An adrenal crisis is a sudden, life-threatening drop in cortisol, the hormone your adrenal glands produce to help your body handle stress, maintain blood pressure, and regulate blood sugar. Without enough cortisol, blood pressure can plummet dangerously low, leading to shock and organ failure. Before steroid replacement therapy existed, adrenal insufficiency had a one-year survival rate of about 20% or less. Today, adrenal crises are treatable, but they still carry a mortality rate of roughly 6% per episode.
Why Cortisol Matters This Much
Cortisol does far more than manage stress. It keeps blood vessels responsive, helps the body retain sodium and water, maintains blood sugar between meals, and modulates inflammation. When cortisol drops sharply, blood vessels lose their ability to constrict, fluids shift out of the bloodstream, and blood pressure falls. The heart races to compensate, blood sugar drops, and cells throughout the body begin to fail. That cascade, from cortisol depletion to cardiovascular collapse, is the core of an adrenal crisis.
People with primary adrenal insufficiency (where the adrenal glands themselves are damaged) also lose a second hormone called aldosterone, which controls sodium and potassium balance. That’s why blood tests during a crisis often show dangerously low sodium, rising potassium levels, and signs of dehydration, all of which compound the cardiovascular instability.
Who Is at Risk
Two broad groups face the highest risk. The first includes people with a diagnosed adrenal condition: Addison’s disease, congenital adrenal hyperplasia, or secondary adrenal insufficiency caused by pituitary problems. These individuals rely on daily steroid replacement, and any disruption to that supply can trigger a crisis. Large surveys covering patients in Germany, the UK, Canada, Australia, and New Zealand found that adrenal crises occur at a rate of about 6 to 8 episodes per 100 patient-years, even among people who had received detailed instructions on adjusting their medication during illness.
The second group is less obvious: anyone who has been taking steroids regularly and stops abruptly. Chronic steroid use suppresses the body’s own cortisol production. This suppression can happen with doses as low as 5 mg of prednisone taken for four weeks or more. It isn’t limited to pills. Steroid joint injections, prescription skin creams, and inhaled steroids for asthma can all suppress adrenal function enough that a sudden stop leaves the body without adequate cortisol.
Common Triggers
The single most common trigger is a gastrointestinal illness or flu-like infection. Vomiting and diarrhea are especially dangerous because they can prevent the body from absorbing oral steroid replacement, creating a cortisol gap at the exact moment the body needs more of it. Other well-documented triggers include:
- Infections of any kind: bacterial, viral (including COVID-19), fungal, or parasitic
- Surgery, trauma, or childbirth
- Extreme temperatures, both heat and cold
- Severe emotional distress or intense physical exertion
- Missed steroid doses or abrupt discontinuation of chronic steroid therapy
- Certain medications, including some cancer immunotherapy drugs and antifungal agents that interfere with cortisol production
Starting thyroid hormone replacement in someone with undiagnosed adrenal insufficiency is another overlooked trigger. Thyroid hormones speed up cortisol metabolism, so correcting a thyroid problem can unmask an adrenal problem that was previously hidden.
Symptoms to Recognize
An adrenal crisis can come on over hours or develop more gradually over a day or two as an illness worsens. The hallmark symptoms are severe weakness, dizziness, nausea, and vomiting. Abdominal pain or flank pain is common and sometimes severe enough to mimic a surgical emergency. Blood pressure drops, heart rate climbs, and the person may feel faint or confused.
If untreated, the progression moves toward full cardiovascular shock: cold and clammy skin, altered consciousness, and eventually loss of consciousness. The danger is that these symptoms overlap with many other conditions, from food poisoning to sepsis, so an adrenal crisis can be missed if the medical team doesn’t know about the person’s adrenal history. That’s one reason medical alert bracelets and carrying an emergency card matter for people with adrenal insufficiency.
How It Is Treated
An adrenal crisis is a medical emergency treated with an injection of hydrocortisone and intravenous fluids to restore blood pressure and cortisol levels. The response is usually rapid once cortisol is replaced, but delays increase the risk of organ damage. That’s why people with known adrenal insufficiency are prescribed an emergency injection kit and trained to use it before reaching the hospital.
Once stabilized, the underlying trigger (an infection, a missed dose, a surgical stress) is identified and addressed. Hospital stays vary depending on the severity of the crisis and the condition that provoked it, but many people recover within 24 to 48 hours after cortisol replacement and fluid resuscitation.
Preventing a Crisis With Sick Day Rules
Most adrenal crises are preventable with a set of guidelines commonly called “sick day rules.” These are simple dose adjustments that mimic what healthy adrenal glands would do naturally: produce more cortisol when the body is under stress.
For a mild illness without fever, no dose change is needed. For a flu or infection with fever, the standard guidance is to double your usual steroid dose for the duration of the illness and contact your doctor if you’re not improving within 48 hours. The critical scenario is vomiting more than once, diarrhea, or severe illness: double the steroid dose immediately, and if you can’t keep it down, use the emergency hydrocortisone injection and get to an emergency department without delay.
If you feel weak, dizzy, nauseated, faint, or are losing consciousness, that’s a signal to administer the injection immediately and call for emergency help. Waiting to “see if it gets better” is the most common mistake that turns a manageable situation into a crisis. Among children with adrenal insufficiency, the crisis rate mirrors that of adults at 5 to 10 episodes per 100 patient-years, so caregivers need to be equally prepared.
Living With the Risk
Even with good education, adrenal crises remain a persistent risk for people with adrenal insufficiency. A German prospective study found a crisis rate of 8.3 per 100 patient-years among patients who had already received detailed written instructions on dose adjustments. That means roughly 1 in 12 patients experienced a crisis each year despite knowing the rules.
Practical preparedness makes the biggest difference. That means keeping an emergency injection kit at home, at work, and while traveling. It means ensuring that family members, partners, or close colleagues know how to give the injection. It means wearing medical identification and carrying a steroid emergency card. And it means understanding that any illness involving vomiting is an urgent situation, not a wait-and-see one. The gap between knowing the rules and acting on them quickly enough is where most preventable crises happen.