Adrenal Insufficiency
Also written as AI.
Severe adrenal insufficiency resulting in dangerously low testosterone levels
ADRENAL INSUFFICIENCY (ADDISON'S DISEASE)
- Definition: Inadequate cortisol ± aldosterone production.
- Primary causes: Autoimmune ( 1 in developed world), TB ( 1 in developing world), Waterhouse-Friderichsen syndrome, metastases, fungal infections.
- Secondary causes: Prolonged steroid use ( 1 overall), pituitary tumours, Sheehan's syndrome.
- Clinical: Fatigue, weight loss, postural hypotension, salt craving, nausea, hypoglycaemia, hyperpigmentation (primary only).
- Diagnosis: Short ACTH stimulation test (gold standard), ↑ACTH (primary), ↓ACTH (secondary), hyponatraemia, hyperkalaemia, anti-21-hydroxylase antibodies.
Read this in Endocrine & Renal Pathology
What our notes say
- Severe adrenal insufficiency resulting in dangerously low testosterone levels (Internal Medicine 4th Year Endocrinology CAT: 30 MCQs)
- Severe adrenal insufficiency resulting in dangerously low serum cortisol levels (Internal Medicine 4th Year Endocrinology CAT: 30 MCQs)
- | Endocrine | Adrenal cortex (zona fasciculata) and medulla (chromaffin cells) | Sepsis‑induced cytokines suppress ACTH release and cortisol synthesis, leading to relative adrenal insufficiency; catecholamine surge from sympathetic activation further stresses the system. | (Sepsis and septic shock)
- Acute kidney injury, ARDS, DIC, liver dysfunction, hypoglycaemia, adrenal insufficiency, ischaemic bowel, and multi-organ failure. (Sepsis and septic shock)
- Endocrinology and metabolism — diabetes mellitus; DKA and HHS; hypoglycaemia; hypothyroidism and thyrotoxicosis; thyroid storm and myxoedema coma; adrenal insufficiency and Cushing syndrome; calcium and parathyroid disorders; pituitary disease; obesity and metabolic syndrome. (Year 4 Internal Medicine: Exam Revision Roadmap)
- | Hyponatraemia | Excess free water intake, SIADH, heart failure, liver cirrhosis, nephrotic syndrome, thiazide diuretics, adrenal insufficiency | Severe malaria (SIADH), TB meningitis (SIADH), HIV‑associated adrenal disease, chronic diarrhoea from dysentery | (Sodium, potassium and calcium disorders)
Study material on Adrenal Insufficiency
- Adrenal insufficiency and Cushing syndrome
- Hypoglycaemia
- Endocrine & Renal Pathology
- Endocrine & Renal Pathology — Must Know Notes
- Pituitary disorders
- ENDOCRINE PATHOLOGY
- Chemical Pathology Practice Examination
- Internal Medicine 4th Year Endocrinology CAT: 30 MCQs
- Fluid balance
- MCQ: <!DOCTYPE html>
Practice questions on Adrenal Insufficiency
A patient with lung cancer has adrenal glands nearly obliterated by metastases on CT but shows no clinical signs of adrenal insufficiency. This is explained by
- Adrenal metastases replacing medullary tissue first and entirely sparing cortical function
- Compensatory contralateral adrenal hypertrophy maintaining sufficient cortisol output
- Residual islands of cortical cells being sufficient to maintain adequate adrenal function
- Ectopic cortisol production from the lung tumour masking clinical adrenal insufficiency
Answer: C. Even when adrenal glands are nearly obliterated by metastatic tumour, residual islands of cortical cells persist and produce sufficient cortisol to prevent clinical Addison disease.
Which of the following is TRUE regarding primary and secondary adrenal insufficiency?
- Primary adrenal insufficiency involves the pituitary/hypothalamus
- Secondary adrenal insufficiency involves the adrenal glands directly
- Primary adrenal insufficiency has low ACTH and low cortisol
- Secondary adrenal insufficiency has target gland atrophy
Answer: D. In primary adrenal insufficiency (e.g., Addison's disease), the adrenal glands fail, leading to low cortisol and high ACTH (due to loss of negative feedback). In secondary adrenal insufficiency, the pituitary fails to produce ACTH, leading to low ACTH and low cortisol; the adrenal glands become atrophic due to lack of stimulation.
Secondary adrenal insufficiency is MOST accurately diagnosed using which test?
- Random morning cortisol
- Short Synacthen test (SST)
- Insulin tolerance test (ITT)
- High-dose dexamethasone suppression test
Answer: B. The Short Synacthen Test (SST) assesses the adrenal glands' ability to respond to ACTH. A normal response is a cortisol level >500-550 nmol/L 30-60 minutes after Synacthen injection. ITT is the gold standard for assessing the entire HPA axis (including pituitary response) but is more complex and risky.
Secondary adrenal insufficiency is characterized by
- Low ACTH, low cortisol, high aldosterone
- Low ACTH, low cortisol, low aldosterone
- High ACTH, low cortisol, normal aldosterone
- Low ACTH, high cortisol, low aldosterone
Answer: B. Secondary adrenal insufficiency is due to pituitary (ACTH) or hypothalamic (CRH) failure. This leads to low ACTH and consequently low cortisol production by the adrenal cortex. Aldosterone production is primarily controlled by the renin-angiotensin system and is usually preserved, though it can be affected if CRH deficiency is severe.
The confirmatory test for primary adrenal insufficiency is ---
- Random cortisol
- Insulin tolerance test
- Short Synacthen (ACTH stimulation) test
- Overnight dexamethasone suppression
Answer: C.