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Endocrine

Terms in this set (49)

Blood glucose in the fasting state is maintained by decrease in which hormone?
↓Insulin → ↓peripheral utilization of glucose
In the fasting state, increase in hepatic gluconeogenesis and glycogenolysis is stimulated by which hormones?
Epinephrine and glucagon - released early in response to low blood sugar

Growth Hormone and Cortisol - released later in response to low blood sugar.
Normal dogs can fast up to _________ number of days without alterations in their serum biochemistry profile.
30 days
So fasting could result in low normal but not hypoglycemia.
What is the normal Blood glucose range in a dog?
80 to 120mg/dL
This is a cause of hypoglycemia in young small breed dogs due to higher energy requirements.
Puppy Hypoglycemia
Puppies have 2-3 x higher energy requirements than adults. Limited glycogen and body fat stores compromising substrate availability for gluconeogenesis and glycogenolysis
A rare congenital hepatic enzyme deficiency due to which animals cannot convert glycogen o glucose is called?
Glycogen storage disease
Name an endocrine disorder that leads to hypoglycemia?
Hypoadrenocrotisism/Addisons
Cortisol deficiency results in impaired hepatic gluconeogenesis and increased peripheral uptake of glucose. Present in about 20% of the cases
This type of tumor may be associated with hypoglycemia due to secretion of a polypeptide that has insulin like activity.
Non pancreatic tumors
Usually of mesenchymal origin such as hepatoma, fibrosarcoma, hemangiopericytoma
This functional tumor episodically elaborates insulin production regardless of the blood glucose level.
Insulinoma
Beta cell tumor of the pancreas.
May respond excessively to glucose load (post prandial)
This is the most common cause of hypoglycemia in the adult dog.
Insulinoma
Name a species other than dogs in which insulinomas are more commonly seen.
Ferrets
Animals with significant functional loss of this organ exhibit hypoglycemia.
Liver
(liver disease, animals with PSS)
Can test bile acids to confirm if suspect hepatic disease
Deficiency in this hormone can cause ↓ in hepatic glucose production and facilitate peripheral uptake of glucose leading to hypoglycemia.
Growth hormone deficiency
GH normally antagonizes the actions of insulin
Dog breeds at higher risk for insulinomas:
Standard poodles, boxers, Fox terrier, GSD, irish terrier
Most diagnostic method of insulinoma
normal or increased insulin levels in the face of hypoglycemia
Usually have to fast 8 to 48 hrs...to wait for the animal to be hypoglycemic.
Fulfilling criteria of:
i. neurologic signs
ii. that occur during hypoglycemic state
iii. that resolve by exogenous glucose administration
is called ________________________, and is used as a diagnostic tool for Insulinomas.
Whipple's Triad
These hormones influence cellular metabolism in multiple organs by increasing the metabolic rate.
T4 thyroxine and T3 triiodothyronine
Most common endocrinopathy affecting cats >8 years (older)
Hyperthryroidism
Fluffy butters, Mrs. McPuffin's aggressive cat, presents for weight loss even though she is eating well, if not better. She is tachycardic, palpable thyroid and has a heart murmur upon physical exam. What diagnostic test are you thinking about other than a CBC, Biochem and UA?
Basal T4

This is the best, easiest and most reliable means of diagnosing hyperthyroidism.
T3 levels are less reliable indicators of disease
fT4 levels - useful in cats with concurrent illness.
Mid to high end of normal T4 + ↑fT4 = hyperthyroid
Normal to low end of T4 + ↑fT4 = euthyroid sick syndrome (this is when concurrent illness may falsely increase the fT4. Thyroid is not diseased.
What can you do in cases you highly suspect to be hyperthyroid and T4 repeatedly tests normal and fT4 is not available?
T3 suppression test
The normal pituitary - thyroid axis is suppresses following supplimentation with T3.
Protocol:
Take baseline T4 and T3
Give 25mcg T3 orally 3 times a day for 2 days
On day 3 give the 7th dose and 2 to 4 hours later test T3 and T4 levels.
T3 increases but T4 does not increase = Hyperthyroid
T3 increased and T4 decreases or suppresses to >50% of pretreatment value = Normal
This is a curative but irreversible treatment for hyperthyroidism in cats.
Bilateral Thyroidectomy
Wont work if there are mets or ectopic tissue
Spare the parathyroid or risk post op hypocalcemia
This is considered the gold standard treatment for hyperthyroid cats.
Radioactive Iodine I131 therapy.
Especially for cases with thyroid adenocarcinoma and metastasis (treated at a higher dose)
Typically cured with one dose (>95%) only carcinoma cats require a 2nd higher dose.
What is the oral drug of choice for hyperthyroidism?
Methimazole (Tapazole)
BUT you need to pill your cat EVERY DAY! Yeeowzers!!!!
10 year old, male, neutered Boxer, Ali, presents for recently becoming disinterested in his food and it started after he "vomits" right after he eats. On PE, you find is a firm, non-movable mass. You aspirate it on cytology it is non diagnostic due to contamination with blood. CBC , chemistry and UA are WNL. T4 level is WNL.
What would you like to do?
Rads - looking for ectopic thyroid tissue or mets.
Pertechneate scan - this helps in location thyroid tissue and this does not indicate functional hyperthyroidism.
This type of hyperadrenocortisism accounts for >85% of all the cases.
Pituitary dependent
50% of tumors in this type of hyperadrenocortisism are benign(adenomas) and 50% are malignant.
Adrenal dependent
The malignant tumors tent to be larger, more invasive and tend to metastasize to the lungs and liver. They episodically secrete large amounts of cortisol and cause atrophy of the contralateral adrenal gland
If you have a case of a dog with hypertension, calculi, glomerular disease and dibetes mellitus, what endocrine disease should you consider even though the animal shows no classic signs.
Silent manifestation of hyperadrenocortisism
a 9 year old mini schnauzer presents with PU/PD/PP and has hyperpigmentation and comedones on the skin, has bilateral symmetrical truncal alopecia and superficial pyoderma. What is your most likely doagnosis.
Cushings Disease
What tumor is caused in females and neutered males as a result of cushings disease.
Perianal adenomas
This may be due to the overproduction of androgens.
What is a common abnormality found on UA of a cushinoid animal.
USG of <1.014 (due to polyuria)
Proteinuria (glomerular disease) treating cushings may reverese glomerular disease.
What is the most common Biochemistry abnormality seen in a cushinoid cat?
Hyperglycemia
What biochemistry abnormalities may be seen in a dog with hyperadrenocortisism (Cushings)
1) ↑ ALP not accompanied by hyperbilirubinemia
2) ↑ ALT (mild to moderate) due to glycogen accumulation/ mild hepatic necrosis
3) Hypercholestrolemia (glucocorticoids promite fat catabolism)
Name 2 primary screening tests for hyperadrenocortisism
1) Low dose dexamethasone test
2) ACTH stim test
This screening test for Cushings disease is extremely sensitive (>95%, but less specific, potentially discriminating between the type of hyperadrenocorticoidism and cheaper but takes longer.
Low dose dexamethasone suppression test (LDDST)
This screening test for Cushings disease is extremely sensitive (>95%, but less specific, potentially discriminating between the type of hyperadrenocorticoidism and cheaper but takes longer.
Low dose dexamethasone suppression test (LDDST)
Which test is most helpful when difeerentiation PDH from ADH
High dose dexamethazone suppression test

