I’m sharing the story of my cat Freya, whom I lost to sepsis a few months ago, in search of similar experiences. My cat had lived strictly indoors since she was a kitten.
It all started with a tooth root that had caused local inflammation. It was removed without any antibiotic coverage at home. A few days later, she developed symptoms of respiratory infection (anorexia, drooling, sneezing, nasal discharge, and then eye discharge).
They empirically diagnosed bronchitis. She received one injection of antibiotics but no treatment for home. A few days later, hospitalization was needed. During this hospitalization, there was no examination of the oral cavity; she was quickly discharged, and at home I discovered blood in her mouth. I brought her back for another hospitalization — this time, they examined her mouth and found ulcers, which she didn’t have a few days earlier. They empirically diagnosed calicivirus. Unfortunately, no differential diagnosis was made to rule out other causes for the ulcers, e.g. a complication from the dental procedure, during which she had no at-home antibiotics. Unfortunately, no nasal culture or calicivirus test was done, and a thoracic X-ray was canceled. She was discharged again but remained anorexic and symptomatic. So, a third hospitalization was required within one month.
Unfortunately, a feeding tube was never suggested, and she was syringe-fed, but intake was inadequate due to pain from the ulcers. As a result, after one month of undernutrition, she was found to have mild liver disease (hepatic lipidosis) on ultrasound. During the month-long infection, she was given 4 different antibiotics without completing a full treatment cycle, along with immunosuppressive doses of corticosteroids each time. She received Zithromax, Marbocyl, Vibramycin, and Stomorgyl. During the third hospitalization, she was given the antiviral Farmiv (together with steroids) without ever confirming a viral infection.
Her bloodwork at the beginning of the infection showed neutrophilia with a left shift, leukocytosis, and anemia. Right after the second hospitalization, she developed hematuria, and instead of a urine culture, an ultrasound was done and sediment was found in the bladder. Unfortunately, no antibiotic treatment was given for the suspected UTI, and one week later she showed signs of sepsis. She was transferred to another clinic with hypothermia, dehydration, and a few hours later collapsed, became unresponsive, and was placed in an oxygen chamber. I had to make the heartbreaking decision to euthanize her.
I believe she may not have had calicivirus. Maybe the ulcers were caused by the fact that she didn’t get antibiotic treatment after the removal of the inflamed root. Perhaps the frequent change of antibiotics led to bacterial resistance. Perhaps the repeated corticosteroid use suppressed her immune system. And the possible urinary infection may have contributed to the sepsis. I feel deep guilt for not seeking a second opinion from the start of the infection, but I trusted her vets. While researching the antiviral she was given, I found out after her loss that it’s intended for feline herpesvirus and not calicivirus. I feel guilty that I didn’t know that earlier, because I bought the drug myself hoping it would help her.
Has anyone had a similar experience, even with calicivirus?
I’m sorry to hear about your kitty Freya and this tragic series of events. I can try to provide some of my own insights, though it is not possible for me to provide a fully accurate assessment looking at it through a 3rd person perspective.
The tooth root causing inflammation, I’m presuming based on your description, may have been a resorptive lesion, or FORL, as these are common in cats. They are not caused by infection like true cavities are (which are exceedingly rare in cats) but by an immune response leading to a breakdown of the tooth where it eventually dissolves and disappears. This process takes weeks to months and does cause pain and inflammation, so it is common to remove them.
We don’t always have to remove the entire tooth, just depending on how much of the tooth is already resorbed. In the case of a single tooth, where removal was not very invasive, antibiotics may not be sent home, as these sites can heal very quickly.
It is common in cats to use the single injectable antibiotic convenia, which has a 2-3 week duration of action. I am guessing that in the cases where you mention a single antibiotic injection, that this may have been what was used. If so, sending home additional oral antibiotics for use at home is not common.
Convenia is also often used for upper respiratory signs like you mentioned occurred a few days later.
The respiratory infection signs you mention are most consistent with an upper respiratory infection. You mentioned bronchitis, which is a lower airway condition. With bronchitis, we might see signs more like coughing or increased breathing effort in the lower airway. I’m still not clear if that was a concern earlier or actually developed later.
But I agree that those early upper respiratory signs, combined with the ulcerations in the mouth, could be very consistent with a flare of calicivirus +/- feline herpesvirus. Calicivirus can cause all of the signs you mentioned all by itself, including the upper respiratory signs and the mouth ulcers. Feline herpesvirus and calicivirus can also occur together with herpesvirus contributing to some of the upper respiratory signs.
For the oral ulcerations, I would agree that calicivirus is the most likely cause. Although other causes are possible, the timing and history would still support calicivirus the most. Dental infections and immune disease affecting the mouth can cause ulcers, but most likely these would have been present prior to the dental procedure and with more significant dental disease than has at least been described here. As for some kind of injury incurred during the dental to cause them, I can only say that I have not encountered thermal or chemical burns during a dental procedure, especially not to address a concern with a single tooth. I also would think the effects of such injuries, however they would occur, would present much sooner, like later that day or the next day, not a few days later.
The lag time of when signs started does match with the incubation period of calicivirus, which is anywhere from 2 days up to 2 weeks.
