🩺 Adrenal Insufficiency (Addison’s Disease) & Low Blood Pressure

When the adrenal glands stop producing enough cortisol and aldosterone, the result is a disorder called adrenal insufficiency. The most well‑known form is Addison’s disease (primary adrenal insufficiency). One of its hallmark features is low blood pressure — often accompanied by salt cravings, fatigue, and darkening of the skin. Dr. Ravi Sishir Reddy explains how adrenal failure leads to hypotension, how to recognise the signs, and why prompt diagnosis is life‑saving.

1. What Are the Adrenal Glands and What Do They Do?

The adrenal glands are small, triangular organs sitting on top of each kidney. Despite their size, they produce hormones that are essential for life:

• Cortisol: Helps the body respond to stress, maintains blood sugar, and supports vascular tone. Without cortisol, blood vessels cannot constrict properly, contributing to low BP.
• Aldosterone: A mineralocorticoid that tells the kidneys to retain sodium and water and excrete potassium. Aldosterone deficiency leads to excessive sodium loss in urine, volume depletion, and a drop in blood pressure.
• Androgens: Weak male‑type hormones that contribute to libido and well‑being in both sexes.

When both cortisol and aldosterone are deficient (as in primary adrenal insufficiency), the cardiovascular system loses a critical support system — volume drops, vessels cannot constrict adequately, and blood pressure falls.

2. Types of Adrenal Insufficiency

• Primary adrenal insufficiency (Addison’s disease): The adrenal glands themselves are damaged, usually by an autoimmune attack. Both cortisol and aldosterone production fail. Tuberculosis, fungal infections, and certain genetic disorders can also cause it.
• Secondary adrenal insufficiency: The pituitary gland fails to produce enough ACTH (adrenocorticotropic hormone), which stimulates the adrenals. Cortisol production drops, but aldosterone is often preserved because it is mainly regulated by the renin‑angiotensin system, not ACTH. Hypotension is less severe than in primary disease, but can still occur.

Primary adrenal insufficiency is rarer but more likely to cause significant hypotension, salt wasting, and electrolyte disturbances.

3. Why Does Adrenal Insufficiency Lower Blood Pressure?

• Aldosterone deficiency → sodium loss, volume depletion: Aldosterone normally reabsorbs sodium in the kidneys. Without it, large amounts of sodium are lost in the urine, dragging water with it. Blood volume shrinks, and BP drops — particularly when standing.
• Cortisol deficiency → vascular collapse: Cortisol is required for blood vessels to respond to catecholamines (adrenaline). Without it, vessels remain in a state of relative relaxation, and systemic vascular resistance falls.
• Electrolyte imbalances: High potassium (hyperkalemia) and low sodium (hyponatremia) can affect heart rhythm and muscle function, further destabilising blood pressure.

The combination of volume loss and vasodilation makes orthostatic hypotension a classic feature of Addison’s disease.

4. Symptoms of Adrenal Insufficiency

The symptoms often develop gradually over weeks to months and can be mistaken for other conditions:

• Progressive fatigue and weakness.
• Dizziness or fainting when standing (orthostatic hypotension).
• Salt craving — a distinctive symptom; patients may eat salt directly or crave salty foods.
• Weight loss and loss of appetite.
• Nausea, vomiting, and abdominal pain.
• Darkening of the skin (hyperpigmentation) — particularly visible in skin creases, knuckles, gums, and scars. This is unique to primary Addison’s and is caused by high ACTH levels stimulating melanocytes.
• Muscle and joint pain.
• Irritability or depression.

If you have unexplained low blood pressure, particularly if accompanied by salt craving or skin darkening, Dr. Reddy advises seeing a doctor for testing.

5. Adrenal Crisis: A Life‑Threatening Emergency

An adrenal crisis occurs when cortisol levels are so low that the body cannot maintain blood pressure, often triggered by an infection, surgery, or sudden withdrawal of steroid medication. Symptoms include:

• Severe hypotension and shock.
• Vomiting and diarrhoea leading to profound dehydration.
• Confusion or coma.
• Hypoglycemia (low blood sugar).

An adrenal crisis is a medical emergency requiring immediate injection of hydrocortisone (or another glucocorticoid) and intravenous fluids. Without prompt treatment, it can be fatal. Patients with known Addison’s disease carry an emergency injection kit and a medical alert card.

6. How Is Adrenal Insufficiency Diagnosed?

If adrenal insufficiency is suspected, the following tests are performed:

• Morning cortisol and ACTH levels: A very low cortisol (<3 mcg/dL) is suspicious; a high ACTH suggests primary disease.
• ACTH stimulation test (Synacthen test): The definitive test. A synthetic ACTH is injected, and cortisol is measured at 30 and 60 minutes. Failure of the adrenals to respond appropriately confirms the diagnosis.
• Renin and aldosterone: High renin with low aldosterone points to mineralocorticoid deficiency.
• Electrolytes: Low sodium, high potassium.
• Adrenal antibodies: 21‑hydroxylase antibodies are often present in autoimmune Addison’s.
• Imaging: CT scan of the adrenal glands may show shrinkage or calcifications (from old TB).

7. How Is Adrenal Insufficiency Treated?

Treatment is lifelong and replaces the missing hormones:

• Glucocorticoid replacement: Hydrocortisone (taken 2‑3 times a day) or prednisolone. The dose is increased during illness, injury, or stress (“sick day rules”).
• Mineralocorticoid replacement: Fludrocortisone is given to replace aldosterone. It helps retain sodium and water, raising blood pressure. Patients on fludrocortisone are advised to maintain adequate salt intake.
• Emergency injectable hydrocortisone: Every patient must have an emergency kit and know how to use it in case of vomiting or crisis.
• Medical alert identification: A bracelet or necklace stating “Adrenal Insufficiency – Needs Steroids” is critical in emergencies.

With proper treatment, blood pressure normalises, energy returns, and patients can lead normal lives.

👉 Read more: Fludrocortisone for Hypotension →