Septic Arthritis: Causes, Symptoms, and Treatment Options

This is an acute infection of the joint space.

Aetiology

1. Haematogenous spread from a primary focus elsewhere in the body.
2. Directing penetrating injuries onto the joint.
3. Extension of infection from a compound fracture of the neighbouring bone.
4. The commonest causative organisms are staphylococcus aureus, streptococcus pyogenes, and haemophilus influenzae, and to a lesser extent salmonella typhimurium or typhy.
5. large joints such as shoulder, knee, ankle, and hip are more often affected
6. Septic arthritis is the most common in children under 3 years of age.

Clinical Features

1. Fever, chills and irritability
2. Swollen, warm, very tender joint(s)
3. Pseudoparalysis of the joint
4. Multiple joints may be affected

Investigations

1. Haemogram-Anaemia and leukocytosis present
2. Pus for culture and sensitivity
3. Radiograph of the affected joint shows increased joint space, synovial thickening, and later rarefaction of the adjacent bone surfaces.

Management

1. Admit the patient
2. Take pus sample for culture and sensitivity.
3. Start on antibiotics: Flucloxacillin 5o-100mg/kg 6 IV hourly. Change according to culture and sensitivity results and continue for a period of 4-6 weeks
4. Splint the joint and initiate physiotherapy.
5. Give analgesics and antipyretics: tabs ibuprofen 400mg orally 8 hourly OR aspirin 600mg orally 8 hourly for 3 days.
6. Aspirate the joint: if there is frank pus then form an arthrotomy. Review daily until drainage.
7. Review monthly after discharge.
8. Watch for features of a worsening condition, which include the following:

• The fever persists for more than 7 days of full treatment.
• The joint swelling does not subside within 3 weeks.
• New joints get involved  while on treatment.

1. As much as possible, refer the patient to an appropriate facility before the following complications have developed, or refer immediately if they present with any of these complications:

• The affected joint starts to discharge pus spontaneously.
• Shortening of the limb occurs.
• There is a persistent deformity of the joint.
• There is loss of function related to the infection.