Compared with biopsy of other sites, native renal biopsy has the greatest risk of post-procedure hemorrhage (1.2%). However, the incidence of major bleeding and death due to bleeding is very low (0.3 and 0.02% respectively).
Post-biopsy bleeding can occur into the perinephric space or the collecting system or in the form of a subcapsular hematoma.
On a sonogram, fresh hematomas appear anechoic and organizing ones are of mixed echogenicity due to clotting. There will be little to no Doppler flow because the blood is not flowing.
Note that urinoma can appear similar to fresh hematoma (urine is anechoic as well) and should be included in the differentials depending on the context (e.g. recent kidney transplant).
Patent track sign: a color Doppler signal along the course of a biopsy, indicating that the needle track has not collapsed and that there is still active bleeding from the procedure. The track usually extends out of the biopsied organ into a surrounding hematoma. Case courtesy of Dr Matt A. Morgan, Radiopaedia.org, rID: 50201
Excellent post, thanks for sharing..So, based on US data, when to intervene and when to stay on conservative management ?
Thank you. There is some data on suggested observation period after biopsy depending on when most complications occur.
However, I’m not aware of data guiding when to intervene. Usually, intervention (e.g. angiography and selective embolization) is undertaken when active bleeding is noted. For example, persistent patent track sign despite applying adequate pressure or continued drop in hematocrit.