Woman found to have Cushing’s despite negative cortisol tests

Doctors used specialized blood test to diagnose patient in case

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Despite repeatedly testing negative for high cortisol levels on standard lab tests, a woman in her 30s was found to have Cushing’s syndrome after undergoing a specialized blood analysis.

That test allowed doctors to measure the levels of the hormone cortisol — too much of which is a hallmark of Cushing’s — in the veins near the patient’s adrenal glands, which sit atop the kidneys. The results, showing elevated cortisol, ultimately confirmed the woman’s Cushing’s syndrome diagnosis, according to a new case report.

“This case highlighted the importance of maintaining a high index of suspicion for patients presenting with several signs and symptoms of the disease and a negative workup,” the researchers wrote.

The woman’s case was described in a study, “Rare Challenges in Diagnosing Cushing’s Syndrome and Primary Aldosteronism: A Case Report of a Female With a Negative Workup,” published in the journal Cureus.

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Patient shows signs of Cushing’s despite negative cortisol tests

Cushing’s syndrome is a broad term that encompasses any condition where symptoms are driven by excessive levels of the stress hormone cortisol. Cushing’s disease is a specific form of the syndrome, in which the underlying cause is a tumor in the brain.

Tests to measure cortisol levels in the blood or urine are a key part of diagnosing Cushing’s syndrome. When such tests don’t reveal clear abnormalities, however, the negative results can pose a serious challenge in establishing a diagnosis.

In this report, a pair of U.S. scientists described the case of a 37-year-old woman who sought medical care due to muscle weakness, chest pain, and an abnormally fast heart rate (tachycardia).

Preliminary tests showed that she had high blood pressure. She was prescribed several medications, but her blood pressure continued to increase despite treatment. The patient also reported easy bruising, weight gain, and hair loss — all symptoms associated with Cushing’s.

However, when clinicians performed standard tests to measure cortisol levels, all of them were within the normal range for this hormone. Levels of another hormone, called aldosterone — which, like cortisol, is mainly produced in the adrenal glands — were slightly elevated.

A CT scan of the patient’s abdomen revealed a small mass on her right adrenal gland. Given that the woman’s clinical condition was highly suggestive of Cushing’s, the team decided to perform a more specialized test that allowed them to measure cortisol levels in the veins near her adrenal glands.

Those results showed that cortisol levels in the right adrenal vein were extremely high, as were those of aldosterone.

“The amount of aldosterone and cortisol were both significantly higher on the right side,” the researchers wrote.

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Blood tests for cortisol may help in cases with uncertain diagnosis

Despite the earlier negative tests, these findings were sufficient to confirm the diagnosis of Cushing’s syndrome.

Given the importance of this test in this patient’s case, the researchers noted that, “in those with an uncertain diagnosis, adrenal venous sampling can provide a clearer picture and lead to a more accurate understanding of the case.”

The patient underwent a successful surgery to remove her right adrenal gland. Testing of the removed gland revealed that the mass was a type of tumor called adrenal cortical adenoma.

Following the surgery, the patient’s condition improved, though her blood pressure dropped to abnormally low levels. The researchers said this probably was the result of reduced adrenal activity.

Corticosteroids, which are medicines that mimic the activity of cortisol in the body, helped to stabilize the patient’s condition.

The woman reported that her brother and mother had also experienced high blood pressure starting in their 30s, leading clinicians to wonder whether the patient might have a genetic condition that predisposed her towards developing adrenal problems. However, due to financial constraints, the patient was unable to undergo genetic testing to confirm or refute this speculation.