Whooping Cough

Whooping cough has four somewhat overlapping stages: incubation, catarrhal stage, paroxysmal stage, and convalescent stage.

An individual usually acquires B. pertussis by inhaling droplets infected with the bacteria, coughed into the air by an individual already suffering from whooping cough symptoms. Incubation is the period of seven to 14 days after exposure to B. pertussis, and during which the bacteria penetrate the lining tissues of the entire respiratory tract.

The catarrhal stage is often mistaken for an exceedingly heavy cold. The patient has teary eyes, sneezing, fatigue, poor appetite, and a very runny nose. This stage lasts about 10-14 days.

The paroxysmal stage, lasting two to four weeks, is heralded by the development of the characteristic whooping cough. Spasms of uncontrollable coughing, the "whooping" sound of the sharp inspiration of air, and vomiting are hallmarks of this stage. The whoop is believed to occur due to inflammation and mucous which narrow the breathing tubes, causing the patient to struggle to get air in, and resulting in intense exhaustion. The paroxysms can be caused by overactivity, feeding, crying, or even overhearing someone else cough.

The mucus which is produced during the paroxysmal stage is thicker and more difficult to clear than the waterier mucus of the catarrhal stage, and the patient becomes increasingly exhausted while attempting to cough clear the respiratory tract. Severely ill children may have great difficulty maintaining the normal level of oxygen in their systems, and may appear somewhat blue after a paroxysm of coughing due to the low oxygen content of their blood. Such children may also suffer from encephalopathy, a swelling and degeneration of the brain which is believed to be caused both by lack of oxygen to the brain during paroxysms, and also by bleeding into the brain caused by increased pressure during coughing. Seizures may result from decreased oxygen to the brain. Some children have such greatly increased abdominal pressure during coughing, that hernias result (hernias are the abnormal protrusion of a loop of intestine through a weaker area of muscle). Another complicating factor during this phase is the development of pneumonia from infection with another bacterial agent, which takes hold due to the patient's weakened condition.

If the patient survives the paroxysmal stage, recovery occurs gradually during the convalescent stage, and takes about three to four weeks. Spasms of coughing may continue to occur over a period of months, especially when a patient contracts a cold or any other respiratory infection.

Children who die of pertussis infection usually have one or more of three conditions present: 1) severe pneumonia, perhaps with accompanying encephalopathy; 2) extreme weight loss, weakness, and metabolic abnormalities due to persistent vomiting during paroxysms of coughing; 3) other pre-existing conditions, so that the patient is already in a relatively weak, vulnerable state (such conditions may include low birth weight, poor nutrition, infection with the measles virus, presence of other respiratory or gastrointestinal infections or diseases).