EXAM #2: ADRENAL INSUFFICIENCY Flashcards
What is the definition of adrenal insufficiency?
Clinical manifestations of deficiency of hydrocortisone
What is the difference between primary and secondary adrenal insufficiency? Specifically, what is the difference in hormone deficiencies?
Primary= destruction of adrenal gland causing deficiency in:
- Corticosteroids
- Mineralcorticoids
- Adrenal androgens
Secondary= damage to the hypothalamus causing deficiency in CORTICOSTEROIDS ONLY
Why are deficiencies in catecholamines and adrenal androgens spared in adrenal insufficiency?
- Extra-adrenal sites–paragnaliomas–produce catecholamines
- Ovaries and testes are the major source of DHEA
Thus, other organs are primarily responsible for the synthesis of these hormones
Why is aldosterone production unaffected by secondary adrenal insufficiency?
Aldosterone is NOT regulated by ACTH; rather, the RAA, which increases aldosterone secretion in response to:
1) Renal hypotension
2) Decreased Na+ delivery to distal tubules
What effect does aldosterone have on Na+ and K+?
1) Conserves Na+
2) Excretes K+
What are the four major functions of ANGII?
1) Release of aldosterone from adrenal cortex
2) Release of ADH from posterior pituitary
3) Vasoconstriction
4) Increased renal Na+ retention
When do cortisol levels peak? When are they the lowest?
Peak= early morning Low= evening
What stimuli will cause the secretion of CRH, ultimately leading to increased cortisol?
1) Stress
2) Hypoglycemia
3) Cold temp.
4) Pain
What is the larger precursor peptide to ACTH? What are the three derivatives from this peptide?
Propiomelanocortin (POMC)
- ACTH
- Lipotropin
- MSH
What is the most common cause of primary adrenal insufficiency in developed countries?
Autoimmune destruction (Addison’s Disease)
Worldwide, what is the most common cause of primary adrenal insufficiency?
TB
What hormonal deficiencies are seen in primary adrenal insufficiency?
1) Cortisol
2) Aldosterone
3) DHEA
What lab findings are seen in primary adrenal insufficiency?
1) Decreased cortisol with increased ACTH
2) Decreased aldosterone with increased renin
3) Decreased DHEA
What two clinical manifestations are unique to primary adrenal insufficiency?
1) Hyperpigmentation
2) Hyperkalemia
How is primary adrenal insufficiency diagnosed?
1) Random cortisol less than 5 mcg/dL or am cortisol less than 3 mcg/dL
2) Simultaneously elevated ACTH
3) Cortrosyn stimulation test
What is the expected response to a cortrosyn stimulation test?
Cortisol greater than 18 mcg/dL
How is primary adrenal insufficiency treated?
1) Hydrocortisone twice daily or prednisone once daily
2) Fludrocortisone*
*Synthetic corticosteroid with moderate glucocorticoid potency and much greater mineralocorticoid potency.
What endpoints do you want to monitor in the treatment of primary adrenal insufficiency treated?
1) Weight
2) Blood pressure
3) Electrolytes
4) Sense of well-being
What major consideration do you need to keep in mind about patients with primary adrenal insufficiency?
Stress dosing
- Minor= 30-60mg/day
- Major= 200-300 mg/day
How is an adrenal crisis treated?
5s
1) Saline
2) Sugar: dextrose
3) Steroids: hydrocortisone
4) Support
5) Search (underlying cause)
What are the two major etiologies of secondary adrenal insufficiency?
Transient= iatrogenic steroid use Permanent= panhypopituitarism
What is the most common cause of secondary adrenal insufficiency?
Abrupt cessation of exogenous glucocorticoids
*Drug suppresses CRH/ACTH and then it takes time for the HPA axis to “wake-up”
What hormonal changes are expected in secondary adrenal insufficiency?
Decreased ACTH and Cortisol
Why can a Cortrosyn stimulation test show a lack of cortisol stimulation in secondary adrenal insufficiency?
Corticol atrophy
What are two methods of stimulating ACTH production?
1) Metyrapone (reduces cortisol–should increase ACTH)
2) Insulin induced hypoglycemia (stress should increase ACTH)
How is secondary adrenal insufficiency treated?
Replacement of cortisol BUT NOT aldosterone
