What is the appropriate management and treatment plan for a patient with a history of autoimmune disorders, diagnosed with Addison's disease (primary adrenocortical insufficiency), presenting with hyperpigmentation and hyponatremia, who has been treated with hydrocortisone (cortisol replacement) and fludrocortisone (mineralocorticoid replacement)?

Management of Addison's Disease Following Initial Treatment

The patient should continue lifelong dual hormone replacement with oral hydrocortisone 15-25 mg daily in 2-3 divided doses and fludrocortisone 50-200 μg once daily, with comprehensive patient education on stress dosing, annual monitoring of weight, blood pressure, serum electrolytes, and screening for associated autoimmune conditions, particularly thyroid disease. 1, 2

Ongoing Glucocorticoid Replacement

• Hydrocortisone should be administered in divided doses (typically 2-3 times daily) to approximate the natural cortisol rhythm, with the first dose immediately upon waking and the last dose at least 6 hours before bedtime 1, 2
• The typical dosing pattern is 10 mg + 5 mg + 2.5 mg (at 07:00,12:00, and 16:00 hours) or 15 mg + 5 mg (at 07:00 and 12:00 hours), with total daily doses ranging from 15-25 mg 1, 2
• The lowest effective dose should be used to minimize long-term complications such as glucocorticoid-induced osteoporosis while maintaining adequate symptom control 1, 2

Mineralocorticoid Replacement Continuation

• Fludrocortisone 50-200 μg once daily should be continued, taken as a single morning dose 3, 4
• The dose of 62.5 μg mentioned in the case presentation falls within the standard range and is appropriate 4
• Dosing should be guided by blood pressure (including postural measurements), serum electrolytes, and assessment of salt cravings—not plasma renin activity 3
• Patients should be advised to consume salt and salty foods freely without restriction, while avoiding potassium-containing salt substitutes 1, 3

Critical Patient Education for Crisis Prevention

• Patients must be educated to double or triple their oral hydrocortisone dose during minor illnesses, infections, vomiting, injuries, or other stressors 1, 2
• All patients should wear medical alert identification (bracelet or necklace) and carry an emergency steroid card 2, 3
• Patients should carry emergency injectable hydrocortisone and know when to self-administer or seek immediate medical attention 2
• Education should emphasize that failure to increase glucocorticoid doses during stress can lead to life-threatening adrenal crisis, which manifests with shock, fever, impaired consciousness, and severe abdominal pain 1

Annual Monitoring Protocol

Clinical Assessment

• Weight measurement at each visit to detect under-replacement (weight loss) or over-replacement (weight gain) 1, 5
• Blood pressure assessment, including postural measurements: postural hypotension indicates insufficient mineralocorticoid therapy or inadequate salt intake 1, 5
• Assessment of general health, well-being, energy levels, appetite, and timing of symptom patterns 1, 5
• Normal skin color should be observed in the majority of patients on sufficient replacement therapy; persistent hyperpigmentation may indicate under-replacement 1

Laboratory Monitoring

• Serum sodium and potassium determinations annually to detect hyponatremia or hyperkalemia 1, 5
• Serum cortisol measurements are not useful for monitoring adequacy of replacement therapy due to highly variable peaks and troughs throughout the day 5
• If under-replacement is suspected, a morning cortisol absorption test (serum or saliva at 0,2,4, and 6 hours after morning dose) can identify patients with rapid cortisol disappearance who may benefit from more frequent dosing 1, 5

Screening for Associated Autoimmune Conditions

• Thyroid function testing every 12 months (TSH, free T4, and thyroid peroxidase antibodies) is essential, as autoimmune hypothyroidism or thyrotoxicosis commonly develops in patients with autoimmune Addison's disease 1, 5
• Annual plasma glucose levels and HbA1c to screen for diabetes mellitus 1, 5
• Complete blood count annually to screen for anemia 1, 5
• Vitamin B12 levels annually, as B12 deficiency due to autoimmune gastritis is common 1, 5
• In patients with frequent or episodic diarrhea, screening for celiac disease should be performed 1

Bone Health Monitoring

• Bone mineral density assessment every 3-5 years to monitor for glucocorticoid-induced osteoporosis 5, 2

Management of Stress Situations

Minor Illness or Stress

• Double or triple the usual oral hydrocortisone dose during febrile illness, gastroenteritis, or other acute stressors 2
• Continue increased dosing until the illness resolves 2

Major Surgery or Severe Illness

• Administer 100 mg hydrocortisone IV or IM before anesthesia, followed by 100 mg every 6-8 hours until recovery 2, 6
• Taper parenteral glucocorticoids over 1-3 days to oral maintenance doses as the patient's condition permits 1

Pregnancy Considerations

• Small adjustments to both hydrocortisone and fludrocortisone doses may be needed, particularly in the third trimester when progesterone has anti-mineralocorticoid effects 2, 3
• Parenteral hydrocortisone should be administered during delivery 2

Common Pitfalls to Avoid

• Do not discontinue fludrocortisone if essential hypertension develops; instead, reduce the dose and add a vasodilator antihypertensive agent 1, 3
• Do not rely on serum cortisol or ACTH levels to guide dose adjustments in established Addison's disease 5
• Do not overlook screening for associated autoimmune conditions, as continuous surveillance is necessary given the high prevalence of polyendocrine autoimmune syndromes 1, 5
• Avoid under-replacement of mineralocorticoids, which is common and may predispose patients to recurrent adrenal crises 1
• Ensure patients understand that low salt consumption can precipitate adrenal crisis 1

Recognition of Under-Replacement vs. Over-Replacement

Signs of Under-Replacement

• Persistent fatigue, weight loss, poor appetite, salt cravings 1
• Postural hypotension, hyponatremia, hyperkalemia 1, 5
• Persistent hyperpigmentation 1

Signs of Over-Replacement

• Weight gain, hypertension, peripheral edema 1
• Cushingoid features with prolonged excessive dosing 1