Will the client's cortisol level be low or high given symptoms of fatigue, weakness, unintentional weight loss, hyperpigmentation, and salt cravings?

Cortisol and ACTH Levels in Primary Adrenal Insufficiency

In a client presenting with fatigue, weakness, unintentional weight loss, hyperpigmentation, and salt cravings, the cortisol level will be low and the ACTH level will be high, consistent with primary adrenal insufficiency. 1

Laboratory Profile in Primary Adrenal Insufficiency

Primary adrenal insufficiency (Addison's disease) presents with a characteristic laboratory profile:

• Cortisol: Low (typically <3 μg/dL or <110 nmol/L in morning samples) 1
• ACTH: Elevated (>2-3 times upper limit of normal) 1
• Electrolytes: Hyponatremia and hyperkalemia 1
• Other findings: Possible hypoglycemia, elevated plasma renin activity, low aldosterone 1

Clinical Correlation with Symptoms

The constellation of symptoms described strongly suggests primary adrenal insufficiency:

• Fatigue and weakness: Result from cortisol deficiency and electrolyte imbalances
• Unintentional weight loss: Common in adrenal insufficiency due to metabolic changes
• Hyperpigmentation: Caused by elevated ACTH levels (which have melanocyte-stimulating properties) 2
• Salt cravings: Result from mineralocorticoid deficiency (aldosterone) 1

Diagnostic Approach

When these symptoms are present, the following diagnostic steps are recommended:

1. Morning cortisol and ACTH levels: Primary screening tests 1
2. Basic metabolic panel: To assess for hyponatremia, hyperkalemia 2
3. Renin and aldosterone levels: To evaluate mineralocorticoid function 2
4. ACTH stimulation test: For indeterminate results (cortisol between 3-15 μg/dL) 2

Important Distinctions

It's crucial to distinguish between primary and secondary adrenal insufficiency:

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

1

Common Pitfalls to Avoid

• Misinterpreting partial cortisol deficiency: Cortisol levels may be "normal" but inappropriately low for the degree of stress/illness 3
• Overlooking adrenal crisis: A life-threatening emergency requiring immediate IV hydrocortisone and fluid resuscitation 1
• Failing to consider medication effects: Certain medications (e.g., etomidate) can suppress cortisol production 4
• Relying solely on random cortisol measurements: These can be misleading without considering the diurnal variation and stress state 5

Management Implications

Once diagnosed, management includes:

• Hormone replacement therapy: Glucocorticoids (hydrocortisone 15-25 mg daily in divided doses) and mineralocorticoids (fludrocortisone 0.05-0.2 mg daily) 1
• Patient education: On stress dosing, emergency injections, and medical alert identification 1
• Regular monitoring: Of symptoms, electrolytes, and blood pressure 1

The early recognition of this pattern of low cortisol and high ACTH is critical for timely diagnosis and treatment to prevent potentially fatal adrenal crisis.