Asthma Medicines

In the last several years it has become clear that a group of patients with all the characteristics of asthma (airway obstruction, inflammation, and hyperresponsiveness) may never manifest wheezing. In these patients a persistent cough is the main symptom. Although the physical exam may be unremarkable these patients often have typical histories of cough attacks at night or triggered by exposure to allergens. Laboratory evaluation will often demonstrate all the features of asthma. This syndrome is often identified as the “asthma equivalent syndrome” or “cough asthma.” In the past too much weight has been put on the presence of wheezing in the diagnosis of asthma.

Wheezing Without Asthma

Just as the absence of wheezing has often led to patients being misdiagnosed as nonasthmatic, the presence of wheezing also may lead to the erroneous diagnosis of asthma. It has been said that “all that wheezes is not asthma” since many illnesses may produce turbulent airflow through the airways. Tho often patients are “diagnosed” simply on this one physical finding.

Wheezing may occur in a variety of illnesses, such as when lesions produce a fixed blockage or obstruction in an air passage. In a child or an adult this may be as simple as a foreign body that has been aspirated. In these cases wheezing may be localized to one area or one lung, which should alert the physician to such a possibility. The history of onset may have been sudden, following a “choking spell.” In an adult with a history of smoking a lung tumor that may be benign or malignant may also produce wheezing by growing within the bronchial tube and blocking the air flow. In these and similar cases, chest x-rays and diagnostic techniques such as bronchoscopy often produce the correct diagnosis.

Emphysema and Chronic Bronchitis

Many respiratory illnesses are characterized by wheezing and may be mistaken for asthma. Emphysema is a disease in which the elasticity of the lung is reduced, often resulting in closure of the airways. The term “floppy airways” is often used in this disease to describe how easily the bronchial tubes may close and produce wheezing. Chronic bronchitis is a disease in which there is chronic cough and mucus production. Wheezing is often produced by the clogged and inflamed airways of these patients.

Cystic Fibrosis and Bronchiectasis

Patients with cystic fibrosis, a genetic deficiency disease occurring in children and young adults, often have wheezing due to the clogging of their bronchial tubes by an abnormally viscous mucus. A similar mechanism explains the wheezing found in patients with bronchiectasis, an illness in which infections have permanently damaged the bronchial tubes, leading to plugging and inflammation.

Heart Failure (”Cardiac Asthma”)

In patients with heart failure fluid may collect in the lungs around or within the bronchial tubes. These patients often complain of wheezing, especially at night, mimicking the asthma patient. Due to these similar features this has been called “cardiac asthma” although it is a heart syndrome that often resolves with mobilization of the lung fluid by specific medication. The diagnosis is often made by additional physical findings of heart disease as well as by the chest x-ray and other tests of heart function.

Laryngeal Asthma

A rare but increasingly reported illness that produces wheezing and may be misdiagnosed as asthma is vocal cord dysfunction syndrome. This syndrome is also known as “laryngeal asthma” since in this illness wheezing is produced at the voice box by an abnormal closure of the vocal cords when the patient breathes in (inspiration). Normally, the vocal cords separate on inspiration allowing more air to flow into the lungs. In these patients the sounds of turbulent flow are transmitted over the lung fields, mimicking the wheezing of asthma. The cause of this disorder is unknown. It is thought to be involuntary and often responds to voice therapy. The diagnosis may only be made by direct visualization of the vocal cords by the physician. This is increasingly done with a fiberoptic scope.

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