New research has shown Cushing’s syndrome to have a substantially higher prevalence than previously thought

Diagnosing and treating Cushing’s syndrome is sometimes just as difficult as it was 70 years ago.

Though uncommon, it is difficult to consider Cushing’s syndrome a rare occurrence. New research has shown Cushing’s syndrome to have a substantially higher prevalence than previously thought. Unexpected endogenous hypercortisolism may occur in 0.5% to 1% of patients with hypertension, 2% to 3% with poorly controlled diabetes, 6% to 9% with incidental adrenal masses and 11% with osteoporosis and vertebral fractures.

This article quotes several notable endocrinologists. Each makes the case for Cushing's being both more prevalent than first thought and less easily diagnosed with "gold-standard" testing than once thought. Raff and Findling's research, which I've previously quoted in When the Gold Standard becomes Tarnished, is cited in this article.

Mary Ruppe, an endocrinologist at the University of Texas Health Science Center at Houston, says, “We are gaining an appreciation that Cushing’s is more common than it was once believed to be."

Laurence Katznelson, associate professor of medicine and neurosurgery at Stanford University, emphasizes "delving deeper" when a patient presents with multiple symptoms. He includes depression, hypertension, supraclavicular and dorsicervical fat pads (the notorious "buffalo hump"), and depression among those symptoms.

An open mind is essential according to John's Hopkins endocrinologist, Roberto Salvatori, especially when dealing with mild/subclinical Cushing's.

“Sometimes Cushing’s is obvious. Sometimes, when it is mild, it may not be diagnosed for many years. One must screen a lot of patients to find one with Cushing’s. However, anytime a physician thinks about the possibility of a patient having the disease, work-up should be initiated,” he said.

Lynne Nieman, an NIH researcher/physician/endocrinologist, is quoted in the article saying " testing should be individualized", when in the past the standard has been pretty much the same for all who were tested for Cushing's.

Briefly, the article makes the following points:

• The "gold-standard" testing using dexamethasone and urinary free cortisol levels (UFCs) is not optimum testing for many with mild/subclinical/episodic Cushing's
• No test is 100% sensitive or specific
• A combination of many tests is needed for adequate testing and evaluation
• Late-night salivary and serum cortisol testing seems to be the best options overall for many patients, with salivary the easiest to obtain
• Lab assays need to be standardized across the various labs
• Half of patients with ACTH-secreting microadenomas are estimated to have a normal pituitary MRI
• Bilateral inferior petrosol sinus sampling has an important role in differentiating between adrenal/ectopic and pituitary sources
• With surgical treatment, the experience of the surgeon is instrumental in remission and cure success rates
  
• New treatments, especially drug treatments, are being tested and evaluated in clinical trials

To read more:
The difficulties of Cushing’s syndrome

Testing 101: Biochemical analysis

When "the next episode" takes on new meaning....

Recent Advances in Neuroendocrine Imaging Lead to Improved Diagnosis

Testing 101: Biochemical analysis