Acromegaly, Pituitary dwarfism, Insulinoma Flashcards
What disease arises from excess growth hormone?
Acromegaly
Where is the tumor located in patients with acromegaly?
- Benign adenoma of the pars distalis (pituitary gland tumor)
How do cats with acromegaly typically present?
Usually present as an unstable diabetic with organomegaly, prognathism inferior, stridor/stertor, and neuro signs
What concurrent disease do cats with acromegaly typically have?
Diabetes mellitus (uncontrolled)
What clinical effects occur in cats and dogs with acromegaly?
- Diabetes mellitus
- Organomegaly
- Soft tissue hypertrophy (stridor, stertor)
- Neuro dsyfunction
- Cardiomyopathy
- Hypertension
- Renal failure
- Joint disease
What organs become hyperplastic in cats and dogs with acromegaly?
- Adrenal glands
- Parathyroid and thyroid glands
- Pancreas
- Chondroid hyperplasia in bone
What heart changes can occur in cats and dogs with acromegaly?
- Cardiac hypertrophy
- Systemic hypertension
- Arrhythmias, murmur
How is acromegaly in dogs and cats diagnosed?
- Unstable DM
- Ultrasound changes
- Measuring GH (hard to do)
- Measuring IGF-1 (easier than GH)
- MRI/CT
- Intact dog on progesterone or in diestrus
What treatment options are available for cats with acromegaly?
- Radiotherapy
- Hypophysectomy
- Medical management with insulin, ACEi, diuretics, and B blockers
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?
- Insulin (no more than 1IU/kg BID)
- ACEi
- Diuretics
- Beta blockers
(Insulin for DM, ACEi to ↓ BP and control proteinuria, Diuretics to help with CHF and effusions, B blocker to control arrhythmias)
What is the cause of canine acromegaly?
- Intact female treated with progesterone to prevent estrus
- Intact female in diestrus
Why is history a crucial part in diagnosing acromegaly in dogs?
Occurs in intact females receiving progesterone or intact females in diestrus
An intact female dog is diagnosed with acromegaly. What is the treatment plan?
- Progesterone withdrawal or OVH (spay) reduces GH and IGF-1 levels
Which pituitary tumor in dogs can be controlled by spaying the animal?
Canine acromegaly
List the 6 hormones synthesized and secreted by the anterior pituitary
- GH
- ACTH
- TSH
- PRL
- FSH
- LH
What is the cause of proportional dwarfism in dogs?
Congenital defect in the anterior pituitary resulting in ↓ GH, TSH, PRL, and gonadotropins
Which hormone is unaffected in dogs with pituitary dwarfism?
A. TSH
B. ACTH
C. GH
D. PRL
B. ACTH
What dog breed is most associated with pituitary dwarfism?
GSD
What clinical signs do dogs with pituitary dwarfism typically present with?
- Proportionate dwarfism
- Retention of puppy coat
- Hyperpigmentation
- CRF from undeveloped kidneys
- Slow and dull from underactive thyroid
- Failure of testis to descend
How is pituitary dwarfism in dogs diagnosed?
- Failure to respond to pituitary stim testing
- Low TSH
- Low GH
What is the treatment protocol for a dog with pituitary dwarfism?
- Levothyroxine (T4 supplement)
- Porcine GH
What is the prognosis for a dog with pituitary dwarfism?
- 3-5 years without treatment
- Longer with tx
What is the most common endocrine pancreatic tumor in dogs?
Insulinoma
Where are most insulinomas in dogs located?
Left lobe of the pancreas
What is the first approach in treating a dog with insulinoma?
Surgical resection
If surgical resection is not an option, how can insulinoma in dogs be medically managed?
- Frequent small meals
- High protein, fat, and carb diet
- Prednisolone (inhibits insulin)
- Diazoxide (inhibits insulin)
- Octreotide (inhibits insulin)
List the pathological causes of hypoglycemia in dogs
- Pancreatic or hepatic neoplasia
- Insulinoma
- Hypoadrenocorticism / Addisons
- Sepsis
Which of the following is not a differential for hypoglycemia in a canine patient?
A. Insulinoma
B. Hyperadrenocorticism
C. Sepsis
D. Hypoadrenocorticism
B. Hyperadrenocorticism
What clinical signs do dogs with insulinoma present with?
- Non specific, waxing and waning CS
- CS of hypoglycemia
- Seizures
- Collapse
- Ataxia
- Weakness
What clin path changes can be seen in dogs with insulinoma?
- Low BG
- Azotemia
- Normal to ↓ BP
- Normal or isothenuric urine
- Normal CBC
(fairly non specific findings)
How can insulinoma in dogs be diagnosed?
- 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
True or False: Majority of dogs with insulinoma have a benign adenoma of the endocrine pancreas
False, can be adenoma or carcinoma, metastasis common if carcinoma
Which endocrinopathy in cats can result in stridor / stertor sounds?
Acromegaly (due to soft tissue hypertrophy)
Why should no more than 1 IU/kg of insulin BID be given to cats with acromegaly?
GH and IGF-1 secreted in bursts, insulin can result in intermittent hypoglycemia
An intact female dog receiving progesterone is at risk for developing what endocrinopathy?
Canine acromegaly
What is the main cause of death in dogs with pituitary dwarfism?
Underdeveloped kidneys causing chronic renal failure
