ENDOCRINE DISEASES Flashcards
WHAT IS THE NORMAL WATER INTAKE?
60-100ml/Kg/24 hrs
what is the normal urine output?
20-45 ml/Kg/24hrs
what is diabetes insipidus?
insufficient ADH secretion/ action causing inadequate urine concentration.
define polyuria
> 50ml/Kg/ 24hrs
define polydipsia
> 100 ml/Kg/ 24hrs
A 5-year-old male neutered Domestic Short haired cat presents for ongoing evaluation of Diabetes Mellitus. The cat was diagnosed 6 months ago and has continued to be markedly polyuric, polydipsic, polyphagic and losing weight. The owner noted that the cat’s head seems to be larger than her other cats.
- State two concurrent diseases that can be causing insulin resistance in this case.
hyperadrenocorticism (Cushing’s disease) and acromegaly.
state the usual ranges for USG in fenine, canine and large animals
feline….. 1.035- 1.060 ….. (>1.040)
canine…….1.015- 1.045……(>1.030)
large……1.015-1.030………(>1.025)
LIST THREE THERAPIES THAT CAN BE USED FOR BOTH CENTRAL AND NEPHROGENIC DIABETES INSIPIDUS
- CHLOROTHIAZOLE……THIAZIDE DIURETIC
- DIETARY SODIUM RESTRICTION
- DESMOPRESSIN ACETATE…..SYNTHETIC ADH
LIST FIVE CLINICAL SIGNS TYPICALLY ASSOCIATED WITH DIABETES INSIPIDUS
- POLYURIA
- POLUDIPSIA
- WEIGHT LOSS
- NOCTURIA
- RECURRENT UTIs From diluted urine
OTHERS…….INSATIABLE THIRST, ANOREXIA, REZTLESSNESS, INCONTINENCE
STATE THE TWO MAIN TYPES OF DIABETES INSIPIDUS AND DESCRIBE THEIR PATHOGENESIS
- CENTRAL…….decreased ADH secretion
- NEPHROGENIC……DECREASED ADH ACTION DUE TO RENAL TUBULAR RESISTANCE
STATE THE CLINICAL SIGNS ASSOCIATED WITH PITUITARY OR HYPOTHALMIC TUMOURS ASSOCIATED WITH DIABETES INSIPIDUS AND STATE THE PROGNOSIS……WHICH FORM OF DIABETES INSIPIDUS IS THIS ASSOCIATED WITH?
- VISUAL DEFECITS
- SEIZURES
- INCOORDINATION
PROGNOSIS…….GRAVE….ESPECIALLY IF TUMOURS ARE GROWING
STATE THE PROGNOSIS FOR CENTRAL AND NEPHROGENIC DIABETES INSIPIDUS
GOOD WITH TREATMENT FOR CENTRAL
GUARDED WITH NEPHROGENIC
state five causes of secondary NEPHROGENIC diabetes insipidus
- pyelonephritis
- hyperadrenocorticism
- hyperthyroidism
- pyometra
- hypokalemia
state four methods of diagnosing diabetes INSIPIDUS and the parameters to look for in each test.
- biochem…….hyponatremia, hypokalemia
- urinalysis….isosthenuria, hyposthenuria
- modified water deprivation test…….USG is unchanged I. a clinically dehydrated animal
- DDVAP …DESMOPRESSIN ACETATE STI ULATION TEST…..INCREASED USG AND REDUCED WATER CONSUMPTION…..DIAGNOSTIC FOR CENTRAL DI.
STATE THE TYPICAL SIGNALMENT FOR CUSHINGS …….BE SPECIFIC
HYPERADRENOCORTICISM
…..SEEN IN DOGS MORE THAN CATS
….. CATS NORMALLY ALSO GET A DIABETES
….. SEEN MOSTLY IN MIDDLE AGE TO OLDER ANIMALS….MORE THAN SIX YEARS
WHAT ARE THE THREE MOST COMMON. AETIOLOGIES ASSOCIATED WITH CUSHING’S DISEASE…BE SPECIFIC, EXPLAIN THE PATHOPHYS
- PITUITARY DEPENDANT HYPERADRENOCORTICISM
MOSTLY A PITUITARY ADENOMA…BUT CAN ALSO BE A PITUITARY ADENOCARCINOMA OR A PITUITARY HYPERPLASIA.
