endocrine / renal disorders Flashcards
How can hypoadrenocorticism can an acute renal emergency?
- no aldosterone so very dilute urine
- hypovolaemia if not adequate intake (e.g. Vom and dia)
- reduced GFR - azotaemic + hyperkaelaemia so bradycardic
How do you diagnose hypoAC?
ACTH stimulation test
How do you long term manage hypoAC?
glucocorticoid and mineralcoticoid therapy for life
What is the function of calcium?
intracellular second messenger nerve conduction and neuro-muscular transmission coagulation muscle contraction membrane stability
What 3 things control calcium?
PTH
VitD
calcitonin
how does PTH affect calcium?
increase calcium release from bone
increase calcium absorption from GIT
decrease calcium excretion from kidney
what hormone causes an increase in calcium and a decrease in phosphate?
PTH
How does VitD affect calcium?
increase calcium release from bone
increase calcium absorption from GIT
increase calcium reabsorption from kidney
how does calcitonin affect calcium?
decreases ca
what are the 3 components of total serum ca?
ionised 55%
albumin bound 35%
anion bound 10%
How can blood albumin affect Ca levels?
- bound so if high serum albumin then get high total ca
what is the first thing you do when have hypercalcaemia?
repeat bloods
what are signs of hypercalcaemia?
PU/PD anorexia dehydration weakness / lethargy V and D facial puritis oral discomfort cardiac tachyarrhythmias seizures/twitching ARF death
How does hypercalcaemia affect the kidney?
- vasoconstricts afferent a - reduced GFR - azotaemia
- decreases sensitivity to ADH - low USG
- stops Na absorption out of LoH so alters conc gradient so get PU and low USG
- if have high phosphate too get insoluble CaPO4 causing nephrocalcinosis and renal failure
what can cause hypercalcaemia?
- growing animal
- lipaemia
- hypoAC
- haemoconc
- hyperproteinaemia
- hyperPTH
- PTHrP
- renal failure
- high VitD
- granulomatous disease (macrophages contain vit D)
- skeletal lesions
- idiopathic in cats
what are 2 key toxins that can increase VitD?
psoriasis cream
rat poison
what are 2 key neoplasms that release PTHrP?
lymphoma
anal sac adenocarcinoma
what are some temporary treatments for hypercalcaemia?
diuresis bisphosphonates calcitonin furosemide dialysis
what are signs of hypocalcaemia?
muscle tremors/ cramps stiff gait behaviour changes panting hyperthermia tacchycardia hypotension death
what can cause hypocalcaemia?
CRF eclampsia acute pancreatitis iatrogenic ethylene glycol toxicity malabsorption hypoPTH
how can you treat acute hypocalcaemia?
calcium gluconate
what is hypersomatotrophism?
high GH - liver (with insulin) - high IGF1
what is the difference in causes of hypersomatotrophism in dogs and cats?
cats - pit tumour
dogs - normal mammary tissue producing excess GH (hyperprogesteronaemia)
what are some clinical signs of hypersomatotrophism?
soft tissue and flat bone proliferation thick set face increased interdental spaces PU/PD polyphagia wt gain
when would you be highly suspicious of hypersomatotrophism in cats?
poorly controlled DM from insulin resistance
how can you diagnose hypersomatotrophism?
- serum IGF high
- MRI for cat
- abd US and serum P4 for dog
what can predispose dogs to hypersomatotrophism?
entire
progestin administration
How do you treat hypersomatotrophism in cats and dogs?
dogs - remove P4
cat - radiation, dopamine agonist, refer to RVC
what causes hyposomatotrophism?
congenital malformation of pituitary adenohypophysis or trophic cell producing lines
get low GH, low TSH
what are the signs of hyposomatrotrophism?
small stature
immature hair coat
persistent oestrus
hypothyroidism too
how do you diagnose hyposomatotrophism?
- low serum IGF1
- spinal rads at 6mo - persistent epiphyses
what is the pathogenesis of central diabetes insipidus?
post pit not making ADH - CD impermeable to water - dilute urine
what level of PD is seen with DI?
> 200ml/kg/24 hr
how do you diagnose DI?
USG < 1.008
water deprivation test (be careful)
give desmopressin and see if USG increases
how do you teat DI?
desmopressin
