General MSK Disorders

Question 1

Acute Compartment Syndrome: Def, pathophys, Etiology, Risks, & s/sxs

Answer 1

• Definition:
  
  • muscle & nerve ischemia (decreased tissue perfusion) when the muscle compartment pressure > vascular perfusion pressure.
• Pathophys:
  
  • increased compartment pressure → decreased arterial pressure & increased venous pressure → capillary bed collapse → decreased tissue perfusion → tissue death
• Etiology:***Trauma
  
  • Increased volume: long bone fracture (75%), hemorrhage, swelling from the direct soft tissue trauma, burns (increased fluid), post-ischemic swelling (reperfusion), snake bite
  • Decreased volume: tight casts, dressings
  • **Most common: fracture of the tibia, elbow, forearm, femur (leg, forearm, thigh)
• Risks:
  
  • male < 35yo (any age possible, but compartments of younger pts don’t expand as well), unconscious drunk pt, IVDA, underlying bleeding disorder
• Most common location = anterior compartment of the leg
• S/sxs:
  
  • 7 Ps:
  • pain out of proportion to injury = most important
  • -Pallor
  • -Paresthesia (tingling)
  • -Paresis (motor loss)
  • -Poikilothermia (cool skin)
  • -Pressure (tight to palpation)
  • -Pulselessness
  • *Many of these may be normal so depend on pain
• 4 compartments of the lower leg-
  
  • lateral
  • -anterior
  • -deep posterior
  • -superficial posterior
  • *Each contain several muscles surrounded by fascia which has limited ability to stretch

:

*

Question 2

Acute Compartment Syndrome: PE, Dx, & Tx

Answer 2

• PE:
  
  • Pain with passive stretching of the affected muscles
  • -“Wood-like” feeling → d/t tense compartment
  • -Document neurovascular status carefully
  • will have an underwhelming physical exam in comparison to DVT
• Dx:
  
  • Pain is severe, out of proportion, not relieved by rest or meds, focal or referred.
  • -Prior trauma
  • -**Other Ps not reliable
  • -Compartment pressure > 30 mmHg = require emergent fasciotomy, Elevated > 20, Normal 0-10 (measure with solid-state transducer intracompartmental catheter [STIC Monitor]); if >20 it is elevated (repeat measurement)
  • Delta pressure aka P value (diastolic BP - compartment pressure) = <30 mmHg (Emond say <20)
• Tx:
  
  • Medical Emergency!!
  • Up to 15% morality. Tissue death by 8 HOURS → irreversible damage. Nerve damage irreversible after 6 hours.
  • -Loosen tight bandages, casts, splints
  • -Pain medication → IV opioids (but don’t overmedicate)
  • -Elevate extremity to level of heart ONLY
  • -Refer out emergently→ Emergent fasciotomy to decompress
  • *Wounds are left open & delayed closure/skin grafting is performed after swelling subsides

Question 3

Chronic Exertional Compartment Syndrome

Answer 3

• General Info:
  
  • Occurs in younger athletic patients due to overuse (multiple small traumas)
  • Simvastatin** **(statin drug):
  • Risks: male 50-60yo, been on medication > 10 years, concomitant use of clopidogrel, hx of DVT; Statins can predispose you to get compartment syndrome
• S/sxs:
  
  • crampy pain related to activity & relieved with rest
  • +/-Weakness & paresthesias
• Pe:
  
  • No abnormal findings when they are NOT exercising
• Dx:
  
  • -Rest/exertional compartment measurements
• Tx:
  
  • Refer to Ortho
  • -Single or double incision fasciotomy
  • -Post-surgery: ROM exercises, weight bearing on crutches, light jogging

Question 4

Deep Vein Thrombosis

Answer 4

• Etiology:
  
  • venous stasis, endothelial injury, & hypercoagulable state (Virchow’s Triad)
• Risks:
  
  • high-risk surgeries (total joint arthroplasties, internal fixation of hip fracture), trauma, acute illness, Acute HF
• Epidemiology:
  
  • 50% of blood clots are healthcare associated, DVT more common than Pe
• S/sxs:
  
  • Edematous, painful/tender leg
  • -Ankle Edema
  • -Dilated veins
  • -Fever
• PE:
  
  • Homan’s sign: sharp pain in the calf on dorsiflexion of the foot (passive test NOT active test)
  • -Leg tenderness
• Dx:
  
  • U/S with doppler
  • -D-dimer: if unlikely → good to r/o
• Well’s Criteria:
  
