Surgical Thyroidectomy for Cats with Hyperthyroidism: Intraoperative Considerations

Surgical thyroidectomy is a highly effective treatment for hyperthyroidism in cats. While thyroidectomy is most often successful, it can be associated with significant morbidity and mortality (1-4). Hyperthyroid cats are older to geriatric, can suffer from marked weight loss, and may have cardiac complications. Both before and during surgical thyroidectomy, a number of factors must be considered to ensure a successful outcome (4-7).

As discussed in a recent post on preoperative management of the hyperthyroid cat, all cats should, therefore, be prepared for surgery by administration of an antithyroid drug, a ß-adrenoceptor blocking drug, or iodide to decrease the metabolic and cardiac complications associated with hyperthyroidism. Establishing euthyroidism in these cats preoperatively will help make them much better candidates for anesthesia and surgery (5-7).

Just prior to anesthesia and surgery, it is important to rule out concurrent kidney problems that may have been masked by the untreated hyperthyroidism. The cardiovascular status should also be reevaluated to ensure that any cardiac issues or hypertension are controlled. Both renal and cardiac disease complicate anesthesia and may even mean that surgery is not a good option for a particular hyperthyroid cat.

Anesthetic Considerations
Anesthetic management of the hyperthyroid cat should include the judicious use of agents that have minimal cardiac arrhythmic effects (1-4,8). A variety of anesthetic agents and techniques can be used and none has advantages that exclude use of all others, especially if the hyperthyroid state has been controlled with methimazole prior to surgery. Due to their weight loss, poor body condition, older age, and overactive metabolic state, hyperthyroid cats tend to be very sensitive to many common drugs used to induce surgical anesthesia (8).

During the anesthetic period, continuous monitoring of the anesthetic level, blood pressure, and electrocardiogram is essential. Cardiac arrhythmias are common, especially in cats not rendered euthyroid prior to surgery. If arrhythmias develop, the anesthetic concentration should be lowered and the cat ventilated with a higher concentration of oxygen. If the arrhythmia persists, small doses of intravenous ß-adrenoceptor blocking drugs  (e.g., propranolol) usually helps to restore normal sinus rhythm.

Unilateral vs. Bilateral Thyroid Tumors?
About 30 percent of hyperthyroid cats have disease in only one thyroid lobe (unilateral tumor), whereas the remaining 70 percent have tumors in both thyroid lobes (i.e., bilateral tumors) (5-7).

As discussed in my last post on thyroid imaging for preoperative staging of hyperthyroid cats, nuclear scintigraphy is ideally done prior to surgery to determine with certainty which thyroid lobe should be removed or if bilateral thyroidectomy is needed. If this is not feasible, then the surgeon will have to make a decision to remove one or both thyroid lobes based on the visual appearance of the glands during surgery.

Unilateral disease
In cats with unilateral thyroid tumors, the adenomatous thyroid will be obviously large and abnormal, whereas the other “normal” thyroid lobe is of normal size or even small (Figure 1) (1-4). Removing the single abnormal thyroid lobe cures the hyperthyroid state in these cats. Relapse of hyperthyroidism will not occur in these cats unless they develop a “new” adenoma in the remaining thyroid lobe in the future. However, relapse is rare and, when it does occur, hyperthyroidism generally takes years to redevelop.

Figure 1: Unilateral thyroid adenoma (notice the large tumor on right).
The smaller thyroid lobe (on left) was normal.

After unilateral thyroidectomy, a low serum calcium will not develop, even if both of the parathyroid glands associated with the excised thyroid lobe have also been removed. Cats can easily maintain a normal serum calcium with the remaining 2 parathyroid glands that are still intact, associated with the other thyroid lobe that was not surgically removed.

Bilateral disease
With bilateral thyroid tumors, enlargement of both lobes can easily be identified at surgery in most cats (Figure 2) (1-4). However, about 15% of cats with bilateral lobe involvement have one lobe which is only slightly enlarged and may be easily mistaken as normal. If a cat has bilateral lobe involvement but the smaller thyroid lobe is mistaken as normal and not removed, many of these cats experience a temporary cure but relapse of hyperthyroidism will usually occur within 6 to 12 months of surgery (9).

Figure 2: Bilateral thyroid adenomas.
Notice that both thyroid lobes are large and nodular.

