Signs Symptoms and Complications

What is whooping cough?

Whooping cough (pertussis) is an acute, highly contagious respiratory infection that is caused by a bacterium. The first outbreaks of pertussis were described in the 16th century. The bacterium responsible for the infection, Bordetella pertussis, was not isolated until 1906. The incidence of pertussis has been steadily increasing since the 1980s. According to the U.S. Centers for Disease Control and Prevention (CDC), a total of 25,827 cases of pertussis were reported in 2004 in the U.S.

What are the stages, symptoms, and signs of whooping cough?

The first stage of whooping cough is known as the catarrhal stage. In the catarrhal stage, which typically lasts from one to two weeks, an infected person has symptoms characteristic of an upper respiratory infection, including

• runny nose,
• sneezing,
• low-grade fever, or a
• mild, occasional cough, similar to the common cold.

The cough gradually becomes more severe, and after one to two weeks, the second stage begins. It is during the second stage (the paroxysmal stage) that the diagnosis of whooping cough usually is suspected. The second stage is characterized by

• Bursts (paroxysms) of coughing, or numerous rapid coughs, are apparently due to difficulty expelling thick mucus from the airways in the lungs. Bursts of coughing increase in frequency during the first one to two weeks, remain constant for two to three weeks, and then gradually begin to decrease in frequency.
• At the end of the bursts of rapid coughs, a long inspiratory effort (breathing in) is usually accompanied by a characteristic high-pitched "whoop."
• During an attack, the individual may become cyanotic (turn blue) from lack of oxygen.
• Children and young infants appear especially ill and distressed.
• Vomiting (referred to by doctors as posttussive vomiting) and exhaustion commonly follow the episodes of coughing.
• The person usually appears normal between episodes.
• Paroxysmal attacks occur more frequently at night, with an average of 15-24 attacks per 24 hours.
• The paroxysmal stage usually lasts from one to six weeks but may persist for up to 10 weeks.
• Infants under 6 months of age may not have the strength to have a whoop, but they do have paroxysms of coughing.

The third stage of whooping cough is the recovery or convalescent stage. In the convalescent stage, recovery is gradual. The cough becomes less paroxysmal and usually disappears over two to three weeks; however, paroxysms often recur with subsequent respiratory infections for many months.

Complications of whooping cough (pertussis)

The most common complication and the cause of most pertussis-related deaths is secondary bacterial pneumonia. (Secondary bacterial pneumonia is bacterial pneumonia that follows another infection of the lung, be it viral or bacterial. Secondary pneumonia is caused by a different virus or bacterium than the original infection.) Young infants are at highest risk for whooping cough and also for pertussis-associated complications, including secondary pneumonia. Data from 2001-2003 indicate that secondary pneumonia occurred among 4.9% of all reported pertussis cases.

Pertussis can cause serious illness and even death in young children; 13 children died from the infection in 2003. From 2004-2005, 66 deaths due to whooping cough were reported to the CDC, and 56 of these were children under 3 months of age. Most of the pertussis-related deaths have occurred in children who have not been vaccinated or who are too young to have received the vaccine.

Other possible complications of pertussis include seizures, encephalopathy (abnormal function of the brain due to decreased oxygen delivery to the brain), reactive airway disease (asthma), dehydration, and malnutrition.

http://www.medicinenet.com/pertussis/page3.htm

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