Adrenal Disease

Question 1

a 10 yo FS lab presents for recurrent UTIs, PUPD, and increased panting. on urinalysis, the USG is 1.018 and the UPC is 1.5. On blood chemistry she has a high ALT, AST, and ALP. Differentials?

Answer 1

hyperadrenocorticism (cushings)

Question 2

which kind of cushings is more common in dogs, pituitary or adrenal?

Answer 2

pituitary depndent (85), usually a small pituitary pars distalis tumor.

Question 3

iatrogenic cushings is caused by

Answer 3

giving steroids for long periods of time

Question 4

what are the most common clinical signs of cushings in dogs?

Answer 4

PUPD
alopecia
pendulous abdomen
hepatomegaly
polyphagia

Question 5

pituitary dependent cushings is more common in younger or older dogs? larger or smaller dogs?

Answer 5

younger and small dogs: pituitary

adrenal is often older and bigger dogs

Question 6

true or false: most cushings dogs come to you happy and not ill

Answer 6

true! some owners might not bring the pet in because their dog seems just fine at home and they think it’s just overweight or changes more common in old dogs like accidents in the house and PUPD

Question 7

a 12 yo cockapoo comes to you with PUPD, a big belly, and some bilateral alopecia on the flank. You suspect cushings. what changes on chemistry and urinalysis panel would confirm your suspcision?

Answer 7

high ALP, high ALT, hyperlipidemia, USG lower than 1.020, UPC>1 (proteinuria)

Question 8

list some diferentials for an ALP that is higher than an ALT?

Answer 8

endocrinopathy, diabetes mellitus, cholangitis, cholestatis disease, cholecystolith, steroids, phenobarb, chronic hepatopathies, neoplasia

Question 9

why do dogs with cushings have a high ALP, high ALT, high lipids, and isosthenuria?

Answer 9

ALP: steroid isoenzyme is induced with cortisol
ALT: swollen hepatocytes and glycogen accumulation
Lipids: lipolysis=high TG and high cholesterol
isosthenuria: diruesis

**note we dont know why they get proteinuria

Question 10

besides CBC/chem and urinalysis, what are some other diagnostics to confirm cushings in dogs?

Answer 10

blood pressure: many will be hypertensive
urine culture: up to half of dogs have UTIs that are silent due to flushing

screen for hypothyroid, make sure they dont have it

Question 11

what might you suspect to see on ultrasound in a suspected cushing dog?

Answer 11

hepatomegaly, can check for gallbladder mucocele, can check adrenal gland size

Question 12

why do cushings dogs show bronchial and tracheal ring mineralization and potential pulmonary thromboembolism?

Answer 12

they are in a hypercoagulable state from the cortisol which increases a bunch of the coagulation factors

Question 13

what is the difference between a screening test and a differentiating test for cushings? list examples of tests under both categories

Answer 13

screning: do they have cushings or not?
- LDDST (sensitive), ASTH stim (specific), urine cortisol creatinine test (sensitive)

differentiating: what kind of cushing do they have?
- LDDST (4 hr suppression), abdominal ultrasound, HDDST (almost never done anymore)

Question 14

explain the urine cortisol to creatinine ratio test for cushings

Answer 14

it’s not the best test, although it’s sensitive, it is not very specific (anything causing stress can make it high), I am unlikely to use this test but is an option, owner can bring a urine sample from home

Question 15

describe the ACTH stim test for cushings

Answer 15

measures the response of adrenal glands in response to ACTH, it tests the adrenal reserve. in cushings dogs they will have an exaggerated response (except if it’s iatrogenic).

You give synthetic ACTH and then collect blood at 1 hour post.

think of the dog knocking on the doors and the doors open and overflow with excess cortisol. adrenals are JACKED ASF

Question 16

the ACTH stim test is specific but not sensitive, which means

Answer 16

you can miss some cushings but if it’s positive, the patient likely has cushings

Question 17

true or false: ACTH stim test can differentiate between pituitary and adrenal cushings

Answer 17

false

Question 18

describe the LDDST 8hr test for cushings?

Answer 18

low dose dex suppression test: the bread + butter test :)

normal animals, if given dex (a steroid), should have negative feedback and suppress ACTH and therefore suppress cortisol

in cushings animals there is little or no suppression

it is sensitive but less specific so if it’s negative it’s less likely to be cushings

Question 19

proper way to interpret a LDDST?

Answer 19

sample at 4hrs and 8 hrs

look at the 8 hr number first: it’s considered cushings if cortisol is higher than the lab reference

then look at the 4 hr number: most of the time if there is suppression at 4 hr with an increase at 8 hr this indicates pituitary dependent (essentially it dips down and then goes back up, 50% suppression or greater)–>pituitary dependent retains some ability for negative feedback with exoogenous steroids. this does not happen with adrenal dependent

Question 20

how does an endogenous ACTH test work

Answer 20

with pituitary cushings, endogenous ACTH is high because the pituitary is producing it

with adrenal cushings, endogenous ACTH is low because of the negative feedback and excessice cortisol production

Question 21

why isn’t the endogenous ACTH test done more?

Answer 21

it’s super expensive and the samples are fragile and need to be shipped in a special vial, it is not practical

Question 22

the main treatments used for cushings are

Answer 22

trilostane*** and mitotane–>reduce adrenal reserves to what you need. this takes weeks to months to work

could do a hypophysectomy but it’s complicated and not often done

Question 23

how does trilostane work? what are some potential complications of the drug?

