Greetings TWiP team
The patient is suffering from a generalized muscle weakness that as this is TWiP I will assume is the result of a parasitic infection.
Myopathy refers to a muscle fiber disorder.
This myopathy present as pure motor syndromes without any disturbance of sensory or autonomic function, deep tendon reflexes are preserved.
The high muscle enzyme levels are the result of damaged muscle tissue releasing enzymes into the blood. So whatever the parasite is appears to invade the muscles.
A search of Parasitic Diseases volume six found no mention of myopathy other than cardiomyopathy from Chagas disease.
Well you said it was a rare parasite, it is not even in your textbook!
What could this be, a nematode, something like similar to Trichinella? Maybe a strange Australian Apicomplexan? Onto Google with a search for Australian parasitic myopathy.
The search results look encouraging.
The patient is suffering from Australian parasitic myositis caused by the muspiceoid nematode Haycocknema perplexum
The second item in the search result is the actual case mentioned in TWiP, hers was only the ninth recorded case of Haycocknema perplexum:
|Short report H perplexum emerging cause a – health.gov.au
CDI Vol 40 No 4 2016 E499 Short report supports the potential importance of close wildlife contact as a risk factor in those who develop clinical
Haycocknema perplexum is a rare parasitic nematode infection, believed to be zoonotic in origin though the primary host species is not known. The patient was treated with albendazole, which was ineffective at preventing continued decline in her muscle strength. Very little is known about this parasite, more research is needed:
|Fact sheet – wildlifehealthaustralia.com.au
WHA Fact sheet: Haycocknema perplexum: disease of humans of unknown origin | March 2008 | 3 to a life-threatening illness (loc. cit.) and may delay diagnosis by …
infection caused by Sarcocystitis species, possibly S. lindemanni
Greetings from Omaha, NE where it’s a pleasant 19 degrees Celsius. Having been to Australia (including Darwin) this past summer, I want to submit a guess to case study #128. I stumbled upon this review paper about Nonbacterial Myositis:
The paper reports that Haycocknema perplexum, a nematode, can cause myositis and cases from Australia and Tasmania have been described. Patients experience muscle weakness, eosinophilia and elevated creatine kinase levels. Diagnosis is made by muscle biopsy and treatment is made with albendazole.
I’m teaching Parasitology this semester at Creighton University and I play your Case Studies during lab. The students get a bonus point on their lab quiz if they guess correctly. They’ve been doing fairly well so far. If I guess correctly on this Case Study, I won’t get any bonus points, but I’ll look really good in front of my students 😉
Sorry I didn’t snag any pictures of parasites while in Australia (except for some fungi), but attached is a picture of the cane toad and Galah bird mentioned on the last episode.
Keep up the good work.
I am so excited to learn that I won a copy of the 6th Edition of Diagnostic Medical Parasitology! Thank you!
I am currently on a flight back to Atlanta from Tokyo, where I was fortunate to be able to visit the Meguro Parasitological Museum. While I did find it interesting, I do regret to say that the museum is disappointingly small and that most of the labels and descriptions are in Japanese, which unfortunately is not part of my trilingual repertoire. However, admission is free, I picked up a t-shirt, and at least this particular curiosity has been quenched, so there’s that.
Sooo, since I am already writing to you, and since I’m at the beginning of a 12-hour flight, I suppose I should venture a guess at this week’s case study. I think the 80-year-old lady has Paragonimiasis. This is a mostly food-borne infection caused by the lung fluke Paragonimus westermani, however, domesticated animals may also harbor the fluke and transmit the disease to humans. That being said, I believe her contact with marsupials to be a red herring. Nice try, Dr. Griffin!! Diagnosis would require demonstration of P. westermani eggs in CSF or brain biopsy material. But because neurological symptoms occur during the chronic phase of disease, CSF examination may not be as helpful as neuroimaging or other diagnostic testing, which may reveal characteristic lesions. If the lady is indeed infected with P. westermani, she should be treated with praziquantel. According to the literature, bithional and triclabendazole are also effective, but may require repeat or prolonged therapy.
Well, there you have it, my uneducated, and probably entirely incorrect guess, but hey! At least I tried!
Dear TWIP masters
Thank you for all your hard work as always.
For this week’s Parasite guess:
After all the testing mentioned the only test I can think of next is a muscle biopsy!