  • *DVT likely if score > 2
  • -Active cancer, paralysis, bedridden for 3 days recently or major surgery within last 12 weeks, surgery, localized tenderness, entire leg swollen, calf swelling, pitting edema confined to affected leg , collateral superficial veins, previously documented DVT
• Tx:
  
  • Hospital admission
  • -IV heparinthen oralWarfarinx 3 months once discharged
  • -Alternatives: fondaparinux, dabigatran, rivaroxaban, apixaban

Orthopedic Surgery Prophylaxis:

• IV heparin, IV fondaparinux, oral warfarin or ASA initiated within 24 H of surgery
• Post-op warfarin or ASA x 7-10 days
• Pneumatic compression with foot, calf, & thigh pumps

Question 5

Pulmonary Embolism

Answer 5

• Definition:
  
  • Blood clot travels to lungs → blocks one of the pulmonary arteries
• Risks:
  
  • Factor V Leiden (hypercoagulable), fat embolism syndrome (associated with fracture)
• S/sxs:
  
  • *Triad: dyspnea, hypoxia, tachycardia
  • Dyspnea, pleuritic pain
  • cough, 2-pillow orthopnea, calf or thigh pain/swelling
• PE:
  
  • Tachycardia, tachypnea
  • -Rales, wheezing
  • -Decreased breath sounds
  • -JVD
• Dx:
  
  • CT pulm angiography = gold standard, but most invasive & it is dangerous with a high mortality rate, especially in pts with PE
  • US of legs bilaterally
  • V/Q scan (if US is negative)
• Tx:
  
  • Mortality rate without treatment = 30%, 2-8% with treatment
  • -Heparin or LMWH
  • -Refractory: embolectomy

Question 6

Acute Osteomyelitis: def, Risks, Organisms, S/sxs

Answer 6

• Definition:
  
  • infection/inflammation of the bone & marrow. Most commonly occurs as a primary isolated infection but can occur secondary to systemic infection
• Femur & tibia = Most common bones in children affected
• Risks:
  
  • Local (alter vascularity of the bone): trauma, radiation, Paget’s, osteoporosis, major vessel disease, malignancy
  • Systemic: DM, malnutrition, sickle cell disease, anemia, autoimmune, HIV, immunosuppression (chemotherapy, steroids)
  • Predisposing factors: open fractures = MCC in adults, post-op infections, orthopedic implants
• Organisms:
  
  • -S. Aureus = Most common, ASK if they are a MRSA carrier
  • -E. Coli, Klebsiella: IVDA, GU infx
  • -Pseudomonas: puncture wound, IVDA, GU
  • -Salmonella: sickle cell anemia
  • -H. Flu, group B strep: neonates
  • -Pasteurella multocida: cat bite
  • -Eikenella corrodens: human bite
  • -S. Epidermis: prosthetic joint placement
• S/sxs:
  
  • **Acute Onset
  • -High fever, chills, sweats
  • -bone pain & swelling: acutely painful & skin appears red, warm
  • -Limitation of movement: restricted ROM of the joint near the affected bone

Question 7

Acute Osteomyelitis: PE, Dx, & Tx

Answer 7

• PE:
  
  • Red Flags:
    
    • -Adults: drainage post-op for fracture
    • -Peds: focal tenderness, fever
  • PE-DM:
    
    • -large diabetic foot ulcer with palpable bone → must think of osteomyelitis!!
• Dx:
  
  • Bone Aspiration:
  • -Positive bacterial cx from bone biopsy = preferred diagnostic criteria
  • -Aspirate: Gram stain only positive 50% of the time, need to culture it!
  • Labs:
    
    • -Leukocytosis
    • -Elevated ESR/CRP
    • -Cultures (need to cx before abx initiated)
• Tx:
  
  • Medical emergency
  • -IV abx x 4-6 weeks:
    
    • → MRSA: vancomycin
    • → MSSA: nafcillin or oxacillin
    • → Pseudomonas: Cefepime
  • -Surgical debridement
  • *Abx therapy is only effective before pus formation (soft tissue injury without joint or bone involvement) → deeper infections need surgical drainage
  • *If removal is effective then abx will prevent reformation & primary wound closure is safe

Question 8

Chronic Osteomyelitis

Answer 8

• Definition:
  
  • chronic infx of the bone (months to years)
• S/sxs:
  
  • *Slower onset
  • -Limb may be warm, swollen, tender, decreased ROM (d/t pain)
  • -irregular thickening of bone
  • -Multiple sinuses
  • -Scar & muscle contractures
  • -Discharge of bony spicules/ pus
  • -Deformities
  • -Pathological fracture
• Dx:
• Bone Biopsy
• Xray: sequestrum (segments of necrotic bone that has become separated from normal bone), involucrum (new periosteal bone formation around the necrotic bone)
• MRI: more sensitive

