History: Presenting symptoms vary based on age. Neonates and infants present with signs of septicaemia, cellulitis, or fever without a focus. Aim to get information on the site of pain/swelling, duration of symptoms, prodromal symptoms, and recent trauma. Also, one should enquire about some underlying medical conditions e.g. sickle cell disease, chronic heart or lung conditions, and immunodeficiency. Immunisation history is essential as children with incomplete immunisation records of Haemophilus influenzae type b (Hib) and streptococcus pneumoniae (PCV) are at greater risk.

Examination: A thorough musculoskeletal examination should be completed on a child suspected of having SA or OM. Inspection of the affected limb for its resting position, swelling, erythema, differential warmth and tenderness is essential. The range of limb movement across the joint should be compared to the unaffected side. Limping gait or refusal to bear weight on the affected joint should further raise our suspicion. It is also important to document the vital signs of the child.

Investigation: Labs should include full blood count (FBC), erythrocyte sedimentation rate (ESR), C-reactive protein, blood culture, and plain radiograph of the affected limb. Ultrasound of the joint can contribute to establishing the diagnosis of SA. The diagnosis of SA is generally made by joint aspiration followed by microbiological examination (microscopy, culture and sensitivity) of the joint fluid or tissue. The aspirated fluid is cloudy and the demonstration of bacteria is diagnostic. However, cultures are negative in one-third of cases but this does not exclude infection. Blood cultures are positive only in 30-50% of cases in both OM and SA.

It is important to note that the X-ray findings in acute osteomyelitis is likely to be normal in the first 2 weeks of illness. Other imaging modalities include Magnetic resonance imaging of the affected Bone or joint which is the Gold standard in the diagnosis. Technetium radionuclide bone scanning can also be use especially in acute Osteomyelitis.

This includes trauma, cellulitis, pyomyositis, thrombophlebitis, juvenile idiopathic arthritis, rheumatic fever, sickle cell disease in vaso-occlusive crisis, reactive arthritis, Perthe’s disease, etc.

Optimal treatment of skeletal infections requires collaborative efforts of paediatricians, orthopaedic surgeons, and radiologists. Empirical antibiotics should be started immediately and adjusted based on the bacterial identification and antibiotic sensitivity results. For SA, drainage should be done promptly and intravenous antibiotics should be started immediately.

Choice of antibiotics:

• Neonate: nafcillin or oxacillin (150-200 mg/kg/24 hr divided q6h IV) PLUS cefotaxime (150-225 mg/kg/24 hr divided q8h IV). If methicillin-resistant Staphylococcus aureus (MRSA) is suspected, replace nafcillin with vancomycin (60 mg/kg/24 hr divided q6h IV).
• Infant/children: Cefazolin (100 mg/kg/24 hr divided q8h IV) or nafcillin (150-200 mg/kg/24 hr divided q6h) for methicillin-susceptible S. aureus. Replace with vancomycin or clindamycin (40 mg/kg/24 hr q8hr IV) if MRSA is suspected.
• Streptococcus pneumoniae or group A streptococci isolates: penicillin is the drug of choice.
• Penicillin resistance or salmonella spp: Cefotaxime (150-225 mg/kg/24 hr divided q8h IV) or ceftriaxone (50-75mg/kg/24 hr OD IV).
• Kingella kingae: β-lactam antibiotics (cefotaxime or cephalexin).
• Sickle cell disease: cefotaxime PLUS vancomycin or clindamycin.
• Penetrating injuries or compound fracture: clindamycin
• Immunocompromised patient: Ceftazidime PLUS vancomycin or use a combination of penicillin PLUS β-lactamase inhibitor PLUS aminoglycoside.

NOTE: Individualise the duration of antibiotic therapy based on the organism isolated and clinical course. A total of 4-6 weeks of therapy may be required. Change antibiotics from the intravenous route to oral when the patient’s condition has improved and the child is afebrile for ≥48-72 hours. For susceptible staphylococcal or streptococcal infection, cephalexin (80-100 mg/kg/24 hr q8h) or oral clindamycin (30-40 mg/kg/24 hr q8h) can be used to complete therapy.

Indication for surgery:

• Septic arthritis of the hip
• Frank pus is obtained from subperiosteal or metaphyseal aspiration
• Penetrating injury with retained foreign body
• Failure to improve or worsening symptoms after 72 hours on appropriate antibiotics
• Chronic osteomyelitis

Long-term follow-up is necessary with close attention to the range of motion of the joint and bone length.

Osteomyelitis and septic arthritis in children are serious infections of the bone and joints, respectively, often caused by bacteria like Staphylococcus aureus. These conditions can result in significant pain, fever, and impaired movement. Early diagnosis through clinical evaluation, imaging, and laboratory tests is critical to prevent complications. Treatment typically involves antibiotics and, in some cases, surgical drainage or debridement. Prompt medical intervention is essential to avoid long-term damage to the affected bones and joints.