Flashcards in SBJ Deck (158):
What is actinic cheilitis
Equivalence of actinic keratosis but on the lips instead of skin (precursor lesion of squamous cell carcinoma)
Basophilic rhomboid crystal in joint. What is it?
Calcium pyrophosphate (pseudogout)
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?
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?
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?
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?
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?
Effect: increase production of RANKL and M-CSF -> go to affect osteoblasts
Fracture of midshaft of humerus will affect what nerve and what artery?
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?
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?
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?
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?
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?
1. 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
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
3 hip flexion muscles?
Illiopsoas (most important): psoas major, psoas minor, iliacus
Tensor fascia lata
4 hip extension muscles?
Biceps femoris - long head
2 hip abduction muscles?
3 hip adduction muscle?
Multinucleate cells in tibia bx that are TRAP positive + bilateral hearing impairment. Dx?
Paget's disease of the bone
Skull affected leading to hearing loss
Mutinucleate cells = osteoclasts that can have up to 100 nuclei (normal osteoclasts have much fewer)
What does TGF-B do to bone?
Decreases osteoClasts (by increasing their apoptosis)
What does IGF-I do to bone?
Anabolic effects (it's from GH remember?)
Specifically, it increases replication of osteoBlasts and collagen synthesis, and inhibits MMP-13
What does osteocalcin do and what cells secrete this?
Limits bone mineralization (so get increased bone mass when low level)
Secreted by osteoBlast, marker of bone formation
How do you prevent RECURRENCES of genital herpes?
Daily tx w/ acyclovir, valacyclovir, famciclovir
Where does hematogenous osteomyelitis commonly affect in children? In adults?
Children: metaphysis of long bones (slower blood flow and capillary fenestrae) -> don't confuse w/ Ewing sarcoma which happens in diaphysis, but affects older children age 10-15 yo w/ less acute sx
Adults: vertebral body
Does HPV integrate into genome?
Yes, viral DNA is integrated into host cell genome.
Components of junctional complex from cell apex to bottom?
1st component (top): tight jx (zonula occludens)
2nd: intermediate jx (zonula adherens)
How do osteocytes communicate w/ neighbors? And what is their fx?
Communicate thru GAP jx
Osteocytes sense mechanical stresses and send signals to modulate surface osteoblast activity
Rapidly spreading pruritic rash w/ erythematous papules and excoriations on extremities in a person working in a daycare center?
Dx of necrotic keratinocytes 1-3 weeks after infection (by CMV/Mycoplasma)?
Stevens Johnson syndrome
Typically doesn't involve palms and soles
Bone changes assc. w/ primary hyperparathyroidism
"subperiosteal resorption w/ cystic degeneration" -> likes cortical bones (in contrast to osteoporosis which likes trabecular bones)
Subperiosteal erosions of hand phalanges, salt-and-pepper skull, osteolytic cysts in long bones (osteitis fibrosa cystica)
Compact bone in appendicular skeleton most commonly involved
What happens in serum Ca2+ and phosphorus in Paget disease of the bone?
Bone changes seen in vit D deficiency?
Osteoid matrix accumulation around trabeculae (excessive un-mineralized osteoid w/ widened osteoid seams) -> "osteomalacia"
Widening bet. osteoid seams (measured by bone histomorphometry and by double tetracycline labeling)
Dx of "persistence of the primary spongiosa in the medullary cavity w/ no mature trabeculae"?
Normal ppl -> primary spongiosa is normally replaced by bone marrow
Dx of "trabecular thinning w/ fewer interconnections"?
How do you get winged scapula?
From penetrating trauma or axillary LN dissections (think radical mastectomy) -> injur long thoracic nerve!
What do you see on valves in Libman-Sacks endocarditis?
Sterile, finely granular, fibrinous eosinophilic material -> might result from immune complex deposition
What are extramuscular manifestations of dermamyositis?
Interstitial lung disease
Bone layers from middle to end?
Diaphysis -> metaphysis -> epiphyseal cartilage -> epiphysis
What would happen w/ obturator n. lesion? How do you get this lesion?
Weakened thigh adduction, sensory loss over small portion of medial thigh
The only n. that exits thru obturator foramen, so can be damaged during pelvic surgery (esp in LN dissection)
Difficulty w/ stairs & frequent falling 2ndary to knee buckling + diminished patellar reflex on pt on warfarin therapy. What happened?
