Monday, July 24, 2006

Systemic lupus erythematosis (SLE)

Systemic lupus erythematosis (SLE)

As I mentioned in my previous post ( 100 common questions in MRCP), SLE is always a popular question in either MRCP Part 1 or 2. There are a few typical and popular questions about SLE in MRCP, these include,

a) Photo-based question, usually a patient with malar rash would be shown in exam. Find a photo of SLE here, click www.passpaces.com/MRCP/issue1.html
b) The criteria to diagnose SLE, remember about American Rheumatic Association (ARA) criteria,
c) Common presentations of SLE and its complications
d) Drugs used in SLE and its side effects
e) Drug-induced SLE

ARA criteria

The mnemonic to remember HAI, MOPD ‘N’ RAS

Haematological involvement- can be thrombocytopenia, neutropenia , haemolysis or even pancytopenia.

Antinuclear antibody- seen in more than 90% of patients

Immunological disorder- anti-DNA, positive syphilis test, low C3,C4

Malar rash

Oral ulcers

Photosensitive rash

Discoid rash

Neurological involvement-pyschosis, fit

Renal involvement- lupus nephritis, protenuria

Arthritis- joint involvement

Serositis –pleuritis,pericarditis, endocarditis (Libman-Sacs)

To diagnose SLE, any four out of 11 criteria above!

Common drugs that cause drug-induced lupus are procainamide, isoniazid and hydralazine (PIH)

To diagnose drug-induced lupus, remember that
1) There will be sparing of renal and central nervous system
2) Anti-histone antibodies will be positive

Common presentations of SLE

Almost any thing under the sun, however, in MRCP, they would usually give you a case who is a young lady presents with unexplained fever and you notice that almost every organ is involved, investigations may show low white cell +/- platelets, renal involvement ( presence of RBC or protein) etc. Remember, 99% is a female patient!!

Common drugs used in SLE

I would cover this in my serial of popular drugs in MRCP in my coming posts. These drugs include prednisolone, azathioprine, hydroxychloroquine, cyclophosphamide and cyclosporin. ( immunosuppresants)

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