Can adrenal insufficiency cause orthostatic hypotension?

Adrenal Insufficiency as a Cause of Orthostatic Hypotension

Yes, adrenal insufficiency is a significant cause of orthostatic hypotension, which can progress to supine hypotension and potentially fatal shock if not promptly treated. 1

Pathophysiology

Adrenal insufficiency leads to orthostatic hypotension through several mechanisms:

• Insufficient cortisol production leads to progressive loss of vasomotor tone and impaired alpha-adrenergic receptor responses to noradrenaline 1
• The resulting decrease in vascular tone causes blood pooling in the lower extremities upon standing 1
• In primary adrenal insufficiency, aldosterone deficiency compounds the problem by causing sodium loss and volume depletion 2
• The autonomic nervous system cannot adequately increase peripheral vascular resistance in the upright posture 1

Clinical Presentation

Orthostatic hypotension in adrenal insufficiency presents as:

• A drop in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg within 3 minutes of standing 1
• Early sign of impending adrenal crisis that may precede more severe hypotension 1
• Often accompanied by symptoms such as dizziness, light-headedness, fatigue, and weakness 1
• May be accompanied by other features of adrenal insufficiency including unintentional weight loss, anorexia, profound fatigue, muscle and abdominal pain, and hyponatremia 3
• In primary adrenal insufficiency (Addison's disease), additional features include skin hyperpigmentation and salt craving 4

Diagnosis

To diagnose adrenal insufficiency as the cause of orthostatic hypotension:

• Measure both sitting (or standing) and supine blood pressure to detect orthostatic changes 1
• Check plasma sodium levels, which are often low in adrenal insufficiency 1
• Measure basal plasma cortisol (though this is an insensitive screening test) 4
• Perform a synthetic ACTH stimulation test (250 μg) as a dynamic test 4
• Confirm the diagnosis with elevated plasma ACTH and renin levels (in primary adrenal insufficiency) 4
• Exclude other common causes of orthostatic hypotension such as medications, hypovolemia, and autonomic neuropathy 1

Management

Treatment of orthostatic hypotension due to adrenal insufficiency involves:

• Replacement of deficient hormones (glucocorticoids and mineralocorticoids) 4
• Hydrocortisone administration, preferably via IV infusion in acute settings 1
• Increasing steroid doses during intercurrent illness, medical procedures, or profound stress to prevent adrenal crisis 3
• Patient education on managing adrenal insufficiency, including how to adjust medication during illness 3
• Providing patients with a steroid emergency card, parenteral hydrocortisone, and training for self-administration 3

Clinical Pearls and Pitfalls

• Volume-resistant hypotension is a cardinal sign of acute adrenal insufficiency but may be a late or even agonal event 1
• Diagnosis of adrenal insufficiency is often delayed because initial presentation can be non-specific 3
• Persistent pyrexia may be due to adrenal insufficiency but is often misattributed to postoperative sepsis 1
• Steroid supplementation should not be reduced or withdrawn while a patient is pyrexial 1
• Patients with adrenal insufficiency who develop complications should be managed in a critical care environment 1
• Always consider adrenal insufficiency in patients with unexplained orthostatic hypotension, especially when accompanied by hyponatremia, hyperkalemia, or skin hyperpigmentation 2, 4