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Puswhisperer Blog

09/21 My Blog. I thought when Medscape and I parted ways that it was time to move on from blogging. Turns out I was wrong, I missed writing. Although I am not sure anyone gives a rat’s ass, I decided to resume the blog. Content is uncertain. Certainly ID cases. Maybe other stuff. I don’t know. We will see.

Strikeout

Mark Crislip

Oct 20, 2021

The patient, elderly, is being worked up for rapidly enlarging pulmonary masses. It was thought to be due to granulomatosis polyangiitis based on a positive c-ANCA and a perhaps consistent lung biopsy. Like many a skinny needle biopsy, there were a lot of artifacts that made the read soft. But the patient improved somewhat on steroids and Rituxan until a stroke.

That led to an ECHO that slowed a vegetation flopping on the aortic valve and an ID consultation.

I did not have granulomatosis polyangiitis in my head as a cause of marantic endocarditis.

It happens. Granulomatosis polyangiitis can involve mostly the aortic, and other, valves, albeit rarely. I find a handful of cases on the Pubmeds.

Cardiac valvular involvement is a rare and potentially fatal complication of GPA and may misleadingly suggest infectious endocarditis. A review of literature revealed few cases of histologically well-documented cardiac valvular involvement in GPA. Pathologists should be aware of valvular heart diseases in GPA, which usually comprise valvular necrotic lesions without any microbial agents.

But maybe the patient has two processes, even though I am an Occams kind of guy. Endocarditis and granulomatosis polyangiitis.

Multiple blood cultures are negative off antibiotics, and history for exposures has only a childhood in urban S. America and young cats at home.

Here is where it gets curious.

Bartonella (and Coxiella) endocarditis can present like granulomatosis polyangiitis even with a positive ANCA.

Bartonella infection mimicked anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis in 83% with PR3-ANCA and presented as cryoglobulinemic vasculitis in 8%. Glomerulonephritis was present in 92%, and 88% had endocarditis. ....Five cases of Coxiella infections were added to 16 from literature review. Sixteen had small-vessel vasculitides, mainly cryoglobulinemia vasculitis in 75%. One patient had polyarteritis nodosa-like vasculitis and four large-vessel vasculitis.

Conclusion: Coxiella and Bartonella are both able to induce vasculitis but display distinct vasculitis features. Bartonella mimics PR3-ANCA-associated vasculitis in the setting of endocarditis, whereas Coxiella may induce vasculitis involving all vessel sizes.

So I got all excited that this was Bartonella, a common cause of culture-negative endocarditis. Even though it is a different ANCA and pulmonary nodules do not seem to reported in the granulomatosis polyangiitis cases, it is more at the glomerulonephritis end of the disease presentation. However, there are the rare cases of Bartonella causing pulmonary nodules.

Nope. Work-up for infections, including molecular testing, is a big, fat negative.

It's all granulomatosis polyangiitis.

But still, fun to think about, And it is the strikeouts that are more edumacational than a home run.

Rationalization

Cardiovasc Pathol . Nov-Dec 2014;23(6):363-5. doi: 10.1016/j.carpath.2014.07.007. Epub 2014 Aug 4. A case of aortic and mitral valve involvement in granulomatosis with polyangiitis https://pubmed.ncbi.nlm.nih.gov/25194969/

Bartonella and Coxiella infections presenting as systemic vasculitis: case series and review of literature https://academic.oup.com/rheumatology/advance-article-abstract/doi/10.1093/rheumatology/keab691/6368082

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