Endocrine

Question 1

chemistries related to endocrine

Answer 1

electrolytes and hormones

Question 2

electrolytes related to endocrine

Answer 2

Na: hyponatremia seen in renal failure, vomiting, diarrhea, use of diuretics, excessive ADH, CHF, water toxicity, excessive fluid administration
K+: hyperkalemia seen in adrenal cortical hypofunction, late stage renal failure, and acidosis

Question 3

hormones related to endocrine

Answer 3

thyroxine (T4) functions: increases cell metabolism, affects growth/development, reproduction, resistance to infection
triiodothyronine (T3): produced by thyroid gland through deiodination of T4, has more biologic activity
TSH: helps sustain thyroid gland and stimulates it to produce T3 and T4
TRH (thyrotropin-releasing hormone): triggers TSH release
glucagon: increases serum sugar concentration
insulin: decreases serum sugar concentration

Question 4

common endocrine diseases

Answer 4

thyroid (hyper/hypo), diabetes mellitus, hyperadrenocorticism, hypoadrenocorticism

Question 5

hyperthyroidism basics

Answer 5

common in cats
98% of cases are caused by benign functional thyroid adenoma, 2% of cases are caused by malignant thyroid carcinoma

Question 6

hyperthyroidism feedback loop

Answer 6

hypothalamus produces TRH (thyrotropin-releasing hormone) — TRH stimulates pituitary gland to release TSH — TSH stimulates thyroid gland to produce T3/T4 — T3/T4 go into the serum

Question 7

hyperthyroidism CS

Answer 7

weight loss, polyphagia, vomiting, diarrhea, polydipsia, tachypnea, hyperactivity, dyspnea, aggression, thickened nails
metabolism is increased so you will most likely see an angry/hyperactive cat that is losing weight and eating a ton

Question 8

hyperthyroidism dx

Answer 8

total T4 (measures all T4 in body: bound and unbound), free T4 (best!!, measures only unbound T4), T3 suppression test, TRH stim test

Question 9

hyperthyroidism tx

Answer 9

thyroidectomy (careful not to mess with parathyroid gland –> hypocalcemia
radioactive iodine, meds (methimazole decreases production of T3/T4, pill or transdermal 2 times a day), diet (Hill’s y/d iodine free diet)
anything outside of surgery or radioactive iodine needs B/W done every 2-3 weeks for 3 months, then annual or bi-annually

Question 10

hypothyroidism basics

Answer 10

common in dogs
autoimmune - body attacking thyroid gland causing decreased T3/T4 production or can be idiopathic

Question 11

hypothyroidism CS

Answer 11

decreased activity levels, increased body weight, skin/haircoat changes (alopecia, hair thinning, hyperpigmentation), tragic facial expression, reproductive failure (no heat), bradycardia, megaesophagus

Question 12

hypothyroidism dx

Answer 12

total T4, free T4, TSH levels, TRH stim test
total T4 is ideal and confirm with free T4

Question 13

sick euthyroid syndrome

Answer 13

patient could show a decreased T4 on blood work if animal is sick but the animal doesn’t have hypothyroidism
confirm by doing another T4 when animal is healthy

Question 14

what is an important thing to know about medicine for hypothyroidisim?

Answer 14

human hypothyroid meds are in mcg but dog hypothyroid meds are in mg
can not give a dog human meds!!

Question 15

hypothyroidism tx

Answer 15

supplement thyroid hormones
Levothyroxine
do bloodwork every 6 weeks for 6-8 months then annually or bi-annually
do bloodwork 6 hours after patient takes a pill

Question 16

diabetes mellitus (DM) basics

Answer 16

disorder of fat, carbs, and protein metabolism caused by absolute or relative insulin deficiency
beta cells secrete insulin
alpha cells secrete glucagon
type 1: pancreas doesn’t produce insulin
type 2: cells don’t respond to insulin properly
often seen concurrent with pancreatitis

Question 17

diabetes cell insulin mechanics

Answer 17

when there is glucose floating through the blood, pancreas beta cells secrete insulin — insulin binds to an insulin receptor on a cell and the cell becomes more permeable to glucose — glucose from the bloodstream can now flow into the cell and give it energy to perform its functions in the body

Question 18

diabetes CS

Answer 18

polyphagia, polyuria, polydipsia, sweet breath, weight loss, lethargy, cataracts (dogs)
can see plantigrade stance in cats (will be on flat feet on hindlegs, whole part of leg distal to hock will be flat on ground) – caused by weakness in muscle tissue = diabetic neuropathy

Question 19

normal blood glucose level

Answer 19

70-140 mg/dL

Question 20

diabetes dx

Answer 20

blood sample
can’t tell you which type of diabetes
make sure to spin the sample right after it clots in serum separator tube so the cells don’t eat up all the glucose and lead to false negative

