Uncommon endocrine disorders Flashcards
Pituitary dwarfism is a growth disorder caused by a deficiency of growth hormone
What are the presenting features of a dog with pituitary dwarfism?
Proportional dwarfism, soft wooly hair coat, truncal alopecia sparing head and extremities, hyperpigmentation, pyoderma, cryptorchidism, persistent oestrus
Pituitary dwarfism is a growth disorder caused by a deficiency of growth hormone. Is/are there typically affected breeds?
GSD
What is the difference between proportional and disproportional dwarfism?
Proportionate dwarfs are small but in proportion, in disproportionate dwarfism the animal has a shorter stature than appropriate for head size.
Is there a diagnostic test to help differentiate pituitary dwarfism from other disorders causing stunted growth?
IGF-1 most easily available. GHRH/Clonidine stimulation tests used in research
How does our knowledge of the pathophysiology of metoestrus associated diabetes help us devise an alternative treatment to Growth hormone injections?
We could treat with a progestogen which would induce release of GH into the circulation from the mammary glands.
Acromegaly is a disorder of growth hormone excess. It can be the result of a pituitary adenoma or a result of metoestrus or pharmacological action. The relative frequency depends on the species. Growth hormone is a potent insulin antagonist and so insulin insensitivity is a consequence of acromegaly often to the extent of overt diabetes mellitus.
What are the relative species frequencies (e.g., rare/common/never reported etc)?
Acromegaly is a not uncommon cause of poor diabetic control in cats (persistent high insulin requirement). What is an unusual clinical feature of poor diabetic control in acromegalic cats as compared to diabetic cats with poor diabetic control for other reasons?
They have poor diabetic control but despite that they maintain or increase bodyweight. Poor diabetic control would normally be expected to cause animals to lose weight.
How do dogs and cats differ in the growth hormone response to progesterone?
In the dog, progesterone stimulates GH production in the mammary gland but it leaks into the general circulation. Cat mammary tissue keeps GH local – it doesn’t get into the circulation.
A diabetic cat has acromegaly, what are your treatment options?
Increasing the insulin dose as required to get some control even if this is much more insulin than you would give normal diabetic cats (e.g. dose of 30-40 IU are not unheard of).
More advanced therapies:
- somatostatin (expensive injection – still at research stage);
- pituitary surgery (if you can find one of the <5 international surgeons that do them);
- pituitary radiotherapy
Ferrets commonly get adrenal disease in the form of a functional adrenal tumour.
What is the clinical presentation?
- >3yrs old
- Hair loss
- Vulvar swelling
- Unusual sexual behavior and aggressiveness
- Difficulty urinating
- Lack of energy (lethargy)
- Muscle atrophy
- Skin disorders and itching
Ferrets commonly get adrenal disease in the form of a functional adrenal tumour.
What is different about the endocrinology of this condition compared to classic hyperadrenocorticism due to an adrenal tumour in dogs?
The main product of the ferret adrenal tumour is not cortisol. It is adrenal androgens.
Apart from ferrets what else can get functional adrenal gland tumours?
Cats and dogs
If surgery is not an option for functional adrenal tumours, what medical treatments could be used:
In ferrets?
In a dog with progesterone secreting adenoma?
In aldosteronoma?
In ferrets
Desorelin (Suprelorin)
In a dog with progesterone secreting adenoma
Trilostane (Vetoryl) – inhibits at level of 3hydroxysteriod dehydrogenase
In aldosteronoma
Sprinolactone (Prilactone)
What clinical signs would be expected in a dog with phaechromocytoma?
Pheochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells), or extra-adrenal chromaffin tissue that failed to involute after birth, that secretes high amounts of catecholamines, mostly norepinephrine, plus epinephrine to a lesser extent.
PU/PD, panting, inconsistent hypertension, collapse, dysrhythmia
What other canine endocrine disease could this clinical presentation of a pheochromocytoma be confused with?
PU/PD, panting, inconsistent hypertension, collapse, dysrhythmia
PU/PD panting on a geriatric dog might cause consideration of hyperadrenocorticism as a differential diagnosis, unilateral adrenal mass on ultrasound could further cause confusion between the 2 diseases.