Answer 23

it is a competitive inhibitor of beta hydroxysteroid dehydrogenase enzyme which inhibits the production of progesterone and therefore the production of cortisol (and a little bit aldosterone)

possible adrenal suppression for months if overdosed, adrenal necrosis, mild hyperkalemia from aldosterone suppression, adrenal atrophy

Question 24

you diagnose a 10 yo dog with cushings and decide to start the dog on trilostane. how will you monitor the dog going forward?

Answer 24

start at 1mg/kg q12 with food, then recheck in 7-10 days, 4-6 hours after the morning dose. We want to see the results of the ACTH stim to be decreased ( we are trying to decrease the adrenal reserves).

if it’s between 70 and 250 and there’s improved clinical signs, keep the dose the same. If it’s between 70 and 250 and there’s no improvement in clinical signs, give it one more month and recheck. If it’s higher than 250, increase dose by 25% and re check in a week. And if it’s below 70, stop the med and start pred (youve given the dog addisons now)

Question 25

how does mitotane work?

Answer 25

it has a cytotoxic effect on the adrenal cortex and kills the adrenal glands

it is considered the “old” drug and it can induce addisons

Question 26

should you use trilostane or mitotane?

Answer 26

depends on owner compliance, cost, and comfort. Trilostane is way more expensive but is the “newer” drug. Both treat the disease well, and both can have complications. Trilostane is often chosen first

Question 27

an owner brings their dog Pal to you and you diagnose cushings. the owner is very overwhelmed and explains to you they have very limited funds and cannot afford trilostane. What treatment options are there?

Answer 27

we focus on treating the most common complications: hypertension and proteinuria. the dog will however continue to be PUPD and polyphagic.

Question 28

true or false and explain why: cushings is a benign disease

Answer 28

false!!

common complications: hypertension, bladder stones (more calcium excretion, calcium stones), UTIs, proteinuria, diabetes due to insulin resistance, hypercoagulability, mucocele

Question 29

true or false: feline cushings is common

Answer 29

false, but when it happens, it’s really bad. they are usually also diabetic

Question 30

what’s the difference between typical addison’s and atypical addisons?

Answer 30

typical: deficiency of both mineral and glucocorticoids, way more common
atypical: deficinecy of just glucocorticoids

Question 31

why are addison’s dogs “sick”?

Answer 31

mineralocorticoids normally cause sodium reabsroption and potassium secretion

glucocorticoids normally control metabolism, cellular stability, and the stress response. essentially effects anything.

addison’s patients dont have enough of either of these

Question 32

what causes addison’s?

Answer 32

immune mediated adrenalitis most commonly

iatrogenic (gave too much steroids and cause adrenal atrophy)

Question 33

common signalment for addison’s?

Answer 33

poodles, duck tollers, protugese water dog, bearded collie

females

young dogs, average 4 years

Question 34

clinical signs of addisons?

Answer 34

vague waxing and waning signs: anorexia, vomiting, lethargy, diarrhea, weight loss, weakness, shivering, dehydration, bradycardia, shock

it can be ANYTHING

Question 35

a 4yo poddle named Booger comes to you with waxing and waning vomiting and diarrhea. Her heart rate is 60 and she has a body condition score of 3/9. What CBC/chem findings would you expect based on the top differential?

Answer 35

lack of a stress leukogram, hyperkalemia, azotemia (dehydration), USG less than 1.030 (they dont have enough sodium), could have hyponatremia, hyperphosphetemia, many more too.

Question 36

you do a CBC chem on Booger and find lack of a stress leukogram and an Na/K ratio of 18. what diagnostic test will you do now?

Answer 36

ACTH stim test: if post cortisol is above 55 it’s unlike to be addisons, and if its below the detection limit, Booger has addisons.

could also consider a baseline cortisol test: if it’s below detection limit, addison’s is confirmed.

Question 37

if the Na/K ratio is less than 24, you should ALWAYS do what test

Answer 37

an ACTH stim because this is highly suggestive of addison’s

Question 38

a duck toller named Fwimsy comes to you in shock. the owner says she’s been vomtting recently on and off and has been acting a bit lethargic. You suspect addions disease. how will you treat Fwimsy in her acute crisis? (assume typical addisons)

Answer 38

IV fluids: treat the shock with a 10ml/kg bolus over 5 mins and restore normal electrolytes

Dexamethasone: 0.1-0.1mg/kg IV (dex does not interfere with cortisol testing)

fix the hyperkalemia: calcium gluconate, dextrose, insulin, can start mineralocorticoids but not right away

usually 1-2 days in hospital and then can go home.

Question 39

why dont we use 0.9% NaCl to treat addisons?

Answer 39

it is acidifying, it squishes bicarb

Question 40

what mineralocorticoid options are there for addisons patients?

Answer 40

Fludrocortisone and DOCP

DOCP is often chosen most of the time, it is an injection every 25 days and it’s easier than pills. You give them pred at the same time. more expensive.

Fludcrocortisone is an oral pill and there’s only 1 size so big dogs need like 6 pills twice a day. more annoying. also has some gluco action not just mineralo. So you could consider stopping pred on this one.

Question 41

true or false: owners should increase the pred dose during stressful situations for addison’s patients

Answer 41

true! double the dose the day before, during, and the day after. this mimics normal physiology

Question 42

how often should you monitor addions’s patients?

Answer 42

1 month after discharge: do bloodwork, we want Na/K above 27 (if it’s below 24 you may need to increase DOCP dose). then every 3-6 months at the time of a DOCP injection

Question 43

true or false; there is no way to effectively monitor atypical addions

Answer 43

true! just based on clinical signs

Question 44

true or false: pred interferes with cortisol testing

Answer 44

true