In cats with bilateral thyroid adenomas, removal of both thyroid lobes with preservation of at least a single parathyroid gland is necessary to cure hyperthyroidism and avoid postoperative hypocalcemia (low serum calcium level) secondary to parathyroid damage (hypoparathyroidism).

Uncertain if unilateral or bilateral disease
If it’s not clear if the cat has unilateral or bilateral thyroid tumors and preoperative thyroid imaging has not been done, I recommend removal of only the obviously enlarged thyroid tumor. However, the associated external parathyroid gland should be preserved. By saving a parathyroid gland during the first unilateral thyroidectomy, this helps minimizes the risk of hypoparathyroidism should removal of the second thyroid lobe be required in the future.

Figure 3: Hyperthyroid cat with one thyroid tumor (bottom of photo) that was clearly large,
whereas the other thyroid lobe is equivocally enlarged (top smaller lobe).
The final diagnosis was bilateral thyroid disease (bilateral adenomas).

In my next post, I’ll be discussing the specifics of the ins and outs of thyroid surgery for cats with hyperthyroidism.

References

1. Flanders JA. Surgical therapy of the thyroid. Veterinary Clinics of North America. Small Animal Practice 1994;24:607–621. 
2. Birchard, SJ. Thyroidectomy in the cat. Clinical Techniques in Small Animal Practice 2006;21, 29-33. 
3. Padgett S. Feline thyroid surgery. Veterinary Clinics of North America. Small Animal Practice 2002;32:851–859. 
4. Panciera DL, Peterson ME, Birchard, SJ: Diseases of the thyroid gland. In: Birchard SJ, Sherding RG (eds): Manual of Small Animal Practice (Third Ed), Philadelphia, Saunders Elsevier, pp 327-342, 2006.
5. Kintzer PP: Considerations in the treatment of feline hyperthyroidism. Veterinary Clinics of North America. Small Animal Practice 1994;24:577–585.
6. Mooney CT, Peterson ME: Feline hyperthyroidism, In: Mooney C.T., Peterson M.E. (eds), Manual of Canine and Feline Endocrinology (Fourth Ed), Quedgeley, Gloucester, British Small Animal Veterinary Association, 2012; 199-203.
7. Baral R, Peterson ME: Thyroid gland disorders, In: Little, S.E. (ed), The Cat: Clinical Medicine and Management. Philadelphia, Elsevier Saunders. 2012;571-592. 
8. Peterson ME: Considerations and complications in anesthesia with pathophysiologic changes in the endocrine system. In: Short CE (ed), Principles and Practice of Veterinary Anesthesiology. Philadelphia, Williams and Wilkins Co. 1987;251-270. 
9. Peterson ME, Randolph JF, Mooney CT:  Endocrine diseases, In: Sherding RG (ed): The Cat: Diagnosis and Clinical Management (2nd Ed) New York, Churchill Livingstone. 1994;1404-1506. 
10. Broome MR. Thyroid scintigraphy in hyperthyroidism. Clinical Techniques in Small Animal Practice 2006;21,10-16.

Ideally amicable: beauty and behaviour (part 2)

Hellloooo Julie,

(source)

Isn’t it interesting that bigger eyes are a preferred attribute for attractiveness, yet we find animals covering their faces (and therefore obscuring their eyes!) super cute? The eyes have it, but they obviously aren’t the full story. 

I look forward to hearing more!

While you tell me about what rings our bells in terms of physical looks, I'd like to get back to telling you about Tammie King's research into behaviour assessment and contemplating what behavioural traits we prefer in our companion dogs (Part 1 here).

I think I was up to telling you how Tammie set about creating an assessment with the aim of measuring the canine personality trait, ‘amicability’. She wanted to see if this was possible using a relatively SIMPLE protocol (because remember, we need this to be feasible for use in the real world). 

(Abstract from King et al., 2012, details below)

Tammie modified a well-known protocol called the Ainsworth Strange Situation Test for this purpose. Dogs were filmed undergoing the assessment in which they were exposed to a novel environment and unfamiliar person, initially with their owner and then without.

Tammie then gathered a focus group of dog behaviour experts (dog trainers, vets, people who work in animal shelters, breeders, etc. etc.) who independently watched videos of dogs who had undergone the pilot study and rated them on their level of amicability, based on a previously described list of attributes. There was a high level of agreement between which dogs the experts considered more or less amicable. This demonstrated that the protocol was able to elicit a range of behaviours which is excellent as it means we should be able to accurately identify what it was that enabled the experts to identify ‘amicable’ and ‘non-amicable’ dogs.

