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Parathyroid cancer, tumors and Hyperparathyroidism in Dogs
Hyperparathyroidism
Parathyroid gland tumor - Blue Heeler
Parathyroid adenoma
also see dog cancer
also see Hypocalcemia
Hyperparathyroidism in Dachshund
Question: Dr. Richards,
My 10 year old miniature dachshund Sweetpea recently had a blood test
that came back with an elevated calcium level of 12.7. She was to have
cryosurgery at Ohio State Univ. vet hospital for a benign melanoma on
the sclera of her left eye and that is why we had the blood tests. She
had laser surgery on this eye two years ago because at that time the
melanoma was on the iris.My vet has sent another blood sample to Michigan State's Vet lab for
further testing. She suspects a tumor on the parathyroid gland since
Sweetpea did not have any of the other things she suspected such as anal
gland tumors.My questions are are these parathyroid tumors usually malignant? Could
this be related to the melanoma that she has had for 3 years? What
exactly are the additional blood tests going to tell us? Also, she has
been on Prednisone many times during her life because of ongoing
problems with intervertebral disk disease. She finished a three week
course of Pred in mid-December. Could this medication be a factor in
the test results? Thank you so much for your help.
Answer: N-
It is a good idea to recheck calcium tests at least once, and sometimes two
or three times, prior to believing that the calcium is actually elevated.
It can help, when possible, to get an ionized calcium test, which can help
to clarify the importance of the rise in total calcium serum levels. We
have found a single high calcium level in serum tests on a number of dogs
who did not have elevated calcium levels on subsequent lab work.Assuming that the calcium rise is real, there are several possible
problems. Malignant cancers (lymphoma, anal sac adenocarcinomas, others),
kidney failure, hyperparathyroidism, hypoadrenocorticism (Addison's
disease), diseases that destroy bone and a currently unavailable form of
rat poison are the causes that I can think of. I think that the order
these are listed in is approximately most common to least common.When hyperparathyroidism is present, the lab work usually shows high
calcium levels, low phosphorous levels and increased levels of parathyroid
hormone (PTH) and there should be no evidence of kidney disease in the lab
work.If this is hyperparathyroidism, the most likely cause is a benign tumor of
the parathyroid gland, followed by malignant tumors of the gland and
then hyperplasia (increase in gland size not from cancer). As far as I
know, the only treatment for these conditions is surgical removal of the
parathyroid gland tumor or hyperplastic region.Hope that this helps some.
Mike Richards, DVM
1/15/2001
Parathyroid gland tumor - in Blue Heeler
Question: Dear Dr. Mike,
I Have a 14 1/2 year old female spayed Queensland Blue Heeler named
Windy. Two years ago during a routine exam and lab work her calcium
level was noted to be slightly elevated, 11.5. My vet told me that an
elevated calcium level can be indicative of a cancer somewhere in the
body. They did an abdominal ultrasound and found a mass. She underwent
exploratory surgery and they found a large benign necrotizing lipoma
which they removed. Everything else looked normal as far as they could
tell. A repeat calcium level post op was 10.3. All of her other labs
have been normal except for a slight elevation of her ALT which has been
stable in the 200 to 400 range for about 2 years. Her next blood work
about 6 months later again showed an elevation in calcium to 11.9. My
vet suggested we could do all kinds of diagnostic work ups to try to find
the cause. Because of my dogs age and the fact that she has been acting
perfectly normal ( eating, active, peeing and pooping fine) I decided to
be conservative and just follow it. For the next 1 1/2 years her calcium
remained between 11 and 12. Windy has remained completely asymptomatic.
Even my vet has been stumped. She says that if she had cancer somewhere
it would surely have shown up by now. Last month she had repeat lab work
and now her calcium is up to 13.2. I took her to UC Davis where she had
an ultrasound of her thyroid and abdomen. Her abdomen is fine, however
she has multiple nodules on one side of her parathyroid gland. The other
side apparently looks normal. The recommendation is surgery. I guess
this is not a very common thing in dogs. I have called around to several
vets and most of them have only done a few cases. I have her scheduled
or surgery in 2 weeks. Can you tell me a little about possible post op
complications. i am most worried about what if the other side dosen't
wake up and kick in. I have been assured that this should not happen,
but I am trying to get as much info as possible. Thank you UrsulaUrsula-
Answer: It is a good idea to have this sort of surgery done at a veterinary school.
