Clinical aspects of the adrenal gland

Question 1

What could cause hyposecretion of the adrenal gland?

Answer 1

• Addison’s disease

- Adrenal enzyme defects

Question 2

what are the causes of addison’s disease?

Answer 2

• Immune destruction (auto)
• > 85% UK cases of adrenal failure
• +ve adrenal autoantibodies (to 21-OHase) in 70% cases
• lymphocytic infiltrate of adrenal cortex
• associated autoimmune diseases are common
• thyroid disease (20%)
• Type 1 diabetes mellitus (15%)
• premature ovarian failure (15%)
• Invasion
• Infiltration
• Infection
• Infarction
• Iatrogenic

Question 3

What are the symptoms of hyposecretion?

Answer 3

• Weakness, fatigue, anorexia, weight loss 100%
• Skin pigmentation or vitiligo 92%
• Hypotension 88%
• Unexplained vomiting or diarrhoea 56%
• Salt Craving 19%
• Postural symptoms 12%

Question 4

What are the possible clues to the diagnosis of adrenal failure?

Answer 4

• Disproportion between severity of illness & circulatory collapse / hypotension / dehydration
• Unexplained hypoglycemia
• Other endocrine features (hypothyroidism, body hair loss, amenorrhoea)
• Previous depression or weight loss

Question 5

How do you diagnose adrenal insufficiency?

Answer 5

• Non-specific symptoms: so must think of the diagnosis in the first place!
• Routine bloods: U&E, glucose, FBC
• Random cortisol
  □ >700 nmol/l (not Addison’s)
  □ <700 nmol/l (adrenal status uncertain)
• Synacthen test (and basal ACTH)
• If suspicion high & patient unwell, treat with steroids and do Synacthen test later

Question 6

How does one replace glucocorticoids?

Answer 6

• Usual total daily doses & relative potencies
  □ Hydrocortisone 20-30mg =
  □ Prednisolone 7.5mg =
  □ Dexamethasone 0.75mg
• Given in divided doses to ‘mimic normal diurnal variation’
  □ e.g. HC 20mg at 08.00h & 10mg at 18.00h

Question 7

How does one replace mineralocorticoids?

Answer 7

• Synthetic steroid, fludrocortisone
• Binds to mineralocorticoid (aldosterone) receptors
• 50-300 micrograms daily
• Adjust dose according to:
  □ clinical status (postural BP, oedema)
  □ U&E
  □ plasma renin level

Question 8

What should one do (in regards to the treatment of adrenal hyposecretion) when one has a minor short lived illness or stress?

Answer 8

double glucocorticoid dose

Question 9

What should be done (in regards to the treatment of adrenal hyposecretion) when one has a major illness or operation (especially if nil by mouth or GI upset)?

Answer 9

• 100mg hydrocortisone iv stat
• 50-100mg HC iv 8-hourly
• as stress abates, reduce HC by 50% per day until back on usual replacement dose

Question 10

What are the endocrine causes of hypertension?

Answer 10

○ Primary hyperaldosteronism
- unilateral adenoma 
- bilateral hyperplasia
○ Rarer causes
- Pheochromocytoma
- Conn's syndrome (aldosterone)
- Cushing’s syndrome (corticosteroids)
- Acromegaly
- Hyperparathyroidism
- Hypothyroidism
- Congenital Adrenal hyperplasia

Question 11

What are the investigations for Cushing’s disease

Answer 11

• screening for hypercortisolism: overnight Dex test and 24 hour urine free cortisol
• Confirmation of hypercortisolism: 24 hour urine free cortisol and low dose dex test
• ACTH dependent or not: Paired morn-midnight ACTH cortisol
• ACTH (pit/ no pit): high dose dex test
• Localisation: MRI sella, CT adrenal, BIPSS, CT chest

Question 12

What are the clinical features of phaeochromocytoma?

Answer 12

• Hypertension (persistent in 70%)
• Paroxysmal attacks
  □ headache
  □ sweating
  □ palpitations
  □ tremor
  □ pallor
  □ anxiety/fear

Question 13

Explain adrenal hyperplasia

Answer 13

• >90% cases due to 21-hydroxylase deficiency
• Severe cases
○ neonatal salt-losing crisis
○ ambiguous genitalia (girls)
• Incomplete defects
○ pseudo-precocious puberty (boys)
○ hirsutism (women)