L9 HPA Clinical Aspects

Question 1

Effects of glucocorticoids

Answer 1

Maintenance of homeostasis during stress
e.g. haemorrhage, infection, anxiety

Anti-inflammatory

Energy balance/metabolism

Formation of bone and cartilage

Regulation of blood pressure

Cognitive function, memory, conditioning

Question 2

Classic symptoms of Cushings

Answer 2

Too much cortisol

Weight gain
Central obesity
thin skin with easy bruising
buffalo hump
round moon face
Hirustism

Hypertension
Insulin resistance
Neuropsychiatric problems
Osteoporosis

Question 3

Pathogenesis of cortisol

Answer 3

Excess cortisol production

Causes:
Pituitary adenoma: ACTH secreting cells 
Adrenak tumours
Ectopic ACTH 
Iatrogenic: steroid treatment 
CRH secreting tumour

Question 4

How would you diagnose too much cortisol? (e.g Cushings)

Answer 4

24hr free cortisol in urine levels

Midnight saliva/blood cortisol

9AM ACTH levels compared with cortisol
-Determines if it is pituitary, adrenal or ectopic

Dexamethosone suppression

• Inhibits ACTH production
• Should see a drop in cortisol if normal

Imaging after biochemical tests

• CXR
• MRI Pituitary
• CT adrenal

Question 5

How would you diagnose too little cortisol? (e.g. Addisons)

Answer 5

Hypoglycaemic stress

• Insulin resistance test
• Injection of insulin will not see rise in cortisol levels

SynACTHen test
-ACTH injection will not see rise in cortisol

9am cortisol
-Lower than normal

U & E

• low sodium
• high potassium
• low aldosterone and renin

Blood glucose test
-Hypoglycaemic

Question 6

Treatment of Cushings

Answer 6

Surgical

• Transphenoidal adenectomy
• Adrenalectomy

Pituitary radiotherapy

If iatrogenic: slowly ween off steroids then stop

Question 7

Treatment of Addisons

Answer 7

Steroid replacement therapy (glucocorticoid)

if primary adrenal insufficiency (glucocorticoid and mineralocorticoid)

if secondary adrenal insufficiency
-mineralocorticoid not needed

Question 8

AUTOIMMUNE POLYENDOCRINE SYNDROMES

-TYPE 1

Answer 8

Genetic condition that gives rise to many endocrine and autoimmune conditions

Rare
Onset in infancy
Mutated Ar (AIRE gene)

Common phenotype:

• Addison’s disease
• Hypoparathyroidism
• Candidiasis

Question 9

AUTOIMMUNE POLYENDOCRINE SYNDROMES

-TYPE 1

Answer 9

Commoner (still rare!)
Infancy to adulthood
Polygenic
Common phenotype:
-Addison’s disease
-T1 diabetes
-Autoimmue thyroid disease