06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD
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06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD Disclosures of Financial Relationships with Relevant Commercial Interests • None Bone, Joint and Musculoskeletal Infections Sandra B. Nelson, MD Director, Musculoskeletal Infectious Diseases Division of Infectious Diseases Massachusetts General Hospital Osteomyelitis: Osteomyelitis: General Principles • Hematogenous Osteomyelitis • MRI and CT are the best radiographic studies – Metaphyseal long bone (more common in children) – Bone scan has good negative predictive value but lacks specificity – Vertebral spine (Spondylodiscitis) – MRI and CT not useful as test of cure – Usually monomicrobial • Diagnosis best confirmed by bone histopathology and culture • Contiguous Osteomyelitis – Identification of organism improves outcomes – Trauma / osteofixation – Swab cultures of drainage are of limited value – Diabetic foot ulceration • Optimal route and duration of therapy an evolving target – Often polymicrobial – 6 weeks of IV antimicrobial therapy commonly employed – Longer oral suppression considered in setting of retained hardware 3 4 Brodie’s Abscess (Subacute hematogenous osteomyelitis) Case #1 • 57 year old male presented with a 3 month • More common in children and history of progressive lower back pain young adults • On ROS denied fevers or chills but wife • Bacteria deposit in medullary canal noticed weight loss of metaphyseal bone, become • Originally from Cambodia, emigrated as a surrounded by rim of sclerotic bone child. Employed at a seafood processing → intraosseous abscess plant • ESR 84 CRP 16 • “Penumbra sign” on MRI • MRI with discitis and osteomyelitis at L5-S1 – Granulation tissue lining abscess cavity inside bone gives appearance of • Blood cultures grew Staph epidermidis in 2 of double line Simpfendorfer Infect Dis Clin N Am 2017;31:299 4 bottles • Staph aureus most common 5 6 ©2020 Infectious Disease Board Review, LLC 06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD Pyogenic Vertebral Osteomyelitis: Case #1: Vote diagnosis What is the best next step in management? • Blood cultures (positive in 60%) – No further diagnostics if Staph aureus or Staph A. Repeat 2 sets of blood cultures lugdunensis B. Initiate vancomycin; place PICC for six week treatment course • Brucella serologies, PPD/IGRA C. Obtain interferon gamma release assay – In appropriate epidemiological setting D. Percutaneous biopsy of disc space • Percutaneous biopsy (paraspinal or bone/disc space) E. Empiric treatment with rifampin, isoniazid, ethambutol, and pyrazinamide – When blood cultures and serology negative – Yield 36-65% – In absence of sepsis and/or neurologic compromise, withhold antibiotics 1-2 weeks if feasible – If negative repeat percutaneous or consider open procedure (open procedure higher yield) 7 9 Pott’s Disease • Clinically: – More indolent than pyogenic osteomyelitis – Constitutional symptoms common – Anterior collapse may lead to gibbus deformity Septic Arthritis • Radiographic: – Thoracic>lumbar with anterior involvement – Relative sparing of the disc space until later – Multi-level disease, large paraspinal abscesses • Treatment: – Conventional TB therapy, 6-12 months – Surgery often not necessary Simpfendorfer Infect Dis Clin N Am 2017;31:299 10 11 Septic Arthritis: Clinical Pearls Polyarthritis • Synovial fluid cell counts: No diagnostic threshold • 10-20 % of septic arthritis is polyarticular: – Higher probability of SA if WBC >50,000/mm3 • Associated with bacteremia/sepsis – Lower cell counts do not exclude septic arthritis – Staph aureus most common (look for endocarditis) • More subtle presentations in immunocompromised hosts and with • Streptobacillus moniliformis indolent organisms – Rat bite fever (fever/rash) – Polyarthritis, usually symmetric – Subacute history – If bitten in Asia – Spirillum minus – Lower synovial fluid cell counts – Rx: penicillin • Negative cultures and/or delayed culture positivity: • Consider also: Giorgiutti NEJM 2019: 381:1762 – think Gonococcus, HACEK, Lyme, Mycoplasma – gonococcal, viral, non-infectious 12 13 ©2020 Infectious Disease Board Review, LLC 06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD Gonococcal Arthritis Viral arthritides • Tenosynovitis, arthralgias, skin lesions • Symmetric polyarthritis, often involving small joints, often associated with fever – Especially extensor surface tenosynovitis and rash – Migratory arthralgias • Diagnose serologically (+IgM or 4 fold rise in IgG titer) • Purulent arthritis Most common viruses to cause arthritis Clinical and Epidemiologic Clues – May be polyarticular; knees most common Rubella Non‐immune (non US born). See cervical lymphadenopathy, fever, rash. – Lower