Congratulations! In our last installment, despite the odds, you (presumably) reached the correct verdict: The villain responsible for your patient's misery is indeed IgG4-related disease, not one of the many other suspects. Now, what's the sentence?
Congratulations: You've come to grips with the identity of the culprit in Chapter I of this tale, and despite the odds, you managed to confirm in Chapter II that your patient indeed has IgG4-related disease (and not one of the many false suspects).
Now, how should you proceed?
Predictably, the management of this highly complex disorder varies. However, typically corticosteroids are very effective at the outset.23
A common regimen: 40-60 mg daily for 2 weeks
Taper over 3 months
Sometimes, maintenance low-dose prednisone after taper
About 1/3 to 1/2 of patients will flare following steroid treatment.
For those intolerant of corticosteroids or unable to taper without flaring, numerous steroid-sparing agents (azathiprine, mycophenolate mofetil, methotrexate) have been tried, with limited success.
The best alternative appears to be rituximab.24 Typically patients are able to taper steroids rapidly following rituximab therapy.
Rituximab may also be used in place of steroids as induction therapy, especially for those with less severe disease not requiring urgent treatment.
The regimen: Two 1-gm infusions, 15 days apart
Some patients (it is difficult to predict which ones) require re-treatment after about 6 months.
Serial measurements may be useful to assess disease activity in those cases where serum IgG4 is elevated. However, this is variable and not always reliable.25
Organ-specific interventions such as ureteral or biliary stents may be necessary initially to manage disease. Often these can be removed when medications take effect.
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23. Khosroshahi A, Carruthers MN, Deshpande V, et al. Rituximab for the treatment of IgG4-related disease: lessons from 10 consecutive patients. Medicine (Baltimore) (2012) 91:57-66.
24. Khosroshahi A, Bloch DB, Deshpande V, Stone JH. Rituximab therapy leads to rapid decline of serum IgG4 levels and prompt clinical improvement in IgG4-related systemic disease. Arthritis Rheum (2010) 62:1755-1762.
25. Nirula A, Glaser SM, Kalled SL, Taylor FR. What is IgG4? A review of the biology of a unique immunoglobulin subtype. Curr Opin Rheumatol (2011) 23:119-124.