Systemic Lupus Erythematosus

Definition/diagnostic criteria Systemic lupus erythematosus (SLE) is a complex autoimmune disease with a wide spectrum of clinical manifestations, characterised by immune system dysfunction. There is no diagnostic test specific for SLE and investigations should be guided by the extent of the organ involvement

Epidemiology SLE is a chronic condition primarily affecting young women of childbearing age. Lupus affects nearly 1 in 1000 of the population in the UK and is most frequently observed in people of African-Caribbean and South Asian descent

Diagnosis
Clinical features: The clinical presentation of SLE can be highly variable and may mimic various other conditions. Common clinical features include:

• Skin manifestations: Photosensitive rashes, malar rash (butterfly rash), and discoid lesions may be present.
• Joint pain: Arthralgia and arthritis are frequently reported, with symmetric polyarthritis affecting multiple joints.
• Fatigue: Patients often complain of debilitating fatigue.
• Renal involvement: Lupus nephritis can manifest with proteinuria and haematuria.
• Haematologic abnormalities: Anaemia, leukopenia and thrombocytopenia can occur.
• Raynaud’s phenomenon: Digital colour changes in response to cold or stress.
• Neuropsychiatric symptoms: Cognitive impairment, seizures and mood disorders may be seen.

Investigations: Timely and accurate diagnosis requires a combination of clinical assessment and laboratory investigations. Typical abnormalities in laboratory findings include:

• Antinuclear antibodies (ANA): Almost all SLE patients are ANA-positive.
• Specific autoantibodies: Anti-dsDNA and anti-Smith antibodies are highly specific for SLE.
• Full blood count (FBC): Anaemia, leukopenia and thrombocytopenia are common.
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): Elevated in active disease.
• Complement levels: Reduced levels of C3 and C4 complement proteins are often observed.
• Renal function: Serum creatinine and urinalysis help assess renal involvement.
• Imaging: Radiographs or MRI may be used to evaluate joint damage or organ involvement.

Treatment The management of SLE aims to control symptoms, prevent flares and minimise organ damage. A multidisciplinary approach involving rheumatologists, nephrologists and other specialists is often required. Key components of treatment include:

• Non-pharmacological measures: Sun protection, smoking cessation and exercise are recommended.
• Analgesics: Paracetamol is the first-line choice for pain relief.
• NSAIDs: For joint and musculoskeletal pain.
• Disease-modifying anti-rheumatic drugs (DMARDs): Hydroxychloroquine is commonly used.
• Glucocorticoids: For severe flares or organ involvement, prednisolone is prescribed.
• Immunosuppressive agents: Methotrexate, mycophenolate and azathioprine may be considered for more aggressive disease.
• Biologic therapies: Rituximab and belimumab can be options for refractory cases.

Prognosis SLE prognosis varies widely, with some patients experiencing mild disease and others facing severe complications. Early diagnosis and appropriate management can significantly improve outcomes. Mortality rates have decreased over the years, primarily due to better therapeutic options and monitoring.