What is your differential diagnosis?
Monday, February 26, 2018
Case of the Week 483
This week's case was donated by Dr. Lars Westblade. The patient 'coughed' up the following worm (which was still moving!) after approximately 1 month of intermittent hives.
The posterior end was damaged unfortunately, but here is the anterior end:
What is your differential diagnosis?
What is your differential diagnosis?
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11 comments:
Among the nematodes that may at times be coughed up, Ascaris lumbricoides is the most commonly encountered. The anterior portion of this worm seems to fit the scenario, although a bit difficult to ascertain.
Florida Fan
This is most likely a "juvenile" migrating Ascaris lumbricoides worm. The "key" shown in the photo is a hint. An adult Ascaris worm is much larger than a key!
Seems to be Ascaris lumbricoides.
The lips on the worm (3?) might place it in the Ascarid worms, but the size and color make me think of Pseudoterranova decipiens. One of the Anisakis-like worms, found often in fish. They also have 3 fleshy lips! We shouldn’t rule out this possibility... Did the patient eat (undercooked) fish?
Anisakid nematode; genus-level ID not possible from these images.
What is most interesting, is the clinical history of hives. If the hives were in reaction to this individual worm, I would expect gastric symptoms as well (to spend a month in the patient, it would have had to start the attachment process to the gastric mucosa). Of course, if they are eating fish on a regular basis, the allergies could have come from past exposures and not necessarily this individual worm. Also, the hives could have been from the fish (this case was brought to my attention as well initially, but I don’t remember the complete clinical history).
Testing for allergies to anisakids can be performed initially by a skin-prick test. It should be confirmed by: 1)using anti-IgE antibodies by a different methodology (e.g. radioimmunoassay), 2) in conjunction with epidemiological data (recent consumption of seafood) AND 3) a lack of allergies to host fish proteins.
Anisakis simplex probably because size is smaller to tell that it's Ascaris lumbricoides..in the differential diagnosis list Pseudoterranova decipiens can be included...
Thanks Blaine for the nice explanation!
I remember indeed the possibility of allergic reaction to anisakids (mimicking fish allergy).
Thanks Blaine for the nice explanation!
I remember indeed the possibility of allergic reaction to anisakids (mimicking fish allergy).
I would posit that this tiny nematode is likely Anisakis sp. These nematodes are known for causing allergic reactions, some of these severe. Furthermore, they can be "coughed up" or regurgitated, and the tiny size (a mere 10-20 mm) is characteristic for Anisakis.
All things considered, I believe Blaine and Idzy are right. The size and color are the hints, just curious about the allergy aspect.
Florida Fan n
Intermittent hives and then "coughing up" (which could indicate migration up the esophagous or perhaps post tussive emesis so does not rule out GI source) an almost key sized worm indicates it's an invasive nematode infection where either the adult or larvae is a little smaller than a key. toxocariasis, angiostrongylus, baylisascaris larvae are too small and do not develop into adult. Acanthocephelans can develop to adults in humans but would not have this anterior morphology. The family onchocercidae (loa, wucheria, brugia, mansonella, dirofilaria) can also develop into adults but their form is more threadlike so does not fit morphology. The size, 3 lips on anterior end, and presentation seems best to fit an anasakid worm (pseudoterranova, anasakis, contracaeceum). Also, to use context clues, the Doctor who gave this case has a name that is nordic in origin and these cultures are known for raw fish consumption. So, my guess is a nordic person who ingested raw fish and perhaps had some abdominal pain prior to the hives. The hives would be a diffuse allergic reaction known to occur with gastrointestinal tissue invasion with anasakid larvae. The person then "coughed up" the anasakid larvae which was actually migrating up the esophagus and not actually from the lungs.
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