CLINICAL CASE 35, ANSWERS AND SUMMARY

Which one of these drugs is associated with Drug Induced Lupus or vasculitis?

Procainamide	9 (15%)
Etanercept	2 (3%)
Methyldopa	7 (11%)
Prophylthiouracil	3 (5%)
Methimazole	0 (0%)
Furosemide	1 (1%)
All except Furosemide	24 (40%)
All of them	10 (16%)
None of them	4 (6%)

Good work. Most of you got this one right.  All the above mentioned medications can lead to Drug induced lupus or vasculitis( ANCA positive) or both with the exception of Furosemide to my knowledge.  The presentation of each one of them is different and unique. Anti Histone antibodies are usually present in the classic drug induced lupus that affects the skin.  When the kidney is involved in such cases, usually the anti histone is negative and there might be a positive Anti DSDNA and/or ANCA( usually the atypical kind).

Anti-double stranded DNA antibodies are typically absent in drug-induced lupus due to procainamide, hydralazine, and isoniazid, such antibodies are associated with drug-induced disease with other agents, particularly with interferon-alfa and anti-TNF agents. Drug-induced ANCA are sometimes associated with necrotizing vasculitis.  Anti-tumor necrosis factor alpha therapy with infliximab, adalimumab, and etanercept has been associated with the development of positive test results for ANA and anti DSdNA.

The renal disease in drug-induced lupus is most  often due to a necrotizing glomerulonephritis with little or no immune complex deposition. Usually this is Anti MPO or p ANCA or atypical ANCA( classically in hydralazine). These patients may also have anti-double-stranded DNA antibodies when renal involvement is seen.

Check out the references:

http://www.ncbi.nlm.nih.gov/pubmed/9933467

http://www.ncbi.nlm.nih.gov/pubmed/12241963