AIM STEP 10
4th Year MBBS
Endocrine + Reproduction
4th Year MBBS
Endocrine + Reproduction
Student Memory Support
Adrenal Insufficiency: Primary and Secondary Adrenal Failure
High-yield memory reinforcement for rapid revision of causes, hormonal patterns, diagnostic distinctions, adrenal crisis and treatment principles.
1. High-Yield Flashcards
Tap each question to reveal the answer.
What is primary adrenal insufficiency?
Failure of the adrenal cortex causing inadequate cortisol production, often with aldosterone deficiency.
What hormonal pattern characterizes primary adrenal insufficiency?
Low cortisol with increased ACTH; aldosterone may also be reduced.
Why does hyperpigmentation occur in Addison disease?
Loss of cortisol feedback raises ACTH/POMC-derived melanocortin activity, increasing pigmentation.
Why does primary adrenal insufficiency cause hyperkalemia?
Aldosterone deficiency reduces renal potassium excretion.
What is the typical hormonal pattern in secondary adrenal insufficiency?
Low cortisol with low or inappropriately normal ACTH.
Why is aldosterone generally preserved in secondary adrenal insufficiency?
Aldosterone is regulated mainly by the renin-angiotensin system and serum potassium rather than ACTH.
Which electrolyte finding particularly favors primary over secondary adrenal failure?
Hyperkalemia.
Can hyponatremia occur in secondary adrenal insufficiency?
Yes. Cortisol deficiency can impair free-water excretion despite preserved aldosterone.
What does an ACTH stimulation test assess?
The ability of the adrenal cortex to produce cortisol in response to ACTH stimulation.
What happens to renin when primary adrenal failure causes aldosterone deficiency and volume loss?
Renin activity increases as a compensatory response to sodium and volume depletion.
What is an adrenal crisis?
An acute, life-threatening state of severe corticosteroid deficiency with hypotension and metabolic disturbance.
What are the immediate treatment priorities in adrenal crisis?
Parenteral hydrocortisone, intravenous isotonic fluid, glucose if hypoglycemic, and treatment of the precipitating cause.
Why is hydrocortisone useful in acute primary adrenal failure?
It provides glucocorticoid activity and also some mineralocorticoid activity.
What long-term replacement is generally required in primary Addison disease?
Glucocorticoid replacement plus mineralocorticoid replacement when aldosterone is deficient.
What replacement is generally required for the adrenal defect in secondary adrenal insufficiency?
Glucocorticoid replacement; routine mineralocorticoid replacement is generally unnecessary.
2. Mnemonics
Mnemonic Title: Primary Addison Clues
HASP
Meaning: Hyperpigmentation • high ACTH • Salt craving • high Potassium
Mnemonic Title: Secondary Adrenal Pattern
PAL
Meaning: Pituitary problem • ACTH low • Low cortisol, with aldosterone generally preserved
Mnemonic Title: Adrenal Crisis Immediate Priorities
HFG
Meaning: Hydrocortisone • Fluids • Glucose when hypoglycemia is present
3. Memory Tables
Primary vs Secondary Adrenal Insufficiency
| Feature | Primary | Secondary |
|---|---|---|
| Site | Adrenal cortex | Pituitary |
| Cortisol | Low | Low |
| ACTH | High | Low / inappropriately normal |
| Aldosterone | May be low | Generally preserved |
| Pigmentation | Present | Absent |
| Potassium | May be high | Generally normal |
| Replacement | Glucocorticoid ± mineralocorticoid | Glucocorticoid |
4. Rapid Revision Points — Last-Minute Revision
Must Remember:
- Addison disease is chronic primary adrenal cortical failure.
- Primary disease produces low cortisol with raised ACTH.
- Pigmentation reflects increased ACTH/POMC-derived melanocortin activity.
- Aldosterone deficiency produces sodium loss, volume depletion and potassium retention.
- Secondary disease produces low cortisol with low or inappropriately normal ACTH.
- Aldosterone is generally preserved in pituitary adrenal insufficiency.
- Hyponatremia can occur in both primary and secondary adrenal failure.
- An ACTH stimulation test assesses adrenal cortisol-producing capacity.
- Severe illness can precipitate crisis because physiological cortisol requirements rise.
- Suspected adrenal crisis requires immediate glucocorticoid and fluid treatment rather than delayed confirmation.
Common KMU Trap: Hyponatremia alone does not distinguish primary from secondary disease. Hyperkalemia plus raised ACTH strongly favors primary adrenal failure.
5. Clinical Memory Hooks
Dark palmar creases + postural dizziness + salt craving
→
Primary Addison disease with high ACTH and mineralocorticoid deficiency
→
Primary Addison disease with high ACTH and mineralocorticoid deficiency
Low cortisol + low ACTH + normal potassium
→
Pituitary/secondary adrenal insufficiency
→
Pituitary/secondary adrenal insufficiency
Known adrenal insufficiency + infection + vomiting + profound hypotension
→
Adrenal crisis requiring immediate steroid and fluid replacement
→
Adrenal crisis requiring immediate steroid and fluid replacement
Pituitary lesion + cortisol deficiency + another pituitary hormone deficiency
→
Central adrenal insufficiency from pituitary dysfunction
→
Central adrenal insufficiency from pituitary dysfunction
⭐ 6. Starred High-Yield Exam Points
- ⭐ Low cortisol + high ACTH = primary adrenal insufficiency.
- ⭐ Hyperpigmentation is a high-yield clue to increased ACTH in primary disease.
- ⭐ Hyperkalemia indicates mineralocorticoid deficiency and strongly favors primary failure.
- ⭐ Low cortisol + low or inappropriately normal ACTH = secondary adrenal insufficiency.
- ⭐ ACTH stimulation testing evaluates adrenal cortisol response.
- ⭐ Adrenal crisis is an emergency: parenteral hydrocortisone and intravenous isotonic fluid should not be delayed for complete confirmation.