Wednesday, April 27, 2011

Cushing's Diagnosis ~ Think Like a Doctor: A Litany of Symptoms Solved!

On Wednesday I challenged readers to solve a complicated case of a 76-year-old woman who became physically and mentally debilitated over a matter of months.

More than 500 readers weighed in with diagnoses that included porphyria, thrombotic thrombocytopenic purpura and lupus. As of late Wednesday night, 15 readers had come up with the right diagnosis. And the winning answer is:

Diagnosis: Cushing’s syndrome.

The first answer came early. At 12:54 a.m. Eastern time, Dr. Elizabeth Neary, a pediatrician in Madison, Wis., was the first reader to put all the patient’s symptoms together and reach the correct diagnosis.

The wide range of complaints that characterize Cushing’s syndrome was first described by Dr. Harvey Cushing in 1932. In this disease, the adrenal glands churn out too much cortisol, an essential hormone involved in our body’s response to stress. Cortisol helps maintain blood pressure, reduces the immune system’s inflammatory response and increases blood sugar levels — all vital processes for helping our bodies cope with biological and environmental stress.

But long-term exposure to high levels of cortisol can cause osteoporosis, diabetes, high blood pressure, muscle weakness, memory loss and psychiatric disease. It causes the skin to thin and weaken, making it susceptible to bruises that are often dark and dramatic looking. The lesions on this patient’s arms and legs were signs of this.

Cushing’s syndrome is unusual, but a milder version of the disease can be seen in patients who use steroid hormones like prednisone for the treatment of asthma, rheumatoid arthritis or other inflammatory diseases. However, in this case, the syndrome is believed to have been caused by a tiny tumor that was triggering the constant release of high doses of cortisol.

How the Diagnosis Was Made:

When the patient and her two daughters arrived at Waterbury Hospital, Dr. Rachel Lovins met them in the emergency room. She had been introduced to their mother some years earlier, but now she didn’t recognize the woman who sat before her in the wheelchair.

She had gained a lot of weight, her face was much rounder than Dr. Lovins remembered, and her hair, which had been dark and curly, was thin, gray and uncombed. Over the past year or so, Dr. Lovins had heard her friends talk about their mother’s weakness and decline. Seeing her now, it was clear that her illness had taken its toll. Dr. Lovins excused herself to allow the patient to change into her hospital gown. She would see her again once she had been evaluated in the E.R. and admitted to the hospital.

When she returned later, she stood in the doorway and watched as Dr. Chris Mikos, an E.R. physician, lifted the woman’s hospital gown to examine her abdomen. When he did that, Dr. Lovins saw that the woman had red, almost purple stretch marks on her abdomen.

Suddenly the whole case made sense. Dr. Lovins realized the patient might have Cushing’s syndrome. These stretch marks, known as striae, are the result of the thinning of the skin caused by the excess cortisol. It’s a classic finding in Cushing’s. The patient’s primary doctor may not have seen these marks because she probably didn’t have this debilitated elderly woman change into a gown for every visit.

The test used to look for Cushing’s syndrome is called the dexamethasone suppression test. In this test, you give the patient a dose of a steroid hormone, dexamethasone. If the patient has a normal stress hormone system, then the amount of cortisol in the body will drop dramatically as the body reacts to the steroid and begins to suppress its own cortisol production. A normal patient would post a reading of less than five when it’s measured several hours into the test. This patient’s cortisol was eight times that.

Most of the time, Cushing’s syndrome is caused by a tumor in the pituitary gland in the brain, which in turn causes the adrenal gland to overproduce cortisol. In these cases, surgical removal of the tumor will cure Cushing’s.

But in this case, no tumor was found in the pituitary or elsewhere in the patient’s body. Even so, her doctors still believe that a tumor is triggering the excessive cortisol release, but the tumor is too small to locate.

This patient was started on a medication that prevents the overproduction of cortisol, but she had to stop because of side effects. She is waiting to start the next medicine. If that fails, she will have surgery to remove her adrenal glands. When I saw her last she was doing better but wondered out loud whether she would ever walk again.

Why It Was a Difficult Case:

Because cortisol is a hormone that affects every part of the body, the effects of Cushing’s syndrome are wide ranging, and there is no single symptom that announces that a patient has the disease.

Some of this patient’s complaints were pretty common for a woman her age. She’d gained weight. She was tired. She was depressed. She had high blood pressure. She had cataracts. She had swelling in her legs. All of these are symptoms of Cushing’s, but they are also common in patients without Cushing’s.

On the other hand, she had some unusual problems as well. Her muscles were weak. She had a high white blood cell count. She’d had a gastrointestinal bleed. Still, it wasn’t until you put it all together that it became clear that this woman’s many health problems were all related to Cushing’s.

The patient’s oldest daughter sent an e-mail to her friends telling the story of her mother’s ordeal and of her own frustration in pursuing this unifying diagnosis.

We were told that her psychological state, her neurological problem, her circulation issues and her excessive bleeding were an unrelated bunch of unfortunate circumstances conspiring to make this woman ill. “It happens when you are old,” we were told more than once.

With a disease like Cushing’s, our specialist approach to medicine makes us seem like the proverbial blind men examining the elephant. Each specialist can identify what he is seeing, and yet the whole picture will be missed.

Most of the time, that kind of piecemeal medicine works just fine. But the problem is that the cases in which a different approach is required often are tough to distinguish from the bread-and-butter stuff we see every day.

Readers who come to this column already know it will highlight an unusual case, and as a result, you are ready to take on all the exotic possibilities. Because of that, you are way ahead of the doctor who has to figure out which patient, out of all the patients she’s seen that day, needs something special. That recognition is the start of diagnosis.

Read the article and comments at http://well.blogs.nytimes.com/2011/04/21/think-like-a-doctor-a-litany-of-symptoms-solved/?partner=rss&emc=rss