(source)

Tammie put her scientist hat back on and decided the most objective way to work out what was important to measure, was to begin by measuring absolutely every freaking behaviour, from every freaking angle. So she did. Data were collected from over 200 dogs and their owners.

Take a look at some of the footage:

She kept tally of all behavioural variables and went about conducting analyses to determine which variables to retain and which to discard, basically which ones were important in predicting ‘amicability’ Her ethogram is the king kong of canine ethograms.

(source)

To further evaluate the assessment, Tammie  asked two of the experts to rate ALL of the dogs to examine the intra-inter- rater reliability (which was very high = good!). Tammie also examined test-retest reliability and predictive validity. She also compared the owners’ reports of their dogs’ amicability. Interestingly, experts and owners don’t always agree. 

Dogs were behaving differently than owners expected. This might be due to a number of factors. Perhaps the assessment only offers a small snapshot of the dogs’ behaviour in the limited time available; perhaps owners are biased at look at their dogs through rose tinted glasses, etc. 

After a whole lot of statistical analysis, Tammie was able to determine which behavioural variables best predict ‘amicability’. The amount of contact the dog made with the stranger, its locomotion, vocalisations, time spent in particular areas of the arena and body posture were  all considered important.

Tammie has copped a bit of flack from ‘concerned individuals’ who seem afraid that this assessment will be the be-all-and-end-all of dog temperament tests and that every dog will be forced to be AMICABLE. 

But honestly, this is just a starting step. Step 1 in developing an accurate behaviour assessment for dogs, using the canine personality dimension of ‘amicability’ as a test case.

Tammie won’t really know how successful it is as a test protocol until a lot more data is collected from many dogs far and wide. Longitudinal data would be helpful, as would examining different breeds, puppies to adults, dogs from varying regions, etc. etc. Tammie also believes strongly that having a test like this in existence does not mean we take the emphasis off TRAINING dogs. We still need educate people about dog behaviour, welfare and training to ensure dogs and people live together harmoniously.

Dogs, like people and other animals, are constantly evolving. Perhaps some of the newer dog types around are already being selected for amicability without people realising it? Perhaps new breeds might be developed for this identified niche of FAMILY PET/COMPANION dog. This still leaves room for the people who want whatever dog they want and leaves them free to train it to do what they want.

Tammie suggests we will benefit from being TRANSPARENT about the sort of dog/s we have. Because having ACCURATE information on our dogs’ behaviour can help us make informed decisions regarding their breeding, training, housing and socialisation requirements. It has the potential to help with dog-owner matching, breeding decisions, etc. and also pave the way for future behaviour assessments aimed to measure other traits. In my mind, that has to be a good thing!

So what about their looks?
Are there physical traits that could also make for better companion animals?

Mia

Further reading:

King, T., Marston, L.C. & Bennett, P.C. (2012). Breeding dogs for beauty and behaviour: Why scientists need to do more to develop valid and reliable behaviour assessments for dogs kept as companions, Applied Animal Behaviour Science, 137 (1-2) 12. DOI: 10.1016/j.applanim.2011.11.016

Ley, J., Bennett, P. & Coleman, G. (2008). Personality dimensions that emerge in companion canines, Applied Animal Behaviour Science, 110 (3-4) 317. DOI: 10.1016/j.applanim.2007.04.016

King, T., Marston, L. & Bennett, P. (2011). Development of the Monash Canine Amicablity Assessment (MCAA), Journal of Veterinary Behavior: Clinical Applications and Research, 6 (1) DOI: 10.1016/j.jveb.2010.08.033

© Mia Cobb 2012

Video Special: Cutest thing ever? Paws on the face!

I'll start with some eye candy

Hi Mia, 

"What do you think is the most common role of dogs these days?"

             

As I read that in your last post, I blurted out, "companionship" (the guy sitting next to me in the coffee shop didn't even flinch. New Yorkers are expected to talk to ourselves. I succeed). For many people in many societies and cultures, dogs are brought into our lives to be companions.  

But what are the behaviors that make up "companionship"? That's where you come in! Tell me more about Tammie's work into dog behavior and her finding that people want "amicable" dogs, and I'll stick with looks.

