What is the pathogenesis and treatment of vasculitis caused by infection?

From the Guidelines

Vasculitis caused by infection develops when pathogens directly invade blood vessel walls or trigger immune responses that damage vessels, and the most recent and highest quality study 1 suggests that treatment primarily focuses on eliminating the underlying infection with appropriate antimicrobial therapy. The pathogenesis involves either direct microbial invasion of vessel walls (as with syphilis or tuberculosis) or immune complex deposition and complement activation in response to infection (as with hepatitis B-associated polyarteritis nodosa).

Key Points to Consider

• For bacterial infections, targeted antibiotics are essential, such as penicillin G for syphilis or combination therapy for tuberculosis.
• Viral infections like hepatitis B may require antiviral medications such as entecavir or tenofovir.
• In severe cases with significant inflammation, adjunctive immunosuppressive therapy with corticosteroids may be necessary to control vessel damage while treating the infection, as recommended by 1.
• However, immunosuppression must be used cautiously as it can worsen the underlying infection, and the use of cyclophosphamide is strongly associated with the risk of bladder cancer, as noted in 1.
• Regular monitoring of inflammatory markers (ESR, CRP) and clinical symptoms is crucial to assess treatment response, and the prognosis generally improves once the causative infection is controlled, though some patients may experience residual vascular damage requiring long-term management.

Treatment Approach

• The treatment approach should be guided by the severity of the disease and the presence of organ-threatening or life-threatening manifestations, as recommended by 1.
• A combination of cyclophosphamide and glucocorticoids may be used for remission induction of generalized primary small and medium vessel vasculitis, as recommended by 1.
• Alternative immunomodulatory therapy choices should be considered for patients who do not achieve remission or relapse on maximal doses of standard therapy, and these patients should be referred to an expert centre for further management and enrolment in clinical trials, as recommended by 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Pathogenesis of Vasculitis Caused by Infection

• The pathogenesis of vasculitis caused by infection is complex and involves various mechanisms, including direct and indirect damage to the vascular wall 2.
• Direct damage occurs when infectious agents, such as Staphylococcus spp, Streptococcus spp, and Cytomegalovirus, destroy the vascular wall, leading to an inflammatory response 2.
• Indirect damage occurs when infectious agents, such as Mycobacterium tuberculosis and Hepatitis B Virus, stimulate an immune response against blood vessels, leading to a cross-self reaction of the immune system 2.
• The immune response can be classified as type I-IV by Gell-Coombs, and most infectious agents can cause vasculitis in both direct and indirect ways (mixed forms) 2.

Treatment of Vasculitis Caused by Infection

• The treatment of vasculitis caused by infection typically involves immunosuppressive therapy, such as cyclophosphamide and steroids 3, 4.
• Combination treatment with rituximab, low-dose cyclophosphamide, and plasma exchange has been shown to be effective in treating severe antineutrophil cytoplasmic antibody-associated vasculitis 5.
• The use of lower cyclophosphamide doses and shorter corticosteroid courses has been associated with decreased infectious rates in elderly patients with ANCA-associated vasculitides 6.
• New therapeutic schemes, such as interferon-free oral antiviral agents, have shown excellent short-term efficacy and safety in the treatment of hepatitis C virus-associated cryoglobulinemic vasculitis 6.

Key Points

• Infections are a common cause of secondary vasculitis, and the pathogenesis involves direct and indirect damage to the vascular wall 2.
• Immunocompromised patients are at increased risk of developing vasculitis, and infections can contribute significantly to increased mortality 6.
• The treatment of vasculitis caused by infection requires a comprehensive approach, including immunosuppressive therapy and appropriate prophylaxis 3, 4, 6.