Some background: one of my cats has had ongoing constipation for about a year. Prior to that he was vomiting on a regular basis, we just thought he was a pig stuffing himself too much, until we recently realised he's most likely allergic to chicken and tuna. Based on his regular vet's advice, we tried high fiber, wet food only, miralax, laxatone, etc. and it was an endless cycle of him being fine for a few days, then clogged up bad enough to need an ER visit for manual feces removal, and cycle starts over again. Turnss out fibers make everything worse and he does better on miralax with low residue. At some point his regular vet felt an abdominal mass, we went for an ultrasound expecting he had cancer, they saw inflammation and thickening of the small intestines, told us "allergy, IBD or lymphoma we don't know" and to go see internal medicine. Basically convinced myself my cat has lymphoma and will die. Finally see internal medicine, he basically tells us the ultrasound is inconclusive for anything really except to show no visible obstructions, believe that obstructions lower down the intestinal tracts are also unlikely, does blood tests to rule out hypothyroid, electrolyte anomalies, etc and tells us to just keep going with wet food and miralax. Blood tests come in, the only abnormal value is very, very high T4. Vet doesn't understand what is going on because he has absolutely no signs of being that hyperthyroid.
TL;DR: Cat with allergies and chronic constipation had elevated T4 on blood tests but has no symptoms, trying to understand what's going on.
We feed him mostly frozen raw food, and some dry kitten kibble. Both contain fish. And we've been supplementing him with oral B12 lately. Has anyone heard of these two things (fish based diet and/or B12) causing falsely elevated T4? The food manufacturer does specify they don't use gland tissues in their products so it's less likely the extra T4 is dietary, but I suppose one never knows.
Looking for any anecdotes of someone who went through something similar to help investigate the possible cause (also he's scheduled for a follow up of course).
TL;DR: Cat with allergies and chronic constipation had elevated T4 on blood tests but has no symptoms, trying to understand what's going on.
We feed him mostly frozen raw food, and some dry kitten kibble. Both contain fish. And we've been supplementing him with oral B12 lately. Has anyone heard of these two things (fish based diet and/or B12) causing falsely elevated T4? The food manufacturer does specify they don't use gland tissues in their products so it's less likely the extra T4 is dietary, but I suppose one never knows.
Looking for any anecdotes of someone who went through something similar to help investigate the possible cause (also he's scheduled for a follow up of course).