The morning of September 20th Ms. Langley came into the clinic with her 7 year-old intact, male New Zealand White rabbit named Gus. After introducing myself, we started chatting and Ms. Langley explained that her husband and two kids had just moved to Guelph a few months ago. I asked Ms. Langley what brought her in today and she explained that she has been noticing Gus losing considerable weight in the last two months. Moreover, he had eaten very little in the last two weeks. I told Ms. Langley that this was definitely odd, and we would work together to figure out exactly what’s been going on.
When Ms. Langley took Gus out of the carrier, he appeared rather dull and quiet. I also noticed a moderate head tilt and when I inquired about it, Ms. Langley said that she first noticed it about the same time Gus stopped eating. I asked Ms. Langley whether Gus had contact with any other animals and she replied that he was the only pet in the house. Although, about a week after they moved in, the kids had a playdate with the children next door who happened to have some Guinea pigs. Apparently, they had set up an outdoor pen for all the animals to play in for a few hours. On palpation I noticed moderately decreased muscle mass. I confirmed Ms. Langley’s thought that Gus had be losing weight and told her it was great that she picked it up as it can be hard to tell with so much fur. I asked Ms. Langley whether there were any other changes in Gus’ behavior, and she mentioned that he might be drinking more lately as she finds herself having to fill his water bottle more frequently. She also noted his litter has felt heavier whenever she changes it, and his stool has recently seemed smaller and perhaps a little drier. As I continued my physical exam Gus urinated and I collected some to run a specific gravity.
I explained to Ms. Langley that due to the fact Gus has been anorexic for almost 2 weeks and has lost quite a bit of weight, it wold be best to hospitalize him, at least for the day so we could provide some intensive nursing to help get him back on track. I explained that rabbits can develop GI stasis when they stop eating or in other words his digestive tract was no longer moving properly. I explained that we would keep Gus warm and provide intravenous fluid therapy along with some nutritional support via syringe feeding to help overcome this issue. I further expressed to Ms. Langley that since Gus has been drinking and peeing a lot more lately, we should run some blood tests to check his kidney function. I explained that a CBC and biochemical profile are some such blood tests that allows us to evaluate organ function. In this case, it could help rule in or rule out the possibility of kidney disease. Ms. Langley consented to both the hospitalization and the bloodwork. I assured her we would call her in a couple of hours with an update.
When Ms. Langley came back to pick up Gus, I told her the good news that we were able to get his digestive system moving again. I then expressed that I would like to go over the blood results with her and she complied. I brought out the paper with the test results and explained that there were several values that were higher than normal – I pointed out the Phosphorus, BUN and creatinine – which is indicative of renal disease. I also pointed out the low PCV and explained that Gus was in fact anemic, which indicates chronicity. Finally, I concluded that together with the chronic loss in body condition and the fact that he has been drinking and peeing more, I was diagnosing Gus with chronic kidney disease. I explained that the GI stasis was likely secondary to this disease. Often rabbits with chronic kidney disease will tend to eat less which then slows the motility of the GI tract. Ms. Langley was initially quite distraught, but I assured her that many rabbits are still able to live happily with kidney disease and we would determine the best treatment plan to make Gus one of these rabbits. I informed Ms. Langley that kidney disease can be caused by a variety of things however, due to the fact the Gus has a concurrent head tilt I had two main differential diagnoses.
The first being a bacterial infection with Pasteurella multocida. I explained that although infection often involves the upper respiratory tract the bacteria can also spread to infect the ears and cause a head tilt. Moreover, the infection could enter the bloodstream and cause abscesses in various internal organs, including the kidneys and thus result in chronic kidney disease. At this point Ms. Langley mentioned that Gus had been dealing with a chronic respiratory disease and has been treated with tetracycline in the water for the past 2 years according to her previous veterinarian’s instructions. After confirming that Gus has still been receiving his antibiotics as prescribed, I told her it is unlikely that the cause would then be bacterial.
Rather, Encephalitozoonosis was now the top differential. I asked whether she had heard of this disease before and she replied not. I explained that Encephalitozoonosis is caused by a microscopic parasite that rabbits can ingest. Once infected, the parasite enters the bloodstream and travels to various organs including the kidneys and brain. Clinically this can cause signs of kidney disease and neurologic disease such as the head tilt as exhibited by Gus. I also noted how if the problem was parasitic, it would make sense why Gus had suddenly gotten sick despite being on antibiotics. I explained that Encephalitozoonosis is difficult to diagnose but our best option would be to send another blood sample off to the laboratory for serology. Ms. Langley consented so I quickly grabbed another blood sample from Gus.
