Muscle + Rheumatology + Skin (JR)

zoyogasa's version from 2016-04-14 02:24

Skeletal System

Achondroplasiadwarfism, FGF3 activating mutation, ↑ paternal age, short extremities (endochondral bone) but normal skull (membranous bone). Normal life span, mental function, fertility
Osteogenesis ImperfectaCollagen I defect, blue sclera (choroid veins), multiple fractures vs. child abuse, hearing loss
Osteopetrosis↓ osteoclast, marble bones, carbonic anhydrase II mutation (loss of acid environment = needed to break bone). Pancytopenia (bone in BM = Myelophthisic), vision/hearing loss (bone compress), hydrocephalus (narrow foramen magnum), renal tubular necrosis (Metabolic acidosis). Tx = BM transplant (monocyte --> macrophage & osteoclast)
Rickets/Osteomalacia↓ Vit D = ↓ Ca+, ↓Phosphate, ↑PTH, ↑ALP. Defective mineralization. Children = pigeon-breast deformity, frontal bossing (big forehead), rachitic rosary, bowing of legs
Osteoporosis↑ osteoclast w/ age & menopause. ↓ in Trabecular bone mass. Normal Labs. DEXA Scan (look at bone density). Bone pain + fractures in VERTEBRAE (loss of height, kyphosis) + distal radius (colle's). Tx = Bisphosphonate (apotosis of osteoclast). NO GLUCOCORTICOIDS
Padget's Disease↑ osteoblast & ↑ osteoclast. Mosaic patter of lamellar bone. ↑ hat size, hearing loss, lion-facies. ISOLATED ↑ALP. Tx = bisphosphonate & calcitonin. Complications = HIGH-output cardiac failure (AV shunts in bone) + Osteosarcoma (b/c of ↑osteoblast)
Osteomyelitisinfection of marrow & bone. Bacterial spread via blood. Children = Metaphysis (b/c growing, ↑blood supply). Adults = Epiphysis (open-wound). Bone pain + infection. Xray = abscess surrounded by bone
S. aureus = most common
N. gonorrhea = sex active
Salmonella = sickle cell
Pseudomonas = IV drug use or diabetics
Pasteurella = dog/cat scratch
Myobacteria Tb = Pott's disease

Bone Tumors

Osteomabenign bone tumor, face bones, GARDNER Syndrome
Osteoid Osteomabenign tumor of osteoblast, <2cm, cortex of long bone, pain resolves w/ aspirin
Osteoblastomabenign tumor of osteoblast, >2cm, veterbrae bones, pain DOES NOT resolve w/ aspirin
Osteochondromalateral growth at metaphysis, most common benign tumor of bone
Osteosarcomamalignant osteoblasts, Rb gene, Paget's Disease, metaphysis of long bones (femur/tibia), bone pain w/ swelling, sunburst appearance & codman's triangle.

Giant Cell Tumorepiphysis of long bones, soap bubbles, multinucleated giant cells and stromal cells
Ewing Sarcomat(11,22). Neuroectoderm. Diaphysis of long bones. Onion-skin. Round blue cells --> look like lymphoblasts --> can look like lymphoma

Chondromabenign tumor of cartilage, medulla of small bones of hand/feet
Chondrosarcomamalignant tumor of cartilage, medulla of pelvis or central skeleton
Metastatic Tumorsusually ↑ OSTEOCLAST (lytic lesions)
Prostatic carcinomametastasize to bone, ↑ OSTEOBLAST

Bone tumors by location

Question Answer
EpiphysisGiant Cell Tumors (Adults)
MetaphysisOsteochondroma, Osteosarcoma
DiaphysisEwing's Sarcoma (11,22)
Cortex of bonesOsteoid Osteoma
Medulla of bonesChondroma, Chondrosarcoma

Soft tissue tumors

Question Answer
Lipomabenign tumor of fat
Liposarcomamalignant tumor of fat, lipoblast cells
Rhabdomyomabenign tumor of skeletal muscle. CARDIAC RHABDOMYOMA --> TUBEROUS SCLEROSIS
Rhabdosarcomamalignant tumor of skeletal muscle. DESMIN +. Head + Neck. Vagina in girls (grape-like mass protruding from vagina, Desmin+)

Bone + Joint + Skin disease

Question Answer
Osteoarthritis (wear and tear)PIP (Bouchard node) + DIP (Heberden node) + Bone spurs + Osteophytes, worse w/ activity
Rheumatoid Arthritis (autoimmune IgG)Symmetric MCP + Swan neck + Boutonneire + Pannus + Symmetrical + Ulnar deviation + Swan-neck deformity, HLA-DR4, vasculitis/baker cyst, IgM against Fc of IgG, amyloidosis
Sjogren (Lymphocytes)Arthritis + dry eyes + dry mouth
Gout (Uric Acid)Monosodium Urate crystals, HGPRT deficiency, Big toe (MTP) (Podagra) + Tophus in external ear + olecranon bursa + achilles tendon, renal failure, worse / alcohol or meat. Negative birefringent, yellow-parallel
PseudogoutKnee pain, Calcium Pyrophosphate dihydrate, rhomboid crystals, positive birefringence
Infective ArthritisArthritis from STD, 1 joint (knee), N. gonorrhea or S. aureus. ↑ESR, fever + ↑ WBC
Psoriatic ArthritisPsoriasis + joints + sausage fingers + pencil in cup
Ankylosing SpondylitisSacroiliac joint + bamboo spine + Uveitis + Aortic Regurgitation (aortitis)
Reactive Arthritis (Reiter's Syndrome)Can't see, Can't pee, Can't climb a tree from GI/Chalamydia infection
Polymyalgia RheumaticaMuscle pain + joint pain from Temporal arteritis
FibromyalgiaChronic muscle pain
PolymyositisProximal muscle weakness, endomysial (skeletal muscle only)
Dermatomyositisskin + skeletal muscle --> Muscle weakness + Gottron's Papules, Heliotrophe rash, anti-JO-1, perimysial (near skin)
Myasthenia GravisAuto-antibodies against ACh receptor, THYMOMA, muscle weakness worse w/ use, Tx = ACh (rest)
Lambert-Eaton SyndromeAuto-antibodies against Ca2+, Small Cell Lung Cancer, muscle weakness better w/ use
Duchenne Muscular Dystrophydeleted dystrophin gene (muscle anchor --> connects to ECM), skeletal muscle --> replaced by fat. Pseudohypertrophy of calf, ↑CK
Becker Muscular Dystrophymutated dystrophin, less severe form of Duchenne Muscular Dystrophy