Looking at looks

That's what my research talk at the Association of Pet Dog Trainers Conference was all about. I presented our lab's research on what humans find aesthetically pleasing about dogs’ physical appearance. In our study, people viewed images of mixed-breed, adult dogs. We found that they preferred:

This dog has a number of the "preferred" attributes

• bigger eyes
• colored irises  
• approximating a “human” smile 

 
Interestingly, these attributes were not preferred by everyone, just people who self-labelled as “dog people” or “animal people.” Apparently, what humans find aesthetically appealing in dogs might differ based on how they view dogs and animals in the first place.

What is cute?
I've spent a lot of time reading about what's perceived as cute and physically appealing, and apparently, this is considered the cutest thing ever...

(Source)

Why is this cute? Part of the reason for the "cuteness" might come from an idea suggested by Horowitz and Bekoff (2007): Cute is the ability to use one's limbs to cover one's face. I think they're onto something... 

(Source)

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(Source)

Bye for now!
Julie  
 

References
King, T., Marston, L.C. & Bennett, P.C. (2009). Describing the ideal Australian companion dog, Applied Animal Behaviour Science, 120 (1-2) 93. DOI:10.1016/j.applanim.2009.04.011

Horowitz, A.C. & Bekoff, M. (2007). Naturalizing Anthropomorphism: Behavioral Prompts to Our Humanizing of Animals, Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 20 (1) 35. DOI: 10.2752/089279307780216650

Bekoff, M. Dogs: Looking At the Way We Look At Our Best Friends. Psychology Today. August 21, 2012

© Julie Hecht 2012

Ideally amicable: beauty and behaviour (Part 1)

Hi Julie!

How was the APDT conference? 

Those citizen science projects in your last post were completely awesome – I still can’t decide if the slowed down baby laughter sound is hilarious or scary! Not sure I’d want to hear my kid’s giggle turned into Uncle Fester’s slow-play snicker is all I’m saying.

Looking at those babies’ behaviour, we can obviously tell they are happy little campers, but what assessments can be made about dog behaviour? More importantly, what are the behaviours that contribute to dogs thriving and living happily as modern-day companion dogs and members of our families?

(source)

The Anthrozoology research group considered this question a few years back. We often have discussion about dogs with our science goggles on (no, not literally – we don’t even wear lab coats! *snicker*). We talked about the idea of dogs having their behaviour scored and assessed in the same (best practice) way as their hips/elbows/eyes/insert physical trait are prior to breeding. Wouldn't that be amazing? This would be more than simply a breed standard description (e.g. Lhasa Apso: “Gay and assertive, but chary of strangers”; Dalmatian: "stable and outgoing, yet dignified", AKC breed standards), as you touched on in an earlier post. This would be an actual assessment of an individual dog’s behaviour.

This could be such a helpful tool. For potential owners (e.g. check out the documented behaviour profiles of the individual parents before purchasing a pup), for local councils (e.g. could help them better manage the dogs living in their community, including the dangerous ones), breeders, trainers, shelters, etc. etc. etc.

Tammie and her dog Kade

Tammie King was part of those discussions and her research is taking on this huge piece of big-picture pie, head first. Tammie began her PhD journey wanting to improve our capacity to accurately and objectively assess canine behaviour with the goal of improving transparency of the types of dogs we have (own/breed) in our communities. This is a continuously challenging area of study and one of significance for many sectors of our society.

(source)

But hasn’t someone already worked out how to do that?

There are already plenty of behaviour assessments in existence. The problem is that they’re all trying to measure different things, in different ways, guided by different ethics (specifically regarding eliciting aggression), using different equipment and different assessors in all different scenarios in varying parts of the world. Many have not been evaluated regarding their effectiveness. As scientists, we’d like to limit variability by producing an objective (not biased), standardised assessment which has been shown to be valid (accurate), reliable (repeatable by different people on different occasions) and is feasible (can be safely used by a range of organisations).

That sounds easy!

Does it? Awesome! What would you measure? Objectively, remember. How would you score it? What would you use in your test to prompt the behaviour that informs your assessment? Keep in mind the assessment needs to have a practical time frame to be useful in a real-world context. What would you involve in your protocol? The owner? A stranger? Another dog? A small child? Food? Cats? Penguins? Wait!

(source)

I changed my mind.
That sounds hard!

You’re right. It’s not an easy task. Tammie decided to tackle this the way we all should take on any big task – by breaking it down into manageable pieces. She started by asking “WHAT should my assessment be measuring?” Rather than just take a stab in the dark, Tammie took the question to the masses and asked the Australian public what their ‘ideal’ dog would be.

