ADRENAL: 120 Flashcards
Name the 3 zones of the adrenal cortex
glomerulosa: mineralcorticoids
fasciculata: glucocorticoids
reticularis: sex hormones
describe the mechanism of secretion of aldosterone
juxtaglomerular apparatus produces renin.
-Renin converts angiotensinogen (by liver) in Angiotensin 1
-Angiotensin 1 is converted in Angiotensin 2 in pulmonary capillary endothelium
-angiotensin 2 stimulates secretion of aldosterone
what stimulates secretion of aldosterone? what are it’s functions?
-sintesi dell’aldosterone viene generato quando l’organismo richiede una maggiore pressione sanguigna, un maggior volume plasmatico e un aumento di ioni Na+ nel sangue
-riassorbimento del sodio e di acqua
circulating cortisol percentages bound/unbound
75% transcortin
15% albumin
10% unbound
ratio epinephrine/norepinephrine dogs and cats
DOGS: 60/40 epi-nor
CATS: 70/30 api-nor
what cells synthetize catecholamines?
chromaffin cells
dimensional cutoff value for malignant/bening adrenal masses
> 20 mm usually malignant
<20 mm usually benign
how to distinguish adrenal vs pituitary hyperadrenocorticism?
ACTH
almost undetectable with functional adrenal tumor (also with iatrogenic hyperadrenocorticism)
ultrasound findings in dogs with pheocromocitoma: differences with carcinoma
1) controlateral gland in pheo is normal sized
2) usually pheo invade phrenicoabdominal and cava (no erosion)
how many dogs fail to suppress after low dose dexamethasone test?
40%
blood exams for pheocromocytoma
urinary and plasma catecholamine metabolites (NORMETANEPHRINE++)
suggested time passed from Trilostane start to surgery
30 days.
Most specific predictor of pheocromocytoma in dogs ratio
urine creatinine to normetanephrine ratio
(creatinine to epinephrine and norepinephrine significan overlap with hyperadrenocorticism)
anesthesia consequences with manipulation of pheocromocytomas
1) Hypertension
2) ventricular tachicardia
3) arrythmias
4) cardiac arrest
what is phenoxybenzamine?
non competitive alpha-adrenergic receptor blocker
phenoxybenzamine dosage
initiated 2-3 weeks before surgery 0.5 mg/kg
increase until
-adverse drug reaction (vomit…)
-hypotension (lethargy…)
-maximum dosage is reached (2.5 mg/kg)
When maximum dosage reached, surgery after 1-2 weeks
postoperative complications following adrenalectomy
1) dyspnea
2) thromboembolism
3) acute pancreatitis
4) oliguric renal failure
5) hypoadrenocorticism
6) hemoperitoneum