Question 21

diabetes tx

Answer 21

insulin SQ BID, titrated to effect
types of insulin: rapid absorbed - R on label, regular insulin
intermediate acting - NPH, N, or Lente “L” on label
long acting - U or PZI on label

Question 22

glucose curve

Answer 22

used to monitor blood glucose levels, measures fructosamine levels
prick for blood or do blood draw
take baseline — eat — insulin — test every 2-4 hours
glucose curve should go down, hit nadir, then climb back up
one curve is complete when it hits nadir
insulin not working anymore when the curve climbs back up

Question 23

client education for diabetes

Answer 23

teach client proper dose and how to admin insulin, proper storage/mixing of insulin, diet and when to admin, when not to admin

Question 24

diabetic ketoacidosis (DKA) basics

Answer 24

when carbs aren’t available cells will go after fats/protein which makes ketones as a byproduct
liver normally keeps ketones in check but excessive amounts leads to DKA

Question 25

DKA CS

Answer 25

dull mentation, vomiting, PUPD, anorexia, tachypnea, lethargy, tachycardia, recumbent
dehydration can lead to hypovolemia: pale mm, prolonged CRT, weak pulse

Question 26

DKA dx

Answer 26

biochems and urinalysis
hyperglycemia, glucosuria, ketonuria, ketonemia, electrolyte imbalances

Question 27

DKA tx

Answer 27

main goal: stop ketone production
give IVF through large bore catheter, give insulin CRI (yellow bottle of regular insulin)

Question 28

Cushing’s disease: hyperadrenocorticism (HAC) basics

Answer 28

increased cortisol which is a steroid hormone type and the stress hormone
causes: tumors on adrenal gland or pituitary gland, or we give too much steroids (can happen with allergy patients being treated with steroids) – called iatrogenic Cushing’s dz

Question 29

Cushing’s feedback loop

Answer 29

ACTH (adrenocorticotropic hormone) from pituitary gland stimulates cortisol production from adrenal cortex
high cortisol levels = decreased CRH (corticotrophin releasing hormone) from hypothalamus = decreased ACTH from pituitary

Question 30

Cushing’s CS

Answer 30

pot-bellied appearance, polyphagia, PUPD, thinning haircoat and skin, muscle weakness
diffuse alopecia - hair gets thinner, hyperpigmentation, rat tail (no hair on tail)
pot-belly appearance caused by muscle weakness so abdominal muscles are weak and organs aren’t sitting right

Question 31

Cushing’s dx

Answer 31

biochems - elevated liver enzymes, low S.G. on urinalysis
screen for urine cortisol:creatinine ratio and confirm with LDDST
LDDST = low-dose dexamethasone suppression test: measures cortisol
- collect baseline serum sample – inject Dexamethisone IV catheter – sample 4hr post injection – sample 8hr post injection schedule 1st thing in the morning positive = no suppression of cortisol

Question 32

Cushing’s tx

Answer 32

some patients can live a good life without treatment so think about QOL, if treatment risks outweigh benefits
mitotaine (Lysodren) (chemo drug!! that selectively destroys adrenal gland, wean on - too much causes iatrogenic Addison’s), Trilostaine, Anipril

Question 33

breeds predisposed to hypothyroidism

Answer 33

Boxers, Dobermans, Goldens

Question 34

breeds predisposed to Addison’s

Answer 34

Great Danes, Westies

Question 35

Addison’s: hypoadrenocorticism basics

Answer 35

deficient in glucocorticoids and mineralocorticoids
most commonly effects dogs, young-middle aged females
causes can be idiopathic, iatrogenic following withdrawal of long-term steroids, drug overdose related

Question 36

Addison’s dz CS

Answer 36

anorexia, vomiting, diarrhea, PUPD, weakness, collapse, shaking, addisonian crisis

Question 37

Addison’s dx

Answer 37

ACTH stim test - there will be failure to stimulate and no increase in cortisol, electrolytes - high potassium/low sodium, urinalysis - isoethenuria or low SG

Question 38

addisonian crisis

Answer 38

signs: pale mm, increased CRT, weak pulse
stabilize with large bore catheter isotonic IVF, supplement potassium (KCL-) and steroids (Dexamethasone sodium phosphate - fast acting steroid)

Question 39

Addison’s tx

Answer 39

mineralocorticoid
forms: Fludrocortisone po BID or Percortin-V (DOCP) injection IM q25 days (can be very expensive for larger dogs)
prednisone can also be given to replace glucocorticoids before a scary event because stress can cause an addisonian crisis

Question 40

how do you perform an ACTH stim test?

Answer 40

give synthetic ACTH to see how it affects feedback loop
baseline sample — inject synthetic ACTH cortrosyn — sample 1-2 hours after injection

Question 41

Addison’s feedback loop

Answer 41

decreased steroids = decreased cortisol = decreased glucocorticoids (corticosteroids)
also = decreased aldosterone (mineralocorticoids) = increased Na and decreased K+ = bradycardia and arrhythmias