Now, I couldn’t say why a thoracic radiograph was cancelled, unless at that time there was no lower airway disease present, only upper airway, and chest x-rays might have been considered of low yield.
But nasal swab culture and testing for virus (usually also with nasal swabs) is less commonly performed in cats than you might think, and certainly less common than in people. I think we are so used to nasal swabs with COVID that it would seem to make sense, but I even rarely do them myself.
The issue is that cats can be asymptomatic carriers for a variety of viral and bacterial organisms, including calici, herpes, Mycoplasma, and others. If a PCR test confirms their presence, it still doesn’t confirm that any of them are causing the signs of illness being seen. Not finding them also doesn't mean they're not there, so interpretation has to be very measured.
Nasal culture likewise is highly inaccurate, as multiple bacterial strains may end up in the culture. In cats, their nares are so small that it’s nearly impossible to get very far back, so we really just get a small portion of the front of the nasal passage, if we can get the sample at all. Heavy sedation or brief anesthesia may be needed just to collect such samples from cats because it’s so uncomfortable and irritating for them.
If the infection did reach the lower airways, as it sounds may have occurred if bronchitis was at some point suspected, the only way to culture at that point is a bronchoalveolar lavage (BAL) or transtracheal wash (TTW). They both carry risk and I feel are best performed by a specialist. While some GP’s may be comfortable doing them, I would not consider these routine general practice procedures.
Calicivirus infections are most often diagnosed based on the characteristic combination of illness signs vs. definitive testing. Upper respiratory signs as you describe combined with oral ulcerations would be considered highly suspicious for calici over anything else. It’s believed that a majority of feline upper respiratory infections involve calicivirus, at least in part, because it is so contagious.
Calicivirus does present some challenges. In a large majority of cases, it causes only mild illness. The worst I’ve usually seen are mild upper respiratory infections and occasionally some more concerning oral ulceration. A majority of cases also resolve with supportive care.
But there are many strains of calicivirus and the virus mutates, which is why cats who are vaccinated with FVRCP/HCP (the “C” for which stands for calicivirus) can still get infections. There is no simple way I’m familiar with in a clinical setting to subtype the viral strains to be of use for adjusting treatment plans.
Even though in a clinical setting we can’t differentiate strains, the severity of calicivirus does depend largely on the strain. Some can certainly lead to pneumonia and from there, secondary bacterial infection can also occur.
There is also a very rare version of calicivirus called feline calicivirus-associated virulent systemic disease, or FCV-VSD. These cases are very severe where the virus migrates into other organ systems and can be fatal in 60-80% of cases.
I’m wondering at this point if Freya may have had either a more severe strain of calicivirus leading to bronchopneumonia and complications or if it may have been a case of FCV-VSD, given how severe things became.
Feeding tubes have to be considered very carefully in animals. In 24 hour hospital centers where patients are being monitored around the clock, placing a nasopharyngeal tube is routine and not overly difficult, but usually these are not for at home use. In a general practice setting, our options are more limited to placing esophagostomy tubes. These require a great deal of home care and maintenance and carry their own risk. I know many vets may not be comfortable placing them and it’s easy for complications to occur at home. I’ve seen cats scratch them out, tear them out, and for them to be used improperly despite detailed written instructions. I had one patient I saw when doing emergency work who chewed his PEG tube in half, leaving half of it in his stomach, now requiring a procedure to remove it. My point being that a feeding tube may have been advantageous here, but I can’t say they’re placed often by GPs. Of the six doctors in my own practice, I think only myself and one other doctor have ever placed one and not often.
With the hematuria, the ultrasound was very reasonable to include. I think the only rationale to not do a urine culture that could be argued is that if Freya was actively on one or more antibiotics at the time already, the culture may have had a false negative result. Otherwise a culture would be a consideration.
I would question whether a UTI was a cause of sepsis. For this to happen, a UTI would have to first reach the kidneys and cause pyelonephritis. We know that more cats than we think develop quiet pyelonephritis, contributing to some cases of kidney disease but no visible signs of illness, but these don’t inevitably lead to sepsis.
Sepsis could occur as a complication of pyelonephritis, but there would have to be some evidence for kidney injury on lab work to identify that. It is also entirely possible that the blood in the urine was related to a sterile, non-infectious process too.
Bacterial resistance to antibiotics may have been possible, but with the respiratory tract, it is very difficult to obtain any kind of accurate bacterial culture information.
I think the biggest challenge of the more rare but serious calicivirus infections, if that’s what this was, is that you can’t primarily treat calicivirus. There is no antiviral labeled to treat it. We rely on most cases resolving on their own with supportive care, but it is possible for more virulent strains or FCV-VSD cases to quickly worsen. It’s not unreasonable to try an antiviral labeled to treat herpesvirus because it’s unlikely to hurt, but they are of course different virus types.
In summary, I do think it could be argued that an uncommon but more severe strain of calicivirus could have been responsible that led to continued further complications. It makes sense to me with the signs that initially developed and a poor response to antibiotic use. It can be very easy to second guess all decisions that were made, as hindsight is 20/20, though you can always find in any clinical case where some things may have been done better, even if care standards were met.
But ultimately, losing your beloved cat is a tragedy in any case, especially with something so difficult for you both to go through, and you have my condolences.