Systemic Lupus Erythema-tosus

Question 1

What is SLE?

Answer 1

multi-system inflammatory autoimmune disorder

Question 2

Aetiology of SLE?

Answer 2

UNKNOWN
• Tissue damage may be caused by vascular immune complex deposition
• Could be due to a combination of hormonal, genetic and exogenous factors

Question 3

What are the risk factors for SLE?

Answer 3

Female
Reproductive age (15-45)
African or Asian decent (in EU or US)

Drugs;
Isoniazid - TB
Phenytoin
Anti TNFa monoclonal antibodies

FH
Sun exposure
Smoking

Question 4

What are the presenting signs and symptoms of SLE?

Answer 4

• General Symptoms
○ Fever
○ Fatigue
○ Weight loss
○ Lymphadenopathy
○ Splenomegaly

• Raynaud’s phenomenon
• Oral ulcers
• Skin Rash; malar & discoid, photosensitive rash
○ Atypical rashes (e.g. photosensitivity, vasculitis, urticaria, purpura)
- Alopecia

Question 5

What are the presenting signs and symptoms of SLE, more indicative of systemic involvement?

Answer 5

• Systemic Involvement
○ Musculoskeletal - arthritis, tendonitis, myopathy

○ Heart - pericarditis, arrhythmias, (chest pain, SOB)

○ Neurological - headache, stroke, cranial nerve palsies, confusion, chorea

○ Psychiatric - depression, psychosis

○ Renal - glomerulonephritis
- Gastro; abdominal pain, vomiting, diarrhoea

• Vascular; arterial or venous thrombosis, HTN
• Signs of nephrosis; oedema, proteinuria etc
• Alopecia
• Dysphagia
• Nose ulcer

Question 6

Identify appropriate investigations for SLE?

Answer 6

• Bloods
- Auto Antibodies
Urine - haematuria, proteinuria, red cell casts
• Joints - plain radiographs
• Heart and Lungs - CXR, ECG,
• Kidneys - renal biopsy (if glomerulonephritis suspected)
• CNS - MRI scan, lumbar puncture

TSH - exclude hypothyroidism

Question 7

What would the blood tests show?

Answer 7

○ FBC
anaemia, leukopenia, thrombocytopenia; rarely pancytopenia

○ U&E
elevated urea and creatinine

○ Activated PTT - prolonged (if have antiphospholipid abx) - partial thromboplastin time (clotting)

○ Raised ESR raise or normal CRP - indicates infection though

○ Complement ; low C4 and C3

Autoantibodies
○ Anti-dsDNA (60%)
○ Rheumatoid factor (30-50%)
- Antinuclear abx

Question 8

What is the best diagnostic test for lupus?

Answer 8

Antinuclear antibody (ANA) is the best diagnostic test and is positive in virtually all patients with SLE. Clinically relevant ANAs are IgG antibodies.

Currently the most sensitive test for confirming the diagnosis of SLE when accompanied by typical clinical findings.

As ANA can be positive in so many conditions and in healthy people, the result of a positive ANA has to be interpreted in the light of the clinical history and symptoms.

Question 9

Why can ANA be negative in SLE at times?

Answer 9

the ANA can be negative in SLE, especially in anti-Ro-antibody-positive lupus (Ro is also known as Sjogren’s syndrome A

Question 10

What other autoantibodies most be looked out for in SLE?

Answer 10

Anti-ENA
○ Anti-RNP
○ Anti-SM
○ Anti-Ro
○ Anti-La
○ Anti-histone
○ Anti-cardiolipin

Question 11

What may a cxr show in sle?

what is the purpose of an ecg?

purpose of an echo?

Answer 11

pleural effusion, infiltrates, cardiomegaly

to exclude other casues of chest pain

echo only done if cardio signs present to exclude pericarditis, pericardial effusion, pulmonary hypertension