Osteomyelitis and septic arthritis Flashcards
What is the primary cause of septic arthritis?
Bacterial infection, most commonly from Staphylococcus aureus.
What are the three primary diagnostic tests for septic arthritis?
Synovial fluid analysis, blood cultures, and imaging studies.
Why is septic arthritis considered a surgical emergency?
It can cause irreversible joint damage within 8 hours if untreated.
What are common routes of infection for septic arthritis?
Hematogenous spread, direct inoculation, and contiguous spread.
What specific joint characteristics make neonates more susceptible to septic arthritis?
Transphyseal blood vessels allow infection to spread from the metaphysis to the joint.
What is the most common joint affected by pediatric septic arthritis?
The hip joint (35% of cases).
Which patient populations are at the highest risk for septic arthritis?
Infants under 2 years old, elderly patients, and immunocompromised individuals.
What are the most common clinical signs of septic arthritis?
Fever, joint swelling, redness, pain, and restricted joint motion.
Why are fight bites considered a high-risk factor for septic arthritis?
They introduce bacteria directly into the joint, increasing infection risk.
How does osteomyelitis typically present in children?
Acute fever, localized pain, swelling, and irritability.
What is the primary cause of chronic osteomyelitis?
Persistent bacterial infection from trauma, open fractures, or implants.
How does hematogenous osteomyelitis develop?
Bacteria spread through the bloodstream and seed the bone.
Which bone structure is most affected in acute hematogenous osteomyelitis?
The metaphysis due to its rich vascular supply.
What is the characteristic pathological sequence in osteomyelitis?
Pus formation → sequestrum (dead bone) → involucrum (new bone) → fistula (sinus tract).
What radiographic sign suggests osteomyelitis in infants?
Widening of the joint space due to pus accumulation.
Which diagnostic method is the gold standard for identifying the causative organism in osteomyelitis?
Bone biopsy and culture.
What are common pathogens in neonatal osteomyelitis?
Staphylococcus aureus, Group B Streptococcus, and Escherichia coli.
Why is osteomyelitis more common in children than adults?
Children’s bones have a richer blood supply and are more prone to hematogenous spread.
What is a Brodie abscess?
A localized, walled-off form of subacute osteomyelitis.
Which factors increase the risk of developing osteomyelitis?
Diabetes, poor circulation, open fractures, and intravenous drug use.
What are the clinical signs of vertebral osteomyelitis?
Localized back pain, fever, and neurological deficits if severe.
How does chronic osteomyelitis develop in patients with diabetic foot infections?
Infection spreads from soft tissue to bone due to poor circulation and immune function.
What are the common pathogens causing osteomyelitis in adults?
Staphylococcus aureus, coagulase-negative staphylococci, and Gram-negative bacteria.
What is the significance of elevated ESR and CRP in osteomyelitis?
They indicate inflammation and infection severity.
What type of osteomyelitis is commonly associated with sickle cell anemia?
Salmonella osteomyelitis.
How does the joint capsule contribute to septic arthritis in pediatric patients?
The joint capsule attaches under the growth plate, facilitating infection spread.
Why is arthrocentesis critical in diagnosing septic arthritis?
It allows direct analysis of synovial fluid for cell count, Gram stain, and culture.
What is the treatment protocol for acute septic arthritis?
Urgent surgical drainage, broad-spectrum antibiotics, and supportive care.
What is the clinical significance of “flexion and external rotation” in hip septic arthritis?
It indicates joint effusion and is a hallmark of infection.
