Infectious Diseases (PEARLS)
The NCCPA™ Musculoskeletal Content Blueprint infectious diseases (PEARLS)
Acute and chronic osteomyelitis (ReelDx) |
Acute or chronic infection and inflammation of bone and bone marrow – can occur as a result of hematogenous seeding, the contiguous spread of infection or direct inoculation into intact bone (trauma/surgery)
- Fever, restriction of movement of involved extremity or refusal to bear weight
Acute osteomyelitis is most commonly seen in children with S. aureus as the most common organism
- Sickle cell disease - Salmonella is pathognomonic
Chronic osteomyelitis is most common in adults secondary to open injury of bone and surrounding soft tissue
- S. aureus is the most common organism (80%)
- Staph epidermidis in prosthetic joints
- Gram-negative pseudomonas in IVDU
- Pasteurella seen in cases caused by cat/dog bites
- Mycobacterium TB seen in vertebral involvement (Potts DZ)
Diagnose with bone aspiration = gold standard
- X-ray triad: demineralization, periosteal reaction, bone destruction (lags behind symptoms 7-10 days); MRI shows changes before XR
- Labs: CRP elevated for 4-6 weeks, WBC and ESR high in most cases
- Definitive diagnosis = blood culture or by needle aspiration/bone biopsy
Treatment: IV antibiotics for 4-6 weeks and at least 2 weeks of IV antibiotics
- Newborn (<4 months) - Group B Strep - nafcillin or oxacillin + 3rd gen cephalosporin
- > 4 months S. aureus - MSSA - Nafcillin + Ancef MRSA - Vancomycin or Linezolid
- Sickle cell - Salmonella - 3rd gen cephalosporin or FQ (Cipr)
- Puncture wound - Pseudomonas - Cipro or levofloxacin
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Septic arthritis (ReelDx) |
Direct bacterial invasion of joint space - most dangerous form of acute arthritis ⇒ medical emergency
- A single, swollen, warm, painful joint that is tender to palpation + constitutional symptoms (fever, sweats, myalgia, malaise, pain)
- MC = knee, and hip
- Caused by: hematogenous spread, direct inoculation, contiguous spread
- S. aureus is most common (40-50%); N. gonorrhea in sexually active young adults, streptococci; pseudomonas in IVDU
- Diagnose with arthrocentesis: joint fluid aspirate for definitive diagnosis (WBC > 50,000 primarily PMNs)
- WBC > 1000 is positive in pt with prosthetic joints
Treatment is based on gram stain- 2-4 week course of antibiotics + arthrotomy with joint drainage
- Staph aureus = Vanco/nafcillin (Vanco or Clindamycin if PCN allergic)
- Gonorrhea = ceftriaxone
- IVDU = Cipro/Levaquin
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