What is the recommended approach for monitoring Addison's disease?

Monitoring Addison's Disease

Patients with Addison's disease should be reviewed at least annually with assessment of general health and well-being, measurement of weight, blood pressure, and serum electrolytes, with bone mineral density monitoring every 3-5 years to detect complications of glucocorticoid therapy. 1

Annual Clinical Assessment

Core Monitoring Parameters

• Weight and blood pressure should be measured at each annual visit to detect signs of over-replacement (weight gain, hypertension) or under-replacement (weight loss, hypotension) 1

• Serum electrolytes (sodium and potassium) must be checked annually, as hyponatremia may indicate glucocorticoid under-replacement or fludrocortisone excess, while hyperkalemia suggests inadequate mineralocorticoid replacement 1, 2

• Assessment of health and well-being is critical, with specific questioning about energy levels throughout the day, morning nausea, appetite, and timing of symptom patterns to guide dose adjustments 1, 3

Signs of Glucocorticoid Imbalance

• Under-replacement manifests as lethargy, nausea, poor appetite, weight loss, and increased or uneven pigmentation distribution 3

• Over-replacement presents with weight gain, hypertension, hyperglycemia, and features of Cushing's syndrome 1

• The goal is to use the lowest dose compatible with health and a sense of well-being, typically 15-25 mg hydrocortisone daily in split doses 1

Mineralocorticoid Monitoring

• Fludrocortisone dosing (50-200 µg daily) should be guided by blood pressure, serum electrolytes, and assessment of salt cravings 1

• If essential hypertension develops, reduce the fludrocortisone dose but do not discontinue it entirely 1

• In hypertensive patients with Addison's disease where renin is in the upper normal range or elevated, an ACE inhibitor or angiotensin II receptor antagonist is the treatment of choice, and fludrocortisone should remain unchanged 4

• Avoid diuretics in hypertensive Addison's patients, as they can worsen electrolyte imbalances 4

Screening for Associated Autoimmune Conditions

• Thyroid function testing should be performed periodically, as autoimmune hypothyroidism is common in patients with autoimmune Addison's disease 1, 3

• Consider screening for other autoimmune disorders including diabetes mellitus, pernicious anemia (vitamin B12 levels), and celiac disease, particularly in patients with autoimmune etiology 3

• The frequency of autoimmune screening is not rigidly defined, but occasional monitoring is worthwhile given the high prevalence of polyendocrine syndromes 1

Bone Health Monitoring

• Bone mineral density (DEXA scan) should be assessed every 3-5 years to monitor for glucocorticoid-induced osteoporosis 1

• This is particularly important because even physiologic replacement doses can have cumulative effects on bone health over decades of treatment 1

Laboratory Monitoring Limitations

What NOT to Monitor Routinely

• Serum cortisol levels are not useful for monitoring adequacy of replacement therapy, as hydrocortisone produces highly variable peaks and troughs throughout the day 1

• ACTH levels do not guide dose adjustments in established Addison's disease, as they remain elevated regardless of replacement adequacy 1

• Plasma renin activity (PRA) can be misleading for fludrocortisone dose adjustment, especially during pregnancy when PRA normally increases 1

Special Monitoring Situations

During Pregnancy

• Small dose adjustments to both hydrocortisone (increase by 2.5-10 mg daily) and fludrocortisone may be needed, particularly during the third trimester 1

• Monitor using blood pressure, serum electrolytes, and assessment of salt cravings rather than PRA, which physiologically increases during pregnancy 1

Patient Education and Self-Monitoring

• Patients should be educated to recognize signs of under-replacement (fatigue, nausea, dizziness, salt craving) and over-replacement (weight gain, edema, hypertension) 1, 5

• All patients must understand stress dosing protocols and when to double or triple their glucocorticoid dose during illness 5

• Patients should wear medical alert identification and carry emergency injectable hydrocortisone 5

Common Pitfalls to Avoid

• Do not rely solely on electrolytes to assess replacement adequacy—10-20% of patients may have normal electrolytes despite inadequate replacement 3

• Do not use cortisol or ACTH levels to titrate chronic replacement therapy, as these are not helpful in established disease 1

• Do not stop fludrocortisone if hypertension develops; instead, reduce the dose and consider adding an ACE inhibitor or ARB if needed 1, 4

• Morning nausea and poor appetite often indicate under-replacement; consider having patients take their first hydrocortisone dose earlier upon waking, then returning to sleep 3