ACTH/Cortisol Ratio May Be Simple, Reliable Test to Diagnose Cushing’s Disease

The ratio between adrenocorticotropic hormone levels and cortisol levels in the blood is higher among Cushing’s disease patients than in healthy people, a new study has found, suggesting that measurement could be used to help diagnose the disease.

Also, higher values at diagnosis could predict if the disease will recur and indicate larger and more invasive tumors.

The research, “The Utility of Preoperative ACTH/Cortisol Ratio for the Diagnosis and Prognosis of Cushing’s Disease,” was published in the Journal of Neurosciences in Rural Practice.

Cushing’s syndrome (CS) is characterized by excess levels of cortisol. In patients with suspected CS, clinicians recommend testing late-night salivary or plasma (blood) cortisol, 24-hour urine-free cortisol (UC), as well as morning cortisol levels after low-dose suppression with dexamethasone, a corticosteroid.

CS may be ACTH-dependent or ACTH-independent, meaning that the high cortisol levels are caused by excess ACTH production.

Patients with CD have elevated levels of ACTH. A tumor, usually an adenoma, causes the pituitary gland to produce excess levels of ACTH, which stimulate the release of cortisol from the adrenal glands. Cortisol usually inhibits ACTH production. However, in CD patients, this feedback mechanism is absent.

Despite extensive research and clinical data, the variable and usually nonspecific signs and symptoms of CD still represent relevant challenges for diagnosis. Clinical manifestations must be associated with biochemical tests, which often have led to conflicting results.

Studies showed that although ACTH levels correlate with the size of the pituitary adenoma, the levels of cortisol do not increase as much. In fact, lower cortisol/ACTH ratios have been reported in patients with macroadenoma – which is greater than 10 millimeters in size – than in those with microadenoma, which is smaller than 10 millimeters.

Conversely, the research team hypothesized that besides their utility for determining the cause of CS, the inverse ratio – ACTH/cortisol – also may be useful for diagnosis.

The team evaluated the pretreatment plasma ACTH/cortisol levels in CS patients with excess cortisol production due to abnormal pituitary or adrenal function. Data from patients were compared with that of individuals without CS.

The study included 145 CS patients diagnosed from 2007 to 2016, 119 patients with CD, 26 with ACTH-independent CS (AICS), and 114 controls with no CS.

Patients’ clinical, laboratory, imaging, postsurgical and follow-up data were analyzed.

Results showed that patients with CD had a significantly higher basal ACTH/cortisol ratio than controls or those with AICS.

“These results showed ACTH/cortisol ratio might be a simple and useful test for the diagnosis of ACTH-dependent CS,” the researchers wrote.

Importantly, the scientists observed that a ACTH/cortisol ratio above 2.5 indicated identified 82 percent of positive CS cases and 63 percent of controls.

Overall, “an ACTH/cortisol ratio [greater than] 2.5 would be beneficial to diagnose CD together with other diagnostic tests,” they concluded.

Patients with recurrent CD showed higher pretreatment ACTH levels and ACTH/cortisol ratio than those who achieved sustained remission. CD patients also exhibited more invasive, atypical and larger tumors, as well as lower postoperative remission and higher recurrence rates.

“Higher ACTH/cortisol ratio might predict poorer prognosis,” the investigators said.


Case Report Shows Rare Adrenal Tumors Associated with Cushing’s Disease

Pituitary tumors that produce too much adrenocorticotropic hormone (ACTH) have been associated with the development of rare tumors on the adrenal glands, called adrenal myelolipomas, for the first time in a case report.

The study, “Case report of a bilateral adrenal myelolipoma associated with Cushing disease,” was published in the journal Medicine.

Myelolipomas, composed of mature fat cells and blood-forming cells, are usually asymptomatic and do not produce hormones. In many cases, these tumors are detected by accident when patients undergo imaging scans for other conditions.

