Day 8.3 MSK/Derm Flashcards
What are the seronegative spondylo-arthropathies?
Arthritis w/o RF (sero-negative- so no anti-IgG Ab).
Strongly a/w HLA-B27 (which codes for MHC-I). More common in males.
Ankylosing spondylitis
Reactive arthritis (Reiter’s)
Psoriatic arthritis
Ankylosing spondylitis
Chronic inflam dz of spine and sacroiliac joints leads to ankylosis (stiff spine dt joint fusion), uveitis, and aortic regurg.
Stiffness improves w (or requires) exercise
Sacroiliitis = think ank spond!
Bamboo spine - IV discs outlined by calcifications.
Reactive arthritis (Reiter’s)
Classic triad: 1. Conjunctivitis and anterior uveitis 2. Urethritis 3. Arthritis Can't see, pee, climb a tree Often post-GI (shigella flexneri) or post-Chlamydia infection
Psoriatic arthritis
Joint pain and stiffness a/w psoriasis. Asymmetric and patchy involvement. Dactylitis (sausage fingers) Pencil in cup deformity on xray. Seen in fewer than 1/3 of pts w psoriasis
Rx for seronegative spondyloarthropathies
Anti-TNFa agents: Etanercept, Infliximab, Adalimumab
also NSAIDs and steroids can be used.
SLE lab results
ANA+ (anit-nuclear Ab. good screening test, but not specific for SLE)
Anti-dsDNA Ab (esp for renal dz. poor pgx)
Anti-Smith Ab
Anti-histone Ab (for drug-induced)
Also, will have false-pos VRDL for syphilis dt anti-phospholipid Ab, which cross-react w cardiolipin (aka anti-cardiolipin Ab)
SLE epi and sx
Black Female, 14-45 yo Fever, fatigue, weight loss non-bacterial verrucous endocarditis hilar adenopathy Raynaud's Wire-loop lesions in kidney w immune complex deposition (usu nephritic syndr) Death from renal failure and infections.
Causes of drug-induced SLE
SHIPP: Sulfonamides Hydralazine INH Phenytoin Procainamide
SLE: I’M DAMN SHARP sx
Immunglobulins (anti-dsDNA, anti-Sm, antiphospholipid)
Malar rash
Discoid rash
ANA+
Mucositis (oropharyngeal ulcers)
Neurologic disorders (seizure, psychosis)
Serositis (pleuritis, pericarditis) Hematologic disorders (anemia, leukopenia, lymphopenia, thrombocytopenia) Arthritis Renal disorders Photosens
Things that can give ANA+
SLE Sjorgren's (and sicca) Scleroderma Polymyositis Dermatomyositis RA Juvenile arthritis MCTD
Rx for SLE
Glucocorticoids
NSAIDs
Hydroxy-chloroquine (anti-malarial)
Cyclophosphamide
Sarcoidosis
Immune-mediated non-caseating granulomas that are widespread, plus elevated serum ACE levels.
Common in black females.
A/w GRAIN: Gammaglobulinemia Rheum arthritis ACE increase Interstitial fibrosis Non-caseating granulomas and Restrictive lung dz Bilateral hilar lymphadenopathy Erythema nodosum Bell's palsy epithelial granulomas containing Schaumann and asteroid bodies Uveopartotitis Hyper-calcemia (d.t elevated Vit D, which is converted a lot to its active form in epitheloid macrophages.
Rx: Steroids
What is erythema nodosum?
Painful, nodular inflam of subcutaneous fat, classically on the anterior shin (in front of tibia)
Seen in sarcoidosis
What is polymyalgia rheumatica?
Pain/stiffness in shoulders and hips, often w fever, malaise, weight loss.
Despite the name myalgia, it does NOT cause muscular weakness.
Occurs in pts >50yo
A/w temporal (giant cell) arteritis
Findings: elevated ESR and normal CK (aka CPK), a marker for muscle cell breakdown
Rx: Prednisone (steroids)
What are the findings and Rx for polymyositis and dermatomyositis?
Increased CK, increased aldolase
Positive ANA
Anti-Jo1 Ab
Rx: steroids
Polymyositis
progressive symmetrical proximal musc weakness caused by CD8+ T-cell induced injury to myofibers.
Most often involves shoulders (and pelvis)- most musc dz affects proximal musc, whereas nerve dz affects distal.
Dx by musc biopsy showing evidence of inflam
Dermatomyositis
Like polymyositis (symm proximal musc weakness d.t CD8+ injury to myofibers) But also involves malar rash, heliotrope rash (around eyes), shawl-and-face rash, Gottron's papules, mechanic's hands. Increased risk of malignancy (the normal neoplasms- lung, breast, etc)
Myasthenia Gravis
Most common NMJ disorder.
Auto-Ab to the post-synaptic ACh receptor
Causes ptosis, diplopia, general weakness
A/w thymoma
Sx get worse (!) w musc use
Rx: AChE inhibitors (cause ACh to stay around longer)
Lambert-Eaton syndrome
NMJ dz
Auto-Ab to presynaptic Ca2+ channel, results in decreased ACh release, so proximal musc weakness.
Unlike MG, extraocular musc are spared.
Assc w paraneoplastic dz (sml cell lung cancer)
Sx improve w musc use (test: isometric contraction improves musc strength)
No reversal of sx w AChE inhibtors alone.
So: dry mouth + impotence + muscle weakness, and assoc w sml cell lung carcinoma = lamb-eaton
Mixed CT Dz
Raynaud's FAME: Raynaud's Fatigue Arthralgias Myalgias Esophageal hypomotility
Ab to U1RNP
Responds to steroids
Scleroderma
aka PSS- progressive systemic sclerosis
Excessive fibrosis and collagen deposits thru-out body.
Commonly in skin- puffy taut skin w no wrinkles
There is also sclerosis of renal, pulm, CV, and GI systems
75% female.
“bulking” dz
2 types= diffuse and CREST
Diffuse scleroderma
widespread skin involvement, rapid progression, early visceral involvement.
Anti-Scl-70 Ab (aka Anti- DNA topoisomerase I Ab)
CREST scleroderma
CREST: Calcinosis (subepithelial Ca2+ deposits) Raynaud's Esophageal dysmotility Sclerodactyly (sausage fingers) Telangiectasia
Limited skin involvement- confined to fingers and face.
More benign than diffuse.
Anti-Centromere Ab
Lipoma
Benign
Soft, well-encapsulated fat tumor
Cure by simple excision
