Table 1: Differential diagnosis of arthritis in SLE patient.

 

Diagnosis

SITES

CLINICAL

RISK FACTORS

INVESTIGATION

Inflammatory arthritis

Hand joints, knee, frequently symmetrical.

Frequently presenting problem. May be associated with flare in other organs

 

No clearassociation with ESR, C3, and SLEDAI score

Septic arthritis

Hip, knee

(frequently multiple sites)

Acute onset, hot effusion

Corticosteroid therapy, inflammatory arthritis, osteonecrosis

High CRP, Joint aspiration:type 3 inflammatory fluid (turbid or frank pus, white cell count > 50 000, > 70% of which are neutrophils), positive culture

Osteo-articular Mycobacterium Tuberculosis infection

Spine, Hip, Knee, Wrist

Insidious onset, possible constitutional symptoms

Corticosteroid therapy, other immunosuppressive therapies, lymphopenia, nephritis, inflammatory arthritis

High inflammatory markers. Synovial fluid Gene x-pert and TB culture, synovial biopsy

Osteonecrosis

Hip, knee

(frequently multiple sites)

Cold effusion

High dose corticosteroid therapy, vasculitis, coagulopathy, antiphospholipid antibodies, Raynaudís phenomenon

X- ray may be abnormal if advanced, frequently normal in early stages. MRI is investigation of choice.

 

ESR: Erythrocyte Sedimentation Rate, SLEDAI score: SLE Disease Activity Score, CRP: C - Reactive Protein, TB: Tuberculosis, MRI: Magnetic Resonance Image