Tertiary adrenal insufficiency – Diagnostics – Overview of Information and Clinical Research

Tertiary adrenal insufficiency happens when the hypothalamus, a small area in your brain, doesn’t produce enough of the hormone that triggers cortisol production. Understanding how this condition is diagnosed can help you recognize when to seek medical attention and what to expect during the testing process.

Introduction: Who Should Undergo Diagnostics

If you have been taking glucocorticoid medications (also known as steroids) for conditions such as asthma, arthritis, skin conditions, Crohn’s disease, or multiple sclerosis for extended periods, you should be aware that your body may develop tertiary adrenal insufficiency. These artificial steroid medications can interfere with the normal communication between your brain and adrenal glands, eventually causing your adrenal glands to “go to sleep” and stop producing cortisol on their own.^[1]

You should seek diagnostic testing if you experience symptoms that cannot be explained by another cause. The early signs of tertiary adrenal insufficiency are often quite vague and nonspecific, which can make the condition difficult to identify. Common symptoms include persistent fatigue that doesn’t go away with rest, muscle weakness that affects your daily activities, loss of appetite leading to unintentional weight loss, and general feelings of tiredness and lack of energy. You might also experience nausea, vomiting, dizziness when standing up, low blood pressure, irritability, depression, joint pain, or cravings for salty foods.^[5]^[17]

Children with this condition may show different signs. They might experience ongoing fatigue, weakness, and slow recovery from illness. If a severe or lengthy illness occurs, it can result in vomiting that may quickly become a medical emergency. Children suffering from an adrenal crisis (a life-threatening complication) will show low blood pressure, low blood sugar, lethargy, and possible loss of consciousness.^[3]

Healthcare professionals should maintain a high level of suspicion for this disease because the symptoms vary greatly and can be easily overlooked or confused with other illnesses. The decreasing or suppressed adrenal function may be masked until stress or illness triggers an adrenal crisis. Sometimes symptoms appear for the first time during such a crisis.^[4]

⚠️ Important

It’s crucial to emphasize that even if you stop taking artificial glucocorticoids, your adrenal glands may never recover their function, or recovery may take many years. Never stop taking steroid medications suddenly without medical supervision, as this can be dangerous. Always work with your healthcare provider to taper off these medications safely if appropriate.^[1]

Certain groups of people should be particularly vigilant about seeking diagnostic testing. If you are acutely ill with unexplained symptoms, if you have predisposing factors such as autoimmune conditions, or if you are taking medications that affect adrenal function, clinicians should use a low threshold for diagnostic evaluation. Pregnant women experiencing fatigue, hypotension, and nausea that cannot be explained by pregnancy alone should also consider testing.^[7]

Classic Diagnostic Methods

When your doctor suspects tertiary adrenal insufficiency, the diagnostic process involves several steps designed to confirm the condition and distinguish it from other forms of adrenal insufficiency. The journey begins with a thorough discussion of your medical history and symptoms. Your healthcare professional will pay particular attention to your use of steroid medications, including the type, dose, duration, and how you have been taking them.^[11]

The most important diagnostic tool is the ACTH stimulation test, also called the short corticotropin test. This test is considered the gold standard for confirming adrenal insufficiency. During this test, your cortisol levels are measured in your blood before and after you receive an injection of laboratory-made ACTH. The test shows how well your adrenal glands respond to stimulation. In tertiary adrenal insufficiency, because the adrenal glands have been “asleep” for some time, they may not respond properly to the ACTH signal, resulting in cortisol levels that remain low even after the injection.^[7]^[11]

If the ACTH stimulation test is not immediately available, doctors may begin with simpler blood tests. A morning cortisol test combined with plasma ACTH testing can provide preliminary information. These tests measure the baseline levels of these hormones in your blood. The timing of the blood draw is important because cortisol levels naturally fluctuate throughout the day, typically being highest in the morning and lowest at night.^[7]

Blood tests can also measure other important markers. Your doctor may check your sodium and potassium levels, as people with tertiary adrenal insufficiency often have low sodium levels in their blood, a condition called hyponatremia. However, unlike primary adrenal insufficiency where aldosterone is also deficient, people with tertiary adrenal insufficiency typically maintain normal aldosterone production. This means they usually don’t develop high potassium levels or severe salt imbalances, because the system that regulates aldosterone (the renin-angiotensin system) works independently of the hypothalamus and pituitary gland.^[2]^[4]

Another test that may be used, particularly when secondary or tertiary adrenal insufficiency is suspected, is the insulin-induced hypoglycemia test. This test helps determine whether the pituitary gland is contributing to the problem. During this test, your blood sugar and cortisol levels are checked after you receive an injection of insulin. The insulin causes your blood sugar to drop, which should trigger your body to release cortisol as a stress response. If cortisol levels don’t rise appropriately, it suggests a problem with the hypothalamic-pituitary-adrenal axis.^[11]