I’m going to go with the Parasite Haycocknema perplexum. It is a Parasite that has cocked it’s parasitic head in Australia a few times. You mentioned that she recently traveled to Tasmania, which is where this Parasite had been first discovered in 1998.
Also my Dr Google game is very strong and I found her exact case study,
😉 here is the link.
Lots of love from
Mycheala, Cork Ireland.
P.s a fun fact, in the link I have provided states that a Haycocknema like nematode has been identified in muscle fibres from a horse imported to Switzerland from Ireland, good to know we’re on the parasitic map haha
Thanks again! Please don’t stop the case studies :3
Hello twip team!
The initial workup seems to point at a myositis rather Than neurologic disease (elevated muscle enzymes, normal neurography etc). Further investigation therefore should be focused on muscle. Autoimmune and paraneoplastic aetiology should be considered. If myoglobin is very elevated hydration may be called for to protect the kidneys.
Some aspects here are less typical for autoinflammatory myositis. I think EMG usually show fibrillation, and eosinophilia is not typical. Physical exam and ANA pattern can give more insight into aetiology. As with all myopathies however muscle biopsy should be considered, which is probably the next important diagnostic measure in this case, possibly guided by MRI to point out active muscle group.
In this case I would expect to see Worms in the muscle (trichinella or taenia of course being to common in this case). A Google search leads me to a couple of Australian case studies where the causative agent turns out to be Haycocknema perplexum, a nematode, that occurs in some of the animals to which the lady had been exposed. This will be my guess. Mechanism is possibly through skin penetration, though this is not known for sure.
Treatment in those cases was with albendazole, possibly ivermectin could be effective as well. As the treatment for autoimmune myositis is high-dose steroids this patient would fare well from a correct diagnosis (I guess most patients do), since immunosuppression could put the infection in high-speed. However if you do suspect autoinflammatory myositis and treat with steroids, you would monitor CK to evaluate effect and discontinue treatment when it goes up rather than down!
Resident in Pediatrics at University hospital of Northern Sweden, Umeå
Dear crepuscular professors
Despite my ill-informed kava konfusion last time, I’m back for more…
This week’s case was – as promised – mysterious. The 80-year-old Australian lady has clinical and EMG evidence of myopathy. Tests for other causes of eosinophilia and autoimmune myositis are negative. The next investigation should be a muscle biopsy, which (this being TWiP) might reveal some kind of parasite 🙂
Although she has an extensive travel history, her long history of close contact with indigenous wildlife puts her at risk of zoonotic infection. Parasitic causes of myositis include trichinosis, cystericercosis and toxoplasmosis. After googling for parasites, myopathy and Australia I found some interesting case studies of eosinophilic myositis caused by the nematode Haycocknema perplexum.
It’s a long shot, but it fits Daniel’s description of “a rare parasite”. A few cases of human infection with H. perplexum have been reported in Tasmania and tropical Queensland. The natural host and mode of transmission are unknown. Treatment with albendazole for at least 8 weeks is recommended and recovery may be incomplete. Presumptive use of corticosteroids (standard therapy for polymyositis) led to clinical deterioration and ICU admission in one reported case.
I have to add that I really enjoyed Dickson’s impromptu superhero segment in TWiP 127. Parasitology has such a rich history. More of these, please!
The case is Trichinella spiralis!
This parasite induces the formation of a collagen capsule and lead to eosinophilia!
Dear TWIP Professors,
I am going to take a shot at the case of proximal muscle weakness and eosinophilia in the wild animal rehabilitator from tropical Australia. My approach was to search on DuckDuckGo for parasites in echidnas, cockatoos, and marsupials that could infect human muscle. A cockatoo site led me to Sarcocystis and in the 6th Edition of Parasitic Diseases I found this reference:
Fayer, R.; Esposito, D. H.; Dubey, J. P., Human infections with Sarcocystis species. Clin Microbiol Rev 2015, 28 (2), 295-311.
which said that “by ingesting sporocysts from feces-contaminated food or water and the environment; infections have an early phase of development in vascular endothelium, with illness that is difficult to diagnose; clinical signs include fever, headache, and myalgia. Subsequent development of intramuscular cysts is characterized by myositis. Presumptive diagnosis based on travel history to tropical regions, elevated serum enzyme levels, and eosinophilia is confirmed by finding sarcocysts in muscle biopsy specimens.”
Got my fingers crossed!
