MSK Flashcards
Erb-Duchenne Palsy (“Waiter’s Tip”)
Def’n, Pres?
Superior Trunk (C5-C6) Brachial Plexus injury.
PRES:
- “Neonate with ARM PARALYSIS following difficult birth”
“Fall on an outstretched hand”
Bone + Nerve damaged?
Hook of Hamate -> Ulnar nerve
Bone Disease
Enzyme↑?
Alkaline phosphatase
Skeletal Muscle Injury / Damage
Enzymes↑(2)?
- CKMB (SEVERE injury)
- LD4 + LD5 (damage)
Carpal Tunnel Sx
Def’n, Pres (3)?
Entrapment of Median nerve in carpal tunnel -> nerve compression.
PRES:
- Paresthesia (Tinel sign)
- Pain
- Numbness in distribution of Median nerve
Acute Carpal Tunnel Sx
Cause?
CAUSE = Dislocation of Lunate
Guyon Canal Sx
Def’n, Pres (Epi)?
Compression of Ulnar nerve at wrist / hand.
PRES: Cyclists
Tetany
Mech, Causes (Electrolytic)?
Activation of all nerve cells in body -> muscle overstimulation ->
muscle spasms + cramps.
CAUSES:
- ↓Ca
- ↓Mg
Muscular Dystrophy
Inher, Def’n, Pres?
XR.
XR deletion of dystrophin gene.
PRES:
- Calf pseudohypertrophy
Duchenne Muscular Dystrophy
Def’n, Inher, Genetics, Pres (2)?
Deletion of dystrophin gene.
XR.
Frameshift DNA mutation.
PRES:
- Calf pseudohypertrophy
- “Child uses arms to stand up from squat”
Becker Muscular Dystrophy
** LESS severe than Duchenne **
Def’n, Inher, Pres (Epi + 1)?
Missense mutation in dystrophin gene.
XR.
PRES: Boys
- Slow, progressive muscle weakness
McArdle Disease
Def’n, Pres (5), Urine?
Muscle Glycogen Phosphorylase deficiency.
PRES:
- Chronic exercise intolerance
- Fatigue
- Myalgia
- Cramps
URINE:
- Myoglobinuria
Achondroplasia
Mech (2 steps), Inher (2), Genetics, Pres (2)?
MECH:
Impaired chondrocyte / cartilage prolif in growth plate ->
Failure of Endochondral Ossification = longitudinal bone growth.
INHER:
- AD
- > 85% mutations sporadic and assoc with increased paternal age
FGFR3 Activating Mutation (-> overexpression -> growth inhib).
PRES:
- Short limbs / Dwarfism
- “Large head relative to limbs” (b/c membranous ossification NOT affected)
McCune-Albright Sx (form of Polyostotic Fibrous Dyplasia)
Def’n, Assoc, Pres (2)?
Bone is replaced by fibroblasts, collagen and irregular bony trabeculae.
ASSOC:
- Precocious Puberty
PRES:
- Multiple unilateral bone lesions
- Cafe-au-Lait spots
Osteoporosis
Def’n / Mech (3 steps), 2 Types, Comp (2), Prev (2), Rx (3), CI?
↓TRABECULAR bone mass / density / interconnections ->
Porous bone ->
↑risk of fracture + thin cartilage between vert.
- Type I = Postmenopausal (↓Estrogen -> ↑bone resorption)
- Type II = Senile
COMP:
- Compression / Vertebral Crush fractures
- Colles fracture (fracture of distal radius)
PREV:
- Regular WEIGHT-BEARING exercise
- Adequate Ca + Vit D intake throughout adulthood
RX:
- Calcitonin (inhibits osteoclasts)
- Estrogen (inhibits bone resorption)
- For severe cases: PTH or Bisphosphonates
CI:
- Glucocorticoids
Vertebral Crush Fractures
Def’n / Seen In, Pres (4: 3 + 1 sign)?
Possible comp of Osteoporosis.
PRES:
- Acute back pain
- Loss of height
- Kyphosis
- ‘Dowager’s Hump’
Paget’s Disease of Bone
Pres (6, incl Epi), Labs, Biopsy Finding, Comp (2)?
PRES: Avg age > 60
- “↑hat size” (bone enlargement that commonly affects skull)
- “Lion-like facies”
- Hearing loss (auditory foramen narrowing)
- Bone pain (due to microfractures)
- Arthritis
LABS:
- ALP ↑
FINDING:
- “Mosaic” / “Woven” pattern of lamellar bone
COMP:
- High-Output Cardiac Failure (formation of A-V shunts in bone -> ↑blood flow)
- Osteosarcoma
Osteomyelitis
Pres (2)?
PRES:
- Bone pain w systemic signs of infection
- Lytic abscess surrounded by sclerosis on bone
Osteitis Fibrosa Cystica
Cause, Pres?
