Steroid abnormalities

Question 1

Vitaligo

Answer 1

Autoimmune antibodies against melanocytes

Patches of loss of skin pigmentation

Question 2

What typical symptoms indicates both mineralocorticoid (aldosterone) and glucocorticoid (cortisol) deficiency?

Answer 2

Hyponatraemia and hypotension

Question 3

Typical symptoms of mineralocorticoid deficiency

Answer 3

Hyponatremia - Aldosterone retains Na+ and water therefore leading to secondary ADH secretions

Hypotension - Due to Na+ loss

HYPERKALEMIA IN MINERALOCORTICOID DEFICIENCY - Due to decreased K+ secretions from aldosterone

Metabolic acidosis (failure for kidney to secrete H+)

Question 4

Typical symptoms of glucocorticoid deficiency

Answer 4

Hyponatremia - Loss of cortisol inhibition of ADH

Hypoglycaemia - Loss of gluconeogenesis and glycogenolysis induced by cortisol

Hypo-tension Loss of cortisol effect on vascular tone

Question 5

Causes of adrenal failure

Answer 5

Primary
- Adrenal gland dysfunction

Secondary
- Pituitary/ hypothalamus problem

Question 6

Primary adrenal failure symptoms and pathophysiology

Answer 6

GOOD TAN

• No cortisol production
• Tf no negative feed back on hypothalamus ACTH release
• ACTH is peptide product of POMC
• POMC produces melanocyte stimulating hormone MSH
• MSH causes good tan

Question 7

What are key observations to make with a child facing increasing obesity.

Answer 7

1) Change in appearance over time
If slow - then exogenous (eat too much) and not serious
If sudden - pathological

2) Growth pattern
- If no growth (short stature) then pathological (glucocorticoid excess)

3) Other features suggesting pathological causes

Question 8

Other features of glucocorticoid excess

Answer 8

• Moon face
• Thinned skin:
  
  • Facial plethora (glowing face)
  • Violaceous striae
  • bruising
• Androgen excess as cortisol is in path of making androgens
  
  • Hirsutism
  • Amennorrhoea
    Myopathy
    Hypertension
    Glucose intolerance

Question 9

Why do some patients present with hyperaldosteronism symptoms on top of typical glucocorticoid excess sympotoms?

Answer 9

Cortisol binds with equal affinity to MC and GC receptors. but is normally metabolised before binding to MC receptors.
In pathological conditions where there is excess cortisol produced by adrenal glands this excess overrides the cortisol metabolism.

Question 10

Differentials of glucocorticoid excess

Answer 10

1. Primary adrenal tumor
2. ACTH secreting tumors
   - Pituitary or ectopic
3. Exogenous GC’s

Question 11

What do you get with partial loss of glucocorticoid receptors?

Answer 11

Inc. in ACTH as the hypothalamus’ deficient GC receptors does not read there is sufficient cortisol circulating so no negative feed back.

Therefore excess cortisol is produced causing typical symptoms of GC and MC excess.
SECONDARY MC EXCESS SYMPTOMS
- Hyper-androgenism
- Fatigue/ tiredness - cortisol insensitivity when sick

Question 12

What do you get with loss of MC receptors?

Answer 12

Mineralocorticoid resistance
(Pseudohypoaldosteronism)
- Can’t retain Na+ so HYPONATREMIA
- Fails to excrete K+ and H+ so HYPERKALEMIA and ACIDOSIS.

Question 13

Loss of ACTH receptors?

Answer 13

High ACTH as no receptors to act on

Severely low cortisol levels - Adrenal crisis (bad!!