Thank you for your continued efforts in the production of such an intellectually stimulating podcast.
For this week’s case study involving the 80-year-old Australian wildlife carer, Dr. Griffin provided what I believe is sufficient evidence to arrive at an etiologic diagnosis. I will be the first to admit I had to search through current literature to reach a conclusion, but the following statements outline my thought process along the journey.
The EMG and neurologic exam results suggest myopathic rather than neuropathic origin to the clinically described progressive limb weakness. These findings eliminated the nervous system as the source of this woman’s clinical signs and indicate a myopathic origin, which was further fortified by elevated creatine kinase, an indicator of ongoing muscle damage.
Parasites can result in tissue damage either directly through aberrant tissue migration, or secondary to a robust host inflammatory response targeted against foreign parasitic antigens (i.e., parasitic myositis).
Although there is a laundry list of parasites including cestodes (Echinococcus spp., Spirometra spp. Taenia solium), trematodes (Schistosoma spp.), nematodes (Trichinella spp., Toxocara spp., Hayococknema perplexum, Onchocerca volvulus, Wuchereria bancrofti and Brugia malayi), and protozoa (Toxoplasma gondii,Sarcocystis spp., Trypanosoma cruzi, Leishmania spp.) documented to cause myositis. To the best of my knowledge, only Haycocknema perplexum is capable of causing diffuse wasting of major muscle groups. Furthermore, this organism has only been diagnosed in patients from Queensland and Tasmania, consistent with this case study.
Definite diagnosis depends on histopathology with demonstration of the characteristic nematode in the muscle fibers. Treatment with albendazole may improve muscle strength if instituted early enough in the disease process, although recovery is slow and often incomplete due to extensive tissue fibrosis.
Recently, PCR-based sequencing and phylogenetic analysis has revealed this organism to belong to the nematode phylum, positioned between the Oxyurida and Ascaridida orders. Even with this information, much of this nematodes biology (e.g., life cycle and host animal/s) and epidemiology (host range/s and transmission) remains mysterious.
Additional research is needed to allow for implementation of appropriate preventative health strategies, however the inherent rarity of this disease (currently 9 case reports documented in humans) will continue to limit our understanding of Hayococknema perplexum
Keep up the excellent work,
For our 80 yo Australian patient, I would first want a history of treatments that she has already tried. If certain tests or lab values came up with abnormal values before, I would want to take that into account before doing anything. Also, how does she know she is allergic to doxycycline? Is it because she was being treated for Chronic Q fever or lyme disease already? Chronic Q fever can present with pneumonia, hepatitis, or pericarditis and I would do my best to look out for those things. It takes about 2 years of treatment with doxycycline and hydroxychloroquine to treat the infection.
Trichinella is a parasite that actually fits well with her presentation. The eosinophilia and myopathy can be signs of trichinosis. The signs pointing away from this diagnosis are the lack of fever, or lack of mention of a pro-dromal phase with GI symptoms before the parasites extravasate and spread. I would want to know if she has ever eaten undercooked meat anywhere on her travels and I would normally want an ELISA screening for diagnosis, but in this case I would want a muscle biopsy.
The muscle biopsy would also to be to rule out any autoimmune conditions. Dermatomyositis, Polymyositis and Inclusion-Body myositis would need a biopsy to be definitive. I heard no mention of a rash of any sort so dermatomyositis is most likely out, but polymyositis and inlusion-body myositis are definitely part of my differential. Polymyositis generally presents with a proximal symmetrical muscle weakness like our patient and inclusion-body myositis predominantly affects those over 50. The eosinophilia does not fit with either of them and makes me think of eosinophilic granulomatosis with polyangiitis, but once again I don’t see much to suggest that diagnosis such as kidney problems, GI symptoms and most importantly a rash. I would lastly also order many autoimmune markers such as anti-dsDNA, ANA, anti-SCl, anti-CCP, etc. to rule out some autoimmune conditions such as SLE, Scleroderma, and rheumatoid arthritis.
But there is another reason for the muscle biopsy, and that’s because I believe she is infected with Haycocknema perplexum. Dr. Griffin stated that this was a rare parasite and you know what that means… that case reports would be abundant and from these reports I have found at least 3 cases of Haycocknema infection within Queensland Australia and that seems plenty rare for me. The symptoms match up pretty well: chronic myositis, eosinophilia, right geography; the only thing that doesn’t fit very well is that in the case reports the patients all developed some form of dysphagia.