Spontaneous retroperitoneal hematoma compressing femoral n. (emerges bet. psoas and iliacus m.)
Will also loses sensory over ant. and medial thigh and medial leg
WBC values of gout vs. septic arthritis?
Gout: < 20,000/mm3
So if WBC is grossly elevated and esp if younger age group -> suspect septic arthritis by gonococcus and give ceftriaxone empirically
Pathogenesis behind psoriasis?
Ag-presenting cells stimulate CD4+ -> CD4+ activates CD8+ in epidermis
Histology of psoriasis?
Auspitz, Munro microabscesses (neutrophils form spongiotic clusters in superficial dermis and stratum corneum), hyperparakeratosis, acanthosis, elongation of rete ridges, mitotic activity above epidermal basal cell layer, thin stratum granulosum
4 conditions where you might see erythema nodosum?
5 other ways to get carpal tunnel syndrome besides typing a lot?
Think anything that reduces carpal tunnel space
1. pregnancy - fluid accumulation
2. hypothyroidism - glycosaminoglycan buildup
3. DM - connective tissue thickening
4. RA - tendon inflammation
5. long hx of hemodialysis - beta2-microglobulin deposition (dialysis-assc. amyloidosis)
What happens to hematologic cells in SLE?
Anemia: type II HSR from warm IgG (in contrast to type III seen in renal stuff) -> see spherocytosis, + direct Coombs, extravascular hemolysis
In general, pancytopenia
What ligament is commonly injured in throwers (eg baseball pitchers)?
Ulnar collateral lig (from intense valgus stress at elbow)
What does pityriasis rosea look like?
Begins as solitary pink/brown scaly plaque w/ central clearing (herald patch) -> then ovoid maculopapular rash w/ lesions oriented in oblique direction along skin tension lines on the back (christmas tree pattern)
How does mastocytosis present?
Benign pruritic infiltration of skin by mast cells -> scratching causes degranulation, urticaria, severe flushing/syncope in some cases
What 4 organs are involved in ankylosing spondylitis?
1. peripheral enthesitis (inflammation at tendon insertions)
2. apical fibrosis and enthesopathies of costovertebral&costosternal jx -> limit chest wall expansion -> hypoventilation -> so monitor chest expansion regularly
3. asc. aortitis -> dilatation of aortic ring and aortic insufficiency
4. ant. uveitis
What's a Dupuytren's contracture?
Benign contracture of palmar fascia -> draws fingers into flexion
What is hypergranulosis and what's the assc. disease?
Excessive granulation in stratum granulosum
Seen in lichen planus
What is osteoprotegerin (OPG) and what cell secretes this?
Decoy receptor for RANK
Secreted by osteoblasts to decrease RANK interaction w/ its ligand
Bone turnover is regulated by the ratio of what molecs?
RANKL to OPG (osteoprotegrin)
What 4 conditions are assc. w/ femoral head osteonecrosis? How does it present?
Present w/ groin pain exacerbated by weight bearing -> do MRI
Pos. and lateral thigh and leg pain shooting to inner foot. What nerve root is compressed?
Specifically L5 for this one
Pain purely in pos. thigh and leg and diminished ankle jerk reflex. What nerve root is compressed?
Specifically S1 for this one
What are sx of fibromyalgia?
Poor sleep + muscle pain and stiffness more severe in the morning and exacerbated by exercise
Multiple symmetrically distributed TENDER SPOTS over muscles, joints, tendons
What are sx of polymyalgia rheumatica and what's the disease assc.?
Morning stiffness of muscles of neck, shoulder, pelvic girdle, weight loss, fever, increased ESR
Assc. w/ temporal arteritis
Which one has more tendency to metastasize bet. BCC and melanoma?
What are dermatofibromas? What about dermatofibrosarcoma protuberans?
Dermatofibromas: superficial benign fibrous histiocytomas from fibroblast proliferation -> present in lower extremities as solitary nodules
Dermatofibrosarcoma protuberans: fibroblasts in cartwheel or storiform pattern and supranumerary ring chromosomes (sequence from chr 17 and 22)
How does trochanteric bursitis present?
Chronic, intermittent pain in groin area that radiates to lateral thigh
Pain increased w/ pressure and walking
What nerve/vessels does coracobrachialis muscle overly?
