonlactose-fermenting, oxidase-negative orgs. What is it?
Salmonella osteomyelitis -> common cause of osteomyelitis in sickle cell pts (another one is staph aureus)
What’s the main mechanism in Staph aureus osteomyelitis?
Adhesion to collagen
Empty beer can test (abduct arm 90 degrees, flex 30 degrees w/ thumb down, and examiner put downward force) creates pain. What’s the muscle in trouble? What’s the mechanism of damage?
Supraspinatous muscle
From impingement bet. head of humerus and acromioclavicular joint
Wher are the insertions of long head of biceps and short head of biceps?
Long head: inserts on supraglenoid tubercle of scapula
Short head: ant. tip of coracoid process
Phases of Paget disease of the bone? What is the complication?
- OsteoCLAST first! -> excessive RANK and NF-KB activity -> increased endothelial and fibroblast proliferation during this phase so causes AVM that can result in high-output HF
- Mixed
- OsteoBLAST
2 rashes that can be assc. w/ food consumption and the difference bet. them?
Atopic dermatitis: younger kids have red crusted lesions on extensor, face, scalp, spares diaper area; older kinds have lichenification of flexural distribution
Gluten enteropathy: vesicles and plaques on extensors and buttocks -> but usually 40-50 yos not young kids
What’s the impairment in atopic dermatitis? What would lab show? What are the other 2 conditions it’s assc. w/?
Skin barrier fx is impaired
Lab shows high serum IgE, peripheral eosinophilia, high cAMP phosphodiesterase in leukocytes
Assc. w/ allergic rhinitis and asthma (allergic triad)
Sunscreen ingredients that protect from UVA only? UVB only? UVB and UVA?
UVA only: avebenzone
UVB only: PABA
Both UVA and UVB (broad spectrum): zinc oxide
What muscle groups are important when sitting up from supine position (w/out using hands)?
External abdominal obliques
Rectus abdominis
Hip flexors
3 hip flexion muscles?
Illiopsoas (most important): psoas major, psoas minor, iliacus
Rectus femoris
Tensor fascia lata
4 hip extension muscles?
Gluteus maximus
Semitendinosus
Semimembranosus
Biceps femoris - long head