- In PDH, high dose will overcome resistance of the pituitary tumor to -ve feedback mechanisms and suppression of ACTH occurs with a resultant drop in post cortisol levels is noted.
- In ADH, ACTH levels are already at zero due to the constant high levels of glucocorticpids from the adrenal tumor
What medical therapy is used for the treatment of PDH, ADH and atypical hyperadrenocortism and acts to cause severe progressive necrosis of the zona fasiculata and reticularis but spares the zona glomerulosa.
Mitotane (Lisodren) o,p'-DDD
This is the most common form of diabetes mellitus in dogs
Insulin dependent Diabetes Mellitus
This is the most common form of diabetes mellitus in cats
Non-insulin dependent Diabetes Mellitus
The type of Diabetes Mellitus where medications or concurrent insulin antagonistic diseases and is characterized by hyperinsulinemia.
Type III DM
Hyperadrenocortisism is the most common disease that causes this type of DM
Molly, a 7 year old female spayed mixed breed dog presents for PU/PD/PP, weight loss. Owner says that she think Molly may be losing her eyesight. What is the one chemistry parameter you are really interested in?
Glucose
All the above cilnical signs with persistent fasting hyperglycemia and glucosuria lead to the definitive diagnosis of Diabetes Mellitus
If you have a cat with diabetes mellitus that you are having difficulty regulating, what other test would you like to do?
Thyroid hormone levels
To rule out concurrent hyperthyroidism.
11 year old male castrated cat: PU/PD for 2 months. Anorexia and lethargy more recently.
CBC abnormalities:
Segs 15.0 (2.5 - 12.5)
Bands 2.4 (0 - 0.3)
Lymphocytes 0.9 (1.5 - 7.0)

Biochemical Profile abnormalities:
Glucose 766 (67- 124)
Cholesterol 388 (60 - 220)
ALT 124 (30 - 100)

Urinalysis:
Color Yellow
Transparency Cloudy
Sp. Gr 1.034
Protein 2+
Glucose 2+
pH 5
WBC 6 - 8
Ketones neg
Crystals neg
Bacteria neg

What is your most likely diagnosis?
Diabetes mellitus
Cats diagnosed with DM should have _________________restricted diet and dogs should have ___________ levels of complex carbohydrates in their diet.
carbohydrate, high
True/False: Urine glucose is an excellent parameter to adjust insulin dose in the treatment of Diabetes mellitus.
FALSE
It should NOT be relied upon for adjustment of insulin dose
Excessive insulin administration results in hypoglycemia and sunsequent reboun hyperglycemia. This is called the...
Somogyi effect
(insulin induced hyperglycemia)
__________________ is characterized by dehydration, metabolic acidosis, kenotnuria, ketonemia and hyperglycemia.
DKA
_______________ is characterized by extreme dehydration, renal disfuction, abnormal brain function, marked hyperglycemia and the lack of significant ketoacidosis.
Hyperglycemic Hyperosmolar Syndrome
The development of HHS is attributed to 3 main factors:
1. ↓insulin utilization and glucose transport
2. ↑hepatic gluconogenesis and glycogenolysis (used to make triglycerides)
3. impaired renal excretion of glucose
10 year old MC feline DSH that is not eating well and is lethargic. Slightly dehydrated upon physical exam.
CBC abnormalities
Segs 13 (2.5 - 12.5)
Lymphocytes 0.3 (1.5 to 7.0)
TP 9.0 (6 - 8)

Biochemical Profile Abnormalities
Glucose 328 (67 - 124)
Alb 4.3 (2.3 - 3.9)
ALT 282 (30 - 100)
TCO2 10.5 (14 - 23)

Blood Gas Data
pH 7.28 (7.33 - 7.44)
PCO2 20.0 (35 - 42)
PO2 85.5 (73 - 92)
HCO3 9.2 (16 - 22)
Ionized Ca 4.64 (4.8 - 5.3)

UA
Sp Gr 1.033
Protein 1+
Gluc 4+
Blood 1+
pH 6.0
Ketones 3+

Most likely diagnosis?
DKA
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