What two things could bluish lesion under nail be? And how do you distinguish bet. the two?
Could either be melanoma or glumus tumor (glomangioma)
Glomangioma is extremely tender to touch. It's from modified SMC of glomus body which is a neurovascular organ that plays a role in thermoregulation
How does Langerhans cell histiocytosis present on the skin?
Erythematous papules/nodules/scaling plaques
What is popliteal and gastrocnemius bursitis assc. w/?
Formation of Baker's cysts
What is anserine bursitis and who's susceptible?
Pain along medial aspect of knee -> athletes or chronic trauma in fat pts
What are characteristics of DRESS sydrome? What drugs tend to cause this?
Fever, generalized LAD, facial edema, diffuse rash, EOSINOPHILIA
2-8 wks after anticonvulsants (phenytoin, carbamazepine), allopurinol, sulfonamides (sulfasalazine), antibiotics (minocycline, vancomycin)
Improve following drug withdrawal
What is Marjolin's ulcer? What's the clinical pic?
Aggressive ulcerating SCC
Present in area of previously traumatized skin -> malignant transformation > 10 yrs later
Differences bet. Golgi tendon organs (GTO) and intrafusal muscle fibers?
GTO: at jx of muscle and tendon, senses tension, group Ib sensory axon -> goes thru inhibitory interneurons in spinal cord -> synapsing w/ a-motor neuron -> so this is responsible for inhibiting muscle contraction when a muscle exerts too much force (so get sudden muscle relaxation)
Intrafusal muscle fibers: w/in muscles, senses stretch, group Ia and II sensory axons -> go directly to a-motor neurons for reflex (no interneurons) -> so this is responsible for DTR
What does A-delta fibers do?
Detect temp and noniceptive stimuli -> afferent portion of reflex arc that mediates withdrawal from noxious stimuli
Diff and similarities bet. Pacinian corpuscles and Ruffini's end organs?
Pacinian: rapidly adapting
Ruffini's: slowly adapting
Both mediate touch, proprioception, vibration, and are innervated by myelinated A-beta fibers
Innervation and fx of latissimus dorsi muscle?
Adduct and extend humerus
Innervation and fx of rhomboid major muscle?
Dorsal scapular n.
Draws scapula medially at its medial border
Innervation and fx of teres major muscle?
Adducts and medially rotates arm
NOT part of rotator cuff
What condition is C1 complement deficiency assc. w/?
Course of median n.?
First w/ brachial artery in the groove bet. biceps brachii and brachialis m.
Then under pronator teres m. (bet. its humeral and ulnar heads)
Then bet. flexor digitorum superficialis (top) and flexor digitorum profundus m. (bottom)
Then under flexor retinaculum
What n. courses directly bet. biceps brachii and coracobrachialis m.?
What n. courses bet. flexor carpi ulnaris and flexor digitorum profundus m.?
2 reasons ppl w/ RA are likely to have something going wrong w/ their lungs?
RA itself can cause lung manifestation -> most common is a form of interstitial lung disease similar to idiopathic interstitial pneumonia
Methotrexate (used to treat it) can cause interstitial pneumonitis and fibrosis
Diff in excitation-contraction coupling bet. skeletal m. vs. cardiac m. vs. smooth m.?
Skeletal muscles: L-type channel-RyR mechanical coupling -> does NOT require extracellular Ca2+ to cause Ca2+ release from w/in the cell -> why CCBs don't work on skeletal muscles; also NO calmodulin
Cardiac muscles: Ca2+ induced Ca2+ release (need extracellular Ca2+)
Smooth muscles: similar to cardiac but NO troponin here, use myosin light chain kinase instead (phospho myosin -> allows it to bind actin and cause contraction)
Ant. displacement of tibia/positive ant. drawer test. What structure is damaged?
ACL (goes from ANT of tibial to LATERAL epicondyle of femur) -> also worry about popliteal ARTERY injury (rigidly fixed proximal to the knee by adductor magnus and distal to the knee by soleus)
Pos. displacement of tibia/positive pos. drawer test. What structure is damaged?
PCL (goes from POS of tibial to MEDIAL epicondyle of femur)
Signs of inf. gluteal n. damage?
Difficulty rising from seated position and climbing stairs
What leads to SMC relaxation?
myosin light chain DEphosphorylation
What is the ost common cardiac manifestation in prolonged RA?
