Adrenal Insufficiency: Diagnostic Methods and Laboratory Findings

Adrenal insufficiency (AI) is a condition characterized by inadequate production of adrenal hormones, primarily cortisol and, in some cases, aldosterone. It can be classified as primary (Addison's disease), secondary, or tertiary adrenal insufficiency, depending on the underlying cause.

Diagnostic Methods

Diagnosing adrenal insufficiency requires a combination of clinical evaluation, biochemical tests, and imaging studies.

1. Clinical Evaluation

• Symptoms: Fatigue, weight loss, hypotension, hyperpigmentation (in primary AI), hypoglycemia.
• Physical examination: Signs of dehydration, electrolyte imbalances.

2. Laboratory Findings

• Serum Cortisol Levels: Low cortisol levels (<3 μg/dL in the morning) indicate AI.
• ACTH Stimulation Test: Standard test measuring cortisol response to synthetic ACTH (cosyntropin).
• Plasma ACTH Levels: Elevated in primary AI, low in secondary/tertiary AI.
• Serum Electrolytes: Hyponatremia, hyperkalemia in primary AI due to aldosterone deficiency.
• Renin-Aldosterone Levels: Elevated renin and decreased aldosterone in primary AI.

Imaging Studies

Imaging helps identify adrenal pathology:

• CT/MRI of adrenal glands: Detects adrenal atrophy or enlargement.
• Pituitary MRI: Used in secondary AI to evaluate pituitary lesions.

Conclusion

Adrenal insufficiency is a critical endocrine disorder requiring accurate diagnosis. Laboratory tests such as cortisol assays, ACTH stimulation tests, and electrolyte assessments play a key role in confirming the condition.