Osteomyelitis (Osteon – Bone, Myelo – Marrow, itis – Inflammation) literally means inflammation of the bone and its marrow.
Morrey and Peterson proposed definition and classified osteomyelitis as following –
a) Definitive osteomyelitis, when an organism is recovered from bone or adjacent soft tissue or when there is histologic evidence of infection.
b) Probable osteomyelitis, when there is a positive blood culture in addition to the clinical and radiographic features of osteomyelitis is present.
c) Likely osteomyelitis, when there are typically clinical and radiographic features of osteomyelitis is present along with a response to the antibiotic in the absence of positive culture.
Acute osteomyelitis is a rapidly destructive pyogenic bone infection usually of hematogenous in origin, occurring most frequently in infants and children.
The estimated annual incidence of acute osteomyelitis in children is 1:5000 children.
Specific causes are rare like primary immunodeficiency, however, many risk factors are present.
Risk factors are the antecedent focus of infection like otitis media, pharyngitis, sinusitis, tonsillitis, and other factors like trauma, chronic illness, and malnutrition.
The most common mode of spread infection is by hematogenous route, contiguous spread, and followed by direct inoculation.
Staphylococcus aureus is the most common bacteria followed by Group B streptococci, Streptococci pneumonia, gram-negative bacilli like Pseudomonas (IV drug abusers), Salmonella (Sickle cell disease) and E.Coli, anaerobic bacteria like peptostreptococcus, bacteroids.
The most common bones affected are distal femur and proximal tibia.
Acute and systemic nature of acute hematogenous osteomyelitis is often heralded by additional symptoms such as an abrupt onset of fever, anorexia, irritability, and lethargy.
Focal bone pain is common however children may not verbalize, instead refuse to walk, bear weight, or move the limb.
On examination, the child will be febrile with increased pulse rate, localized bony tenderness with warmth is present.
Complete blood count, erythrocyte sedimentation rate (ESR) and C – reactive protein (CRP) are blood investigation routinely performed.
Radiograph and ultrasound of the affected part are imaging aid helps in making the diagnosis.
Bone aspirate/ pus and blood culture sensitivity are performed to find out specific organism responsible for the infection.
Very rarely higher imaging modalities like magnetic resonance imaging (MRI) and bone scan are required in complicated complex cases.
Treatment of acute osteomyelitis in children is medical with appropriate antibiotic supplemented with surgical intervention (if the abscess is present)
Local term consequences of improperly, inadequately, insufficiently treated cases include chronic osteomyelitis, physeal damage leading to angular deformity and limb length disturbances.