Systemic Lupus Erythematosus

Question 1

Define SLE

Answer 1

Systemic lupus erythematosus (SLE) is a chronic multi-system disorder that most commonly affects women during their reproductive years.

Question 2

Explain the aetiology / risk factors of systemic lupus erythematosus (SLE)

Answer 2

Aetiology/Pathophysiology (unknown):

• Self-reactive B-cells are not cleared and are released into the periphery (risk for autoimmunity)
• There is also a defect in clearance of apoptotic cells which means that there is a lot of apoptosis
• The result of this apoptotis is the exposure of intracellular material (e.g. nucleus and nuclear proteins) to APC
• B-cells produce auto-antibodies against the nucleus and its proteins leading to IMMUNE COMPLEX FORMATION and COMPLEMENT-MEDIATED DAMAGE in diferent organs

RISK FACTORS:

• Female (9:1 ratio F:M)
• Young age (pre-menstrual) 14-45
• Afro-Caribbean & Asian
• Drugs (most commonly Hydralazine, Isoniazid & Procainamide)
  
  • Patients usually have elevated anti-histone and anti-ssDNA antibodies

Question 3

Summarise the epidemiology of systemic lupus erythematosus (SLE)

Answer 3

• occurs most frequently between the ages of 15 and 45 years, 12x more common in females than in males
• In those aged >45 years, the female-to-male ratio is 2:1.

Question 4

Recognise the presenting symptoms of SLE (9)

Answer 4

• Malar rash sparing naso-labial folds
• Discoid rash
• Photosensitive rash
• Raynaud’s phenomenon (Colour changes of digits induced by cold or emotion)
  General malaise / constitutional sx
• Alopecia
• Oral ulcers
• Polyarthralgia/Arthritis (no inflammation)
• Pleuritic Chest Pain ± SOB (pericarditis & pleuritis)
• Frequent abortions/failed abprtions (is anti-phospholipid)
• Neurological manifestation:
  
  • Seizures
  • Headaches
  • Psychosis
  • Depression

Question 5

Common/Classic presentation

Answer 5

• Young female presenting with rheumatoid-like symptoms
• presenting with FEVERS (a hx of several courses of Abx)

The primary symptoms and signs are:
* Fatigue (Often extreme i.e having to go to bed at 19:00 or 20:00)
* Arthralgia (Typically pain in multiple small joints but swelling often absent)
* Rashes (Not dermatitis and photosensitivity is more specific for SLE

Question 6

Recognise the signs of systemic lupus erythematosus (SLE) on physical examination

Answer 6

• Malar rash sparing naso-labial folds
• Discoid rash
• Photosensitive rash
• Raynaud’s phenomenon (Colour changes of digits induced by cold or emotion)
• Alopecia
• Oral ulcers
• Pleuritic/Pericardial rub
• Stony dull percussion & decreased breath sounds (pleural effusion - this is exudative)

Question 7

Identify appropriate investigations for systemic lupus erythematosus (SLE) and interpret the results

Answer 7

• Full blood count:
  
  • Bone Marrow IC deposition: Anaemia, Thrombocytopenia, Leukopenia (lymphoctes > neutrophils)
  • Coombe’s Test +ve for Autoimmune HaemolytiA - SLE is a cause of warm agglutinins
• Complement levels: Low C3 & C4 - this is THE BEST marker of ACTIVE DISEASE
• U&E: Raised urea & creatinine
• Urinalysis: All patients with lupus nephritis (GN) have proteinuria, red cell casts and haematuria
• Elevated ESR and CRP are suggestive of active SLE disease, but infection must be excluded ➔ if CRP >100 admit and investigate for infection as SLE pts are neutropenic
• Auto-antibody test: positive anti-dsDNA and anti-Smith antibodies.
  
  • A positive ANA (present in 99% of cases so VERY SENSITIVE), a strong titre of >1:640
• CXR & ECG for patients complainig of cardiopulmonary symptoms

Question 8

Diagnostic Criteria

Answer 8

Need 4/11 of SOAP BRAIN MD features (including +ve ANA)

• Serositis
• Oral ulcers
• ANA +ve
• Photosensitivity
• Blood cell reduction (AIHA, thrombocytopaenia, neutropenia)
• Renal involvement (lupus nephritis ➔ nephrotic syndrome initially)
• Arthralgia
• Immunological features (anti-Sm, anti-dsDNA, anti-cardiolipin)
• Neurological manifestations (seizures, psychosis)
• Malar rash
• Discoid rash

Question 9

Management

Answer 9

Conservative:
* wear sunblock/UV protection

Medication:
* symptomatic: NSAIDs for pain
* All people with SLE get hydroxychloroquine
Symptomatic management