hyperthyroidism and thyroid gland disorder dx workshop Flashcards
what are the clinical signs associated with hyperthyroidism
- weight loss
- polyphagia
- PU/PD
- tachycardia
- diarrhea
- haircoat changes/unkempt coat
- respiratory abnormalities
- vomiting
- cervical nodule/palpable goitre
why dont elderly cats just eat more to meet their increased needs
- compromised sense of smell and/or taste
- impaired mobility
- concurrent age-related issues
what can we do for our elderly feline patients to address/overcome weight loss issues
- provide smaller meals more frequently
- easy access to food - location in the house, raised food bowls
- platability: strong smelling foods and heating up
- provide food which is easy to digest
- TLC
what information can we get from our history and clinical exam to help determine the cause of weight loss
History:
- EDUD normal? – including information about their diet/feeding habits
- Displaying ‘normal’ behaviour at home?
- Lifestyle – indoor/outdoor
- Preventative treatments
- Multi-cat household? If so, any other cats affected?
Clinical Exam:
- Dental exam
- Heart rate – murmur?
- Weight/BCS
- Abdominal palpation
- Goitre?
An owner of a horse has asked you if you think their horse could be hypothyroid. It is not jumping as well as it used to and they have noticed a lump in the horse’s neck at a position that they have been told is the thyroid. As part of your clinical examination you palpate this lump and agree that it is likely to be a thyroid gland.’
1. how often do horses get hypothyroidism?
2. The owner requests that you do some tests to rule out hypothyroidism as she knows another horse that is getting thyroid treatment and is now livelier than it was. What test(s) would you recommend to rule out or confirm hypothyroidism in her horse? How are the test results interpreted?
- virtually never
- measure TT3 and TT4 following injection with TRH - expect at least 50% increase in thyroid hormone concentrations.
You are presented with a 6yr old Golden retriever for annual check and vaccination. It has alopecia on the dorsum of its muzzle and on questioning; the owner agrees that the dog is less active than previously and that he has been struggling to get it to lose weight. On clinical examination, you notice that the undercoat of the dog is not as full as you would expect. You are thinking about the possibility of hypothyroidism.
- What thyroid diagnostic tests would you recommend? The lab offers a selection of “Thyroid panels”. What would you want your panel to include
- what are the advantages and disadvantages to each
At least TT4 and TSH. TgAA would help you know whether there is a chance that your TT4 result has been interfered with. FT4d is helpful because less affected by non-thyroidal illness and free form TgAA assay interference
interpret these results. does the dog have hypothyroidism? what further actions or tests are appropriate
yes - this is primary hypothyroidism
- low T4 and high TSH
- due to lymphocytic thyroiditis (positive TgAA)
further action: start thyroid replacement therapy
interpret these results. does the dog have hypothyroidism? what further actions or tests are appropriate
No this is not hypothyroidism
- initiate another investigation relevant to the animal’s clinical signs
interpret these results. does the dog have hypothyroidism?
Yes - primary hypothyroidism
- low T4 and high TSH
review the results. both cats have chronic renal failure. explain the results for micha and Boris
A cat with renal failure as bad as these results suggest would be expected to have a very low TT4 if they had normal thyroid gland function (like Micha) because of non-thyroidal illness syndrome/euthyroid sick syndrome. Boris has normal thyroid BUT, you would expect his thyroid levels to fall due to the severity of the illness happening elsewhere. therefore, Boris is hyperthyroid even though his thyroid value is in reference range