Nearly 1,000 people took her online survey and it turns out that most people seem to want dogs which are friendly, easy going, safe with children, affectionate, etc. When it comes to dogs living as companion animals, most people do not want the traditionally bred purpose-type dogs, i.e. hunting/guard/herding dogs (Oh hush your protests, this is what the data said, not what Tammie or I are personally saying). 

Instead, in these current times, most people in Australia want what a dog that can be categorised as AMICABLE.

Amicable is ideal?

The next stage of Tammie’s research involved developing a behaviour assessment specifically designed to measure the canine personality trait, amicability.

I’ll tell you more about all of that next time. But I’d love to hear your thoughts - what do you think the most common role of dog is these days? Should we be breeding dogs for beauty and behaviour in their role as modern companion animals? 

Until next time,

Mia

Further reading:

King, T., Marston, L.C. & Bennett, P.C. (2009). Describing the ideal Australian companion dog, Applied Animal Behaviour Science, 120 (1-2) 93. DOI:10.1016/j.applanim.2009.04.011

King, T., Marston, L. & Bennett, P. (2011). Development of the Monash Canine Amicablity Assessment (MCAA), Journal of Veterinary Behavior: Clinical Applications and Research, 6 (1) DOI:10.1016/j.jveb.2010.08.033

© Mia Cobb 2012

Thyroid Imaging for Preoperative Staging of Hyperthyroid Cats

Thyroid scintigraphy (thyroid scanning or thyroid imaging) provides valuable information regarding both thyroid anatomy and physiology and can play an integral role in the staging and management of thyroid disease in cats with suspected hyperthyroidism.

Ideally, thyroid scintigraphy would be performed in all hyperthyroid cats prior to surgical thyroidectomy to identify the extent and location of the cat's hyperfunctioning thyroid tumor tissue (1-7).  In hyperthyroid cats, thyroid scintigraphy directly visualizes all functional thyroid tissue and will easily reveal whether the hyperthyroid cat has a thyroid tumor affecting only one lobe (unilateral disease) or both lobes (bilateral disease). See the scans in Figure 1 below.

Fig. 1: Thyroid scintigraphy in 3 hyperthyroid cats.
The cat on the left has a single thyroid tumor (Unilateral), whereas the cat on the right has 2 thyroid tumors that involve both thyroid lobes equally (Bilateral symmetric). The cat in the middle panel also has bilateral thyroid disease, but it is possible that the surgeon could mistake the smaller thyroid lobe as normal since the thyroid tumor enlargement is so asymmetric.

Some hyperthyroid cats develop very large thyroid tumors that descend into the chest cavity. making them difficult to palpate or identify at surgery. We often see these tumors in cats that have been hyperthyroid for many months to years (8,9). As the tumor grows progressively larger, gravity pulls progressively harder. This causes the tumor to descend into the chest cavity. Again, thyroid scintigraphy will detect these intrathoracic thyroid tumors that could easily be missed at surgery (Figure 2).

Fig. 2: Thyroid scintigraphy in a hyperthyroid cat with bilateral thyroid tumors.
In this cat, the larger thyroid tumor has descended into the chest cavity because of the effects of gravity. Without thyroid scintigraphy, this tumor could easily be missed at surgery, resulting in persistent hyperthyroidism.

Ectopic thyroid tissue is an embryological phenomenon that we see in about 3-5% of all hyperthyroid cats (8,9).  As the cells that develop into the thyroid gland traverse the embryo, they can leave traces of tissue anywhere from the base of the tongue to the base of the heart. These thyroid remnants can develop into functional thyroid tissue.  If such ectopic thyroid tissue develops a tumor, it will not be palpable or easily found at surgery, especially if the ectopic tumor is located on the tongue or in the chest cavity.  Thyroid scintigraphy can quickly and easily locate these tumors (see Figure 3).

Fig. 3: Thyroid scintigraphy in a hyperthyroid cat with a single ectopic thyroid nodule.
In this cat, no thyroid tumors could be palpated in the neck area where the thyroid gland is normally located. The large thyroid tumor has arisen from ectopic thyroid tissue that is located within the chest cavity. Without thyroid scintigraphy, this tumor could easily be missed at surgery, resulting in persistent hyperthyroidism.

