Whooping Cough
Definition
Whooping
cough, also known as pertussis, is a highly contagious disease which causes classic spasms (paroxysms) of uncontrollable coughing, followed by a sharp, high-pitched intake of air which creates the characteristic "whoop" of the disease's name.
Description
Whooping cough is caused by a bacteria called Bordatella pertussis. B. pertussis causes its most severe symptoms by attaching itself to those cells in the respiratory tract which have cilia. Cilia are small, hair-like projections that beat continuously, and serve to constantly sweep the respiratory tract clean of such debris as mucus, bacteria, viruses, and dead cells. When B. pertussis interferes with this normal, janitorial function, mucus and cellular debris accumulate and cause constant irritation to the respiratory tract, triggering coughing and increasing further mucus production.
Whooping cough is a disease which exists throughout the world. While people of any age can contract whooping cough, children under the age of two are at the highest risk for both the disease and for serious complications and
death. Apparently, exposure to
B. pertussis bacteria earlier in life gives a person some immunity against infection with it later on. Subsequent infections resemble the
common cold.
Causes and symptoms
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 someone already suffering with the infection. Incubation is the symptomless period of seven to14 days after breathing in the B. pertussis bacteria, and during which the bacteria multiply and 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 an extremely runny nose (rhinorrhea). This stage lasts about 10-14 days.
The paroxysmal stage, lasting two to four weeks, begins with the development of the characteristic whooping cough. Spasms of uncontrollable coughing, the "whooping" sound of the sharp inspiration of air, and vomiting are all 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 into his/her lungs; the effort results in intense exhaustion. The paroxysms (spasms) can be induced by over activity, 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 more watery mucus of the catarrhal stage, and the patient becomes increasingly exhausted attempting to clear the respiratory tract through coughing. Severely ill children may have great difficult 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 swelling and degeneration of the brain (encephalopathy), 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 weak area of muscle). Another complicating factor during this phase is the development of
pneumonia from infection with another bacterial agent; the bacteria takes hold due to the patient's already-weakened condition.
If the patient survives the paroxysmal stage, recovery occurs gradually during the convalescent stage, usually taking about three to four weeks. However, spasms of coughing may continue to occur over a period of months, especially when a patient contracts a cold, or other respiratory infection.
Diagnosis
Diagnosis based just on the patient's symptoms is not particularly accurate, as the catarrhal stage may appear to be a heavy cold, a case of the flu, or a simple
bronchitis. Other viruses and tuberculosis infections can cause symptoms similar to those found during the paroxysmal stage. The presence of a pertussis-like cough along with an increase of certain specific white blood cells (lymphocytes) is suggestive of pertussis (whooping cough). However, cough can occur from other pertussis-like viruses. The most accurate method of diagnosis is to culture (grow on a laboratory plate) the organisms obtained from swabbing mucus out of the nasopharynx (the breathing tube continuous with the nose).
B. pertussis can then be identified by examining the culture under a microscope.
Treatment
Treatment with the antibiotic erythromycin is helpful only at very early stages of whooping cough, during incubation and early in the catarrhal stage. After the cilia and the cells bearing those cilia, are damaged, the process cannot be reversed. Such a patient will experience the full progression of whooping cough symptoms; symptoms will only improve when the old, damaged lining cells of the respiratory tract are replaced over time with new, healthy, cilia-bearing cells. However, treatment with erythromycin is still recommended, to decrease the likelihood of
B. pertussis spreading. In fact, all members of the household where a patient with whooping cough lives should be treated with erythromycin to prevent the spread of
B. pertussis throughout the community. The only other treatment is supportive, and involves careful monitoring of fluids to prevent
dehydration, rest in a quiet, dark room to decrease paroxysms, and suctioning of mucus.
