Adrenal Gland Pathology Flashcards
Primary regulatory control and secretory products of zona glomerulosa
Renin-angiotension, aldosterone (Na^+, H2O retention, K^+ secretion)
Primary regulatory control and secretory products of zona fasciculata
ACTH, CRH (corticotrophin-releasing hormone), cortisol secreted
Primary regulatory control and secretory products of zona reticularis
ACTH, CRH, sex hormones (e.g. androgens) secreted
Primary regulatory control and secretory products of chromaffin cells
Preganglionic sympathetic fibres, catecholamines (epinephrine (adrenaline), norepinephrine)
Summary of layers of adrenal gland and hormones secreted
Outline the hypothalamic-pituitary-adrenal (HPA) axis feedback loops
Where are the adrenal glands located?
Adjacent to kidneys + close to blood vv., hard for tumour removal surgery + can be occluded
Degenerative changes of the adrenal cortex (2)
- Amyloidosis
- Mineralisation
Types of amyloidosis (not examinable)
Types of circulatory disturbances of adrenal cortex (2)
- Haemorrhage
- Infarction
Mechanisms of toxicity of the adrenal cortex (3)
Disorders of growth of the adrenal cortex (4)
- Developmental malformations
- Atrophy
- Nodular hyperplasia
- Neoplasia - adenoma, carcinoma
Developmental findings of the adrenal cortex (3)
Grossly, adrenal cortex to medulla ratio should be 1:1
Compare and contrast nodular hyperplasia and adenomas (6)
What are the types of hyperadrenocorticism? (4)
Pituitary-dependent hyperadrenocorticism - adrenal gland gross pathology
Bilateral adrenocortical hyperplasia (+ mass) - ACTH in bloodstream - both glands
Adrenal-dependent hyperadrenocorticism - adrenal gland gross pathology
Bilateral adrenocortical atrophy (+ mass) - compensation
Iatrogenic hyperadrenocorticism - adrenal gland gross pathology
Bilateral adrenocortical atrophy (+ history of corticosteroid use), no tumour
Ectopic ACTH secretion - adrenal gland gross pathology
Bilateral adrenocortical hyperplasia, no tumour
Pituitary-dependent hyperadrenocorticism
Adrenal-dependent hyperadrenocorticism
Iatrogenic hyperadrenocorticism
Ectopic ACTH secretion
Clinical signs of hyperadrenocorticism (8)
- Excess cortisol -> inc stress
- Common in middle-aged dogs
- Poodles and Boston terriers predisposed
- Immunosuppressed
- Pot-belled/get fat - inc protein catabolism, glycolysis + glucose production
- 5 Ps!
What is calcinosis cutis?
Accumulation of calcium salt crystals in skin - calcification of degenerate collagen, localised (dystrophic)
Difference between dystrophic and metastatic calcification
What clinical pathological changes are induced by corticosteroid release? (6)
- Stress leucogram (‘LEMoN’, LE = dec leucocytes, N = inc neutrophils) - lymphopoenia, eosinopenia, neutrophilia + monocytosis (dogs)
- Stress hyperglycaemia
- Hypercortisolism
- Inc ALP (alkaline phosphotase)
- Lipaemia + hypercholestrolaemia
- Hypercoagulable state
Diagnostic tests that differentiate pituitary and adrenal-dependent hyperadrenocorticism (4)
- LDDS = low-dose dexamethasone suppression testing
- HDDS = high-dose dexamethasone suppression
What are the pathogenic mechanisms of cortisol excess in dogs? (5)
Rare in cats, mostly pituitary-dependent, thin fragile skin, curling of tips of ear pinna
- Excess glucocorticosteroid production + excess sex steroids
- Functional adrenal gland hyperplasia, adenomas or adenocarcinomas
- May be related to neutering at an early age
- Middle age (3-4 years)
- Hair loss - begins in tail and progresses toward front to completely bald
- Swollen vulva in spayed females
- Straining to urinate (enlarged prostate)
- Thinning of skin, muscle wasting + pot-bellied appearance in long-term disease
What are the different types of hypoadrenocorticism and which part of the adrenal gland is affect? (3)
What are the non-specific clinical findings of hypoadrenocorticism? (5)
Function of mineralocorticoids in the body
Aldosterone (goes to kidneys) - Na^+ + H2O retention, K^+ secretion (-ive feedback loop), H^+ secretion
Hypoadrenocorticism pathogenesis (1^y + 2^y)
Additional diagnostic tests for hypoadrenocorticism (3)
What is hyperaldosteronism? (2)
Renin-angiotensin-aldosterone system
What are phaeochromocytomas? (4)
- Neoplasm of the adrenal medullary secretory cells
- Rare; mostly seen in dogs and cattle
- May be benign or malignant - invasion of adjacent vessels - vena cava common with malignant form
- May secrete catecholamines (adrenaline and noradrenaline)
- Hypertension - spontaneous haemorrhage, glomerulopathy
- Tachycardia
- Anxiety, restlessness
Malignant - invasion of the caudal vena cava
