Lecture 14: Adrenal Disorders Part 1 Flashcards
Where are adrenal glands located?
Atop the kidneys
What makes up the adrenal cortex layers?
Zona Glomerulosa
Zona Fasciculata
Zona Reticulairs
Superficial to deep: GFR
What are the 3 layers of the adrenal gland?
Capsule
Cortex
Medulla
Superficial to deep
What is made in the Zona Glomerulosa?
Mineralcorticoids (Aldosterone)
Go Find Rex, Make Good Sex
What are the 4 functions of aldosterone?
- Sodium Retention
- Water Retention
- Potassium Excretion
- Increases BP and blood volume
What happens to renin in aldosterone deficiency and excess?
Aldosterone def: Increased renin
Aldosterone excess: Decreased renin
What is secreted in the Zona Fasciculata?
Glucocorticoids (Cortisol)
Go Find Rex, Make Good Sex
What are the 3 functions of cortisol?
- Gluconeogenesis in the liver
- Immune system suppression
- Inflammation suppression
When is our serum cortisol highest and lowest?
Highest in the morning.
Lowest at night.
What overall mechanism controls cortisol release?
HPA Axis
Hypothalamus-Pituitary-Adrenal
What kind of feedback is cortisol controlled by?
Negative feedback
What does the Zona Reticularis secrete?
Gonadocorticoids (DHEA)
RGD
What does DHEA do?
Controls/stimulates the development of sexual characteristics.
What does the adrenal medulla secrete?
EPI
NE
MEN
Chromaffin cells make up the adrenal medulla
What would cause a chronic increase in ACTH and CRH levels?
Adrenal gland destruction.
Lack of cortisol = lack of negative feedback to the hypothalamus
What does ACTH stimulate adrenals to do? What does it need?
Stimulates steroid synthesis.
It requires cholesterol to synthesize steroid hormones.
What is the precursor to all steroid hormones besides cholesterol?
Pregnenolone.
What does a 21A-2 deficiency result in?
Cortisol deficiency
Aldosterone deficiency
Androgen excess
What is unique about primary adrenal insufficiency vs the other 2 types?
It includes aldosterone insufficiency as well.
What is the MCC of addison’s disease and what specific CYP deficiency is it?
Autoimmune (80%)
CYP21A2 (21-hydroxylase) MC autoantigen
What does a CYP11A1 deficiency result in? CYP17A1?
11A1: Excess Cholesterol, deficient in everything else.
17A1: Excess Aldosterone, deficient in everything else.
11A1 is #1, because cholesterol is the precusor steroid.
When does addison’s typically present? Why?
10-40 y/o, because adrenal function decreases over time into insufficiency.
What is adrenoleukodystrophy?
Genetic disorder, resulting in accumulation of very long FA chains in adrenal cortex, inhibiting ACTH effects.
What is congenital adrenal insufficiency/hyperplasia?
Genetic mutation or absence of adrenal cortex.
Although rare to cause addison’s, what is the MC infection that can cause it?
TB
What are the 4 etiologies that result in chronic addison’s?
- Autoimmune (80%)
- Adrenoleukodystrophy
- Congenital adrenal insufficiency/hyperplasia
- Infection
In what 4 ways can drugs induce chronic addison’s?
- Inhibiting cortisol synthesis
- Accelerate metabolism of cortisol
- Adrenocorticolytic drug that inhibit cortisol synthesis
- Suppressing CRH or ACTH release
What drug is used to treat adrenocortical carcinoma and can result in addison’s?
Mitotane
Why does using glucocorticoids suppress CRH and ACTH?
Our body thinks we are making cortisol, so it sends negative feedback to the hypothalamus and pituitary.
This is why we should taper steroid use down if > 10d.
What are the two etiologies of acute addison’s?
- Adrenal hemorrhage
- Adrenal addisonian crisis
What causes adrenal hemorrhage?
- Sepsis
- HIT
- Anticoag
- APS
- Trauma
- Surgery
What is the pathophysiology behind an addisonian crisis?
Insufficient cortisol.
How would an addisonian crisis present?
- Profound fatigue
- Dehydration
- Vascular collapse (decreased BP)
- Renal shut down
- Hyponatremia
- Hyperkalemia
Results of aldosterone and cortisol deficiency.
How does someone with addison’s generally present?
- Bronze pigmentation of skin
- Hypogylcemia
- Postural hypotension
- Weight loss
- Weakness
- GI disturbances
- Changes in distribution of body hair
Why is hyperpigmentation common in addison’s?
ACTH has affinity for melanin. If the adrenal gland is not functioning, the ACTH binds to melaninotic receptors instead.
It is often the first and only symptom!
Why does vitiligo/hypopigmentation occur in addison’s?
Autoimmune destruction of dermal melanocytes
Not related to ACTH affinity for melaninotic receptors.
10% of pts
What are the the typical first symptoms of chronic addison’s?
- Anorexia
- Weight loss
- Fatigue
- Decreased stamina
Why do people with addison’s present with lymph tissue hyperplasia?
Increased immune system responses since lack of modulation.