New dx of hyperthyroid- can vomiting be the only symptom?

[CharlieChoo]

Hi everyone! I was wondering if anyone had any experience or advice on treating a cat with mild hyperthyroidism that seems to be mostly asymptomatic aside from sporadic vomiting episodes.

I took my 15-year-old cat Charlie to the vet after a few days of her vomiting 1x/day, usually around the time she used the litterbox to poop. She has been sporadically "pukey" since I got her from the shelter 5 years ago, despite trying her on several foods both wet and dry, grain-free, limited ingredient etc. She'd been on Evanger's Holistic Quail wet and Blue Buffalo LID Duck dry up until her vet visit.

Her recent labs showed mild hyperthyroidism (T4 was 4.8 and top of range was 4), positive for bilirubin in urine, and a RenalTech kidney test said she has a 95% chance of getting kidney disease in the next 24 months. Everything else was normal. Next step is thyroid meds and an ultrasound on her abdomen, as she was queasy when the vet poked around her liver and bilirubin isn't a normal finding in urine. She wasn't constipated which was my suspicion for the cause of the vomiting, was put on Hills Z/D Prescription dry food (won't touch the wet) and hasn't puked at all today. Is a little bit lethargic but otherwise acting normally.

I've been reading about hyperthyroidism in cats and it seems like weight loss and increased appetite are the most common symptoms, but Charlie has only had the vomiting. The vet palpated her thyroid but didn't make any mention of tumors or enlargement, and noted that her coat looks very shiny and she is mildly OVERweight. Despite the lack of other symptoms aside from vomiting, is the slightly elevated T4 a sure indicator of thyroid disease that needs to be medicated? Anyone have HT cats that didn't have the most

 

[CharlieChoo]

Whoops the end of the post got cut off somehow and I don't know how to edit it Meant to say does anyone have HT cats that didn't have the most common symptoms but still benefited from treatment?

 

[Dos Gatos]

My cat was diagnosed with severe hyperthyroid 2 months ago but did have the classic drastic weight loss symptom (though no increased appetite). She also threw up often, usually around the time she would poop or if she had gone too long without eating. It turn out she probably had it for awhile but because it was untreated, it got much worse (her T4 was 13.2). The vet never mentioned feeling a tumor though I’m sure there is one. No matter how mild, I would recommend treating hyperthyroidism. With meds, the tumor will continue to grow but it will not cause the damage that untreated HT can cause. If you delay treating it, she will likely start showing more symptoms as T4 rises.

 

[neely]

Hyperthyroidism in cats is serious and should not be taken lightly. The T-4 is a standard test to diagnose the severity of the disease. Did your vet recommend treating it with Methimazole? Our cat was diagnosed with H-T several months ago and we have been using the transdermal form of this drug which has helped to bring his levels down. We are considering the 1-131 treatment, (Radioactive Iodine Therapy).

There are several on-going threads about Hyperthyroidism that may have some helpful information for you:
Hyperthyroid cat,methimazole and I131 treatment
Hyperthyroidism advice

 

[Antonio65]

I've been reading about hyperthyroidism in cats and it seems like weight loss and increased appetite are the most common symptoms, but Charlie has only had the vomiting. The vet palpated her thyroid but didn't make any mention of tumors or enlargement, and noted that her coat looks very shiny and she is mildly OVERweight. Despite the lack of other symptoms aside from vomiting, is the slightly elevated T4 a sure indicator of thyroid disease that needs to be medicated? Anyone have HT cats that didn't have the most

My cat was hyperthyroid. I took her in because she had lost interest in food, she was eating less than her usual and I was concerned, because she had always been a great eater.
The vet said she had hyperthyroid, and I asked him if she was sure of the diagnosis, because my cat wasn't eating more, wasn't hyperactive, or showing other typical signs of HT. She was losing weight, but because she wasn't eating enough.
She was also vomiting more often, but that wasn't an issue I worried about, she had always been like that.

Well, it turned out her HT was of the apathetic form, which means that the cat was HT but was showing the opposite symptoms. It happens in less than 10% of HT cats.

All the tests done later this first diagnosis were positive for HT, and so we proceeded with the therapy. Methimazole pills at first, then methimazole eargel (that was easier on her stomach), the I-131.

