What is the difference between primary and secondary adrenal insufficiency?

The Fundamental Difference Between the Two Types

Adrenal insufficiency means the body does not produce enough of certain adrenal hormones, and it can be primary, secondary, or tertiary. The main difference between primary and secondary insufficiency is the location of the problem. In primary insufficiency, the problem is within the adrenal glands themselves; in secondary insufficiency, the problem begins in the pituitary gland, a small gland at the base of the brain that sends a signal that helps the adrenal glands produce cortisol. [1] [2]

In primary insufficiency, often known as Addison's disease, the adrenal cortex is damaged and cannot produce enough cortisol, and aldosterone production may also decrease. In secondary insufficiency, the pituitary gland does not produce enough adrenocorticotropic hormone (ACTH), and therefore the adrenal glands do not receive the signal needed to produce cortisol. [1]

How do the causes and symptoms differ?

Common causes of primary insufficiency include autoimmune diseases that attack the adrenal gland, as well as certain infections, hemorrhages, tumors, and some genetic causes. Secondary insufficiency may result from diseases, tumors, injuries, or surgeries that affect the pituitary gland. Central adrenal insufficiency can also occur after stopping corticosteroids that have been used for a long time, which is usually associated more with tertiary insufficiency than primary or secondary. Therefore, corticosteroids used for a long time should not be stopped suddenly; a doctor determines how to taper them when appropriate. [2]

Both types can share symptoms such as persistent fatigue, muscle weakness, loss of appetite and weight, abdominal pain, nausea, low blood pressure, and dizziness. However, skin hyperpigmentation is more associated with primary insufficiency; in secondary insufficiency, this pigmentation associated with primary insufficiency typically does not appear. [2]

What is the difference in hormones and salt?

Primary insufficiency leads to a cortisol deficiency and may also lead to aldosterone deficiency. This can cause an imbalance in sodium, potassium, water, and blood pressure. Secondary insufficiency mainly affects cortisol, while aldosterone production is usually preserved. Therefore, a patient's need for aldosterone replacement may differ between the two types, and is determined by the doctor according to tests and the patient's condition. [4] [1]

When does insufficiency become an emergency?

An adrenal crisis can occur when there is a severe deficiency of cortisol, especially during severe illness, injury, or surgery. Acute symptoms such as sudden severe pain in the abdomen or back, vomiting or diarrhea, severe weakness, confusion, or loss of consciousness require emergency medical care, because an adrenal crisis can cause a dangerous drop in blood pressure, blood sugar, and sodium. [1] [3]

Therefore, the type of insufficiency cannot be determined by symptoms alone; differentiation relies on a medical assessment and tests of hormones and the function of the pituitary and adrenal glands depending on the case. [1] [2] For further reading: Comprehensive Guide to Adrenal Gland Disorders (Arabic).

Medical references

• Definition & Facts of Adrenal Insufficiency & Addison's Disease - NIDDK
• Symptoms & Causes of Adrenal Insufficiency & Addison's Disease - NIDDK
• Health Alert: Adrenal Crisis Causes Death in Some People Who Were Treated with hGH
• Treatment for Adrenal Insufficiency & Addison's Disease - NIDDK