Mr. Tubbs was a 5 year old male, neutered domestic short-hair cat that lived up to his name. He had a 9 out of 9 body condition score with the cutest little face and tiny little feet. He was quite the charmer too. I first met Mr. Tubbs in November of 2013. He was presented by his owner with a 24 hour history of vomiting. His vomit had turned hemorrhagic and the owner got really worried so she brought him to REACH. The owner reported he was still trying to eat and was mildly lethargic. She also noticed that his nictitans had been protruding for the past few days. No diarrhea was reported but most of the cats in the house had loose stool ever since they acquired a new kitten. The new kitten had been recently diagnosed with Coccidia.
Mr. Tubbs had some other important history to mention. He had quite a few ailments for such a young and handsome fellow – asthma, hypothyroidism (yes, hypo) and a chronic wet cough/wheeze. He was on thyroxine and intermittent prednisone for his cough. The owner had adopted him as stray a few years back and they just moved to Asheville from Florida.
On exam, Mr. Tubbs was mildly depressed, mildly dehydrated and his nictitans were protruding. He was bradycardic (HR 140) but purring. It was difficult to fully assess for a murmur or lung sounds due to his purring. However, his purr sounded moist and he demonstrated a soft, moist cough following the exam. His abdomen was tense and seemed mildly painful.
Diagnostics included whole body radiographs, blood work and fecal exam. The most surprising results were in the fecal exam and radiographs.
The radiographs were interpreted by a board-certified radiologist: “Multiple mass effects within the thorax. The mass in the area of the carina may represent a pulmonary mass or possibly hilar lymphadenopathy. The mass within the caudal thorax may be related to neoplasia or possibly a fungal granuloma.”
Fecal exam identified the egg of the lung fluke Paragonimus kellicotti. This important information was not initially relayed to the radiologist. We later sent an e-mail informing the radiologist of this finding and she confirmed that the pulmonary changes seen on thoracic radiographs could be due to a lung fluke infection.
A complete blood count showed a normal WBC count with a mild basophilia and mild leukocytosis. A general chemistry panel showed mild dehydration indicated by hyperproteinemia and hyperalbuminemia.
Initial treatments included hospitalization for IV fluids at 1 ½ times maintenance (based on lean weight), injectable maropitant, injectable famotidine and oral fenbendazole (50 mg/kg once a day for 10 days). Oral metronidazole (7.5 mg/kg twice daily for 5 days) was started the next day.
Mr. Tubbs responded quickly and was eating 4 hours after admittance. It turned out he did not really like oral medications and it took some finagling to get the medications in him. He stayed in the hospital a few extra days and then transferred to his family veterinarian for boarding to complete his treatments (he did not take his medicine well and the owner could not medicate him at home).
Mr. Tubbs came back to REACH about 7 weeks later for hemorrhagic diarrhea and recheck diagnostics for his lung flukes. A fecal exam showed 1+ Paragonimus eggs as well as 1 + Coccidia. His recheck thoracic radiographs were much improved. The radiologist reported: “There is a generalized bronchial pattern. There is no evidence of pulmonary nodules or cavitating lesions.” This time, we elected to treat the lung flukes with praziquantal (23 mg/kg by mouth three times a day for 3 days) as well as Albon for the Coccidia.
We did not hear from Mr. Tubbs until March of 2014. It was 4 months after his initial diagnosis and 2 months after we prescribed the praziquantal. The owner was only able to administer 3 ½ of the doses of praziquantal before he refused to take them. The owner reported he still had an occasional cough and wanted to medical board him at REACH so he could complete his treatments. We repeated a fecal exam and did not see any ova, however, the sample was poor and he did not provide a better sample during hospitalization.
He was hospitalized at REACH for 3 dramatic days. We were initially able to get him to eat the praziquantal in his food (for about 3 doses), then he refused to eat anything. He would develop respiratory distress any time we tried to “pill” him or restrain him in any way. On day 2, he bit one of the technicians and underwent rabies quarantine. We only had 3 treatments left but could not find a way to get them in his mouth without hurting him. We ultimately had to give the last 3 doses of praziquantal as injections. He had to be anesthetized with isoflourane for each of these 3 injections because he would become so stressed with restraint.
Mr. Tubbs is doing well these days, with no signs of coughing or continued infection on fecal exam. He is still festively plump and as cute as he can be!
Paragonimus kellicotti is the most common lung fluke seen in cats and dogs. Cats typically acquire it from ingesting a freshwater crayfish which is the second intermediate host, with an aquatic snail being the first intermediate host. The metacercariae within the cray fish excyst in the stomach or intestines of the cat (or dog), migrating through the abdominal cavity and penetrating the diaphragm into the pleural cavity. They form cystic lesions both in the pleural space and pulmonary parenchyma. The eggs mature in the cysts which communicate with bronchioles and are coughed up and swallowed, exiting the feces 5-7 weeks after infection. Radiographic cystic changes can be seen around 65 days after infection. Early in disease, there may be no radiographic changes or a mild bronchial pattern may be noted. This often leads to a misdiagnosis of asthma and cats are started on prednisone and bronchodilator, as in Mr. Tubbs case. In many cases, the prednisone can help with the cough as part of the signs are due to the immune system’s response to the parasite. However, the cat will need lifelong medication and experience ongoing pulmonary damage if the underlying parasite is not found.
Paragonimus is one of the few lung flukes that can be diagnosed on a routine fecal exam. Definitive diagnosis is confirmed by a Baermann float. In this case, Mr. Tubb’s history, radiographic and fecal exam findings were enough evidence to warrant treatment without a Baermann float. We found a large number of eggs on both the direct and float samples as well as multiple cystic lesions in his lungs. Both indicating he had a severe, chronic infection. We can assume he most likely acquired the infection when he was a stray several years ago, fending for himself eating cray fish in Florida (and I’m guessing he ate a lot of cray fish).
Note that the length of treatment for lung parasites with fenbendazole is 10-14 days, with 14 days being ideal (50 mg/kg by mouth once a day). Praziquantal (23 mg/kg) can also be given 3 times a day (oral or injectable) for 3 days. We had to use a combination of treatments to ensure Mr. Tubbs was fully treated. The prognosis for lung parasites is good but treatment may need to be repeated.
In Mr. Tubbs case, Paragonimus was really an incidental finding (some might call it a “fluke”). His GI signs were likely unrelated but could have been due to migration of flukes. This case reminds me that I need to be doing more fecal floats, even if the signs don’t seem to be related to the feces. I admit it was Mr. Tubb’s history (he was a previously stray cat from Florida, kitten in the house with diarrhea, etc) that prompted me to run a fecal exam, not necessarily his history of “cough.” A fecal exam should be part of any thorough work-up for pulmonary disease, especially in cats with asthma or the history indicates a high risk. Ideally, a Baermann exam should also be performed if there is a high suspicion of exposure to lung parasites.
This case stresses the importance of obtaining a thorough history and collecting all diagnostics before making a definitive diagnosis. Based on radiographs alone, Mr. Tubbs could have easily been condemned with a diagnosis of pulmonary neoplasia rather than a treatable infection. Fecal exams can save lives!
Kristi Sowers, DVM