Tips for referring asthma patients for an allergy consult
By Edward Doyle
NEW ORLEANS—When should internists refer their asthma patients to an allergist for a consultation? While there is no clear cut answer to that question, there are some definite clues that your difficult-to-manage asthma patients could benefit from a subspecialist's expertise.
At an Annual Session panel presentation on referring patients, allergy specialist Phillip L. Lieberman, FACP, said that there are no set rules that dictate when to make those referrals. While studies have shown improvements in outcomes and costs when allergists treat asthma patients, knowing exactly when to refer depends on the condition of the patient and the skills of the physician.
"When you look at allergic disease," said Dr. Lieberman, clinical professor of medicine and pediatrics at the University of Tennessee College of Medicine in Memphis, "a consultation is often elective."
In one allergist's practice, 10% to 15% of patients referred with a diagnosis of asthma turn out to have a completely different disease.
He was quick to add, however, that there are times when an allergy consult is essential to the proper care of asthma patients. He pointed out that in his group—which has more than 8,000 visits a year from asthma patients—10% to 15% of patients referred with a diagnosis of asthma turn out to have a completely different disease. (About 80% of patients misdiagnosed with asthma have a vocal cord dysfunction.)
He used the statistic to illustrate just how difficult asthma care can be for internists. "It can be a very slippery diagnosis," he said.
To help internists know when to consider referring a patient, Dr. Lieberman took a two-pronged approach, reviewing recent guidelines and dispensing tips from his own experience.
The well-known guidelines from the National Asthma Education and Prevention Program urge physicians to consider referring asthma patients who have persistent disease and need daily control.
According to Dr. Lieberman, recent recommendations from the CDC give even more detail about when to refer asthma patients. Those guidelines suggest that generalists should refer asthma patients with the following history:
- single, life-threatening episode;
- treatment goals not being met;
- atypical symptoms that make diagnosis unclear;
- history of episodes provoked by environmental factors;
- diagnosis of severe, persistent asthma;
- need for additional diagnostic testing;
- patient eligible for immunotherapy;
- patient requires continuous oral or high-dose inhaled steroids; and
- indication for anti-IgE therapy.
Before you refer an asthma patient for a consult, what kinds of tests should you consider ordering? Dr. Lieberman said he sees too many patients referred to him who have had massive workups that don't really help diagnose or treat the patient's disease.
One of the more useful tests for asthma patients, he said, is an eosinophil count. "If you have any patients with respiratory symptoms, cough, shortness of breath, wheeze and an elevated eosinophil count,'' he said, "there is a 95% chance that the person has reversible obstructive airway disease that will respond to steroids, which is my definition of asthma.'' (In his lab, the break point is 266 cells per cubic millimeter.)
He explained that the test is inexpensive (under $10) and easy to administer. In fact, he likes the test better than a methacholine challenge, in large part because an eosinophil count produces fewer false positives.
"If you do a methacholine challenge,'' he explained, "you need to know your lab and what concentration they use. Anything over 12 milligrams per mil concentration has a very high incidence of false positives.''
What about imaging studies? "In difficult-to-treat asthmatics,'' Dr. Lieberman explained, "they should always have sinus imaging.'' When seeing patients in the office, he said, he'll also use fiber optic rhinolaryngoscopy to look for vocal cord dysfunctions.
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