Acromegaly, Pituitary dwarfism, Insulinoma

Question 1

What disease arises from excess growth hormone?

Answer 1

Acromegaly

Question 2

Where is the tumor located in patients with acromegaly?

Answer 2

• Benign adenoma of the pars distalis (pituitary gland tumor)

Question 3

How do cats with acromegaly typically present?

Answer 3

Usually present as an unstable diabetic with organomegaly, prognathism inferior, stridor/stertor, and neuro signs

Question 4

What concurrent disease do cats with acromegaly typically have?

Answer 4

Diabetes mellitus (uncontrolled)

Question 5

What clinical effects occur in cats and dogs with acromegaly?

Answer 5

1. Diabetes mellitus
2. Organomegaly
3. Soft tissue hypertrophy (stridor, stertor)
4. Neuro dsyfunction
5. Cardiomyopathy
6. Hypertension
7. Renal failure
8. Joint disease

Question 6

What organs become hyperplastic in cats and dogs with acromegaly?

Answer 6

1. Adrenal glands
2. Parathyroid and thyroid glands
3. Pancreas
4. Chondroid hyperplasia in bone

Question 7

What heart changes can occur in cats and dogs with acromegaly?

Answer 7

• Cardiac hypertrophy
• Systemic hypertension
• Arrhythmias, murmur

Question 8

How is acromegaly in dogs and cats diagnosed?

Answer 8

• Unstable DM
• Ultrasound changes
• Measuring GH (hard to do)
• Measuring IGF-1 (easier than GH)
• MRI/CT
• Intact dog on progesterone or in diestrus

Question 9

What treatment options are available for cats with acromegaly?

Answer 9

• Radiotherapy
• Hypophysectomy
• Medical management with insulin, ACEi, diuretics, and B blockers

Question 10

A cat presenting with uncontrolled diabetes mellitus, hypertension, and “club feet” is diagnosed with acromegaly. The owner can only afford medical management. What drugs do you prescribe?

Answer 10

1. Insulin (no more than 1IU/kg BID)
2. ACEi
3. Diuretics
4. Beta blockers

(Insulin for DM, ACEi to ↓ BP and control proteinuria, Diuretics to help with CHF and effusions, B blocker to control arrhythmias)

Question 11

What is the cause of canine acromegaly?

Answer 11

• Intact female treated with progesterone to prevent estrus
• Intact female in diestrus

Question 12

Why is history a crucial part in diagnosing acromegaly in dogs?

Answer 12

Occurs in intact females receiving progesterone or intact females in diestrus

Question 13

An intact female dog is diagnosed with acromegaly. What is the treatment plan?

Answer 13

• Progesterone withdrawal or OVH (spay) reduces GH and IGF-1 levels

Question 14

Which pituitary tumor in dogs can be controlled by spaying the animal?

Answer 14

Canine acromegaly

Question 15

List the 6 hormones synthesized and secreted by the anterior pituitary

Answer 15

1. GH
2. ACTH
3. TSH
4. PRL
5. FSH
6. LH

Question 16

What is the cause of proportional dwarfism in dogs?

Answer 16

Congenital defect in the anterior pituitary resulting in ↓ GH, TSH, PRL, and gonadotropins

Question 17

Which hormone is unaffected in dogs with pituitary dwarfism?

A. TSH
B. ACTH
C. GH
D. PRL

Answer 17

B. ACTH

Question 18

What dog breed is most associated with pituitary dwarfism?

Answer 18

GSD

Question 19

What clinical signs do dogs with pituitary dwarfism typically present with?

Answer 19

• Proportionate dwarfism
• Retention of puppy coat
• Hyperpigmentation
• CRF from undeveloped kidneys
• Slow and dull from underactive thyroid
• Failure of testis to descend

Question 20

How is pituitary dwarfism in dogs diagnosed?

Answer 20

• Failure to respond to pituitary stim testing
• Low TSH
• Low GH

Question 21

What is the treatment protocol for a dog with pituitary dwarfism?

Answer 21

• Levothyroxine (T4 supplement)
• Porcine GH

Question 22

What is the prognosis for a dog with pituitary dwarfism?

Answer 22

• 3-5 years without treatment
• Longer with tx

Question 23

What is the most common endocrine pancreatic tumor in dogs?

Answer 23

Insulinoma

Question 24

Where are most insulinomas in dogs located?

Answer 24

Left lobe of the pancreas

Question 25

What is the first approach in treating a dog with insulinoma?

Answer 25

Surgical resection

Question 26

If surgical resection is not an option, how can insulinoma in dogs be medically managed?

Answer 26

1. Frequent small meals 2. High protein, fat, and carb diet 3. Prednisolone (inhibits insulin) 4. Diazoxide (inhibits insulin) 5. Octreotide (inhibits insulin)

Question 27

List the pathological causes of hypoglycemia in dogs

Answer 27

1. Pancreatic or hepatic neoplasia 2. Insulinoma 3. Hypoadrenocorticism / Addisons 4. Sepsis

Question 28

Which of the following is not a differential for hypoglycemia in a canine patient? A. Insulinoma B. Hyperadrenocorticism C. Sepsis D. Hypoadrenocorticism

Answer 28

B. Hyperadrenocorticism

Question 29

What clinical signs do dogs with insulinoma present with?

Answer 29

- Non specific, waxing and waning CS - CS of hypoglycemia - Seizures - Collapse - Ataxia - Weakness

Question 30

What clin path changes can be seen in dogs with insulinoma?

Answer 30

- Low BG - Azotemia - Normal to ↓ BP - Normal or isothenuric urine - Normal CBC (fairly non specific findings)

Question 31

How can insulinoma in dogs be diagnosed?

Answer 31

- Elevated or high normal insulin in the face of hypoglycemia - Can't measure insulin if glucose is normal, must be hypoglycemic when testing - Low fructosamine - Ultrasound / CT

Question 32

True or False: Majority of dogs with insulinoma have a benign adenoma of the endocrine pancreas

Answer 32

False, can be adenoma or carcinoma, metastasis common if carcinoma

Question 33

Which endocrinopathy in cats can result in stridor / stertor sounds?

Answer 33

Acromegaly (due to soft tissue hypertrophy)

Question 34

Why should no more than 1 IU/kg of insulin BID be given to cats with acromegaly?

Answer 34

GH and IGF-1 secreted in bursts, insulin can result in intermittent hypoglycemia

Question 35

An intact female dog receiving progesterone is at risk for developing what endocrinopathy?

Answer 35

Canine acromegaly

Question 36

What is the main cause of death in dogs with pituitary dwarfism?

Answer 36

Underdeveloped kidneys causing chronic renal failure