Monday, January 15, 2018

Case of the Week 477

This week's case was generously donated by Dr. Piryanka Uprety and the excellent Clinical Microbiology and Hematology Laboratories at the University of Pennsylvania. The following structures were initially observed by a hematology fellow in a wet mount (40X) from a BAL specimen. Photographs and videos are courtesy of Joyce Richardson, Vivian Whitener, and Darrin Jengehino from the Hematology Laboratory.

Wet preparation of the BAL fluid with iodine showed the following:


Sunday, January 14, 2018

Answer to Case 477

Answer: ciliated respiratory epithelial cells. These are a common parasite mimic, especially when seen in unfixed wet preparations, since the cilia remain motility for quite some time after being exfoliated from the respiratory mucosa. It is important to note that these are NOT parasites. Unfortunately there are several reports where these are misidentified as Lophomonas blattarum; however, L blattarum is a parasite found in various arthropods and is NOT thought to be a human parasite. 

You can easily identify ciliated epithelial cells by their small size and characteristic shape. Note that the cilia are present in a dense band at the apical surface:

You can really appreciate the columnar shape of the cells in this case.

It can be even more challenging when the ciliary tufts become detached (called detached ciliary tufts/DCTs or ciliocytophthoria). I've featured this multiple times on my blog in the past and have described how to differentiate ciliated host cells from other microorganisms. Check out these past posts for more information:

Case 396
Case 369
Case 283
Case 262

Thank you all for writing in!

Monday, January 8, 2018

Case of the Week 476

This week's case is a worm that was found near the anogenital region of a young child while she was being bathed by her mother. The child is asymptomatic.
 Anterior end:
Posterior end: 

Identification? What is the potential significance of this finding?

Sunday, January 7, 2018

Answer to Case 476

Answer: Adult Toxocara cati; the presence of this adult worm represents either environmental contamination (e.g. from an infected cat) or spurious passage by the child.

This case generated an excellent, entertaining, and somewhat disturbing (!) discussion. As many of you correctly noted, this is an adult Toxocara species. It has a similar appearance to Ascaris lumbricoides, but can be differentiated by the presence of the pronounced short, wide cervical alae:

The shape of the alae allow it to be differentiated from other Toxocara species. Note that the alae narrow towards that anterior end, giving the appearance of an arrow (image by my excellent parasitology technologist, Emily Fernholz).

Humans are not a definitive host, but can acquire infection with the larval form of the worm when accidentally ingesting eggs in contaminated soil or infected paratenic hosts. The larvae cannot mature in humans, but can migrate throughout the body causing a potentially serious condition called visceral larva migrans.

So how did this adult worm end up in a human host? Well, we can't really say for sure that it actually was IN this patient since it was noted outside of the body during bathing. Therefore it could have been expelled by family cat and simply ended up in the bathtub.

Alternatively, it could be that the child had ingested an adult or immature worm from the environment (the term kitty spaghetti will stick with me forever! See the comments for more information) and it had passed through her intestinal tract and was expelled intact. Authors from the US CDC published a interesting series of cases like this in 1998. You can read the article HERE.

Regardless of the scenario, it is clear that there is an infected household cat that needs to be treated. As I mentioned above, eggs that are shed from infected cats can mature in the environment and pose an infectious risk to humans (i.e. visceral larva migrans).

Thank you all for excellent comments!

Monday, January 1, 2018

Case of the Week 475

Happy New Year! This week's case is by Idzi Potters and the Institute of Tropical Medicine Antwerp. The following were seen in an unfixed stool specimen at 400X original magnification. (Hint: maximize the size of the video for best viewing). Identification?

Sunday, December 31, 2017

Answer to Case 475

Answer: Chilomastix mesnili trophozoites.

Congratulations to Martin, Ali, Florida Fan, Mark, Atiya, Sara, and Alexandra who got this correct!

The videos show the beautiful 'spiraling' motility of this organism, similar but distinct from the 'falling leaf' motility of Giardia and the 'jerky' motility of Pentatrichomonas hominis. In the lab, of course, we would also have the final fixed morphology to aid in our diagnosis and confirm our impression from the direct preparation.

For comparison, you can view my (now very old) case of P. hominis at:

And here are some beautiful videos of the falling leaf motility of Giardia by Idzi:

Monday, December 25, 2017

Case of the Week 474

Happy Holidays to all of my readers! This week's case is in the form of a Christmas tree. Can anyone tell what the tree is made out of? (hint: this is from a Trichrome-stained stool specimen)

Sunday, December 24, 2017

Answer to Case 474

Answer: Charcot-Leyden crystals, white blood cells and red blood cells

As Florida Fan mentioned, the C-L crystals are a guise for snow crystals, and the red cells may perhaps represent red delicious apples before man-made ornaments were innovated. I also envision the C-L crystals representing pine needles, perhaps?

I was very pleased to stumble upon this 'tree' when looking for some crystals to photograph. Other than the star, nothing else has been digitally added to this image.

Happy Holidays to all!

Monday, December 18, 2017

Case of the Week 473

The following structures were seen in a trichome-stained stool specimen. They measure approximately 10 to 20 micrometers in diameter. Identification?

Sunday, December 17, 2017

Answer to Case 473

Answer: Blastocystis sp. AND pollen.
Wow, you all impressed me by noting the less obvious Blastocystis in image 1, in addition to the pollen in all 3 images. Also, no one mistakenly thought that the pollen was a helminth egg (e.g. Taenia sp.) - a common pitfall. Excellent job!

While the Blastocystis cyst-like forms are the only parasites presents (image 1), I do agree that the pollen is the most striking finding. And very festive as Florida Fan and Idzi mentioned! I will defer the identification of the pollen to the others as this is outside of my area of expertise, but appreciate the time that some readers took to identifying the specific variety shown here.

Stay tuned for a holiday case next week.