What is the recommended treatment for hyponatremia (low sodium levels) in patients with suspected adrenal insufficiency?

Treatment of Hyponatremia in Suspected Adrenal Insufficiency

Patients with hyponatremia and suspected adrenal insufficiency should receive immediate intravenous hydrocortisone 100 mg followed by hydrocortisone infusion of 200 mg/24h until stabilized, along with fluid resuscitation using normal saline (10-20 ml/kg; maximum 1,000 ml). 1

Initial Management

1. Immediate treatment:

   • Administer hydrocortisone 100 mg IV immediately 1
   • Continue with hydrocortisone infusion of 200 mg/24h until the patient is stabilized 1
   • Provide fluid resuscitation with normal saline (10-20 ml/kg; maximum 1,000 ml) 1

2. Careful sodium correction:

   • Monitor serum sodium levels to ensure they do not increase more than 10 mEq/L/day to prevent osmotic demyelination syndrome (ODS) 2
   • Consider incremental increases in glucocorticoid doses to reduce the risk of ODS, especially in cases complicated by central diabetes insipidus 2

Transition to Maintenance Therapy

Once the patient is stabilized:

1. Oral glucocorticoid replacement:

   • Transition to oral hydrocortisone at double the pre-event therapeutic dose for 48 hours if recovery is uncomplicated 1
   • Standard maintenance dose is hydrocortisone 10-30 mg daily in divided doses (or equivalent prednisone 5-10 mg daily) 1, 3

2. Mineralocorticoid replacement:

   • Add fludrocortisone once enteral feeding is established, particularly for primary adrenal insufficiency 1
   • Standard dose is 0.1 mg daily, though dosage may range from 0.1 mg three times weekly to 0.2 mg daily 4
   • Fludrocortisone should be administered in conjunction with hydrocortisone 4

Differentiating Primary vs Secondary Adrenal Insufficiency

This distinction is crucial for determining the need for mineralocorticoid replacement:

Type	ACTH Level	Cortisol Level	Electrolytes	Hyperpigmentation
Primary	High	Low	↓Na, ↑K	Present
Secondary	Low	Low	Generally normal	Absent

• Primary adrenal insufficiency requires both glucocorticoid and mineralocorticoid replacement 1, 4
• Secondary adrenal insufficiency typically requires only glucocorticoid replacement 1

Important Clinical Considerations

• Diagnostic pitfalls: Hypopituitarism with secondary adrenal insufficiency is frequently overlooked in hyponatremic patients 5
• Laboratory findings: Basal serum cortisol levels in acutely ill patients with adrenal insufficiency may range from 20 to 439 nmol/l, significantly lower than other hyponatremic patients 5
• Treatment efficacy: Even low-dose hydrocortisone has been shown to successfully treat severe hyponatremia in elderly patients with functional adrenal insufficiency 6
• Long-term management: Consider modified-release hydrocortisone preparations that mimic the physiological circadian pattern of cortisol secretion for improved metabolic outcomes and quality of life 7

Patient Education

All patients with adrenal insufficiency require:

• Education on stress dosing during illness
• Training on use of emergency injectable steroids
• Information on when to seek medical attention for impending adrenal crisis
• A medical alert bracelet/card for adrenal insufficiency 1

Monitoring

• Monitor electrolytes, particularly sodium and potassium
• Watch for signs of over-replacement (hypertension, edema) or under-replacement (fatigue, hypotension, hyponatremia)
• Monitor for long-term side effects including lipodystrophy, hypertension, cardiovascular disease, osteoporosis, and metabolic disorders 1