Question 9

Chronic Osteomyelitis

Answer 9

• Definition:
  
  • chronic infx of the bone (months to years)
• S/sxs:
  
  • *Slower onset
  • -Limb may be warm, swollen, tender, decreased ROM (d/t pain)
  • -irregular thickening of bone
  • -Multiple sinuses
  • -Scar & muscle contractures
  • -Discharge of bony spicules/ pus
  • -Deformities
  • -Pathological fracture
• Dx:
  
  • -Bone Biopsy
  • -Xray: sequestrum (segments of necrotic bone that has become separated from normal bone), involucrum (new periosteal bone formation around the necrotic bone)
  • -MRI: more sensitive
• Tx:
  
  • -Surgical debridement
  • *Parenteral followed by oral abx is as effective as long-term parenteral therapy

Question 10

Septic Arthritis: Def, risks, Pathophys, joints, organisms, S/sx

Answer 10

• Definition:
  
  • infection of the joint cavity
• Risks:
  
  • >80yo, DM, RA, SLE, prior total joint regional anesthesia (TJRA), recent joint surgery
• Pathophys:
  
  • Contiguous spread: skin infx, cutaneous ulcers (travel deeper & enters joint)
  • Direct inoculation: intra-articular injection, recent joint surgery
  • Hematogenous spread = Most common: DM, HIV, immunosuppression meds, IVDA, RA, osteoarthritis, sepsis, prosthetic joint, sexual activity (gonococcal arthritis)
• Joints:
  
  • mono-articular 80-90%, large peripheral joints such as knee = common in adults, hip = common in children, elbow or wrist
• Organisms:
  
  • staph aureus (MSSA & MRSA)
  • -Pseudomonas: IVDA (IV drug abuse)
  • -Neisseria gonorrhoeae: see other flashcard
  • -Salmonella: African Americans
• S/sxs:
  
  • **Acute onset
  • -Swollen warm, painful, tender joint with decreased ROM
  • -Redness & warmth of joint
  • -Fever
  • -N/V
  • -pain with passive ROM
  • Children:
    
    • -refusal to bear weight
    • -irritability
    • -tachycardia
    • -decreased appetite

Question 11

Septic Arthritis: Key hx points, Dx, & Tx

Answer 11

• Key hx points:
  
  • -Number of joints involved
  • -Underlying joint disease or trauma
  • -Prior illness/infx
  • -Previous intra-articular infx or joint surgery
  • -IV drug abuse
  • -Time of onset
  • **high index of suspicion in young pts presenting with joint pain**
• Dx:
  
  • Arthrocentesis: Synovial fluid
    
    • WBCs > 75K
    • -PMNs > 90%
    • -Clarity: opaque
    • -Color: dirty/yellow
    • -Viscosity: variable
    • -Glucose: low
    • -Protein: elevated
    • -Gram stain (+60-80% of the time)
    • -Analyzed for crystals
  • *Gold standard: cx & sensitivity (3 Cxs: aerobic bacteria, anaerobic bacteria, AFB)
  • *always get cxs before giving abx
  • Labs:
    
    • -Elevated ESR & CRP
  • Xray: usually normal, but may show soft tissue swelling around the joint & widening of the joint space
  • “Are you a MRSA carrier?”
  • REFER OUT EARLY!!
• Tx:
  
  • Medical Emergency. Can rapidly destroy the joint so do NOT wait
  • IV abx: after fluid collection
    
    • → Cx pending: Vancomycin +/- Cefepime (UTI)
    • → Gram + cocci: vancomycin
    • → Gram - rods: Cefepime
    • → Gram - rods: IV Drug Abuse/critically ill: Cefepime + gentamicin
  • -Refer for surgical drainage: arthrotomy (open surgical drainage) or lavage with arthroscopy
  • -If uncomplicated: IV → oral abx x 4-6 weeks
  • *All pts with septic arthritis need surgery except gonococcal

Question 12

Gonococcal Arthritis

Answer 12

• young, sexually active patient who presents with multiple painful joints. Associated with tenosynovitis. Migratory pattern (i.e. ankle → knee → lower back → elbow)
• S/sxs:
  
  • Swollen warm, painful, tender joints with decreased ROM
  • Gonococcal rash
• Tx:
  
  • IV Abx: Cefepime
  • May NOT need surgery

Question 13

Synovial Fluid Analysis Chart

Answer 13