Case of the Week 255

A Sudanese refugee was seen for progressive confusion, daytime somnolence and personality disturbances. Despite treatment, he died and an autopsy was performed.  Sections of brain revealed the following:

Perivascular lymphoplasmacytic inflammation, H&E 400x

Lymphoplasmacytic inflammation, H&E 1000x

Lymphoplasmacytic inflammation, H&E 1000x

A peripheral blood smear obtained prior to death showed the following:

Diagnosis? 

What is the object seen in image 3 (also present in image 2)?



Answer to Case 255

Answer:  African trypanosomiasis due to Trypanosoma brucei. 

It is not possible to tell the 2 subspecies of Trypanosoms brucei apart microscopically, but the origin of the patient (Sudan) would be consistent with East African trypanosomiasis due to T. b. rhodesiense. 

The flagellated form of T. brucei (called trypomastigotes) are typically seen in peripheral blood, and in late stage disease, in CSF.  They can be differentiated from the similar-appearing T. cruzi trypomastigotes by the small size of their kinetoplast (arrows, below).

Occasionally, trypomastigotes of other zoonotic organisms such as T. rangeli can be transiently present in the blood of humans, although they are not usually associated with disease.  These trypomastigotes can be differentiated from human pathogens by their morphologic features (e.g. position of the kinetoplast) and geographic location of acquisition.

During the meningoencephalic stage, tissue biopsy typically shows a lymphoplasmacytic perivascular infiltrate containing plasma cells engorged with immunoglobulin.  These engorged plasma cells are called "Mott" or "morula" cells.  Although they are often seen with meningoencephalitic trypanosomiasis, they are not definitive for this disease and can be seen in other conditions.

Of interest, the term "Mott cell" is named after Dr. F. W. Mott, who described these cells in the brains of monkeys with trypanosomiasis.  However, he used the term "morula cell," and therefore these 2 terms are used interchangeably.  More interesting history about this HERE.

Thanks to everyone who wrote in about this interesting case!

Case of the Week 254

This week's case is just a fun identification.  (Hint, these objects were obtained at the local hospital pharmacy...)

 

Questions:

1.  What are they used for in the health care setting?

2.  Which bacteria is associated with them?

Answer to Case 254

Answer:  Hirudo medicinalis, the European medicinal leech. 

Today, leeches are not used for 'balancing humors' but instead to to reduce venous pooling of blood in delicate surgeries such as reconstructive and reattachment surgeries.  Medicinal leeches secrete a number of anticoagulants in addition to hirudin which facilitate blood flow and therefore promote wound healing. 

Note that leeches are annelids and not trematodes, despite their superficial resemblence.  You can appreciated their segmented nature in this photograph:

Medicinal leeches carry Aeromonas hydrophila in their gut. Therefore, it is important to give the patient antimicrobial prophylaxis when prescribing medicinal leech therapy. 

Case of the Week 253

The following images are taken from slides submitted to our surgical pathology consult service for identification.  The site was listed as "thigh" biopsy.  The associated gross description describes a tan firm object measuring 0.3 cm x 0.3 cm x 0.1 cm. 

40x magnification

100x magnification

200x magnification

200x magnification

400x magnification

Identification?

Answer to Case 253

Answer:  Arthropod, most likely a hard tick given the presentation and gross description

This case is somewhat reminiscent of Case 251 in which an object that could have been identified by macroscopic examination was submitted for histologic processing, therefore making the identification extremely difficult. However, there are still features present that allow this 'object' to be identified as an arthropod, as shown in the photo below (CLICK ON IMAGE TO ENLARGE):

You'll note that the features in this case are very similar to a previous case of an embedded tick that was sectioned by histology (Case 83).

Here is a poem by Blaine Mathison to go with all of these types of cases!

Why pathologists are so quick to slice-and-dice

when an ID on this bug would be much more precise

if they had just left it intact

and let the entomologists have a crack

Alas a definitive ID is now a roll of the dice

As microbiologists, we can help our physicians by encouraging them to submit possible arthropods to the microbiology lab rather than to surgical pathology, and also ask our histology labs to send these types of specimens to microbiology rather than sectioning them.  As I've mentioned before in previous posts, the CDC also provides an excellent e-consult service with a <24 a="" available="" expertise="" great="" hour="" href="http://www.dpd.cdc.gov/dpdx/HTML/Contactus.htm" is:="" is="" locally.="" microbiology="" nbsp="" not="" service="" site="" their="" this="" turn-around-time.="" web="" when="">http://www.dpd.cdc.gov/dpdx/HTML/Contactus.htm

Case of the Week 252

Here is a bit of an unusual case:  this was noted in a tube of "sterile saline" in another area of the lab and sent to parasitology for identification.   

Thoughts?  Comments?

Answer to Case 252

Answer:  Mosquito, not further identified

I apologize for not providing a genus and species level identification - the mosquito started falling apart when I went to remove it from the tube and I'd like to keep it intact as a display.  However, one of my viewers cleverly suggested that this was the previously undescribed Culex salinenis!

To answer the question of how it got into the tube to begin with, I had to investigate how the saline tubes are made.  First, empty glass tubes are received in bulk from the manufacturer in our media prep lab.  They arrive shrink-wrapped in plastic, and are stored like this until needed.  The tubes are then unwrapped in the media lab and immediately filled with sterile saline (also purchased in bulk) using an automated pipetting device.  This particular lot of saline-filled tubes was prepared in March, which is not a time when mosquitoes are known to be out and about in my neck of the woods (there is still snow on the ground).  Also, I don't think we've ever seen a mosquito in our lab, even in the height of summer.  So our best guess is that the mosquito was in the tube when it arrived in the lab, and we then unknowingly added the saline on top of it.  I doubt that the mosquito was in the saline, since I wouldn't expect it to survive intact through our pipettes. 

After the tubes are filled, they were sealed and autoclaved, so technically, I guess the saline was still sterile(!)  The tubes were then inspected prior to being put into use, leading to this interesting discovery.

So regardless of how it got there, it was a great pick-up by our technologist and a good reminder of why quality control is so important in the laboratory.

Case of the Week 251

This case was generously donated by MicrobeMan and Dr. Euna Choi:

A 56-year old male who had just returned hom from a safari in Uganda presented with a red swollen nodule over the right iliac crest and a 1.5 cm x 0.5 cm white-tan object was removed and submitted to surgical pathology.  The following are H&E stained sections of this object:

20 times original magnification

20 times original magnification

40 times original magnification

100 times original magnification

100 times original magnification

 100 times original magnification

Identification?

Answer to Case 251

Answer: fly larva; clinical presentation is consistent with myiasis

Many commented that identification becomes more challenging when arthropods are sectioned and stained since the external features are obscured or lost.  However, there are still features that allow us to positively identify this as a fly larva such as the overall size and shape, mandibles, and yellow cuticular spines:

Unfortunately, definitive identification to the genus or species level is not possible without macroscopic examination of the larva.  Therefore, we instead must rely on the clinical history, which would suggest that this larva is likely Cordylobia anthropophaga, otherwise known as the mango fly, tumbu fly, or putzi fly.  This myiasis causing fly is endemic to parts of east and central Africa, including Uganda, where it is a common cause of human myiasis.

One reader commented on the difficulty of identifying fly larvae, particularly in settings without access to a microbiology lab with entomologic expertise.  In these cases, a service that I find to be incredibly useful is the free and rapid e-consult service through the CDC DPDx team.  Turn-around-time is generally < 24 hours.  You can access their email and submission form HERE.