DO FIFTH Week One: Feline Hyperaldosteronism

what zone of the cortex secretes aldosterone

zone glomerulosa

aldosterone is the primary _____

mineralcorticoid

in principle cells what is aldosterones primary effect

Na resorption/K excretion

in intercalated cells what is aldosterones primary effect

Na/H exchange (Na in, H out)

_______ will also follow sodium in

water

Two biggest drivers for aldosterone release

plasma K

RAAS

when plasma concentrations rise in the bloodstream that will directly stimulate

aldosterone production from the adrenal gland

anything that activates renin release from the kidneys (decreased blood flow, decreased solute delivery to tubules) stimulate

RAAS

_____ and _____has a minimal effect on aldosterone

ACTH and Na

a four year old NM dog is presented to a dialysis service because of AKI resulting in leptospirosis. The dog is anuric, azotemic, and severly hyperkalemic. What is the expected aldosterone concentrations

aldosterone would be high

A 3 year old SF cat was HBC. She has suffered severe blood loss and is hypovolemic and hypotensive what is the expected aldosterone concentration

aldosterone levels would be high

A 7 year old cat with fanconi syndrome and is wasting potassium through her renal tubules. The cat is euvolemic, normotensive, and mildy hypokalemic. What is the expected aldosterone concentrations

aldosterone levels would be low

most cats with functional adrenal tumors _______ is the primary secretory product

aldosterone

in this class we are focusing on primary adrenal disease which means

there is a primary adrenal gland disease thats leading to autonomous secretion of aldosterone independent of normal regulatory mechanisms

what do people call hyperaldosteronism

conn's syndrome

T/F hyperplasia can probably occur in cats but it is really rare

T

when talking about primary hyperaldosteronism in cats we are talking about

functional adrenal tumors

in PHA in cats they have a ______ that is causing their disease

functional adrenal tumor

PHA is a disease of what age

middle aged to older

having hyperaldosteronism can cause what do to the heightened Na/H exchange

metabolic alkalosis

in cats with PHA what is the direct clinical effect of a low potassium

weakness, need K for normal muscle activity so high CK

biochem features of a cat with primary hyperaldosteronism

hypokalemia

metabolic alkalosis

high CK

2 hallmark clinical features of feline PHA

hypertension

polymyopathy

PHA cats are in a state of

volume overload, lots of Na and water in

3 hallmark biochem features of feline PHA

hypokalemia

increased CK

metabolic alkalosis

why is it uncommon to see hypernatremia in feline PHA

water follows with it

33% of these cats have

cervical ventroflexion

25% of these cats have

hind limb weakness

overall what is the driving clinical findings/complaints in these cats (>50%)

non specific weakness and lethargy

the hypertension in cat with PHA usually manifests as

hypertensive retinopathy, visual deficits

what are the other organs that are targets for hypertension

kidneys and heart

what are some possible other clinical fingings associated with hypertension

azotemia

heart disease and murmurs

neurologic signs

T/F in cats with PHA palpable abdominal mass is rare

T

T/F it is very easy to misdiagnosis this in practice as it looks like CKD

T

T/F many cats with PHA are written off as having other diseases

T

if you have ________ you need to think of PHA as a differential

concurrent hypokalemia and hypertension in an older cat

T/F PHA should be considered in cases of isolated hypokalemia or hypertension, think of it at least

T

in a hypokalemic cat which of the following would be suggestive of primary hyperaldosteronism

low renin, high aldosterone, unaffected ACTH

why do we see low renin with the PHA

really high aldosterone from the adrenal tumor will negative feedback and suppress renin

how do we diagnose PHA in a research setting or in humans but is rarely done in clinic

renin:alodsterone ratio

T/F fludrocortisone (oral mineralcorticoid) suppression tests dont work

T

what is the practical diagnosis for PHA

measure serum/plasma aldosterone concentration

when measuring serum/plasma aldosterone concentration you have to measure it in the face of

hypokalemia

nealry all cats with aldosterone secreting tumors have an aldosterone conc of

>1000

another key component of PHA diagnosis is these cats will have what identifiable on sonogram

adrenal mass

T/F you cant test aldosterone levels if you supplement the cat with potassium first

T

________ offers possibility of cure

surgery

why do we not usually do surgery

expensive and older/geriatric cat

for treatment most owners do

medical managment

what can we give that is a calcium channel blocker and an arterial dilator that is an antihypertensive

amlodipine

what else can we do for the PHA cats

supplement them with potassium

does our medical managment of PHA do anything to aldosterone

No

medical management of PHA is

symptomatoc care

the real mainstay treatment of PHA and is the drug of choice

spironolactone

what does spironolactone do

aldosterone receptor antagonist, blocks physiologic effects of excess aldosterone

you have _______ control if your only using potassium and amlodipine for PHA

poor

spironolactone often decreases

dosages of other meds

T/F spironolactone can be used as sole therapy in some cats

T

MST of PHA

6-8 months