synovial fluid cell counts more common Parvovirus B19 More common in women. History of • Asymptomatic mucosal phase predisposes exposure to young children, often a – Dissemination more common in women teacher or parent. Hands most common; can be severe. • Highest yield diagnosis: mucosal site sampling (cervical, Hepatitis B Virus Serum‐sickness like reaction, resolves with urethral) development of jaundice; also polyarteritis – Blood (<30%) and synovial fluid (<50%) cultures lower yield nodosa (PAN) – Compatible clinical syndrome Hepatitis C Virus Immune complex arthritis associated with cryoglobulinemia 14 Alphaviruses (esp Chikungunya) Travel to endemic areas 15 Crystalline arthritis: clinical pearls Masquerading as Infection… • Acute gout flare mimics septic arthritis (fever) CPPD • Other noninfectious causes of arthritis: – Clues: rapid onset (hours), history of gout, – Reactive arthritis alcohol, CKD, diuretics, elevated uric acid • Following enteric or genitourinary infection – Synovial WBC 10,000-100,000/mm3 • Asymmetric mono or oligo-arthritis affecting knees/ankles • Crystalline disease and septic arthritis can • Associated features: enthesitis (tendon insertion), dactylitis (sausage digits), mucosal lesions, urethritis, conjunctivitis/uveitis, skin lesions coexist (esp. CPPD) Gout (keratoderma blennorhagica) – CPPD rarely has cell count >30,000 – Still’s disease – Sarcoid (Lofgren’s) – Polymyalgia rheumatica – Many others…. Coelho BMJ Case Reports 2017‐222475 Images: Taljanovic RadioGraphics 2015;35:2026 16 17 Osteofixation Infections Case #2 • 44 year old woman, previously healthy, suffered a right ankle closed pilon fracture – Open reduction and internal fixation • Impaired wound healing – Chronically discharging wound despite courses of cephalexin and trimethoprim- sulfamethoxazole • 3 months after ORIF, wound culture grows methicillin-susceptible Staph aureus 18 19 ©2020 Infectious Disease Board Review, LLC 06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD Case #2: Vote Osteofixation Infections What are your next steps? • Infection risk as high as 25% and varies based on: A. Nafcillin followed by long-term trimethoprim- sulfamethoxazole – Open fractures (type and inoculum of bacterial contamination) B. Hardware removal; six weeks of oxacillin – Severity of fracture (Gustilo grade) C. Hardware removal; six weeks of oxacillin and rifampin – Severity of soft tissue injury D. Debridement without hardware removal; six weeks of oxacillin – Fracture location (lower extremity higher risk) and rifampin – Timely antibiotic prophylaxis for open fractures E. Debridement and hardware replacement; six weeks of oxacillin – Usual host risk factors and rifampin 20 20 Osteofixation Infections Prosthetic Joint Infection • Goals: fracture consolidation and infection eradication ‐ Removal of hardware depends upon fracture healing Early or delayed infections Late nonunion prior to fracture union Microbiology Staph aureus most common Indolent organisms (coagulase‐ negative Staphylococcus, Cutibacterium acnes) Surgical Strategy Debride and retain (assuming Hardware removal implants well fixed) Revision fixation (1 or 2 stage) Or external fixation Antimicrobial Pathogen‐directed therapy Pathogen‐directed therapy Management Add rifampin if Staph species Consider suppression until fracture consolidates, especially if Staph aureus 23 24 Prosthetic Joint Infection (PJI): Chronic PJI: diagnostic pearls Clinical presentations • Early surgical site infection (< 3months) • ESR/CRP may be minimally elevated – Acute onset of fever, joint pain, swelling • Plain films often normal or may show – Caused by virulent organisms (Staph aureus) periprosthetic lucency • Delayed / Subacute infection (3 – 24 months) – Insidious onset of pain; fever is uncommon • Synovial fluid aspiration the best test – Less virulent organisms: e.g. Coagulase-negative Staph, Cutibacterium – Lower cell counts than in native joints or acute PJI (> • Acute hematogenous infection 3000 WBCs per μL) – Acute onset of fever, joint pain, swelling in previously healed and pain-free – Yield of synovial fluid culture 50-60% joint » Reduced by prior antibiotics – Hematogenous seeding, virulent organisms (Staph aureus, Streptococcus) – Coagulase-negative Staph can be considered pathogenic if in >1 culture and compatible cell counts 25 26 ©2020 Infectious Disease Board Review, LLC 06 ‐ Bone, Joint and Musculoskeletal Infections Speaker: Sandra Nelson, MD Case #3 Case #3: Vote • A 57 year old woman with a history of diabetes, hypothyroidism, You are asked to provide recommendations about antimicrobial and anxiety has undergone total hip replacement. Three weeks management postoperatively, she developed erythema, swelling, and incisional A. Nafcillin for six weeks drainage. She was taken back