THIS CAUSES EXCESSIVE ACTH SECRETION
THIS CAUSES BILATERAL ADREOCORTICAL HYPERPLASIA
THIS CAUSES EXCESSIVE CORTISOL - ADRENOCORTICAL DEPENDANT HYPERADRENOCORTICISM
USUALLY AN ADRENAL CARCINOMA OR ADENOMA
USUALLY UNILATERAL RESULTING IN THE CONTRALATERAL BEING ATROPHIED
ADRENAL TUMOUR RESULTS IN EXCESSIVE CORTISOL RELEASE. - IATROGENIC
EXCESSIVE OR PROLONGED CORTICOSTEROID USE THAT LEADS TO ATROPHY OF ADRENAL CORTICES
what are the 8 main clinical signs associated with CUSHINGS?
the 8 Ps:
1. polyuria …80% of cases
2. polydipsia…..80% of cases
3. panting…….mineralization of airways
4. pot belly/ pendulous abdomen
5. polyphagia…..90% of cases
6. hyperpigmentation /calcinosis cuti
7. pacing….neurological signs for macroadenoma in PITUITARY…..ataxia, incoordination
8. pyoderma/ poor wound healing due to immunosuppresion
list the 6 non-specific screening tests that can be used in a suspected cushing’s case, and state the specific parameters to look for.
- urinalysis……glucosuria; proteinuria; hyposthenuria/isosthenuria; recurrent UTI
- CBC…stress leukogram: leukocytosis, monocytosis, eosinopenia, neutrophilia, lymphopenia
- biochemistry……elevated ALP and ALT; hypercholesterolemia; low total T4
- abdominal ultrasound——-adrenal HYPERPLASIA/atrophy
- MRI……PITUITARY tumours
- CT scan…..PITUITARY tumours
explain how cushing’s affects the total T4 value
increased CORTISOL secretion suppresses the TSH secretion which is responsible for T4, therefore total T4 is low
why would a patient with cushings be mildly hyperglycemic and have glucosuria?
hyperglycemia due to increased gluconeogenesis in the liver due to excessive CORTISOL release
glucosuria is usually with a concurrent diabetes mellitus
how can an abdominal ultrasound differentiate between PDH and ATH cushing’s?
PDH - BILATERAL ADRENAL hyperplasia- cuz of PITUITARY tumor
ATH- UNILATERAL usually ADRENAL hyperplasia, with an ATROPHIED adrenal
list 3 screening tests and 3 distinguishing tests for ADRENAL function. include the sample needed and sample container
screening:
- ACTH stim test…..blood serum….red top tube
- urine cortisol:creatinine ratio ………urine…..urine sample cup
- low dose dexamethasone suppression test……..blood serum….red top
distinguishing:
- high dose dexamethasone suppression test……..blood serum…..red top
- endogenous ACTH concentration…….blood……purple top
- ultrasound/CT/MRI……..live body
describe 2 ADRENAL function tests most appropriate for a dog with mild clinical signs of cushing’s and a history of prolonged CORTICOSTEROID use
- ACTH stim test….measure CORTISOL levels b4 and after 1-2 hrs of administration of ACTH/ cortrosyn
- IATROGENIC …CORTISOL levels would remain at baseline…usually < 5ug/dL
- normal….CORTISOL levels usually 6- 17ug/dL
- spontaneous cushing’s……CORTISOL levels elevated…usually >30ug/dL - high dose dexamethasone suppression test (if its not IATROGENIC, and is spontaneous)
record CORTISOL levels b4 and after administration of dexamethasone
- PDH……CORTISOL levels suppressed >50% of baseline
- ATH….CORTISOL levels not suppressed
- normal CORTISOL levels suppressed
how can you use endogenous ACTH to differentiate between ATH and PDH cushing’s?
- PDH…..high levels of ACTH
- ATH….lower levels
A 7 year old toy poodle presented with severe PU/PD, polyphagia and panting. the two diagnostic tests done showed only a proteinuria and hypertension. what screening test for ADRENAL function is your best bet to diagnose this dog?
low dose dexamethasone suppression test
- PDH in >505 suppression of baseline CORTISOL concentration at 4 hrs but not 8 hrs
why is it better to do a LDDST than a HDDST?
a hddst will suppress a normal dog and a PDH dog
a lddst will suppress a normal dog, but not a cushing’s dog
list 3 treatment plans for cushings….be specific, state mechanism of action and dosages
- mitotane…..cytotoxic to zona fasicularis(produces glucocorticoids)
- induction 20-25mg/kg PO q 12hrs after meal
- ACTH stim test…to demonstrate adequate control of CORTISOL levels
- maintainance…….50mg/kg/week PO (2-4 treatments/week) - trilostane
inhibits CORTISOL synthesis
- induction 2-10mg/kg SID
- ACTH stim test 2-6 hrs post drug…determine if to increase dose or just monitor and maintain
- monitor/maintain…..every 3 months…then every 4-6 months repeat - adrenalectomy….still have to give mitotane and trilostane…and obv for ATH!!
what part of the ADRENAL glands is responsible for glucocorticoid production? be specific
cortex
- zona reticularis
- zona fasicularis