Pituitary Disease And Insulinoma Flashcards
What is the cause of Acromegaly in cats
It’s a rare condition in middle aged to old male cats due to a secretary pituitary neoplasia causing excess of growth hormone.
What does increased growth hormone cause
-Lipolysis
-Decreased tissue insulin sensitivity causing decreased glucose transport causing uncontrollable diabetes mellitus
-increase of insulin-like growth factor 1 - causing chrondrogenesis, protein synthesis, and mitosis of soft tissue
What are the clinical signs of Acromegaly
Diabetes mellitus, organomegaly, prognathism inferior, soft tissue hypertrophy (causing stridor), neurological dysfunction if tumor is getting bigger and compressing CNS
What are some concurrent diseases that you can see in acromegaly patients
Cardiomyopathy, arrhythmias, hypertension, chronic renal failure, DM, joint disease
Acidophil adenoma, cardiac hypertrophy with variation in myocyte diameter, hepatomegaly, renomegaly, hyperplasia of thyroid/parathyroid/adrenal corticies/pancrease
How would you diagnose acromegaly
-Unstable DM even at high doses of insulin (>1U/kg)
-ultrasound changes (organomegaly)
Blood - GH (hard to do), insulin-like growth facto 1 (IGF-1 is easier to measure and should be very increased)
- MRI/CT for definitive diagnosis
How can you treat acromegaly
-radiotherapy of pituitary ((very costly)
-hypophysectomy (will lead to needing to supplement other endocrine secretions which is costly)
- medical management -> insulin (1U/kg BID), ACE inhib (treat proteinuria), diuretics (if acromegaly cardiomyopathy progresses to CHF, pleural/peritoneal fluid) beta blockers (arrhythmias)
- no treatment
How would you treat canine acromegaly
By progestagen withdrawal and/or ovariohysterectomy you should get the decrease of GH where you have clinical improvement
What is pituitary dwarfism
Any defect in the development of the pituitary gland where you have one or multiple pituitary hormone deficiency (remember the anterior pituitary synthesizes six hormones for body function - GH, TSH, ACTH, sex hormones)
What breed is most often represented with the recessive inherited pituitary dwarfism
German Shepards (and breeds with GSD in their lineage like wolfhounds)
What hormones are/aren’t effected in GSD with pituitary dwarfism
They will be deficient in GH, TSH, and sex hormones
ATCH IS PRESERVED! (Will not present like an addisonian)
What are clinical signs of pituitary dwarfism
-PROPORTIONAL DWARFISM
-retention of puppy coat, when they get adult coat will have alopecia and hyperpigmentation
-underdeveloped kidneys -> chronic renal failure
-slow and dull mentation (due to under active thyroid)
Failure of testicular descent or ovulation
How would you diagnose pituitary dwarfism
Failure to respond to pituitary stim tests (low in TSH, GH, FSH, LH)
How do you treat pituitary dwarfism
Thyroid supplements (levothyroxine)
Growth supplement (Porcine GH)
With treatment they live longer than the few years without treatment
What is insulinoma
It is a tumor of pancreatic beta cells (insulin producing cells) will have high levels of insulin REGARDLESS of blood glucose levels
What clin path would you see in insulinoma cases
Normal hematology
Biochem - low blood glucose, possible azotemia
Urinalysis- normal or isothenuria
BP is normal or decreased
INSULIN LEVELS HIGH WHEN HYPOGLYCEMIC