The biggest complication to removing a functional parathyroid gland tumor
is exactly the one you are worried about. Even when there is only one
tumor, affecting one gland, it usually has caused enough suppression of the
ability to regulate calcium to make for a scary period post-surgically. It
helps a lot to have lots of students to monitor patients on a regular basis
for a day or so to be sure that hypocalcemia won't occur. It is usually
only necessary to supplement calcium for a few days but it is a really
important few days since low calcium levels can be fatal. I haven't had to
deal with this problem in a dog but we do have seen this in cats due to
surgery for hyperthyroidism damaging the parathyroid glands. I
don't' actually do that surgery, either -- but we have managed a couple of
patients through the complications.As long as everyone is aware of the possibility of complications and takes
precautions, this usually works out fine. The long term complication rate
from parathyroid surgery is supposed to be very low.Mike Richards, DVM
9/14/2000
Question: My question is about my 9 year old male Portuegese Water Dog who has had a
really bad year and still is not doing too well. From 1/99 through 2/99 he
was treated with some major antibiotics for what my vet thought was an
infection of a disc space. In late Feb. 99 he had surgery to remove
bladder stones. He still didn't recover very well (continued to drop
weight, no energy) Finally, we noticed his blood calcium level increasing
and further tests revealed a parathyroid problem. My vet sent him to a
surgeon who removed a parathyroid adenoma in 4/99. To make a long story a
little shorter, he still hasn't recovered and he now has a major
fear/hatred of vets and vets' offices. Since 4/99, he has been to the vets
maybe 10 times, mostly for blood tests. These tests have shown no really
significant problems (calcium was well within the normal range). He
continues to drop weight and is now about 48 lb. down from a normal of 62
lb. He eats very little and rejects all but his favorite food (which is
canned Pedigree chicken--not my idea of a great diet) He appears to have
great gastic distress and vomits frequently. My vet now has him on Reglan
and Pred (5 mg/day) When he does eat, his gut is very noisy and he is
restless, pacing back and forth. Pepto Bismol does sometimes give relief.
I suspect the antibiotics and surgeries and various tests and meds have
really messed up his system but the question is where we go from here. My
vet usually refers to Ohio State Vet School and I've taken a few dogs there
over the years and been very pleased with the results. The problem is that
I'm not sure this dog could stand the work up. He now quivers and quakes
if I even put him in the car and throws up instantly when we arrive at the
vets (I should mention that this dog was a show dog for the first 4 years
of his life and travel and new people never bothered him before). Do you
have any suggestions for testing that might be done locally? Any theories
about this problem? Thanks and I apologize for the length of this request.m.
Answer: m-
I have looked through the references that I have on parathyroid disorders.
One reference, "Clinical Endocrinology of Companion Animals" by Chastain
and Ganjam contained information on a condition known as
multiple endocrine neoplasia. In this syndrome, parathyroid tumors are
associated with tumors of the adrenal glands, pituitary glands, pancreas or
thyroid gland. This condition had been reported in one dog at the time of
publication of their book. I am not sure if there have been subsequent
cases reported, or not. While this many not be the most likely problem
since it seems to be fairly rare, it might explain the incomplete recovery
and it seems reasonable to look for signs of problems in these other
organs, such as digestive enzyme deficiencies, hypoglycemia (low blood
sugar), increased drinking and urination, hair loss or palpable
masses. Your vets may have already considered this possibility but it
might be worth asking about. I think that your local vets can help you
determine if there appears to be a chance that this is the problem.
Ultrasound exam is probably the best way to look for adrenal gland tumors
and pancreatic tumors but that is probably only necessary if there are at
least some clinical signs that one of these problems is present.There are lots of other medications to consider for the GI distress.
Cimetidine (Tagamet tm), famotidine
(Pepcid AC tm) and ranitidine (Zantac tm) all are sometimes helpful in
gastrointestinal problems as they are all protective of the
gastrointestinal lining. Cisapride (Propulsid Rx), which helps move
ingested food through the digestive tract is sometimes helpful when
metoclopramide (Reglan Rx) doesn't work well enough. W. These medications
all do have specific purposes and randomly using them isn't the best way to
figure out which one is necessary but sometimes it is the only practical
approach. Of course, switching medications isn't necessary if the current
ones are working well enough.I do think from your description of weight loss and continued GI distress
that something more is wrong. While I don't have extensive experience with
parathyroid adenomas my impression is that there aren't usually long term
side effects except sometimes persistent low blood calcium, which hasn't
been your experience.I don't have much advice on how to get your dog to accept going to the
vet's again. Sometimes if we dispense a pain relief medication and a mild
sedative (like butorphenol and acepromazine or hydrocodone and diazepam)
and have the owners administer them an hour or so before the office visit
it helps to relieve tension enough that a dog can readjust to coming into
the office. This doesn't always work and it can even make the situation
worse by lowering inhibitions about biting, so we are careful when we try
this approach.Your vet was pretty astute to pick up the hypercalcemia and recognize its
significance, so it seems likely that he or she will be pretty good at
recognizing the signs of the other potential endocrine cancers. Hopefully
there won't be any, though.Mike Richards, DVM
1/5/2000
Last edited 01/30/05
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