The cause of these tumors is unknown, but due to their benign nature, they do not spread to other parts of the body. However, they can grow up to 34 centimeters (about 13 inches), leading to tissue death and hemorrhage.

Researchers at Soon Chun Hyang University College of Medicine in Seoul, Korea, described the case of a 52-year-old man with myelolipoma possibly caused by an ACTH-secreting pituitary tumor.

During a routine checkup, researchers detected a mass in the patient’s spleen. Further abdominal evaluations identified tissue lesions in both adrenal glands consistent with myelolipoma. Besides the masses, the patient did not show any other Cushing-associated physical characteristics.

However, the patient’s ACTH levels were two times higher than the normal upper limit. Cortisol levels were also increased and unresponsive to low-dose dexamethasone treatment.

No additional lesions were found that could help explain the high ACTH and cortisol levels. But analysis of blood samples collected from the veins draining the pituitary glands revealed the right gland was producing too much ACTH, strongly suggesting Cushing’s disease.

Both the left adrenal gland and pituitary tumor were surgically removed. The samples collected during surgery confirmed the benign nature of the adrenal tumors, and the diagnosis of abnormal, ACTH-positive pituitary gland tissue.

Three days after the surgeries, hormone levels were back to normal. But a follow-up evaluation five months later again showed increased ACTH levels. Cortisol levels, however, were normal.

For the next seven years, the patient was evaluated every six months. During a five-year period, the size of the right adrenal gland was found to have grown. Imaging analysis confirmed the existence of small, new lesions in both pituitary glands.

“This case confers valuable information about the clinical course of adrenal myelolipoma associated with Cushing disease,” the researchers said. It also “supports the notion that ACTH can be associated with the development of bilateral adrenal myelolipomas.”


Dr. Charles Wilson, One of the world’s greatest neurosurgeons and pioneer of transsphenoidal pituitary surgery died at 88


The UCSF website in an obituary from Kate Vidinsky reads “He took a particular interest in pituitary disorders, those affecting the pea-sized ‘master gland’ at the base of the brain responsible for controlling the body’s hormone levels. He was a pioneer of transsphenoidal surgery – the endonasal approach for removing pituitary tumors – and performed more than 3,300 of these procedures at UCSF Medical Center.”

The New York Times in an obituary published yesterday described him as “a pioneering and virtuosic San Francisco neurosurgeon”.

Dr. Wilson died February 28, 2018.

Cushing’s Patients at Risk for Autoimmune Diseases After Condition Is Resolved

Children with Cushing’s syndrome are at risk of developing new autoimmune and related disorders after being cured of the disease, a new study shows.

The study, “Incidence of Autoimmune and Related Disorders After Resolution of Endogenous Cushing Syndrome in Children,” was published in Hormone and Metabolic Research.

Patients with Cushing’s syndrome have excess levels of the hormone cortisol, a corticosteroid that inhibits the effects of the immune system. As a result, these patients are protected from autoimmune and related diseases. But it is not known if the risk rises after their disease is resolved.

To address this, researchers at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) examined 127 children with Cushing’s syndrome at the National Institutes of Health from 1997 until 2017.

Among the participants, 77.5 percent had a pituitary tumor causing the disease, 21.7 percent had ACTH-independent disease, and one patient had ectopic Cushing’s syndrome. All patients underwent surgery to treat their symptoms.

After a mean follow-up of 31.2 months, 7.8 percent of patients developed a new autoimmune or related disorder.

Researchers found no significant differences in age at diagnosis, gender, cortisol levels, and urinary-free cortisol at diagnosis, when comparing those who developed autoimmune disorders with those who didn’t. However, those who developed an immune disorder had a significantly shorter symptom duration of Cushing’s syndrome.

This suggests that increased cortisol levels, even for a short period of time, may contribute to more reactivity of the immune system after treatment.

