If you’re on immunotherapy and feel wrung out in a new way, don’t brush it aside. Immunotherapy adrenal insufficiency, a rare immune-related adverse event from immune checkpoint inhibitors, is uncommon, but it can become dangerous fast because the body may stop making enough cortisol. That cortisol level shortfall can affect blood pressure, blood sugar, hydration, and the way you respond to illness.
Cancer treatment already asks a lot of your courage. This is one place where quiet attention matters. When you know the warning signs, ask for the right cortisol tests, and keep an emergency plan close, you give yourself a safer path through treatment and remission.
Recognizing immunotherapy adrenal insufficiency symptoms early
Many cases linked to immune checkpoint inhibitors, such as anti-PD-1 therapy with pembrolizumab or nivolumab used in triple negative breast cancer or alongside neoadjuvant chemotherapy, and anti-CTLA-4 drugs, arise from hypophysitis that irritates the pituitary gland. This normally sends signals from the brain to the adrenals to make cortisol, but in secondary adrenal insufficiency the signal gets weak, so the body runs low on a hormone it depends on every day. A review of early warning signs found that diagnosis is often delayed because the first symptoms look so ordinary.
Fatigue is common in cancer care, so how do you tell the difference? Often it feels different from normal treatment tiredness. You may feel weak, dizzy when you stand, sick to your stomach, or more washed out than usual. Some people also get vomiting, belly upset, weight loss, dehydration, hypotension, hyponatremia, or headaches. If the pituitary is inflamed, headache or vision changes can show up too.
These symptoms can start months into treatment. They can also appear when you think the roughest stretch is over. If you’re in remission and suddenly feel faint, confused, or unable to bounce back from a minor illness, it still deserves attention.
If your symptoms feel off-pattern for you, call your oncology team early.
Because these signs can mimic infection, dehydration, or sepsis, doctors may need to rule out several problems at once. A NIH case report on underdiagnosed adrenal insufficiency shows how low blood pressure and ongoing weakness can be missed if nobody is thinking about cortisol. Keeping notes can help. These daily tools for tough treatment days can make it easier to track dizziness, nausea, blood pressure changes, and when symptoms began.
How cortisol tests help confirm what’s happening
When adrenal insufficiency is suspected, timing matters. Cortisol naturally peaks in the early morning, so many teams order an 8 AM morning cortisol test. If that cortisol level is low, they usually pair it with an ACTH test. ACTH is the brain’s signal hormone. Together, those results help show where the problem sits.
This quick guide makes the pattern easier to see:
| Test pattern | What it may suggest |
|---|---|
| Low cortisol, low ACTH (ACTH insufficiency) | Secondary adrenal insufficiency, often from hypophysitis or pituitary inflammation after immunotherapy |
| Low cortisol, high ACTH | Primary adrenal insufficiency, where the adrenal glands are affected directly |
A review of isolated ACTH deficiency after checkpoint inhibitors explains why that low-cortisol, low-ACTH pattern (ACTH insufficiency) is seen so often, especially with drugs like pembrolizumab. Your team may also perform an endocrinology work-up that includes an ACTH stimulation test, pituitary MRI, sodium and potassium (for hyponatremia), thyroid labs (for thyroid dysfunction), and sometimes other hormones, because immunotherapy can cause endocrinopathies or immune-related adverse events upsetting more than one gland at a time.
The takeaway is simple. Ask whether cortisol was checked, and ask what time the blood was drawn. If you already take steroids for another reason, say so, because that can change the results. Still, if you have severe vomiting, confusion, hypotension, hyponatremia, or very low blood pressure, don’t wait at home for routine labs. That situation needs urgent care, not patience.
Build an emergency plan before an adrenal crisis starts
An adrenal crisis can look like a body that suddenly loses its footing. Blood pressure drops. Confusion sets in. Vomiting may keep you from holding down pills. It can happen during fever, stomach illness, injury, or another physical stress, especially with immune checkpoint inhibitors such as pembrolizumab, nivolumab (anti-PD-1 therapy), or anti-CTLA-4, which is why a written plan matters so much.
Once your team confirms adrenal insufficiency, often ACTH insufficiency from immune checkpoint blockade, ask for four things in writing. First, your daily replacement dose for glucocorticoid replacement, often hydrocortisone; include mineralocorticoids if your case is not secondary. Second, clear sick day rules for fever, injury, or infection. Many patients are told to double or triple their dose during illness, but only follow the exact plan your own team gives you. Third, an emergency injection plan if you can’t keep pills down. Fourth, guidance on when to call 911 or go to the ER.
A good plan should also cover these red flags:
- Call emergency help now if you faint, become confused, can’t stop vomiting, have hypoglycemia, hypotension, or severe weakness.
- Use your emergency steroid injection if your clinician has prescribed one and told you when to use it.
- Tell every clinician that you have adrenal insufficiency and may be having an adrenal crisis.
The MSK patient guide on adrenal insufficiency is a helpful plain-language reference for what daily treatment and emergency prep often involve, particularly for hormone dysfunction. Carry a medical alert bracelet or card, and make sure the people close to you know where your medicine is kept. That kind of planning isn’t fear talking. It’s wisdom.
Many people can stay on immune checkpoint inhibitors, or return to them, once hormone replacement is working and the situation is stable, helping manage endocrinopathies. So this isn’t a sign that hope is gone. It’s a sign that your body needs backup. If the stress of planning feels heavy, these tips on managing stress in long-term cancer treatment may help steady the emotional side too.
Conclusion
Sometimes courage looks like noticing dizziness, requesting an 8 AM cortisol level test, and keeping an emergency injection within reach. Immunotherapy adrenal insufficiency, often linked to immune checkpoint inhibitors like pembrolizumab and ACTH insufficiency, is serious but treatable with glucocorticoid replacement and a clear plan to lower risk. Listen to the pattern of your body, share that pattern quickly, and let that small act of attention protect your next step from immunotherapy adrenal insufficiency.
