Acute MSK injuries Flashcards
RHABDOMYOLYSIS etiology
- Injury to skeletal muscle & the release of intracellular contents
– myoglobin, creatine kinase, aspartate aminotransferase, & K + - Disruption of the Na+ K + ATPase pump & calcium transport
– Leading to ↑ intracellular Ca2+ & muscle cell necrosis.
– Ca2+activates phospholipase A2 & various vasoactive molecules &
proteases leading to free oxygen radicals
RHABDOMYOLYSIS: most common causes in adults
– Trauma/crush injury
– Alcohol abuse or illicit drug use
– Some medications (statins)
– Neuroleptic malignant syndrome
– Immobility → ischemic injury
RHABDOMYOLYSIS: most common causes in children
– viral myositis
– trauma
– exercise
– drug overdose (cocaine)
RHABDOMYOLYSIS diagnosis
- Gold standard for definitive diagnosis = ↑ serum creatine kinase (CK)
– concentrations at least 5x upper limit of normal = Rhabdomyolysis
RHABDOMYOLYSIS: management
1st → Treat the cause
* Early & aggressive IV fluid (isotonic saline)
– Initial rate o= 400-1,000 mL/hour
* Titrate based on volume status & urine output
– Goal = urine output of 1-3 mL/kg/hour
* Maintain fluids >10 L/day
* Manage potassium (K+)
– Check q 4h if CK levels >60,000 units/L
– If K+ is >6 mEq/L or ↑ monitor EKG
* Renal replacement therapy (Dialysis)
– Indicatation acute renal injury, inability to correct volume overload,
acidosis or hyperkalemia
RHABDOMYOLYSIS: late complications
– Acute kidney injury
* Most serious complication of
rhabdomyolysis
* ~13-50% of cases
Etiology of osteomyelitis
- acute osteomyelitis
– usually single organism - chronic osteomyelitis
– usually polymicrobial
Most common pathogens (> 50%) - Staphylococcus aureus
– Methicillin resistant S. aureus (MRSA) - ~1/3 of cases
Pathogenesis of osteomyelitis
- Hematogenous seeding of bone
– Common in children - Contiguous spread from adjacent
soft tissues & joints - Direct inoculation of
microorganisms into bone
– Wound contamination during
surgery or trauma
Osteomyelitis clinical presentation: acute
- Typically presents within 2
weeks of initial infection - Children > adults
- Fever, lethargy, irritability
- Cardinal signs of inflammation
- Delayed wound healing
Osteomyelitis clinical presentation: chronic
- Presents months to years after initial infection
- Adults > children
- chronic pain
- persistent wound drainage
- low-grade fever
- delayed wound healing
- bone instability
- soft tissue damage
OSTEOMYELITIS acute diagnosis
- Acute (develops over several days)
– Systemic symptoms (fever)
– Acute pain at affected site
– Warmth, erythema, swelling, &
delayed wound healing
– Clinical Dx
OSTEOMYELITIS chronic diagnosis
– chronic pain
– persistent sinus tract or
wound drainage
– low-grade fever
– delayed wound healing
– bone instability
– soft tissue damage
– presence of risk factors
* Probe-to-bone screening test (Good for ER)
– Insert sterile blunt probe into ulcer
(+) contacts bone (Sen. 87%, Spec. 83%)
* Definitive diagnosis
* Bone biopsy → histopathology consistent
with bone necrosis
OSTEOMYELITIS treatment
- Follows operative debridement
– Removal of necrotic tissue - Based on pathogen(s) from bone culture
- Typically, ABX are started based on
organism suspicion
– Changed based on culture results - Empirical Antibiotic Choices
– Vancomycin + 3rd or 4th generation
cephalosporin
e.g. ceftriaxone,
ceftazidime, or cefepime
OSTEOMYELITIS complications
- Acute osteomyelitis may progress to chronic
illness & bone necrosis
– 5-33% of cases are refractory to ABX
– Possible death & disability
INFECTIOUS (SEPTIC) ARTHRITIS etiology
- S. aureus = most frequent causative agent
in adults & children
– may cause mono- or polyarticular arthritis - Hematogenous (seeding) spread
most common route of infection - Direct inoculation
INFECTIOUS (SEPTIC) ARTHRITIS
- Acute onset
- Unilateral joint pain
- Swelling
- Warmth
- ↓ROM
- Loss of function
INFECTIOUS (SEPTIC) ARTHRITIS diagnosis
Acute onset, hot, red, tender, swollen joint with restricted movement
– Medical emergency & prompt diagnosis is imperative
– Consult ortho if suspected
* Synovial Fluid Analysis
– Purulent, WBC count,
Glucose, Gram Stain, Culture,
Crystals
* Blood Tests
– Blood cultures (+) ~50% of cases
– CBC with diff
– ESR & CRP (Typically elevated)
INFECTIOUS (SEPTIC) ARTHRITIS management
Management – Joint drainage
* Septic arthritis is essentially a closed abscess…we drain abscesses.
– Needle aspiration (necessary for joint fluid analysis)
– Arthroscopic drainage
– Arthrotomy (open surgical drainage)
* Adequate drainage not achieved by needle aspiration or arthroscopy