Finally, thyroid scintigraphy also provides valuable information for diagnosing and evaluating cats with thyroid cancer (carcinomas) and metastasis.  With scintigraphy, a carcinoma will appear as a large, irregularly shaped tumor extending beyond the limits of the normal thyroid region (see Figure 4).  We can also see whether the tumor has metastasized or shows local invasion of the surrounding tissues. Thyroid carcinomas account for 2-3% of all thyroid tumors in cats (8,9).

Fig. 4: Thyroid scintigraphy in 6 hyperthyroid cats with a thyroid carcinoma (thyroid cancer).
In these cats with thyroid carcinoma, notice that the thyroid tumors are very large, multinodular, with extension and metastasis into the chest cavity. Surgery is unlikely to be successful in any of these cats, since these cancers are highly vascular and invasive, and it would be difficult to find all malignant thyroid tissue at surgery.

If thyroid scintigraphy is not available, the surgeon will have to make a decision upon what thyroid tissue to remove based on the visual appearance of the glands during surgery. In some cases, the surgeon may be fooled into leaving abnormal functioning thyroid tissue behind, especially if located in the chest cavity. Failure to identify and remove all hyperfunctional tissue will result in failure to cure the cat's hyperthyroidism.

Why Isn't Thyroid Scintigraphy Always Done Prior to Thyroidectomy?

Apart from expense and the licensing needed to handle and administer radioisotopes, few veterinarians have access to the nuclear medicine equipment needed to obtain thyroid images or perform thyroid uptake determinations. Only a few large referral hospitals in the country offer nuclear scintigraphy to do thyroid scanning. However, if available, I believe that thyroid scintigraphy can play an essential role in the preoperative staging and surgical management of cats with hyperthyroidism.

References:

1. Mooney CT, Peterson ME: Feline hyperthyroidism, In: Mooney C.T., Peterson M.E. (eds), Manual of Canine and Feline Endocrinology (Fourth Ed), Quedgeley, Gloucester, British Small Animal Veterinary Association, 2012; 199-203.
2. Baral R, Peterson ME: Thyroid gland disorders, In: Little, S. (ed), The Cat: Clinical Medicine and Management. Philadelphia, Elsevier Saunders, 2012;571-592.
3. Peterson ME: Hyperthyroidism in cats, In: Rand, J (ed), Clinical Endocrinology of Companion Animals. New York, Wiley-Blackwell, 2012; in press.
4. Panciera DL, Peterson ME, Birchard, SJ: Diseases of the thyroid gland. In: Birchard SJ, Sherding RG (eds): Manual of Small Animal Practice (Third Edition), Philadelphia, Saunders Elsevier, pp 327-342, 2006.
5. Birchard, SJ. Thyroidectomy in the cat. Clinical Techniques in Small Animal Practice 2006;21, 29-33. 
6. Flanders JA. Surgical therapy of the thyroid. Veterinary Clinics of North America. Small Animal Practice 1994;24:607–621. 
7. Broome MR. Thyroid scintigraphy in hyperthyroidism. Clinical Techniques in Small Animal Practice 2006;21,10-16. 
8. Peterson ME, Broome MR. Thyroid scintigraphic findings in 917 cats with hyperthyroidism. Journal of Veterinary Internal Medicine 2012;26:754.
9. Peterson ME, Broome MR. Hyperthyroid cats on long-term medical treatment show a progressive increase in the prevalence of large thyroid tumors, intrathoracic thyroid masses, and suspected thyroid carcinoma. Congress Proceedings, 22^nd ECVIM-CA Congress (The European College of Veterinary Internal Medicine – Companion Animals) 2012; 224

You are Science. Citizen Science.

What a big eye you have! Oh, you're doing science!

Mia!

You are 1,000% right. Your rightness is statistically significant. Citizen Science is awesome.

To keep with the awesomeness of Citizen Science, here are a few more Citizen Science websites and projects.

Citizen Science Aggregators

Citizen Science on Scientific American

• "Scientists collaborating across continents. Now, using the power of the Internet, non-specialists are participating, too."
  

scistarter

• “In a nutshell... This is the place to find out about, take part in, and contribute to science through recreational activities and research projects.” They have an enormous listing of different projects you can join. Through scistarter, you pick an activity, pick a topic and BLAMMO, it shoots out projects that interest you and that you could help with. (you must sign up on scistarter, but that's easy peasy).

Some of my favorite projects

Students' Cloud Observations Online (S'COOL)

• (I partially, fine, mostly, like it's acronym) NASA scientists are interested in learning how clouds affect our atmosphere, particularly because clouds play a role in affecting Earth's overall temperature and energy balance. 

