Sunday, September 16, 2018

Answer to Case 511

Answer: Uric acid crystal AND rare Schistosoma haematobium eggs.

Kudos to those who saw noted both the eggs AND the crystals! I've presented uric acid crystals multiple times in the past to reinforce how they are common (and convincing) mimics of S. haematobium eggs. However, this is the first case I've presented where BOTH are present, and I think it's important to note that the presence of crystals does not preclude the presence of actual parasite eggs.

Here are some of the diagnostic features from this case:

Uric acid crystals and a partially-hidden egg. Note the size variability of the crystals, and the points on both ends (like a lemon).

A true S. haematobium eggs with a defined 'pinched off' terminal spine and larval form (miradium) within.
Case of the Week 464 has many examples of uric acid crystals from previous cases - check it out HERE.

1 comment:

Old One said...

Some of the images seen in case 464 are very similar to' Puff Ball' spores which I occasionally levitated in fecal flotations (particularly from herbivores). Also variable(like many plant derived structures) in size but much darker in color.