CAUSE = Hyperparathyroidism
PRES = “Brown tumors” (due to deposited hemosiderin from hem)
Giant Cell Tumor of Bone (Osteoclastoma)
Location, XR Finding?
Long bones (epiphysis): KNEE region- distal femur / proximal tibia.
XR FINDING:
- “Soap bubble” appearance on XR (lytic expansile lesion)
Ewing Sarcoma
Def’n, Locations (4), Genetics, Pres (Epi)?
Anaplastic malignant (aggressive with early metastases) small round / blue-cell tumor.
Long bones (diaphysis), Scapula, Ribs, Pelvis.
11;22 translocation.
PRES: Boys
Osteosarcoma
Assoc (6), Location, Pres (Epi), XR Findings (2 possible)?
ASSOC: (Predisposing factors)
- Rb suppressor gene
- Familial Retinoblastoma
- Li-Frameuni Sx (germline p53 mutation)
- Paget’s Disease of Bone
- Bone infarcts
- Radiation
Long bones (metaphysis). ** Often around KNEE **
PRES: Men 10-20
XR FINDING:
- “Codman’s Triangle” or “sunburst pattern”
Infectious Arthritis
2 Types?
- Septic
- Chronic
Septic Infectious Arthritis
Causative Agents (3)?
- S aureus
- Strep
- Neisseria gonorrhoeae
GONOCOCCAL Septic Infectious Arthritis /
Disseminated Gonococcemia
Def’n, Pres (2)?
STD (Gonococcemia) in person that is missing C5-C9
-> Disseminated -> MIGRATORY arthritis.
PRES: Asymmetrical. * “STD” *
- Monoarticular arthritis
- Pustules on palm
Chronic Infectious Arthritis
Causative Infections (2)?
- Lyme Disease
- TB ( -> mycobacterial dissemination)
Reactive Arthritis / Reiter’s Sx
HLA, Mech, Pres (Triad)?
HLA-B27.
MECH: HLA-B27 -> envir trigger = Chlamydia or GI infection.
PRES: Male
- Arthritis (“Achilles pain”)
- Conjunctivitis + Ant Uveitis (sterile)
- Urethritis
Osteoarthritis
Joints Affected, Pres, Joint Findings (4)?
PIP + DIP.
PRES: “Swollen, hard + painful FINGER joints”
- Pain in weight-bearing joints after use & improving with rest
JOINT FINDINGS:
- Osteophytes (bone spurs = rx to injury)
- Heberden nodes: Osteophytes on DIP
- Bouchard nodes: Osteophytes on PIP
- Eburnation (polished “ivory-like” appearance of bone at
site of cartilage erosion)
- Subchondral Cysts
- Sclerotic bone (close to joint)
RA
Mech (incl H-S types), Antibodies (2), HLA Assoc, Joints Affected,
Pres (Epi + CLUE + 6), Comp (2), Rx?
Inflammation. Type 3 + 4 H-S.
- Rheumatoid factor (80% of patients)
- Anti-Cyclic Citrullinated Peptide antibody (more specific)
HLA-DR4.
MCP + PIP.
PRES: Often symmetrical. MC in Females.
“Morning stiffness lasting > 30 min and improving with use.”
- Systemic infl
- Joint Pannus
- Boutonniere Deformity
- Baker Cyst (behind knee / in popliteal fossa)
- Subcutaneous rheumatoid nodules (fibrinoid necrosis)
- Ulnar deviation of fingers
COMP:
- Sjorgen’s Sx
- Pericarditis
RX:
- Methotrexate
Sjogren’s Sx
Def’n, Assoc, Pres (Epi + 4), Labs, Comp (2)?
Autoimmune disorder char by destruction of EXOCRINE GLANDS (esp lacrimal +salivary glands).
Can be a primary disorder or a secondary disorder assoc with another autoimmune disorder (eg RA).
ASSOC:
- RA
PRES: Females 40-60. “Dry eyes, dry mouth, arthritis.”
- Xerophthalmia (↓tear production -> corneal damage):
“Sand in my eyes”. Dry eyes + conjunctivitis.
- Xerostomia (↓saliva production): Dry mouth.
- Bilateral Parotid enlargement
- Arthritis
LABS: Antinuclear Antibodies
- SS-A and/or SS-B
COMP:
- Dental caries
- MALT Lymphoma
SLE
Pres (9: Epi, 3, 2, 5), Antibodies (5), Blood Findings (4)
Comp / Causes of Death (3)?