(Source)

The Baby Laughter Project

• Hysterical, espeically when they slow down the babies laughing and they sound exactly like old men. Or maybe walruses? Or maybe someone choking. You tell me. My favorite is "Hysterical Bubbles", although that dog gets kinda close to that baby during his/her bubble enjoyment. "Baby laughing at Wii" is pretty good, too.
  
  

The River Otter Ecology Project

• Kind of fabulous. This is their description: "An OTTER SPOTTER is YOU, a citizen scientist who observes river otters in your  neighborhood stream, river, bay/county state or national park/ and elsewhere and submits your information to this ecology project... As of September 2012: +150 observations submitted from across the Bay Area, keep them coming in!"

I am Science

• Talking about citizen science reminds me of a project called, I am Science which was on kickstarter and reached its goal. From the website: "I AM SCIENCE brings you the personal stories of the individuals who went off the beaten path toward their careers in science. “I am Science” describes the stories behind the people who ended up in science careers. Whether as science writers, academic scientists, pharmaceutical technicians or all of the above there is one thing I have learned: the straight and narrow path is rarely the case."
  

APDT 2012

I just got to Cincinnati for APDT 2012 and will be talking about that Physical Prompts to Anthropomorphism study tomorrow. 

Will try and tweet/Facebook on the conference's content!!

Nighty Night!

Julie

Referenced
Bekoff, M. Dogs: Looking At the Way We Look At Our Best Friends. Psychology Today. August 21, 2012


© Julie Hecht 2012

Surgical Thyroidectomy for Cats with Hyperthyroidism: Preoperative Preparation

Thyroidectomy is a highly curative treatment for cats with hyperthyroidism. However, these patients are generally senior cats, with 95% being older than 10 years of age (1-3).

Performing surgery and general anesthesia on these older to geriatric cats has inherent risks. Hyperthyroid cats frequently have disorders of other organ systems (e.g., heart, kidneys, liver) that should be recognized and appropriately treated prior to surgery (1-3). Anesthesia on hyperthyroid cats can be challenging as a result of their hypermetabolic state and underlying thyroid tumor, as well as their advanced age. Without adequate preoperative preparation, thyroidectomy can be associated with significant morbidity and mortality, especially in those cats with severe or long-standing hyperthyroidism (4-6).

A thorough diagnostic evaluation of the hyperthyroid cat is mandatory prior to the surgery. Using short-term antithyroid drugs to restore euthyroidism before surgery will make these cats much better candidates for anesthesia and surgery (1-3,7,8).

Preoperative Evaluation of the Hyperthyroid Cat

All hyperthyroid cats in which surgical thyroidectomy is planned should have a thorough physical examination and complete laboratory evaluation, including a complete blood count, serum chemistry profile, and complete urinalysis. Often this database simply lends support to the diagnosis of hyperthyroidism, but these screening tests are essential in determining if a hyperthyroid cat also has concurrent medical problems (e.g., kidney, heart, or liver disease) that will need to be addressed prior to surgery.

Many hyperthyroid cats will develop secondary cardiac problems, including a rapid heart rate, heart murmurs, heart enlargement, or abnormal heart rhythms (1-4). Occasionally, especially in cats with chronic or severe hyperthyroidism, congestive heart failure will develop. Therefore, if signs of underlying heart disease is found on physical examination, one or more heart procedures, such as a chest radiograph (x-ray), electrocardiogram (ECG), or echocardiogram, may also be indicated in the presurgical workup of a cat with hyperthyroidism.

Preoperative Medical Management

Antithyroid drug treatment

Ideally, the cat would be treated preoperatively with antithyroid drugs (i.e., methimazole or carbimazole) to lower the high serum T4 levels down into the normal reference range limits (4-9). Initial doses of the antithyroid drug vary depending on the cat’s pretreatment serum T4 value and goiter size (i.e., size of the thyroid tumor). In general, however, most cats are started on 1.25-2.5 mg of methimazole or 2.5-5 mg of carbimazole, both administered twice daily. This dose is adjusted according to T4 measurements done at 2-week intervals, as well as the cat's clinical response. (7-9)

After methimazole or carbimazole treatment has maintained euthyroidism for at least 1-3 weeks, anesthetic and surgical complications will be greatly minimized. The last dose of methimazole or carbimazole should be given on the morning of surgery.