 

[FeebysOwner]

Hi. Feeby (16+ yo) was diagnosed with hyperthyroidism (H-T) last October; her T4 was 4.5 with the normal range of 0.8 - 4.0. She was overweight to begin with (but was losing weight) and less hungry. No other symptoms/signs. So, I believe the symptoms can actually vary widely from cat to cat.

I can't speak to the bilirubin in her urine, but do want to caution you about the meds for treating her H-T. It seems pretty common for vets to prescribe higher doses of methimazole than is needed, which can cause issues of its own. It is preferred to start with a low dose - the one I see most often recommended is no more than 1.25mg twice a day, and then have her T4 checked 3-4 weeks later, and again in another 4 weeks to see if dosage adjustment is needed. This accomplishes two things - 1.) the lower starting dose allows for her body to get used to the meds and thereby reduces the chance of side effects, and 2.) eliminates the chance of putting your cat into HYPOthyroidism. The latter, in particular, is reversible when the dosage is lowered.

You might ask about a free T-4 equilibrium test, if they didn't do one already, as that is just another layer beyond the T4 test in concluding hyperthyroidism. I also want to point out that the majority of cats by the time they are 15 yo will have a Renal Tech reading like your cat. But, because hyperthyroidism can mask kidney issues, your vet will likely be monitoring her kidney function as she begins, and continues, to take H-T meds.

 

[Dos Gatos]

Hi. Feeby (16+ yo) was diagnosed with hyperthyroidism (H-T) last October; her T4 was 4.5 with the normal range of 0.8 - 4.0. She was overweight to begin with (but was losing weight) and less hungry. No other symptoms/signs. So, I believe the symptoms can actually vary widely from cat to cat.

I can't speak to the bilirubin in her urine, but do want to caution you about the meds for treating her H-T. It seems pretty common for vets to prescribe higher doses of methimazole than is needed, which can cause issues of its own. It is preferred to start with a low dose - the one I see most often recommended is no more than 1.25mg twice a day, and then have her T4 checked 3-4 weeks later, and again in another 4 weeks to see if dosage adjustment is needed. This accomplishes two things - 1.) the lower starting dose allows for her body to get used to the meds and thereby reduces the chance of side effects, and 2.) eliminates the chance of putting your cat into HYPOthyroidism. The latter, in particular, is reversible when the dosage is lowered.

You might ask about a free T-4 equilibrium test, if they didn't do one already, as that is just another layer beyond the T4 test in concluding hyperthyroidism. I also want to point out that the majority of cats by the time they are 15 yo will have a Renal Tech reading like your cat. But, because hyperthyroidism can mask kidney issues, your vet will likely be monitoring her kidney function as she begins, and continues, to take H-T meds.

Great point about the meds. Echo was initially given 2.5mg twice a day when her T4 was 13.2. After 3 weeks, her T4 was down to 6 but vet wanted to double her dose to 5mg twice a day. I opted to only increase one dose a day to 3.75 and 4 weeks later her T4 was down to 3.4. I really think if we had doubled her dose, she would have gone hypo.

 

[CharlieChoo]

Thank you so much everyone for all of the helpful advice! This is all a bit overwhelming. It is good to know that the symptoms can be so variable as most websites mention the same symptoms that she doesn't really have. She definitely fits the apathetic hyperthyroid description more than the typical form. Also reassuring to know that most cats her age have similar results from the RenalTech panel because the way they word the results is kind of spooky. The vet did mention the kidney masking so we'll be keeping an eye on it for sure!

I asked the vet about decreasing her starting dosage of methimazole from 2.5mg 2x/day to 1.25mg 2x/day and she ok'd it, but they had already filled the prescription for the transdermal click pens at the higher dose. I'm not sure the dose can be split with those but I will try when I get the prescription tomorrow. Otherwise she said they can be used 1x/day instead but that doesn't seem ideal. If she is a good candidate for the radioiodine then I'll hopefully be doing that after the methimazole trial. Just want to take things slow with her so we don't make anything worse.

 

[neely]

If she is a good candidate for the radioiodine then I'll hopefully be doing that after the methimazole trial. Just want to take things slow with her so we don't make anything worse.

