Bone Infections 2025 PDF

BONE INFECTIONS Learning outcomes Knowledge: Define suppurative bone infections (osteomyelitis). Describe the common pathogens causing bone infections. List the common pathogens causing bone infections with emphasis to different age groups. Describe the laboratory diagnosis of osteomyelit...

BONE INFECTIONS Learning outcomes Knowledge: Define suppurative bone infections (osteomyelitis). Describe the common pathogens causing bone infections. List the common pathogens causing bone infections with emphasis to different age groups. Describe the laboratory diagnosis of osteomyelitis. Skill: Explain pathogenesis of osteomyelitis Pyogenic bone infection (Osteomyelitis) Definition: An infection of bone involving: Periosteum, Cortical bone & Medullary cavity (marrow cavity). The most common etiologic agents are: Pyogenic bacteria Mycobacterium tuberculosis Classification of osteomyelitis According to: 1. The duration & type of symptoms: ❖ Acute ❖ Chronic 2. The route of infection: ❖ Hematogenous: via blood stream ❖ Exogenous : by trauma or surgery ❖ Direct spread infection 3. Type of causative agent: ❖ Specific (e.g. TB) ❖ Nonspecific (most common) any organism other than TB Predisposing factors Age: More common in children (2-12 years) and less common in adults (again common in advanced age) Sex: Boys are more susceptible than girls. Trauma Immunodeficiency, AIDS Diabetes mellitus & debilitating diseases Diabetic patients: are especially susceptible to foot injuries and sores that can become infected, leading to osteomyelitis Renal dialysis & malnutrition Predisposing factors - 2 Sickle cell anemia Presence of septic foci: which act as a source of infection e.g.: - Otitis media - Tonsillitis - Abscesses Intravenous drug abusers Organisms Commonly Isolated in Osteomyelitis Based on Patient Age Infants ( female. ▪ The metaphysis of rapidly growing long bone are most frequently involved.  Clinical Picture of Acute Osteomyelitis Infant Adult History of: UTI, urological procedure, History of septic focus (sore old age, diabetes, immunosuppression throat), trauma Local pain, swelling , redness , failure to thrive tenderness drowsy reluctant to move irritable Fever, malaise metaphyseal tenderness Toxemia decrease range of movement Leucocytosis commonest around the knee Discharge of pus (sometimes)  Diagnosis ❑Clinical diagnosis is the role. ❑Laboratory diagnosis: - CBC (WBC count), ESR & C-reactive protein (CRP) - Blood culture: +ve in 50-70% of cases - X-Ray: initial evaluation - Specimen: bone biopsy, marrow aspirate - Direct detection: Gram stained smear (to identify the type of bacteria) - Culture & sensitivity: of the collected sample - Computed tomography (CT) - Bone scan - Magnetic resonance imaging (MRI): most sensitive study Treatment of Osteomyelitis Acute Osteomyelitis: Osteomyelitis often requires prolonged antibiotic therapy, with a course lasting for weeks or months Osteomyelitis also may require surgical debridement Chronic Osteomyelitis: Systemic Antibiotics Surgical treatment  Tuberculosis of Bone (Tuberculous osteomyelitis)-1 Tuberculous osteomyelitis usually affects children & young adults. It has an insidious onset & chronic course. It is more destructive than pyogenic osteomyelitis & more resistant to treatment. the spine is most frequently affected (50%), especially the lumbar spine (Pott’s disease), followed by the hips & knees. Tuberculosis of Bone (Tuberculous osteomyelitis)-2 Routes of Symptoms: Treatment: infection: - fever, Tuberculosis Hematogenous spread: It - chills, osteomyelitis is originates from a focus of - anorexia, treated with the same active pulmonary disease. anti-TB medications used - weight loss, & for the pulmonary form of Direct extension: From a - local swelling tuberculosis. caseous focus in the lung to the rib or extension of infection from caseating mediastinal lymph nodes to the vertebrae.  Laboratory findings Tuberculous osteomyelitis 1. CBC: anemia, Leukocytosis 2. ESR , CRP 3. Blood culture 4. Tuberculin skin test 5. MRI spine If all initial tests are negative but clinical suspicion remains high, consider: Nuclear medicine scan 6. Culture of CT-guided aspiration bone biopsy 7. Histological examination  Prevention of Osteomyelitis Any bacterial infection should be appropriate diagnosed & treated Effective wound management Thank you