Lecture 21: Endocrine 3 Flashcards
Where are the parathyroid glands located
2 pairs in the Cr. cervical neck region
lots of species variation
What cells comprise the parathyroid glands and what do they do?
chief cells that secrete parathyroid hormone in response to low blood calcium
It acts on kidney and bone to increase blood calcium
What are the 4 causes of hypoparathyroidism
lymphocytic parathyroiditis
primary or metastatic tumor destruction
parathyroid gland atrophy
iatrogenic (ex. accidental surgical removal)
What are the clinical signs of hypoparathyroidism
hypocalcemia =
- weakness
-ataxia
-tremor
- tetany
- seizure
- restless
What are the 3 types of hyperparathyroidism? What are the main causes?
primary (chief cell neoplasia)
secondary (renal or nutritional)
pseudohyperparathyroidism (hypercalcemia of malignancy)
What species is most affected by hyperparathyroidism? What type of tumor is more common?
old dogs > old cats
adenoma > carcinoma
What are the clinical signs of primary hyperparathyroidism
fibrous osteodystrophy
- increased resorptive bone lesions
hypercalcemia
- NS = weak/lethargy/tremble
- GI = anorexia/v/constipation
- urinary = PU/PD (disrupt ADH impact on kidney) + urolithiasis
What are the gross changes associated with primary hyperparathyroidism? How does it influence the tx/supportive care?
one gland is larger (with tumor) and the others are atrophied
If you remove the tumor
- must supplement PTH and watch for hypocalcemia because the other glands are atrophied
How does renal disease result in hyperparathyroidism?
increased PTH levels because there is low blood calcium
- low GFR = retain P = P+Ca bind = low blood Ca
impaired vit D production
mechanism = disease in a non-endocrine organ
How does nutrition influence development of hyperparathyroidism
3 ways:
- low Ca
- Low vitD
- high P (most common)
all cause low Ca
What is bran disease/big head disease? What species does it occur in?
secondary nutritional hyperparathyroidism due to excessive phosphorus in diet
horses
What are the gross changes associated with secondary hyperparathyroidism
bilateral enlargement of all glands
What are 2 common causes of pseudohyperparathyroidism
lymphoma
anal sac carcinoma
They make PTHrp (PTH analog)
What are the gross changes of pseudohypoparathyroidism
all glands should be small/atrophied
associated C cell/thyroid hyperplasia
What cells comprise the endocrine pancreas and what do they make?
islets of langerhaans
- beta cells = insulin
- alpha cells = glucagon
What are the effects of insulin
decreases blood glucose
muscle and liver and adipose uptake of glucose
anabolic metabolism
What are the effects of glucagon
increases blood glucose
increased energy release
- gluconeogenesis
- glycogenolysis
- lipolysis
What are 4 risk factors for developing equine metabolic syndrome
- easy keeper (pony/donkey/spanish breeds/mustang)
- inactive
- high glycemic index diet (grass)
- obese with regional adipose (neck)
What are the clinical signs of equine metabolic syndrome?
endocrinopathic laminitis
+/-PPID concurrant
What are the 2 types of diabetes mellitus? What species are most affect
type 1/absolute def:
- dogs
- juvenile
- insulin dependent
- autoimmune destruction
type 2/relative def
- cats
- adults
- insulin independent
- impacted by lifestyle/obesity/genetics
- islet amyloidosis
What are the gross lesions associated with diabetes mellitus?
few pancreatic lesions
- except if it was chronic pancreatitis
diagnosis when alive is best
What are the extrapancreatic lesions and signs associated with diabetes mellitus
low body condition
dehydrated
secondary infection: emphysematous cystitis (specific to diabetes mellitus because high sugar urine ferments in bladder)
hepatic lipidosis
bilateral cataracts in dogs (not cats)
chronic renal or retinal disease
rarely
- gangrene
- peripheral neuropathy
What is the most common islet cell hyperfunction and what species does it affect?
insulinomas
ferret (mainly)
- adenoma
dogs
- carcinoma
What are the clinical signs of insulinoma
weak
ataxic
confusion
restless
seizure
coma
death
What is the function of chemoreceptor organs?
sense O2/pH/CO2 in blood to regulate respiration and circulation
What are examples of 2 chemoreceptor organs and where are they located?
base of heart = aortic body
bifurcation of common carotid = carotid body
What is the main disorder of chemoreceptor organs
chemodectoma/paraglanglionoma
What organ do chemodectomas usually affect?
aortic body > carotid body
What animals are primarily affected by chemodectomas and why?
dogs
- bracheocephalics because they are always hypoxic and so the chemoreceptors are constantly being stimulated = increased risk of adenoma or carcinoma
What is the main mechanism of chemodectoma damage?
non-functional but space occupying
- compress thin walled structures like atria and the right ventricle = can cause right sided CHF
