Pertussis

Alternative names

Definition

Causes, incidence, and risk factors

Pertussis, also known as whooping cough, is caused by infection with the Bordetella pertussis bacteria. The infection is spread through the air by respiratory droplets from an infected person. The incubation period is usually 7 days.

Whooping cough can affect people of any age. Prior to the advent of widespread immunization, the disease occurred mostly in 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% of recognized cases still occur in infants younger than 6 months of age, however. Early immunization (see childhood immunization schedule) can usually prevent the occurrence of this serious disease, which can sometimes be fatal or lead to permanent disability when it affects babies.

The bacteria invade the nose and throat, the breathing tube (trachea), and the lungs. The infection usually lasts 6 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, 2 or 3 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.

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

Immunization may moderate the course of pertussis when it does not produce complete immunity. When symptoms are not classic, pertussis is difficult to diagnose and as a result, the disorder is likely to be underdiagnosed.

Symptoms

• runny nose
• cough , severe, may be dry or may produce sputum
• slight fever (102 F or lower)
• severe coughing attacks
  • ends in a high-pitched, crowing sound when inhaling, or ends in a high-pitched "whoop" (whooping cough)
  • coughing spell (paroxysm) may end in a momentary loss of consciousness
  • cough with difficulty breathing
• vomiting during a severe bout of coughing
• diarrhea
• choking spells in infants
• choking that occurs when emotional

Signs and tests

• a culture of secretions from the nose and mouth
• a throat swab culture
• a blood count ( CBC ) with an elevated white blood cell count characterized by large numbers of lymphocytes (lymphocytosis)
• serologic (blood) tests for Bordetella pertussis
• immunologic tests

Treatment

Erythromycin, an antibiotic, may shorten the duration of the symptoms somewhat if initiated early enough. Unfortunately, most patients are only diagnosed after the period of time when antibiotics are most effective, and so generally they are not used.

Infants under 18 months of age require constant supervision because breathing may temporarily stop during coughing spells. Infants with severe cases should be hospitalized.

An oxygen tent with high humidity may be used. Intravenous fluid may be indicated if coughing spells are severe enough to prevent adequate oral fluid intake. Sedatives may be prescribed for young children.

Cough mixtures or expectorants and cough suppressants are usually not helpful and should not be used.

Expectations (prognosis)

Complications

• slowed or stopped breathing ( apnea )
• pneumonia
• convulsions due to lack of oxygen can cause permanent brain damage
• nose bleeds
• ear infections
• brain damage from lack of oxygen (anoxic encephalopathy)
• bleeding in the brain (cerebral hemorrhage)
• seizure disorder (permanent)
• developmental retardation

Calling your health care provider

Prevention

DtaP vaccine or pertussis immunization (vaccine) starting in infancy helps protect children against this disease. During epidemics, health care providers or others at risk may be advised to receive a booster dose of the vaccine.

During epidemics, unimmunized children under the age of seven should be excused from school and public gatherings for 14 days after the last reported exposure and isolated from anyone known or suspected to be infected.

Cases of the disease are reported to public health officials by health care providers so that health warning announcements and other preventative measures can be taken. Pertussis is now recognized more often in adolescents and adults.

Pertussis immunization is not 100% effective and it slowly becomes less effective over the years. Individuals who have been immunized in the past may still develop infection, but it is usually atypical or very mild. Therefore, during epidemics, adolescents in school, health care workers, or other adults with high exposure risk should consider a booster immunization.

Update Date: 7/30/2002