I Love Me That Modern Technology
Mark Crislip
"My god, what is this, the Dark Ages?" Bones McCoy. The Voyage Home
For most of my long and storied career, ID has been pretty low-tech. I did an H&P, then hoped we grew something on agar plates. It has been that way forever. In the 21st century, we have finally had access to technologies that allow for the routine diagnosis of some of the oddest infections.
The patient is an elderly male, mostly healthy, who has two months of intermittent fevers, rigors, sweats, and progressive malaise.
Outpatient work has yielded nothing, and by the time he is admitted, there is quite the list of negative studies, from cultures to TEE to a CT of the chest/abdomen/pelvis.
Always a challenge to add to an extensive workup. So back to the H&P to give me a hint as to where to go.
When I see him, there is little in the way of exposures for odd infections, and his exam is negative.
But he looks ill, and his CRP and ESR are markedly elevated.
The only thing of note is several years ago, he had an extensive repair of his aortic arch and descending aorta, and he is full of endovascular graft.
So it is between a vasculitis of some sort or perhaps a graft infection. Reviewing the CT with radiology, the aorta/graft doesn't look infected, but it doesn't look not infected. Too complicated to tell.
So I order a PET CT, as one of many studies notes
FDG-PET scanning showed a better diagnostic accuracy than CT for the detection of vascular prosthetic infection.
I always think FDG stands for fudge, as in "present or deal with (something) in a vague, noncommittal, or inadequate way, especially so as to conceal the truth or mislead." Like most medical studies. Except the PET.
Bingo was his name-o. One section of the arch glowed like Chernobyl. As best could be determined, the infection was in the old clot between aortic and graft and involved the graft. But from what?
And several years out for surgery, was this a new infection, or has it been festering since the repair?
So with negative blood cultures, I sent off a Karius test. Lots of Legionella micdadei DNA. I did not see that coming.
There are a grand total of 2 cases of Legionella causing aortic graft infections, both pneumophilia
So a worlds first: Legionella micdadei aortic graft infection, diagnosis made possible by high tech. Although, I still want Dr. McCoy's tricorder.
Why? No reason I can find. No good water exposure outside of Portland city water and no similar case from the time of his surgery that would point to an infection acquired in the OR.
On a quinolone, symptoms markedly improved (macrolide intolerant), but how long to treat is problematic since
The findings of this meta-analysis confirm the positive association between fluoroquinolones and the development of aortic aneurysm or dissection. The data tend to show that this association may be majorly driven by aortic aneurysm.
Does it matter, given his aorta is mostly replaced/repaired? Got me.
Rationalization
Accuracy of FDG-PET–CT in the Diagnostic Workup of Vascular Prosthetic Graft Infection https://www.sciencedirect.com/science/article/pii/S1078588410003345
Fluoroquinolones and the Risk of Aortic Aneurysm or Aortic Dissection: A Systematic Review and Meta-Analysis https://www.ingentaconnect.com/contentone/ben/chamc/2019/00000017/00000001/art00004