Pertussis
Pertussis (whooping cough) is a highly contagious infection caused by the bacterium Bordetella pertussis, which results in fits of coughing that usually end in a prolonged, high-pitched, deeply indrawn breath (the whoop).
Pertussis was once rampant in the United States but is now uncommon. However, pertussis remains a major problem throughout the world. Local epidemics among unimmunized people occur every 3 to 5 years. A person may develop pertussis at any age, although nearly two thirds of cases occur in children younger than 5 years. One attack of pertussis does not always give full immunity for life, but a second attack, if it occurs, is usually mild and not always recognized as pertussis. In fact, some adults with "walking pneumonia" actually have pertussis. Pertussis is most serious in children younger than 2 years.
An infected person spreads pertussis organisms into the air in droplets of moisture produced by coughing. Anyone nearby may inhale these droplets and become infected. Pertussis usually is not contagious after the third week of the infection.
Symptoms
The illness lasts about 6 weeks, progressing through three stages: mild cold-like symptoms, severe coughing fits, and gradual recovery. Cold-like symptoms include sneezing, runny nose, and a general feeling of illness (malaise). After 1 or 2 weeks, the person develops typical coughing fits. These fits typically consist of 5 to 15 or more rapid consecutive coughs followed by the whoop (a prolonged, high-pitched, deeply indrawn breath). After a fit, breathing is normal, but another coughing fit follows shortly thereafter. The cough often produces large amounts of thick mucus (usually swallowed by infants and children or seen as large bubbles from the nose). In younger children, vomiting often follows a prolonged fit of coughing. In infants, choking spells and pauses in breathing (apnea), possibly causing the skin to turn blue, can occur.
About one fourth of children develop pneumonia, resulting in difficulty breathing. Ear infections (otitis media) also frequently develop as a result of pertussis. Rarely, pertussis affects the brain of infants. Bleeding, swelling, or inflammation of the brain may cause seizures, confusion, brain damage, and mental retardation.
After several weeks, the coughing fits gradually subside, but for many weeks or even months the person has a lingering, persistent cough.
Diagnosis and Prognosis
Doctors suspect pertussis because of the typical whooping cough or other symptoms and confirm the diagnosis by culture of a sample of mucus from the back of the nose or throat. Culture results often are negative after several weeks of illness; other diagnostic tests performed on samples from the nose or throat may be helpful (polymerase chain reaction or rapid detection test).
The majority of children with pertussis recover completely, although slowly. About 1 to 2% of the children younger than 1 year die.
Prevention and Treatment
Children are routinely vaccinated against pertussis. The pertussis vaccine is usually combined with vaccines for diphtheria and tetanus (see Section 23, Chapter 263). The antibiotic erythromycin (or sometimes clarithromycin or azithromycin) is given as a preventive measure to children exposed to pertussis.
Severely ill infants are usually hospitalized because their breathing difficulty may become so severe that they require mechanical ventilation through a tube placed in their windpipe. Others may need extra oxygen and intravenous fluids. Older children who have mild disease are treated at home. Cough medicines are of questionable value and are not usually used.
The antibiotic erythromycin, clarithromycin, or azithromycin is usually used to eradicate the bacteria causing pertussis. Antibiotics are also used for infections that accompany the pertussis, such as pneumonia and ear infection.
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