Systemic lupus erythematosus (SLE)

Question 1

Features

Answer 1

Arthritis is the commonest clinical feature (over 90%).

It is a symmetrical polyarthritis involving;

• mainly small and medium joints
• esp. PIP and carpal joints of the hand.

Question 2

Dx Triad

Answer 2

polyarthritis + fatigue + skin lesions → SLE

Question 3

Investigations

Answer 3

The initial presentation is similar to rheumatoid arthritis.

If suspected, test;

• Antinuclear antibodies (ANA), +ve in at least 95%

and, if +ve, DNA and ENA Antibodies;

• ds DNA Abs → 95% specific but present in only 60%
• ENA Abs, esp. Sm—highly specific for SLE

ESR—proportional to disease activity

Rheumatoid factor—+ve in 50%

LE test—inefficient and not used

Question 4

Drug treatment

Answer 4

Mild—NSAIDs/aspirin (for arthralgia)

Moderate—low-dose antimalarials (e.g. hydroxychloroquine)—up to 6 mg/kg once/d for 3 mths, then 200 mg/d long term

Moderate to severe—corticosteroids (mainstay drug);

• immunosuppressive drugs (e.g. azathioprine, methotrexate + folic acid)
• bDMARDs useful for severe arthralgia

Consider fish body oil 0.2 mg/kg (o) daily (usually 2.7 g)