Imaging tests play a supporting role in diagnosis. A CT scan of your abdomen can check the size of your adrenal glands and look for other abnormalities. In tertiary adrenal insufficiency, the adrenal glands themselves are usually structurally normal, though they may shrink over time from lack of stimulation. An MRI of the pituitary gland may be ordered to look for damage or tumors that could cause problems with hormone production, helping to rule out secondary adrenal insufficiency caused by pituitary disease.^[11]

Your doctor may also look for antibodies in your blood that are related to autoimmune disease. While this is more common in primary adrenal insufficiency (Addison’s disease), checking for these antibodies helps distinguish between the different types of adrenal insufficiency.^[11]

⚠️ Important

If you present with symptoms of an adrenal crisis, which is a potentially life-threatening emergency, treatment should not be delayed while waiting for test results. An adrenal crisis requires immediate medical attention with high doses of hydrocortisone and intravenous fluids. The diagnostic tests can be completed once you are stabilized.^[12]

Understanding the difference between tertiary adrenal insufficiency and other forms is crucial for proper diagnosis. In tertiary adrenal insufficiency, the problem starts in the hypothalamus, which doesn’t make enough corticotropin-releasing hormone (CRH). Without enough CRH, the pituitary gland doesn’t make enough ACTH, and without enough ACTH, the adrenal glands don’t make enough cortisol. This cascade of events can be triggered most commonly by long-term use of glucocorticoid medications, which make the brain think there are too many steroid hormones in the body, causing it to shut down its natural production system.^[1]^[2]

The most important distinction in these diagnostic tests is determining whether you have preserved mineralocorticoid function. Those with tertiary adrenal insufficiency will typically have normal aldosterone levels because this hormone is regulated by a different system that doesn’t depend on signals from the hypothalamus or pituitary. This helps doctors differentiate tertiary adrenal insufficiency from primary adrenal insufficiency, where both cortisol and aldosterone are deficient.^[4]

Unfortunately, there are no easy or reliable tests to assess how effective replacement therapy is once treatment begins. Some doctors prefer to use cortisol day curves for treatment monitoring and dose adjustment, which involves measuring cortisol levels at different times throughout the day. Others rely primarily on the symptoms you report to adjust and optimize your medication dosing. This is why working closely with an endocrinologist who specializes in hormone disorders is highly recommended for managing this condition.^[12]

Diagnostics for Clinical Trial Qualification

While the sources provided do not contain specific information about diagnostic tests or methods used as standard criteria for enrolling patients with tertiary adrenal insufficiency in clinical trials, the general diagnostic methods described above would form the foundation for any clinical research participation. Clinical trials typically require confirmed diagnosis through the standard ACTH stimulation test and comprehensive hormone level measurements to establish baseline function before any experimental treatments can begin.

Prognosis and Survival Rate

Prognosis

The outlook for people with tertiary adrenal insufficiency is generally positive with proper treatment and management. Most people with this condition can live normal, active lives when they receive appropriate hormone replacement therapy. However, the recovery of natural adrenal function varies greatly among individuals. It’s important to understand that even after stopping glucocorticoid medications, your adrenal glands may never fully recover their function, or recovery may take many years. The duration and dose of previous steroid exposure, as well as individual factors, all play a role in determining whether and when the hypothalamic-pituitary-adrenal axis will return to normal function.^[1]^[2]^[3]

The key to a favorable prognosis lies in proper diagnosis, appropriate replacement therapy, and ongoing monitoring. Without treatment, the adrenal glands can shrink and stop working over time, making the condition permanent. With treatment, however, most people experience dramatic improvement in their wellbeing, often within 24 hours after starting hormone replacement. The greatest risks come from not recognizing the condition or failing to increase medication doses during periods of stress, illness, or surgery, which can lead to adrenal crisis. Patients who understand their condition and follow sick-day rules typically have excellent outcomes.^[3]^[12]

Survival rate

Specific survival statistics for tertiary adrenal insufficiency are not provided in the available sources. However, it is noted that adrenal crisis, which can occur in any form of adrenal insufficiency if not properly managed, has a mortality rate of 0.5 per 100 patient-years. The prevalence of adrenal crisis in adrenal insufficiency is reported as 6.6 to 8.3 episodes per 100 patient-years, mainly triggered by gastrointestinal and other infectious diseases. With proper treatment, emergency medication availability, and patient education about managing stress situations and illness, the risk of life-threatening complications can be significantly reduced. The emphasis in management is on prevention of adrenal crisis rather than treatment after it occurs.^[9]

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