What artery is most at risk in femoral neck fracture?
Medial femoral circumflex -> makes the largest contribution to blood supply & close assc. w/ pos. aspect of femoral neck -> so risk of avascular necrosis
What artery supplying femur is esp important in children?
Obturator ar. -> b/c it supplies blood to region of femoral head proximal to epiphyseal growth plate
Minimal clinical significance in adults
Main fexor of humerus?
Deltoid m. (also does other things like medially and laterally rotate, abducting and extending, depending on which part of the muscle contracts)
What lab is elevated in dermatomyositis?
What Ab is involved in epidermolysis bullosa acquisita and cicatricial pemphigoid?
Cutaneous BM proteins
Which one involves oral mucosa: pemphigous vulgaris or bullous pemphigoid?
PV (loves oral most but any mucosal site can be involved)
Markers of osteoBlasts? OsteoClasts?
OsteoBlasts: bone-specific alk phos (easily denatured by heat unlike liver one)
OsteoClasts: TRAP (tartrate-resistant acid phosphatase), urinary hydroxyproline, urinary deoxypyridinoline (most reliable of the three)
How does androgen cause acne?
DHT promotes follicular epidermal hyperproliferation and excessive sebum production
So always suspect anabolic steroids use (methyltestosterone) in athletes coming in w/ acne (excessive perspiration does not CAUSE acne, only exacerbates it)
Size cutoffs for petechiae, purpura, and ecchymoses?
Petechiae < 5 mm
Purpura 5 mm - 1 cm
Ecchymoses > 1 cm
What's a common lung manifestation in scleroderma? How does it develop?
Pulm HTN from damage to pulm arterioles (so will hear accentuated pulm component of S2 and signs of right sided HF)
What are 2 types of myasthenia gravis exacerbations and how do you manage them?
Myasthenic crisis (know from improvement after edrophonium) -> pt is undertreated, so manage by increasing neostigmine dosage
Cholinergic crisis (know from lack of improvement after edrophonium) -> manage by stopping ACEi
What's nummular eczema?
Pruritic, coin-shaped, erythematous patches most commonly in the setting of xerosis (abnormal dryness of skin) -> harsh soaps and environmental irritants make it worse
What's Kennedy disease?
XR bulbospinal muscular atrophy -> trinucleotide expansion w/ anticipation
Sx are difficulty swallowing, tongue and facial fasciculations
What's the pathogenesis of piebaldism or Waardenburg syndrome?
Abnormal melanocyte migration
Abnormally kinky hair + hypopigmented irises?
Reduced serum copper -> Menkes' disease (reduced copper cofactor for lysyl oxidase)
Woven vs. lamellar bones?
Woven: immature and often pathologic in adults
Lamellar: stronger, composed of regular, parallel collagen in sheets
Compact vs. spongy bones?
Compact: harder outer shell
Spongy: inner part, composed of trabeculae separated by spaces that contain bone marrow
Male brought to ER w/ repeated episodes of coffee ground emesis. He's frightened and complains of dizziness upon standing. BP is low both supine and standing. What substance is most likely to accumulate in his vascular SMC?
Think of the sequence of event carefully
Brisk GI hemorrhage and hypotension -> body tries to compensate by releasing epinephrine and NE to prevent circulatory failure -> these neurotransmitters do their job by acting on a1 (to fix hypotension from blood loss) -> IP3 accumulates
Where do rhabdomyomas commonly occur? What do they look like under the microscope?
Head and neck of young males
Fascicles of polygonal cells w/ a vacuolated cytoplasm and peripherally placed nucleus (don't confuse w/ liposarcoma which is more common)
What does desmoid tumor look like under the microscope?
Broad fascicles of rounded fibroblasts w/ abundant cyto and significant surrounding collagenous matrix
What's the mechanism of alopecia areata?
Cytotoxic T cells against hair follicles
What do you have to think about w/ linear erythematous rash that develops after hiking trip?
Poison ivy/oak! -> type 4 HSR
NOT tick bites (would be target rash from lyme)
Dx of "dermoepidermal jx aggregates of large cells that fuse w/ adj nests. Cells have irregular nuclear contours, hyperchromasia, and are round or spindle-shaped"?
Dx of "proliferation of highly atypical and pleomorphic fibroblast, histiocyte-like cells and bizarre giant cells"?
Malignant fibrous histiocytoma