It is not fully known how this infection is obtained or spread and treatment so far has been with several weeks of Albendazole. In terms of outcome, of the 6 cases I found there were 1 death, 2 chronically weakened, and 3 with full/near-full recovery. I hope our patient was able to improve.
P.S. I am a fan of DBZ and I appreciate the meme jokes!
Dear TWIP team,
Alright, confession time: I cheated. I was able to find the case report from the team at Cairns Hospital. This is the 9th ever recorded case of myositis caused by the nematode Haycocknema perplexum. That being said, Dr. Griffin was more interested in what tests we would order.
The workup for eosinophilia is extensive, and this diagnosis was far from obvious (at least to me). In the last case I was justified in making the assumption that our young and healthy traveler with exposure and eosinophilia probably had a helminth. That assumption is not necessarily justified in the case of our puggle-loving octogenarian, and I would perform a full laboratory evaluation.
The EMG and symptoms would warrant a muscle biopsy (which clenched the diagnosis in our case). However, it seems to me that you could easily overlook this infection, considering the tissue sample saved for EM did not contain any parasites. Do you think the physicians suspected H. perplexum based on the CK and eosinophilia? I’d be willing to bet that this was yet another case of luck favoring the prepared mind. A faulty diagnosis of polymyositis + prednisone could have killed this patient. Kudos to her physicians!
Thanks for the truly interesting case! I find it perplexing that so little is known of the life cycle and prevalence of this parasite. I’d be willing to bet that subclinical cases are exceedingly common!
I’m in the process of choosing a medical school. Any advice from Dr. Griffin on what factors he thinks are important would be greatly appreciated!
Haycocknema perplexum. Boom.
Gold Coast, Australia
Dr Stuart Aitken MB BS, Dip Ven, FAChSHM
Sexual Health Physician
Dear Professors Twip,
I am an Infectious Diseases registrar down in Melbourne, Australia and your podcast has served the dual purpose of keeping me thoroughly engrossed and awake at the wheel along my 150km daily return commute to work as well as preparing me for the DTM&H exam through the LSHTM. Thank you for bringing your case down under and making it irresistible for me to respond.
Clinically, this patient has a chronic myositis, eosinophilia and lives in Queensland. We are told that they have a rare parasite. This instantly introduces the diagnosis of Australian Parasitic Myositis – an uncommon conditon associated with residence in Queensland and caused by the (rare) nematode Haycocknema perplexum – it is usually diagnosed on muscle biopsy and treated with albendazole, expecting some improvement in muscle function. Otherwise, it seems little is known about this organism except that it can complete its entire life-cycle in humans and maybe associated with animal exposure.
However, as a physician, it would be remiss of me to not include a long list of investigations and differential diagnoses. My investigation would initially seek to localise an affected area to target for biopsy, either in muscle or central nervous system. This can be accomplished in the resource rich setting through MRI scanning of brain, spine and affected muscle groups. Biopsy and histology should then reveal the diagnosis. Serology, particularly for parasitic diseases endemic to Australia such as strongyloides, echinococcus and (very rarely, but perhaps in proliferative form) sparganosis/spirometrosis may be helpful to explain this presentation. The travel to Tasmania introduces the interesting prospect of trichinella pseudospiralis, however this should not cause such widespread muscle involvement and would most likely require consumption of a Tasmanian Devil or Eastern Spotted Quoll, both of which I imagine to be unpalatable and difficult to catch.
Thank you for your fascinating and addictive podcasts!
Hello TWiP Hosts,
As a second-year medical student, with my first board examination in just under three months, I couldn’t help but use test-taking strategy for finding the next step in treatment. History provided us with vital information, the patient handles animals and travels to many tropical areas, thus, making her more susceptible to zoonoses and tropical diseases. The neurologic exam was normal but muscle strength was reduced. This makes disease of the muscle, and not the nerves, the most likely. The tests support this with normal nerve conduction and myopathic changes on EMG. Elevated muscle enzymes also support damage directed toward muscle cells. One side effect of statins is rhabdomyolysis. No improvement was seen when withdrawing this drug from the patient, meaning that this is probably not the etiology of the muscle weakness. Lastly her eosinophilia and the name of this podcast led me to an initial diagnosis of helminthic myositis. Because there were no ova nor parasites in the stool, the last test needs to find the culprits. The answer to the question is “B,” perform a muscle biopsy.
