Page created on February 14, 2022. Not updated since.
Evaluation
Infectious causes of arthritis require urgent diagnosis and management. For this reason, joint aspiration should be performed in case of patients with fever, elevated inflammatory parameters, and features of infection (warmth, erythema).
Differential diagnosis of monoarticular arthritis
| Etiology | Typical features |
| Septic arthritis | Fever, unwell child, erythema, warmth, swelling, tenderness, WBCs and bacteria in joint aspirate |
| Osteomyelitis | Fever, unwell child, erythema, warmth, swelling, tenderness, positive MRI |
| Haemarthrosis (trauma, bleeding disorder) | Bruising, known or family history of bleeding disorder |
| Acute leukaemia, other malignancies | Anaemia, skin bleedings, infections |
| Reactive arthritis | Recent infection (chlamydia, salmonella), conjunctivitis |
| Bone tumour (osteoid osteoma, etc.) | Pain at night |
Differential diagnosis of polyarticular arthritis
| Etiology | Typical features |
| SLE | Generalised lymphadenopathy, butterfly rash, photosensitivity |
| HSP | Purpuric rash on butt and extensor surfaces, spares the trunk. Abdominal pain |
| JIA | No erythema, stiffness after periods of rest and in the morning |
| Reactive arthritis | Recent infection (chlamydia, salmonella), conjunctivitis |
| Lyme disease | Erythema migrans, fever, malaise, myalgia |
| IBD | GI symptoms, skin symptoms |
| Malignancy | General symptoms of malignancy |