The new disorder was diagnosed, on average, 9.8 months after Cushing’s treatment. The disorders reported were celiac disease, psoriasis, Hashimoto thyroiditis, Graves disease, optic nerve inflammation, skin hypopigmentation/vitiligo, allergic rhinitis/asthma, and nerve cell damage of unknown origin responsive to glucocorticoids.

“Although the size of our cohort did not allow for comparison of the frequency with the general population, it seems that there was a higher frequency of optic neuritis than expected,” the researchers stated.

It is still unclear why autoimmune disorders tend to develop after Cushing’s resolution, but the researchers hypothesized it could be a consequence of the impact of glucocorticoids on the immune system.

Overall, the study shows that children with Cushing’s syndrome are at risk for autoimmune and related disorders after their condition is managed. “The presentation of new autoimmune diseases or recurrence of previously known autoimmune conditions should be considered when concerning symptoms arise,” the researchers stated.

Additional studies are warranted to further explore this link and improve care of this specific population.


High Levels of MMP-9 Enzyme May Predict Tumor Recurrence in Cushing’s Patients

Measuring the levels of a specific enzyme in pituitary tumors producing excess adrenocorticotrophic hormone (ACTH) may help predict the recurrence of Cushing’s disease in patients, a study shows.

The study, “Expression of MMP-9, PTTG, HMGA2, and Ki-67 in ACTH-secreting pituitary tumors and their association with tumor recurrence,” was published in the journal World Neurosurgery.

Cushing’s syndrome is characterized by excess cortisol levels in the blood. In 70 percent of cases, this is caused by pituitary tumors making too much ACTH, a hormone that regulates cortisol production. This condition is called Cushing’s disease.

While transsphenoidal adenomectomy, a surgery to remove a pituitary gland tumor, is the first treatment choice, tumor recurrence rates can be as high as 45 percent.

Only a few studies have investigated the association between biomarkers and the risk of ACTH-secreting pituitary tumors recurring, leaving physicians with limited methods to predict which patients will have a recurrence.

Identifying biomarkers that can effectively predict the potential recurrence of Cushing’s disease would allow clinicians to look for early signs in patients and start appropriate follow-up and therapeutic protocols, avoiding long-term mortality.

Many studies have suggested that matrix metalloproteinase-9 (MMP-9) enzymes, the pituitary tumor transforming gene (PTTG), and high mobility group A 2 proteins (HMGA2) all play vital roles in the development of pituitary tumors.

Metalloproteinases (MMPs) are enzymes that work to degrade the cell’s extracellular matrix, which anchors the cell, thus enabling tumor invasion. PTTG is highly expressed in pituitary tumors, and is a marker of malignancy in many types of tumors. HMGA2 is overexpressed in various tumors, and is also associated with high malignancy.

However, whether levels of MMP-9, PTTG, and HMGA2 are related to ACTH-secreting tumor recurrence has not been investigated.

Researchers set out to determine the expression levels of MMP-9, PTTG, HMGA2, and Ki-67 (a marker of cell growth) in ACTH-secreting pituitary tumors, and evaluate their association with tumor behavior and recurrence.

They conducted a retrospective study that included 55 patients with sporadic Cushing’s disease with long-term remission after a transsphenoidal adenomectomy. Their tumor specimens were collected and examined.

Patients were divided into two groups based on whether or not they had tumor recurrence. There were 28 patients in the non-recurrent group, and 27 in the recurrent.

Results showed there was significantly increased expression of MMP-9 in tumor samples of recurrent patients, compared with the non-recurrent group. Levels of MMP-9 were also strongly associated with a shorter time period to recurrence (recurrence-free interval).

On the other hand, PTTG, HMGA2, and Ki-67 expression was not significantly different between the recurrent group and the non-recurrent group.

“ACTH-secreting pituitary tumors with higher levels of MMP-9 were associated with a higher recurrence rate and a shorter recurrence-free interval. MMP-9 could be a valuable tool for predicting recurrence of ACTH-secreting pituitary tumors,” the researchers concluded.


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