The document discusses two main diseases related to bone and joint infections: osteomyelitis and septic arthritis. Acute osteomyelitis primarily affects children and is mostly caused by S. aureus, while chronic osteomyelitis involves bone destruction and requires surgical intervention along with antibiotics. Septic arthritis often arises from septicemia and necessitates prompt antibiotic treatment based on preliminary diagnoses.

1. INFECTION OF BONE AND JOINTS
• The two main diseases are:
– Osteomyelitis: infection of bone.
– Septic arthritis: Infection of joints Osteomyelitis
– Acute osteomyelitis
– Chronic osteomyelitis

2. Acute osteomyelitis
• Infection of bone which occurs commonly
under ten years old.
• Distal femur, proximal tibia and proximal
humerus are the classical sites.
– Causative agents: S. aureus (80% of cases)
– H. influenzae (especially in young children)
– S. pneumoniae
– S. pyogenes
– Coliforms and Group B streptococci in new born.

3. • Clinical features: Fever, bone pain, local tenderness and
swelling,
• limitation of movement
• Laboratory diagnosis:
• Specimen: Blood culture, Pus from bone by needle
aspiration
• Gram reaction, culture, biochemical tests and serology for
microbe
• identification.
• Treatment: Antibiotics alone are usually effective if started
early and
• continued for several weeks.
• Surgery is needed if there is pus accumulation and bone
destruction.

4. Chronic osteomyelitis
• It manifests with bone pain, bone destruction with
formation of sequestra and discharging sinuses.
• The most common causal organism is S. aureus;
others include M.
• tuberculosis,
• S. typhi and Brucella species.
• Laboratory diagnosis: Same as acute osteomyelitis
• Treatment:
• Antibiotics for several weeks.
• Surgery is usually necessary for pus drainage and
sequestra removal.

5. Septic arthritis
• It is usually seen as a complication of
septicemia or an extension of osteomyelitis.
Causative agents: S. aureus S. pneumoniae H.
influenzae

6. • Neisseria gonorrhea
• Neisseria meningitidis
• M. tuberculosis
• Clinical features: The onset is sudden with fever,
swelling and redness over the joint and severe pain
which limits movement of the affected joint.
• Laboratory diagnosis:
• Specimen: Blood culture, joint aspirate
• Gram reaction, culture, biochemical tests and serology
for microbe identification.
• Treatment: Antibiotic therapy based on “best-guess”
basis, should be started as soon as diagnostic specimens
have been taken.