Prognosis
Just under 1% of all cases of whooping cough cause death. Children who die of whooping cough usually have one or more of the following three conditions present:
- severe pneumonia, perhaps with accompanying encephalopathy
- extreme weight loss, weakness, and metabolic abnormalities due to persistent vomiting during paroxysms of coughing
- other pre-existing conditions, so that the patient is already in a relatively weak, vulnerable state (such conditions may include low birth weight babies, poor nutrition, infection with the measles virus, presence of other respiratory or gastrointestinal infections or diseases)
Prevention
The mainstay of prevention lies in programs similar to the mass immunization program in the United States which begins immunization inoculations when infants are two months old. The pertussis vaccine, most often given as one immunization together with
diphtheria and
tetanus, has greatly reduced the incidence of whooping cough. Unfortunately, there has been some concern about serious neurologic side effects from the vaccine itself. This concern led huge numbers of parents in England, Japan, and Sweden to avoid immunizing their children, which in turn has led to major epidemics of disease in those countries. However, several carefully constructed research studies have disproved the idea that the pertussis vaccine is the cause of neurologic damage. Furthermore, a newer formulation of the pertussis vaccine is available. Unlike the old whole cell pertussis vaccine, which is composed of the entire bacterial cell which has been deactivated (and therefore unable to cause infection), the newer acellular pertussis vaccine does not use a whole cell of the bacteria, but is made up of (between two and five) chemical components of the
B. pertussis bacteria. The acellular pertussis vaccine appears to greatly reduce the risk of unpleasant reactions to the vaccine, including high fever and discomfort following
vaccination.
Resources
Periodicals
Jenkinson, Douglas. "Natural Course of 500 Consecutive Casesof Whooping Cough: A General Practice Population Study." British Medical Journal310, no. 6975 (February 4, 1995): 299+.
Key terms
Cilia — Tiny, hair-like projections from a cell. In the respiratory tract, cilia beat constantly in order to move mucus and debris up and out of the respiratory tree, in order to protect the lung from infection or irritation by foreign bodies.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
whooping cough
[ho̳p´ing kof] an infectious disease characterized by catarrh of the respiratory tract and peculiar paroxysms of coughing, ending in a prolonged crowing or whooping respiration; the causative organism is
Bordetella pertussis. Called also
pertussis. Whooping cough is a serious and widespread disease, with about 300,000 cases a year reported in the United States. Although it may attack at any age, most cases occur in children under 10, and half of these are in children under 5.
The organisms are spread by the victim's coughing and sneezing and by objects he has touched. The incubation period is usually about 7 days, although it may vary between 2 and 21 days. Unlike other respiratory diseases, whooping cough is more likely to occur in spring and summer than in winter. It affects females much more often than males.
Symptoms. Whooping cough frequently starts with a running nose, a slight fever, and a persistent cough. This stage usually lasts about 2 weeks. After this, the child feels chilled and begins to vomit. His coughing increases. He begins to cough in spells of eight to ten times in one breath. This forces the air from the lungs, and the face may turn purple or blue from the effort and the shortage of air. Finally he catches his breath in a long, noisy intake, or “whoop.” In the very young (under 6 months) the true whoop is often not present, even when paroxysms are severe and frequent.
The coughing stage of the disease usually lasts 4 to 6 weeks, and the coughing may be very severe at night. Then the coughing spells become less frequent and less severe until the disease has run its course.
Stage three (convalescent stage) may last from 4 months to 2 years. The coughing spells diminish but the patient usually experiences them again each time he has an upper respiratory infection.
Complications of whooping cough include pneumonia, atelectasis, and emphysema; of these, pneumonia is the most serious, accounting for 90 per cent of the fatalities in young children. Brain damage, another complication, should be suspected if convulsive seizures occur in the pertussis patient.
Immunization. An attack of whooping cough gives immunity but does not confer life-long immunity. The vaccine usually is given in combination with diphtheria and tetanus and is available as a preparation that should be given intramuscularly, preferably in the lateral thigh.
Treatment and Patient Care. Precautions against the spread of the disease entail following respiratory isolation precautions for 7 days after effective therapy is begun. Recommendations for preventive measures after exposure can be found in the CDC Guidelines for Infection Control in Hospital Personnel.
Treatment is primarily supportive, including bed rest as long as the fever persists, antibiotics to avoid secondary infections, and antipyretics to control fever. In very serious cases, especially in infants, whooping cough may cause severe breathing difficulties. Suction may be necessary at frequent intervals to remove accumulations of mucus from the air passages. Fatalities, particularly in infants, are not uncommon. A proper diet is essential during whooping cough. Because vomiting may be a problem, small frequent feedings of bland foods are considered best.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.