Endocrinology

Question 1

Bobby, a 10 year old m/n cat presents to your clinic with history of diabetes mellitus for past 2 years. Despite receiving 10 units of insulin twice a day, he has poor glycemic control with polyphagia, PU/PD and stable weight. The owner has not noticed any physical changes in Bobby’s appearance. Abdominal ultrasound shows hepatomegaly and bilateral adrenomegaly. What is your “best” next step with Bobby?

Answer 1

You measure IGF-1 levels to investigate the possibility of hypersomatotropism

Question 2

Sassy, a 15 year old female spayed DSH presents to your clinic for PU/PD. She is a little overweight but otherwise she has a normal physical examination. You diagnose Sassy with diabetes mellitus based on hyperglycemia, glucosuria, elevated fructosamine and clinical signs. You submit an IGF-1 level and start Sassy on insulin twice a day and low carbohydrate diet. The IGF-1 level comes back at the high end of the normal range. What is your assessment of this result?

Answer 2

Sassy might have hypersomatotropism and IGF-1 should be rechecked 4-8 weeks after starting insulin therapy

Question 3

Which of the following are potential sequelae in a cat with hypersomatotropism and diabetes that is treated with insulin only?

Answer 3

A. Episodes of clinical hypoglycemia
B. Progression of acromegalic phenotype
C. Heart failure and neurological signs
D. Respiratory distress and inability to eat

Question 4

What is the most common cause of hypothyroidism in the cat?

Answer 4

Iatrogenic (I-131 or methimazole)

Question 5

In primary HYPOthyroidism ___ and ___ are high.

Answer 5

TRH and TSH

Question 6

In secondary HYPOthyroidism ___ is low and ___ is high. Disease is in the _______.

Answer 6

TSH, TRH. Pituitary gland.

Question 7

In tertiary HYPOthyroidism ___ and ___ are low. Disease is in the _____.

Answer 7

TRH and TSH. Hypothalamus

Question 8

Visual hints that a kitten may have congenital HYPOthyroidism include:

Answer 8

• Lethargy
• Heat seeking behavior
• Not growing as expected
• Broad, flat face with almond eyes
• Wide set eyes
• Short limbs
• Poor haircoat

Question 9

Which serum hormone is more likely to be falsely elevated due to non-thyroidal illness (NTI) in a cat?

Answer 9

TSH

Question 10

What is the main benefit of evaluating serum TSH prior to radioactive iodine treatment in a hyperthyroid cat?

Answer 10

It can help predict the risk of the cat developing post-treatment hypothyroidism

Question 11

A 10-year-old, neutered male, domestic longhair cat presents with chronic vomiting and diarrhea. The cat’s appetite is normal to slightly decreased. On examination, the cat has a low body condition score (2/9), generalized muscle atrophy, and a small, bilateral thyroid slip. Complete blood count, chemistry, and urinalysis are unremarkable. TT4 is 4.2 µg/dl (53.6 nmol/l); upper reference interval is 4.5 µg/dl (57.4 nmol/l). Which of the following is the best interpretation of thyroid function in this cat?

Answer 11

Possible hyperthyroidism with NTI such as GI disease (repeat TT4 measurement after investigation and treatment of GI disease)