TLDR;
This video provides a comprehensive overview of osteomyelitis (bone infection) in children, covering acute hematogenous osteomyelitis, non-hematogenous osteomyelitis, and chronic osteomyelitis. It discusses the pathology, common pathogens, clinical presentation, diagnostic imaging, and treatment options for each type. The video emphasizes the importance of early diagnosis and appropriate management to prevent complications and long-term sequelae.
- Acute hematogenous osteomyelitis is the most common form in children, typically affecting the metaphysis due to sluggish blood flow.
- Staphylococcus aureus is the most common pathogen, but other organisms like Group B Streptococcus, E. coli, Salmonella, and Kingella kingae can also be responsible.
- MRI is the preferred imaging modality for early and accurate diagnosis.
- Treatment primarily involves antibiotics, with surgical intervention indicated in specific cases like subperiosteal abscess, lack of response to antibiotics, or extension to a nearby joint.
- Chronic osteomyelitis requires surgical management to remove sequestrum and address chronic changes in the bone.
Introduction to Osteomyelitis in Children [0:00]
The lecture will cover the pathology, pathogens, clinical presentation, and treatment of osteomyelitis in children. It will also compare acute and chronic osteomyelitis in terms of pathology, clinical presentation, and treatment. A useful resource for further reading is the "Pediatric Orthopedic: A Handbook for Primary Care Physician" book.
Acute Hematogenous Osteomyelitis: Definition and Pathology [0:40]
Acute hematogenous osteomyelitis is defined as an acute infection of the bone and bone marrow, most commonly affecting boys between 4 to 6 years old. Pathologically, the infection typically begins in the metaphysis, the area of the bone adjacent to the growth plate (physis), due to its sluggish blood flow. Bacteria from a distant focus, such as a skin, teeth, or nose infection, travel through the blood and settle in the metaphysis, forming a focus of infection surrounded by inflammatory cells, eventually leading to a metaphyseal abscess.
Microbiology of Acute Osteomyelitis [2:47]
Staphylococcus aureus is the most common pathogen across all age groups, including methicillin-resistant strains (MRSA). Group B Streptococcus and E. coli are common causes of neonatal osteomyelitis. Salmonella is frequently seen in children with sickle cell anemia, while Streptococcus pneumoniae is common in children under 24 months. Kingella kingae is an increasingly recognized cause of musculoskeletal infections, including osteomyelitis and arthritis, and its identification has improved with PCR testing.
Clinical Presentation of Osteomyelitis [4:12]
Children with osteomyelitis typically present with general signs of infection, such as fever, vomiting, toxemia, and chills, along with local manifestations on the affected bone, including redness, hotness, tenderness, and swelling. These local signs are more easily detected in subcutaneous bones like the proximal tibia or distal fibula. If the lower extremity is affected, the child may be unable to bear weight on the affected side. Elevated markers of infection, such as white blood cell count, ESR (erythrocyte sedimentation rate), and C-reactive protein (CRP), are usually present, although it may take a few days for these to show up.
Imaging Studies for Diagnosing Osteomyelitis [5:02]
Initial imaging should include a plain radiograph (X-ray) to exclude other causes of pain and swelling, such as fractures or tumors. However, X-rays may be negative in the first 10 to 14 days of the disease. After this period, periosteal reaction may be visible. Bone scans, specifically triphasic bone scans, are useful for detecting infection, showing up as a "hot spot" at the site of infection. MRI is increasingly used due to its high sensitivity and ability to detect early changes, showing increased signal on T2-weighted images and enhancement of the medullary cavity. MRI can also reveal subperiosteal abscesses and involvement of nearby joints.
Differential Diagnosis: Conditions Mimicking Osteomyelitis [8:59]
Conditions that can mimic osteomyelitis include Ewing sarcoma and septic arthritis. Ewing sarcoma can present with pain, swelling, and elevated inflammatory markers, but radiographs will show bone destruction, elevated periosteal reaction, and new periosteal bone formation, typically affecting the diaphysis rather than the metaphysis. Septic arthritis can be difficult to differentiate, but pain is usually more localized to the joint, and passive joint movement causes severe pain. MRI can help distinguish between the two, although they can sometimes occur simultaneously, especially in the hip and shoulder.
Treatment of Osteomyelitis: Antibiotics and Surgical Intervention [10:21]
Osteomyelitis is primarily a medical condition treated with antibiotics, but surgical intervention may be necessary in certain circumstances. Obtaining cultures from the affected site is crucial to identify the offending organism and guide antibiotic selection. Antibiotic treatment typically involves 6 weeks of organism-sensitive antibiotics, usually starting with 2 weeks of intravenous antibiotics followed by 4 weeks of oral antibiotics. If oral antibiotics are not suitable, the entire course may be administered intravenously via a peripherally inserted central catheter (PICC) line. Empiric therapy often begins with IV clindamycin or vancomycin in areas with high prevalence of methicillin-resistant Staphylococcus aureus (MRSA). Clinical response and C-reactive protein (CRP) levels are monitored to assess treatment effectiveness.
Indications for Surgical Intervention in Osteomyelitis [13:43]
Surgical intervention is indicated in cases of subperiosteal abscess, lack of response to medical treatment after 36 hours, or extension of infection to a nearby joint. It's important to remember that osteomyelitis is primarily a medical disease that can be treated with antibiotics, but these specific situations warrant an orthopedic consultation.
Non-Hematogenous Osteomyelitis: Causes and Management [15:19]
Non-hematogenous osteomyelitis can result from post-traumatic causes such as open fractures, penetrating trauma, puncture wounds, post-surgical infections, human or animal bites, decubitus ulcers, or local spread of infection. Management includes antibiotics, similar to hematogenous osteomyelitis, but most cases require orthopedic consultation and surgical debridement.
Chronic Osteomyelitis: Pathology and Management [16:37]
Chronic osteomyelitis is characterized by chronic changes in the affected bone, typically resulting from inadequately treated acute osteomyelitis. The key pathological features are sequestrum (dead bone separated from surrounding tissue) and involucrum (periosteal new bone formation). Sequestrum appears as a denser structure on X-rays, while involucrum is a reparative process to strengthen the bone. Management of chronic osteomyelitis requires orthopedic consultation and surgical removal of the sequestrum. Antibiotic treatment is generally not needed unless there is an acute exacerbation of infection.
