All That Wheezes Is Not Asthma


All That Wheezes Is Not Asthma

Page 16

All That Wheezes Is Not Asthma

Pseudo

LAS VEGAS—Tim Myers, BS, RRT, often recognizes a patient with vocal cord dysfunction before he reaches for the stethoscope he carries in his pocket.

“You can hear them wheezing at the doorstep to the emergency room,” he said.

Loud wheezing, which does not resolve with repeated bronchodilator rescue treatments, is likely to end with intubation and mechanical ventilation, Myers added.

While he usually preaches “all that wheezes is asthma,” Myers did discuss two exceptions when he addressed clinicians here at the 45th AARC International Respiratory Congress. The pediatric administrative manager at Rainbow Babies and Children’s Hospital in Cleveland, Ohio, reviewed data and case studies linking non-asthma wheezing with vocal cord dysfunction (VCD) and with transient wheezing in young children. He suggested these “pseudo asthma” conditions lead clinicians on an “asthma masquerade” and shared some tips to help with diagnosis.

Vocal chord laryngeal dysfunction resulting in airway obstruction usually presents in women between the ages of 20 and 40, but exceptions do occur. Myers noted there are a dozen young VCD patients at Rainbow Babies, all under 20. Eight of the 12 are boys.

Cases of Misdiagnosis
The condition is frequently misdiagnosed as asthma. These patients do not respond to asthma medications unless they are among the 30 percent who have asthma plus VCD. This dual diagnosis complicates the picture because these patients gain some relief from their medication, even though their wheezing persists. As a result, they often end up in the ICU on ventilators.

Myers offered several suggestions to help clinicians separate VCD patients from the asthma patients in the ER. If they do not respond to the bronchodilator within five or 10 minutes, clinicians should consider diagnoses other than asthma.

A thorough health history often sheds light on this strange condition. For example, VCD patients do not usually report nocturnal symptoms such as cough or frequent waking. During the day, they do cough, and they report problems with choking and a hoarse voice. They often have a history of ER visits and hospitalizations. Many are steroid-dependent because they were misdiagnosed with asthma.

Examination with a stethoscope may provide clues. If VCD is present, clinicians will notice a stronger wheeze over the vocal cords than in the airway. “If the wheezing seems to be concentrated in the larynx, that may be a clue to where the obstruction is,” Myers explained.

He suggested two exercises that would eliminate real asthma patients: ask them to pant or to hold their breath for three to four seconds after a puff of the bronchodilator. Asthmatics cannot complete either exercise during an exacerbation.

Pulmonary function tests may also provide a clue. If patients present with a blunted response on the inspiratory flow loop, VCD is a likely diagnosis. Myers said VCD causes problems during inspiration whereas asthma obstructs expiration.

Lung scans contribute little to the diagnostic work-up because most patients with VCD present normal perfusion ratios. Likewise, blood gases tend to be normal.

Chemically, patients with VCD may lack eosinophils, suggesting no evidence of inflammation, the hallmark of asthma.

Psychiatric components, such as stress-related disorders, are often present in the VCD picture. Gastroesophageal reflux may also be present.

Transient Wheezing
A second condition that may produce wheezing without asthma is often seen in a small subsection of young children, usually under three years of age. Myers cited two studies—one conducted in Italy and one in Tucson, Ariz.—that identified transient wheezing in young children.

The wheezing resolved by the time the children reached their sixth year. In the Italian study of 16,333 children, investigators labeled about 7.5 percent as “transient early wheezers,” 4.1 percent as “persistent wheezers” and 5.6 percent as “late onset wheezers.”

The Tucson group studied 1,246 children. They labeled 19.9 percent as transient wheezers, 13.7 percent as persistent wheezers, and 15 percent as late-onset wheezers.

F.D. Martinez of Tucson found that persistent wheezers had elevated serum IgE count and more had positive skin tests than the transient wheezers. Transient and non-wheezers presented with reduced peripheral blood eosinophil levels.

Italian investigator (Rusconi) suggested siblings and day care were risk factors for transient wheezing and found transient wheezers were more likely to be breast fed for at least six months and have mothers who smoked.

In conclusion, Myers noted “all that wheezes before the age of three may not be asthma.”

Francie Scott is an ADVANCE senior editor.

This article originally appeared in the May 1, 2000, edition in a longer version.