I proceeded to explain to Ms. Langley, that we would need to make sure Gus continues to eat and drink in order to prevent stasis from reoccurring. I explained that Gus’ head tilt might be making it difficult for him to eat on his own. I then demonstrated how we had been syringe feeding him earlier that day using soaked pellets. I asked whether it would possible for Gus to be hand-fed like this at home and Ms. Langley said that they would make it work. I informed her that they could soak his usual pellets and meal feed him twice a day. I also explained that in the meantime, we could give Gus a single dose of NSAIDs to help reduce the brain inflammation that might be contributing to the head tilt. I explained that it would help Gus feel better as we awaited the confirmatory diagnostic results. Ms. Langley agreed, so I gave Gus a single dose of Meloxicam subcutaneously. We concluded the appointment with a plan that the clinic would call as soon as the test results came back.
A few days later we got the lab results which confirmed a high positive titer for E. cuniculi. Ms. Langley agreed to come back into the clinic to discuss the results and further modify our treatment plan for Gus. Upon her arrival, I asked how Gus had been doing at home and Ms. Langley replied that he seemed more like his usual bright self after she had brought him home from the vet and his stool seems to have become more normal. She said that both her and her husband had been taking turns syringe feeding Gus and the kids have also been eager to help. I expressed that it was really great that Gus seems to be doing a lot better. I then proceeded to explained that the blood test we sent off showed that Gus had very high levels of antibodies against E. cuniculi, the causative agent of Encephalitozoonosis. I explained that although the test is not always diagnostic the current head tilt and chronic kidney disease makes it very likely Gus has an active infection. Before moving on to discussing possible treatment, I asked Ms. Langley what questions she had for me. Ms. Langley indicated that she was curious as to where Gus could have gotten this infection from. I explained that as E. cuniculi is transmitted through the urine of mammals, I suspected that Gus may have picked it during the playdate with neighbour’s guinea pigs. Ms. Langley noted that the guinea pigs had not appeared sick at all and so I clarified that many animals that are infected with E. cuniculi are asymptomatic and Gus may have unfortunately succumbed to clinical disease due to the recent stress of moving temporarily weakening his immune system. I saw a flash of guilt cross Ms. Langley’s face, so I quickly assured her that it was not their fault, but rather an unfortunate combination of events and a bit of bad luck. I also made sure to include that E. cuniculi is a recognized zoonosis, but the risk is minimal in healthy individuals. Furthermore, it’s not something to worry too much about, but just make sure everyone washes their hands with soap and water after playing with Gus and avoid taking him out to play in the kitchen.
Ms. Langley then asked about what the treatment options were for Gus and I informed her that unfortunately E. cuniculi can be difficult to treat. However, the best course of action would be an anti-parasitic drug to kill the parasite and stop the shedding. I brought out a box of Fenbendazole and indicated that it would need to be given orally once a day for 28 days. I asked whether this sounds like something the family would be comfortable with and she complied. Ms. Langley asked whether this would be able to cure Gus, so I explained that some rabbits improve upon completion of the treatment, others end up needing life-long medication. And unfortunately, some rabbits don’t improve despite treatment. In other words, the treatment does not guarantee a full recovery. Ms. Langley seemed a bit disheartened and asked whether it was worth doing anything at all then. I stated that if she decided not to pursue treatment the parasite would continue cause inflammation and damage within Gus’ body causing the clinical signs to likely worsen. Ultimately, the disease could become debilitating enough that euthanasia would be the only human option. After a few moments of silence as Ms. Langley thought things over, she decided she wanted to move forwards with anti-parasiticide treatment. I re-affirmed that this was going to give Gus the best shot at combatting this disease and proceeded to get the prescription ready. I explained that hopefully this treatment will be enough to stop the progression of the kidney disease. Furthermore, the head tilt may or may not improve depending on the extent of damage that’s been caused by the parasite already. In other words, Gus may need to continue to be syringe-fed for life. Ms. Langley said that although it would be easier if it resolved, the family was more than willing to continue with it. We also discussed how treating the parasite is step one and we will need to revaluate Gus’ kidney function after the Fenbendazole course to see whether we might need to add at-home subcutaneous fluids to his treatment plan. I concluded the appointment by confirming we would call in a few days to check and see if there’s an improvement with Gus. We decided that if the treatment did ultimately fail, we would reconvene to further discuss where to go from there.
2020-3-6-1583531918