Zac from Milwaukee
Vince, Dick, and Daniel,
Over the past few weeks, I’ve learned so much from your podcasts! I got into parasitism while reading a fiction book called “Peeps” by Scott Westerfield. I loved learning about the parasites in the book so much that I bought “Parasite Rex” by Carl Zimmer, which I’m very glad to have heard you reference on the podcasts.
Currently, I’m a senior in high school, and, come september, I’ll be a freshman at Colby-Sawyer College in New Hampshire studying environmental science. I know it seems a little early to be doing so, but I’m already thinking about grad school. I guess my question for you gentlemen is if there are any graduate schools that you would recommend for a degree in parasitology?
Thanks, and keep doing what you’re doing!
Becca (an inspired youth)
Re: canning it
Don’t go anywhere! We’re out there and listening, even when we don’t write in 🙂 Thanks for this podcast.
Dear Twip wise-guys,
Based on the eosinophilia, I went through the available worms that may cause this, and strongyloides stercoralis seems to be the most realistic option. The cough would be caused by the parasite traveling through the lungs, diarrhea is a common symptom, the rash manifests where the unfortunate volunteer sat down in faeces. The duration also fits, with Parasitic diseases mentioning on page 245 a typical duration of 6 weeks. The larvae in the stool should confirm this diagnosis, and I expect the patient to have to been cured by either albendazole or ivermectin.
I actually did go through a differential diagnosis, but other options seemed so unlikely and the source of the infection so obvious that I looked no further, and I therefore hope my guess is right.
Let me finish by expressing once more my admiration for your efforts, I know very well that it takes a long time to come up with even mediocre products, and to offer a top class podcast of over an hour (or in Vincent’s case: several of them) on a weekly basis is more than a hobby, it is a mission.
Kind regards from a windy Nicaragua with just 31 C,
Hello TwiP team,
I have been enjoying the Peace Corps cases. My husband and I were in the Peace Corps in northern South Africa about ten years ago. We were north and east of Thohoyandou (https://en.wikipedia.org/wiki/Thohoyandou). Luckily the only parasitism we suffered (at least as far as we know) were bot flies. Our host family had several mango trees in the backyard next to the clothesline. I was very happy to return to my washer and dryer and stop ironing all my underwear! I attached a picture of us in our village.
For the current case, I’m making a guess of strongyloidiasis. Although I may be wrong since spell check seems to think this is not a word. These roundworms are transmitted through contaminated soil, thus the direct contact with stool as well as the initial rash and eosinophilia fit with this diagnosis.
Thanks to all of you for your hard work making TwiP such a fabulous podcast!
Dear Vincent, Dickson and Daniel,
It is cold and wet in Belfast. My guess for this week’s case study is strongyloidiasis which should be remedied by treatment with ivermectin, but only if there are no relevant co-infections.
I have been unable to get a decent diagnosis for the case studies recently and I was particularly stumped by the relevance of cava to the previous case and the hypocrisy of an aid worker living with such expensive tastes. I think I have this week’s though.
I am now the proud owner of a TWiP colour changing mug, and although I’m doubtful of being the fourteenth emailer, I am happy to push someone else into that place.
Many thanks for your work,
School of Biological Sciences
Medical Biology Centre
Queen’s University Belfast
Dear TWIP team,
I love all your podcasts!!!
From not so sunny Ireland:)
From mycheala a long time listener
Dear hosts of my favorite podcast(s),
As long as there will be free books filled with biological scientific knowledge I will keep on participating, so keep up the giving mood. Just heard the latest TWIP, and as it has been from the 14th, I realize I am probably too late. Still, I should take a chance.
Will also try to find some time for a guess in the eosinophilia case today, sincere greetings from Nicaragua,
Greetings to the TWIP team!
This letter is to take a chance on the free book, but more importantly, to answer Vincent’s concern that no one was listening. I don’t know who isn’t, but I know that I am. I listen to the podcasts after the fact on my ipod, and usually the cases and contests are old, so there is not much point to guess at the diagnosis when the following episode is already out.
Regardless, keep up the good work.
I am listening to TWIP and TWIV, though not in real time. So this is a letter from the past to the past, I guess.
Best regards to you all.
General pediatrician, Rochester, NY.