Managing Cough as a Defense Mechanism and as a Symptom

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Cough is a symptom

Acute cough and chronic cough are symptoms of conditions that may require medical attention. Hundreds of conditions can cause cough; about a dozen conditions are the most frequent causes.

The cause of cough may not be immediately apparent. In the case of chronic cough, more than one cause may simultaneously be at work. A full medical examination and laboratory tests may be necessary to arrive at a correct diagnosis and effective treatment. In the greatest majority of cases, the specific cause of cough can be diagnosed and successfully treated with therapy specific for the cause. Specific therapy is so often successful that there is a limited role for nonspecific medicines.

Postnasal Drip Syndrome

PNDS is the most frequent cause of both acute and chronic cough. PNDS plus one or two other conditions, such as GERD, are often involved in chronic cough.

In addition to cough, complaints associated with PNDS are (1) a feeling of something dripping into the throat, (2) a need to constantly clear the throat, (3) nasal congestion or discharge, and (4) hoarseness.

The person with PNDS usually

• has recently had a cold, or
• suffers from allergic rhinitis, or
• suffers from acute or chronic sinusitis.

Treatment of cough due to PNDS is determined by the diagnosis, including diagnosis of underlying conditions such as sinusitis.

Asthma

Asthma is a common cause of chronic cough in both children and adults. In some persons, chronic cough is the only symptom of asthma. In other persons, symptoms in addition to cough include wheezing, shortness of breath, and a feeling of tightness in the chest.

Asthma is a serious medical condition that requires monitoring and treatment with carefully selected drugs. When cough is due to asthma, the cough usually goes away when the asthma is effectively treated.

Gastroesophageal Reflux Disease

GERD is caused when contents from the stomach reflux (backs up) into the esophagus. GERD is a common cause of chronic cough in adults and children. In addition to cough, serious respiratory complications of GERD include chronic bronchitis, worsening bronchial asthma, and other lung diseases.

GERD is often difficult to diagnose. More than half of the persons with cough due to GERD are unaware of reflux; they do not complain of typical gastrointestinal symptoms such as heartburn, sour taste, or regurgitation. Tests to detect GERD may include 24-h monitoring of acidity in the esophagus with a catheter.

GERD is sometimes one of the “other” causes of chronic cough when chronic cough is due to more than one cause. GERD and cough also can have a self-perpetuating cycle in conjunction with another cause of cough: cough due to another cause precipitates reflux from the stomach, which in turn causes cough due to GERD, so that the patient ends up with two causes of chronic cough.

Treatment of GERD includes dietary restrictions and antireflux drugs, and occasionally, surgery. Treatment of cough due to GERD also includes treatment of any other conditions causing cough.

Chronic Bronchitis

Chronic bronchitis is a frequent cause of chronic cough, especially in smokers. Tobacco smoke causes airway inflammation, excessive mucus secretion, and impairment of normal clearance of mucus. Effective cough is important for the smoker, as it helps clear excessive mucus from the airway.

Smoking cessation is the only fully effective treatment for chronic cough due to chronic bronchitis in a smoker.

Because smokers often “expect to cough,” they may not seek medical attention for a cough that persists. Smokers should be aware, however, that cough is also an important symptom of lung cancer, which is primarily a disease of smokers.

Bronchiectasis

Cough is one of the most important symptoms of bronchiectasis, a lung disease in which the bronchial tree is dilated and chronically colonized by bacteria. Bronchiectasis is most likely to occur in persons with cystic fibrosis and persons who have multiple respiratory infections, especially in childhood.

Effective cough is essential for the person with bronchiectasis. Chest physiotherapy and drugs to stimulate clearance of mucus are accompanied by intermittent courses of antibiotics to keep lung infection in check.

Postinfectious Cough

Cough that persists for 3 or more weeks as the only symptom after a viral upper respiratory tract infection may be a postinfectious cough. This cough due to persisting inflammation after infection will usually go away in time, but medical treatment may ease discomfort.

Postinfectious cough is more significant if there was contact with a known case of pertussis (whooping cough). In this case, antibiotic treatment should be given to the persons with this bacterial infection and to all persons who were exposed to pertussis.

Bronchogenic Carcinoma

Bronchogenic carcinoma (lung cancer) is an uncommon cause of chronic cough in nonsmokers. The danger for smokers or recent ex-smokers is that they “expect to cough,” and may overlook a cough that may be symptomatic of lung cancer.

Suspicion of lung cancer is an indication for diagnostic tests including chest x-ray, bronchoscopy, and examination of sputum for presence of cancer cells.

ACE Inhibitor-Induced Cough

Angiotensin-converting enzyme (ACE) inhibitors are blood pressure-lowering drugs that cause chronic cough as a side effect in about 10% of persons who take the drugs. The cough is typically dry and hacking. Discontinuance of the drug causes the cough to improve or resolve within a month.

Habit Cough

Habit or nervous cough is a throat-clearing noise made by a person who is nervous and self-conscious. Medical treatment is not necessary. Occasionally, habit cough overlaps with postnasal drip syndrome, which can be treated.

Psychogenic Cough

Psychogenic cough has no apparent physical cause. Emotional and psychological problems are likely causes. However, other illnesses have to be ruled out before a firm diagnosis is made.

Psychogenic cough is thought to be more common in children than in adults. A possible scenario: psychogenic cough develops in a child who has a chronically ill brother or sister.

Chronic Interstitial Pulmonary Disease

This group of lung diseases that includes idiopathic pulmonary fibrosis is characterized more by shortness of breath than by cough. Before cough is assumed to be due to interstitial pulmonary disease, the most common causes of chronic cough, such as PNDS, need to be ruled out since they may be contributing factors. Then, if cough persists despite specific treatment for the interstitial lung disease, nonspecific medication, such as codeine, may be needed to suppress coughing and ease discomfort.

Other Causes of Cough in Infants and Children

Asthma, sinusitis, and GERD are the most frequent causes of chronic cough in children.

Other causes can be hard to diagnose, especially in infants and small children who cannot describe symptoms and are difficult to examine. Some of these other causes of chronic cough include:

• Congenital diseases or anomalies of the heart and lungs-that is, diseases or anatomic problems that were present at birth
• A foreign body (a peanut or a small toy, for example) lodged in the airway
• Chronic aspiration of milk into the airway while bottle feeding; in some infants this can be a chronic problem that needs medical attention
• Exposure to tobacco smoke from parents or family members who smoke

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