Infectious Disease

Question 1

Osteomyelitis

Answer 1

• Staph aureus has many receptors for adhering to bone

Characterization

• Acute (2 wks + >2cm
• Will usually be largely polymicrobial
• If bone is palpated on probing of an infected diabetic pedal ulcer, this is enough for a dx, don’t need radiographic imaging

Labs/ Investigations
- WBC (usually N), ESR, CRP, sinus tract culture, blood culture, bone xray, MRI, PET (highest accuracy), bone biopsy (surgical - gold std, percutaneous), WBC scan

Dx
- Gold std: isolation of bacteria from bone biopsy + inflamm + osteonecrosis on histology

Tx

• Usually debridement if chronic/ hardware related/ contiguous
• Revascularization if PVD
• Abx as soon as take cultures, usually vanco, cefazolin, or nafcillin. Usually 4-6 wks.
• Watch for endocarditis if suspicion from hx

Question 2

Septic Arthritis

Answer 2

Osteo vs septic arthritis

Question 3

Urinary Tract Infection (UTI)

Answer 3

Labs/ Investigations

• +ve urine leukocyte esterase & urine nitrites = 68-88% sensitivity
• pyuria (>3 leukocytes/hpf)