Pertussis

Alternative names:

whooping cough

Definition:

A highly contagious bacterial disease that affects the respiratory system and produces spasms of coughing that usually end in a high-pitched crowing inspiration (whooping sound).

Causes, incidence, and risk factors:

Pertussis, also known as whooping cough, is caused by infection with the Bordetella pertussis bacteria. The infection can affect all. Prior to immunization pertussis was confined mostly to infants and young children. Now that the majority of children are immunized before school age a higher percentage of cases are seen among adolescents and adults. About 38 percent to recognized cases occur in infants younger than six months. of age, stressing the need for early immunization (see childhood immunization schedule). There were 7,138 cases of whooping cough reported in the U.S. in 1996. The infection is spread through the air by respiratory droplets from an infected person. The incubation period is usually seven days.

The bacteria invade the nose and throat, the trachea, and the bronchial tubes of the lungs. The infection usually lasts six weeks. It starts with symptoms similar to the common cold, and progresses to spasms (paroxysms) of coughing after 10 to 12 days. The cough is characterized by repeated coughing, two or three coughs without inhaling then a characteristic inspiratory whoop. Typically, the face becomes more red with each cough then subtly bluish (cyanotic). The child may momentarily lose consciousness at the end of a coughing spell. During this stage there is heavy mucus production and coughing spells may induce vomiting. Pertussis should always be considered when vomiting is associated with coughing. In infants, choking spells are common.

Convalescence begins about four weeks after the onset of symptoms and may last several weeks. Paroxysms of coughing may recur over the next several months, usually due to irritation from an upper respiratory infection.

Immunization may modify the course of pertussis. When symptoms are not classical, pertussis is difficult to diagnose and as a result, the disorder is likely to be underdiagnosed. Several new studies have suggested that the possible diagnosis of pertussis should be entertained in any adult with an acute respiratory illness in which the cough persists for over two weeks.