DiseaseCauseAntibodies/Markers/LabsClinical PictureTx
Osteoarthritiswear and tear(old age, obesity)not-autoimmuneDIP (Heberden's), PIP (Bouchard), Osteophyte (bone spurs). NO MCP
Pain in weight bearing joints (worse w/ use). Non-inflamamtory. No systemic symtoms
#2=NSAIDS + Steroids
Rheumatoid Arthritisautoimmune - inflammation + destruction of synovial joints. (TYPE III Hypersensitivity)Rheumatoid Factor, anti-IgG Ab, Anti-CCP, HLA-DR4Pannus (inflammatory granulation tissue that invades the joint) on MCP + PIP. NO DIP Ulnar deviation fo fingers, subluxation Baker's cyst in popliteal fossa.

Boutonneire Deformity = extensor tendon on back of fingers ruptures, PIP joints poke through --> flex at PIP, extend at DIP
Swan neck deformity = extend PIP, flex DIP

Better w/ use. (Morning stiffness). Symmetric joint involvement + Systemic symptoms (fever, fatigue, pleuritis, pericarditis)
#1=Celecoxib (COX-2 inhibitor) + Steroids
#2=DMARDs (Methotrexate, TNF-alpha inhibitors)
Sjogren's Syndromelymphocytes infiltrationSS-A (Ro), SS-B (La)Dry eyes, Dry mouth, Arthritis
(Xerophthalmia), (Xerostomia)
↑ risk of B-cell lymphoma, ↑parotid, ↑dental carries
Gout↑ uric acid (HGPRT, lesh-nyhan, ↓ uric acid secretion,↑ cell turnoverNegative birefringent. Yellow-Parallel.
Monosodium Urate Crystals
Asymmetric joint distribution.
Painful, swollen MTP (1st toe) = Podagra
Tophus in external ear + olecranon bursa + achilles tendon
Acute=Indomethacin,Steroids, Colchicine

PseudogoutPositive birefringent
Calcium Pyrophosphate Cyrstals
Large joints (Knee)Acute=NSAIDS, Colchicine, Steroids
Infectious ArthritisS. aureus, Streptococcus, Neisseria gonorrhoeaseAsymmetrical migratory arthritis
STD = synovitis (knee), tenosynovitis (hand), dermatitis (pustules)
Osteonecrosis (Avascular necrosis)trauma, steroids, alcohol, sickle cellFemoral head = infarction of bone and marrow
Seronegative SpondyloarthropathiesNo rheumatoid factorHLA-B27 (PAIR) = HLA MHC Class I
Psoriatic ArthritisPsoriasis + joint pain/stiffness.
Dactylitis ("sausage fingers"), "Pencil-in-cup"
Ankylosing SpondylitisSacroiliac Joint + Spine + Uveitis + Aortic Regurgitation

Stiff spine = fusion of joints --> Bamboo spine
Inflammatory Bowel DiseaseCrohn's disease + Ulcerative colitis
Reactive ArthritisPost-GI infections or Chlamydia infectionCan't see, Can't pee, Can't climb a tree
Conjunctivitis, Urethritis, Arthritis
Systemic Lupus Erythematosus
Polymyalgia RheumaticaTemporal (Giant Cell) arteritis↑ ESR, normal CKJoint Pain in shoulder + hips & fever + malaise + weight loss.
FibromyalgiaChronic muscle pain w/ stiffness + poor sleep + fatigue
PolymyositisCD8+ T-cells infiltration↑ CK, positive ANA, positive anti-JO-1 ANTIBODIESMuscle inflammation --> Muscle Weakness
Proximal muscle weakness, ENDOMYSIAL inflammation
DermatomyositisCD4+ T-cells infiltration↑ CK, positive ANA, positive anti-JO-1 ANTIBODIESPolymyositis (Muscle weakness) + RASH
Gottron's Papules, Heliotrophe rash (around eyelids), "shawl & face" rash, "mechanic's hand"
↑ risk of cancer
PERIMYSIAL~ inflammation
Myasthenic Gravisautoantibodies against ACh receptorPtosis, Diplopia, Weakness WORSE W/ USE
associated w/ THYMOMA
↑ Ach (Pyridostigmine)
Lambert-Eaton Myasthenic Syndromeautoantibodies against pre-synaptic Ca2+ channels = ↓ ACh releaseProximal muscle weakness
SclerodermaDiffuse = Anti-Scl-70 Ab (anti-DNA topoisomerase I)

Local (CREST) = anti-centromere Ab
↑ fibrosis & collage deposit throughout the body (SKIN = puffy, taut, NO WRINKLES).
Sclerosis of kidney, lung, heart, GI

Diffuse = skin + rapid + visceral involvement
CREST = calcinosis + raynaud + esophageal dysmotility + sclerodactyly + talangiectasia