Thread by @AnnKumfer

What infections are on your list for infection-induced thrombosis? Why do infections predispose to thrombosis?

Source: ncbi.nlm.nih.gov/pmc/articles/P…

Here are some:
Bacterial: H. pylori, C. pneumoniae, M. pneumoniae, H. influenzae, S. pneumoniae, S.aureus, E.coli, Fusobacterium species, C burnetii
Vital: COVID-19, Influenza, EBV, CMV, HSV, VZV, HIV, Dengue, Hep A/C
What infections do you think of?
williams.medicine.wisc.edu/viral_coagulop…

The below infections are associated w/ antiphosholipid antibody + (likely through molecular mimicry), but not all infections significantly increase thrombosis risk. Risk ⬆️in HIV, Hep C, and CMV. Also ⬆️ risk with genetic predisposition. Image source: ncbi.nlm.nih.gov/pmc/articles/P…

COVID-19 causes endothelial damage which ⬆️ fibrinogen, D-dimer, and Factor VIII, and ⬇️ antithrombin III> predisposing to clots.
sciencedirect.com/science/articl…

Similarly, infections can cause of vasculitis-like syndrome which can either lead to thrombosis of bleeding. CMV, HIV, parvovirus, and leptospirosis are some causes. COVID-19 can cause MISC syndrome. I heard about a case PAN w/ RP bleed w/+COVID.
academic.oup.com/jid/article/18…

In sepsis w/ GN bacteremia, endotoxins and LPS can activate TF (start of extrinsic pathway) leading to ⬆️risk of thrombosis. Coagulation and fibrinolysis occur independently, so you can see both thrombosis and then later bleeding with consumption of products in DIC.

TF is also activated by damage of endothelial cells. The following viruses can infect endothelial cells causing damage.

Table source: academic.oup.com/jid/article/18…

Some viruses such as respiratory viruses, VZV, HIV, HBV, HCV, hantavirus, DSS, and Ebola virus infection also ⬇️ protein C, protein S, and antithrombin the bodies anticoagulant factors.
williams.medicine.wisc.edu/viral_coagulop…

Inflammation in general predisposes of thrombosis through ⬆️ cytokines increasing leukocyte, platelet, and endothelial cell activation. Think about increased thrombosis risk with IBD.

pubmed.ncbi.nlm.nih.gov/29876337/

Finally, don't forget about suppurative thrombophlebitis causing thrombosis. The first bacteria I think about is Fusobacterium (causing Lemierre's syndrome) but can be seen with a variety of bacterial and fungal infections.

This unplanned #tweetorial was inspired because I recently saw a case of a portal vein thrombosis w/ blood cultures later growing Fusobacterium nucleatum making me wonder about an abdominal Lemierre's syndrome. Has anyone else seen this #idtwitter?

Found a few case reports:
microbiologyresearch.org/docserver/full…
amjmed.com/article/S0002-…
ncbi.nlm.nih.gov/pmc/articles/P…

Conclusions: Infections can ⬆️ risk of thrombosis through various mechanisms. Some of mechanisms may also predispose to bleeding.
1. Inflammation itself predisposes to thrombosis ⬆️ cytokines
2. TF activation LPS/endotoxin or endothelial infection
3. Vasculitis-like syndrome

4. Development of antiphospholipid antibodies through molecular mimicry
5. Decrease in anticoagulant factors in certain viral infections
6. Supportive thrombophlebitis

Further reading: academic.oup.com/jid/article/18…

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