Beta-adrenergic blocking agents (Beta blockers)

In cats that cannot tolerate antithyroid drug treatment, alternate preoperative stabilization with beta-adrenoceptor blocking agents (e.g., propranolol or atenolol) should be used. The basis for use of beta blockers in hyperthyroidism is that excessive thyroid hormone mimics many of the effects of excess adrenalin. Beta blockers act to block the action of endogenous catecholamines epinephrine (adrenaline) and norepinephrine (noradrenaline), which mediates the fight-or-flight response (7,8).

Propranolol and atenolol are used to symptomatically control the tachycardia (rapid heart rate), tachypnea (rapid respiratory rate), hypertension and hyperexcitability prior to surgery when the hyperthyroid cat cannot be made euthyroid with antithyroid drugs. In addition, some cats that have persistent tachycardia (heart rate >220 beats per minute) on antithyroid drugs will also be treated with beta blockers prior to surgery to decrease the cardiac risks associated with general anesthesia.

Alternative drugs used to prepare the hyperthyroid cat for surgery
In cats with advanced or chronic hyperthyroidism that do not tolerate antithyroid drugs, there are a number of alternative drugs, including stable iodine, iopanoic acid, or L-carnitine, that can be added to the beta blocker treatment (7,8,10).

None of these drug are as effective as methimazole or carbimazole for preoperative preparation of the hyperthyroid cat.

Monitoring of Thyroid and Renal Values before Surgery

As serum thyroid levels normalized, it is important to monitor for worsening of serum kidney values as renal disease can sometimes be unmasked by treatment. Clinically significant rises in renal values warrant medical management prior to surgery to avoid postoperative renal failure (1-4).

Hemorrhage from jugular venipuncture sites can discolor and obscure the parathyroid glands. Therefore, jugular venipuncture should be avoided the week prior to surgery. Venipuncture can always be done, however, from either the cat’s saphenous or cephalic veins, located on the inside of the rear leg or top aspect of the foreleg, respectively.

Bottom Line

In most cats, thyroidectomy is relatively simple surgical procedure for an experienced veterinary surgeon to perform. However, thyroidectomy can range from a straightforward operation to one that is fairly complex, and it can be associated with significant morbidity and mortality, especially in cats with severe or chronic hyperthyroidism.

Considering that the average hyperthyroid cat is a geriatric patient with potential for high blood pressure and heart disease, quite a bit of patient preparation is necessary to reduce anesthetic risk.

A thorough preoperative evaluation of the hyperthyroid cat is mandatory. Using short-term antithyroid drugs to restore euthyroidism before surgery will make these cats much better candidates for anesthesia and surgery (1-3,7,8).

References:

1. Mooney CT, Peterson ME: Feline hyperthyroidism, In: Mooney C.T., Peterson M.E. (eds), Manual of Canine and Feline Endocrinology (Fourth Ed), Quedgeley, Gloucester, British Small Animal Veterinary Association, 2012; 199-203.
2. Baral R, Peterson ME: Thyroid gland disorders, In: Little, S. (ed), The Cat: Clinical Medicine and Management. Philadelphia, Elsevier Saunders, 2012;571-592.
3. Peterson ME: Hyperthyroidism in cats, In: Rand, J (ed), Clinical Endocrinology of Companion Animals. New York, Wiley-Blackwell, 2012; in press.
4. Panciera DL, Peterson ME, Birchard, SJ: Diseases of the thyroid gland. In: Birchard SJ, Sherding RG (eds): Manual of Small Animal Practice (Third Edition), Philadelphia, Saunders Elsevier, pp 327-342, 2006.
5. Birchard, SJ. Thyroidectomy in the cat. Clinical Techniques in Small Animal Practice 2006;21, 29-33. 
6. Flanders JA. Surgical therapy of the thyroid. Veterinary Clinics of North America. Small Animal Practice 1994;24:607–621. 
7. Trepanier LA. Pharmacologic management of feline hyperthyroidism. Veterinary Clinics of North America: Small Animal Practice 2007;37:775-788. 
8. Trepanier LA. Medical management of hyperthyroidism. Clinical Techniques in Small Animal Practice 2006;21:22-28. 
9. Animal Endocrine Blog. Treating Cats with Hyperthyroidism: Antithyroid drugs. October 23, 2011.  
10. Animal Endocrine Blog. Alternative Medical Treatments for Hyperthyroid Cats. September 13, 2012.