pseudo pulmonary embolus

Q: What is pseudo-pulmonary embolus syndrome?

Answer: Pseudo-pulmonary embolism is an umbrella term of clinical syndrome, where symptoms like acute pulmonary embolism (PE) occur. It is commonly seen after heparin bolus; many experts consider it a type of Heparin-induced thrombocytopenia (HIT). But it can be seen in other conditions like from tumor burden around pulmonary vessels (reference #2) or in congenital heart diseases (reference #3)

The most common culprits are patients with hemodialysis (HD) who frequently acquire heparin boluses for their dialysis. It occurs shortly after an intravenous heparin bolus and is considered most likely to be one of HIT type II. This is not due to pulmonary embolus but is thought to be due to an endothelial injury, with sudden augmented release of IL-6, von Willebrand factor, and other adhesion molecules, resulting in an acute adult-type respiratory distress syndrome as a result of sudden vascular leak with hypoxia and hypotension.

#pulmonary

#hematology

#nephrology

#oncolgy

#cardiology

References:

1. Hartman V, Malbrain M, Daelemans R, Meersman P, Zachée P. Pseudo-pulmonary embolism as a sign of acute heparin-induced thrombocytopenia in hemodialysis patients: safety of resuming heparin after disappearance of HIT antibodies. Nephron Clin Pract. 2006;104(4):c143-8. doi: 10.1159/000094959. Epub 2006 Aug 10. PMID: 16902310.

2. Salomon O, Leshem Y, Gluck I, Grossman E, Apter S, Konen E. Pseudo pulmonary embolism in cancer patients: a new clinical syndrome. Blood Coagul Fibrinolysis. 2014 Dec;25(8):871-5. doi: 10.1097/MBC.0000000000000174. PMID: 25022841.

3. Cook GJ, Fogelman I. Pseudo pulmonary embolism in complex congenital heart disease. J Nucl Med. 1996 Aug;37(8):1359-61. PMID: 8708773.