Whooping Cough

The common name for pertussis, an acute infection of the upper respiratory tract featuring violent, loud bouts of coughing that end in a whoop. Vomiting usually occurs at the end of the coughing spell. Most serious in young children, whooping cough is highly contagious and will infect virtually all susceptible children who come in contact with the bacterium. It can lead to seizures, PNEUMONIA, brain damage, and death.

Before the vaccine was available in the 1940s about 200,000 children got sick each year and about 8,000 died. Because the disease can be deadly in infants, babies should be isolated from anyone with whooping cough.

While the number of cases has declined since the introduction of the vaccine, it is far from eradicated. In the year 2000 there were nearly 1,900 cases of whooping cough, including 16 deaths in infants under six months of age.

Whooping cough is most serious in infants, who may often develop pneumonia; babies younger than three months of age get the worst cases. Seventy percent of deaths occur in young babies; about one in 200 infected babies will die. The most infectious time is right at the beginning of the illness.

Doctors must report any suspected or confirmed cases of whooping cough to the health department. If the child attends school or child care, the parent must notify the principal so staff and other children can be given preventive medicine.

Cause
The disease is caused by a rod-shaped bacterium called Bordetella pertussis, which produces a toxin that invades the lining of the throat, windpipe, and bronchial tubes. The tissue damage produces a very thick, irritating mucus leading to severe coughing spells as the child tries to expel it. The thick mucus often leads to pneumonia. A similar but less common bacterium called iB. parapertussis may cause a milder form of the disease.

The disease is spread during coughing, which spews the bacteria outward for several feet. These bacteria can survive on tissue or bed covers for a short time; the disease also can be passed on when another person touches these items. Whooping cough is infectious enough that it will be spread to everyone in the household from one infected patient.

Symptoms
Whooping cough occurs in three stages in children: the first stage starts slowly with cold-like symptoms (sneezing, red or sore eyes, and a lowgrade fever). This occurs with an irritating dry cough for one or two weeks (during which the child is most infectious).

These first symptoms are followed by intense, violent spasms of repeated coughing with no time to breathe between spasms. There is a repetitive series of eight or 10 rapid coughs on one breath that often end in gagging or vomiting. The coughs may end in a characteristic “whoop” as the patient tries to take a breath. Babies under six months of age will choke but will not make the whooping sound; these youngest patients can become very sick. The infected child may appear blue, with bulging eyes and a dazed, apathetic expression. Infants may temporarily stop breathing after a coughing spasm. The periods between coughing are comfortable; there is little fever. This stage may last about two weeks.

The final stage dwindles down into a chronic cough for three to four weeks; some children experience a cough of more than two months.

Complications
A child with the disease may have an ear infection or pneumonia. About one in 500 children younger than six months may develop seizures, coma, or brain damage. The chronic cough may cause nosebleeds and bleeding from blood vessels on the surface of the eyes; recurrent vomiting can cause dehydration and malnourishment.

Diagnosis
The disease is diagnosed by identifying the bacterium in a culture grown from a nasal swab taken in the early stages of the illness. There are two tests, neither of which is 100 percent accurate, and there are many false negatives. The rapid test gives results in a few minutes; a blood test done in mid-disease may identify the bacterium or detect antibodies.

Treatment,
If the illness is recognized early enough, antibiotics such as erythromycin or clarithyromycin are often given; they may shorten the duration of illness and the period of contagiousness, although they are not particularly helpful once the severe coughing stage of the illness has begun.

Patients should be kept warm, given frequent small meals and plenty to drink, and protected from things that produce coughing, such as smoke. An infant or child who becomes blue or keeps vomiting after coughing needs to be admitted to the hospital.