You're very wise to be cautious and take things slow. I feel the same way and understand you not jumping into anything before doing all your research. Best of luck and please keep us posted on Charlie's progress.

 

[Dos Gatos]

Thank you so much everyone for all of the helpful advice! This is all a bit overwhelming. It is good to know that the symptoms can be so variable as most websites mention the same symptoms that she doesn't really have. She definitely fits the apathetic hyperthyroid description more than the typical form. Also reassuring to know that most cats her age have similar results from the RenalTech panel because the way they word the results is kind of spooky. The vet did mention the kidney masking so we'll be keeping an eye on it for sure!

I asked the vet about decreasing her starting dosage of methimazole from 2.5mg 2x/day to 1.25mg 2x/day and she ok'd it, but they had already filled the prescription for the transdermal click pens at the higher dose. I'm not sure the dose can be split with those but I will try when I get the prescription tomorrow. Otherwise she said they can be used 1x/day instead but that doesn't seem ideal. If she is a good candidate for the radioiodine then I'll hopefully be doing that after the methimazole trial. Just want to take things slow with her so we don't make anything worse.

My cat is on the twist-a-dose transdermal and her pens are for 5mg per full rotation but we give her partial doses. The pens make a clicking noise and I found one full rotation is 8 clicks. So she gets 4 clicks in the morning and 6 at night.

 

[CharlieChoo]

The Topi-Click twist pen I just got is only 2 clicks for 2.5mg (doesn't seem super-precise) so I will try 1 click for a few weeks and see how it goes. Will keep you guys posted how she's doing after next labs. Thanks again for all the help!

 

[FeebysOwner]

The Topi-Click twist pen I just got is only 2 clicks for 2.5mg (doesn't seem super-precise) so I will try 1 click for a few weeks and see how it goes. Will keep you guys posted how she's doing after next labs. Thanks again for all the help!

Can't you call the vet and/or the pharmacy and ask about how to properly lower the dosage with the pen you have? You are starting her on a new med, I would be hesitant about playing around with the dosing unless you can get some sort confirmation that your approach is a safe one. It seems logical in terms of what you want to try, but if it were me, I would want to at least ask the vet and/or pharmacy. Hopefully, they will tell you what you want to do is fine.

When are her next labs scheduled?

 

[CharlieChoo]

Can't you call the vet and/or the pharmacy and ask about how to properly lower the dosage with the pen you have? You are starting her on a new med, I would be hesitant about playing around with the dosing unless you can get some sort confirmation that your approach is a safe one. It seems logical in terms of what you want to try, but if it were me, I would want to at least ask the vet and/or pharmacy. Hopefully, they will tell you what you want to do is fine.

When are her next labs scheduled?

I read the insert that came with the meds and it says that each turn/click of the base accurately dispenses 0.05mL of the medication, and her original dose was 0.1mL 2x/day, so seemed to me like one click would do the trick. Certainly wouldn't hurt to call the pharmacy to confirm though, good idea! Next labs are in 4 weeks after starting the meds. She will be having an abdominal ultrasound on the 13th to check her liver/GI too.

 

[CharlieChoo]

Hey everyone! So I got Charlie's abdominal ultrasound done and everything looked pretty normal; the tech even remarked her ultrasound was "boring" and she didn't see most of the typical signs of age-related deterioration they see in cats her age. She did note her liver looked a bit bright, but said that it is very likely benign and is common in elderly cats.

Follow up labs on Sunday showed her kidneys and liver look good on the thyroid medication (1.25mg 2x/day), and her thyroid level went down to 3.0 (range 0.8-4.0). They are going to recheck her numbers in 3-4 months; hopefully that is frequent enough testing. Thank you to those who suggested starting on a lower dose; seems like it's doing the trick for now!

She has also been doing well on the Hill's Z/d prescription dry food, only vomiting once since I last posted, though I'm trying to transition her to Young Again hydrolyzed dry food that is almost zero carb and high protein since she is gaining a bit of weight on the Z/d at only 200 cal/day. Vet does seem to think she has an allergy with how well she is doing on the new food, so I'm only introducing one food at a time to see how she does.

Anyway just wanted to share some good news