PRES: Young female, MC African
- Arthritis
- Fever, Fatigue + Weight Loss
- Photosensitivity
- “Butterfly” facial rash
- Oral / Nasopharyngeal ulcers
- Neuro disorders (eg seizures)
- Libman-Sacks Endocarditis
- Renal Disease (Lupus Nephropathy + DP Glomerulonephritis)
- Raynaud Phenomenon
- Autoimmune (IgG) = Warm Agglutinin Hemolytic Anemia
ANTIBODIES:
- ANA (sensitive, not specific)
- Anti-Smith (specific)
- Anti-Cardiolipin (-> False + on Syphilis test)
- Anti-Histone
- Anti-dsDNA (specific & poor prognosis)
BLOOD:
- ↓C3 + C4 (due to IC formation)
- Schistocytes
- Neutropenia
- Lymphopenia
COMP:
- Constrictive Pericarditis / Libman-Sacks Endocarditis (due to serositis -> effusions in lupus)
- Renal Disease / Failure
- Infections
Polymyalgia Rheumatica
Assoc, Pres (Epi +2), Blood Findings (2), RX?
ASSOC:
- Temporal Giant Cell Arteritis
PRES: > 50 y.o, MC Females
- Pain / stiffness in Shoulders + Hips
- Fever, Fatigue + Weight Loss
BLOOD:
- ↑C-reactive protein
- ↑ESR
RX = Prednisone
Fibromyalgia
Pres (Epi + 2)?
PRES: 20-50 y.o, MC Females
- Widespread MSK stiffness, pain + paresthesia
- Poor sleep + fatigue
Dermatomyositis
Def’n, Pres (3, incl 3 rashes), Comp?
Infl disorder of skin + skeletal muscle. PERImysial infl w CD4+ T cells.
PRES: Polymyositis + …
- Rashes
- Malar rash (similar to SLE)
- Heliotrope rash
- “Shawl + Face rash” - Gottron Papules: red papules on elbows, knees + knuckles
- “Mechanic’s hands”
COMP:
-↑risk of occult malignancy
Pseudogout
Def’n, Assoc (2), Micro Finding?
Precipitation of calcium pyrophosphate dihydrate crystals in joints.
ASSOC:
- Hemochromatosis
- Hyper- + Hypoparathyroidism
FINDING:
- POSITIVELY birefringent RHOMBOID crystals
(blue when parallel to light; yellow when perpendicular to light)
* Contrast with Gout *
Gout
Def’n, MC Locations (5), Cause, Mech (2),
Seen In, Pres (6), Micro Finding?
Acute inflammatory MONOarthritis caused by precipitation of monosodium urate crystals in joints.
External Ear, Elbows (olecranon bursa), Fingers, Achilles tendon, Big Toe.
CAUSE = Hyperuricemia.
MECH of Hyperuricemia:
* 1. (90%) UNDEREXCRETION of uric acid. Mostly idiopathic, however
can be exacerbated by certain meds (ie thiazide diuretics).
2. (10%) OVERPRODUCTION of uric acid.
SEEN IN:
- Lesch-Nyhan Sx
PRES: MC in Males. “Sudden swollen + painful big toe.”
- Asymmetric joint distribution
- Red, swollen + painful joints
- Podagra
- Tophi (Chronic Gout ONLY)
- Acute attacks after large meal or alcohol consumption
FINDING:
- NEEDLE-shaped + NEGATIVELY birefringent crystals
(yellow under parallel light; blue under perpendicular light)
* Contrast with Pseudogout *
Polymyositis
Def’n, Location, Pres?
Infl disorder of skeletal muscle. Char by ENDOmysial infl
with CD8+ T cells.
MC in Shoulders.
PRES: Symmetrical
- Progressive PROXIMAL muscle weakness
Psoriatic Arthritis
(although seen in fewer than 1/3 of patients with Psoriasis)
Pres (2), XR Finding?
PRES: Asymmetric + Patchy involvement
- Joint stiffness + pain
- Dactylitis (“sausage fingers”)
XR FINDING:
- “Pencil in cup” deformity
Ankylosing Spondylitis
Def’n + Location, HLA, Pres (3), Labs, XR Finding?
Chronic inflammatory arthritis of Spine + SI joint.
Ankylosed joint = fixed.
HLA-B27.
PRES:
- Stiff / ankylosed spine -> Hunched over back.
“Pain in lower back / SI joint. Pain improves as day progresses”.
- Aortitis + Aortic Regurg
- Uveitis -> risk of Blindness
LABS:
- Bl Gas abnormalities (hunched back affects chest cavity and ability to breathe)
XR:
- “Bamboo spine” on XR (due to vertebral fusion).
Seronegative Spondyloarthropathies
4 Types (“PAIR”), Def’n, Assoc, Pres (Epi)?
- Psoriatic Arthritis
- Ankylosing Spondylitis
- IBD
- Reactive Arthritis / Reiter’s Sx
Arthrites without Rheumatoid factor.
Strong assoc with HLA-B27.
PRES: MC in Males
