Whooping cough

Definition

Whooping cough, also known as pertussis, is a highly contagious disease that 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 bacterium called Bordetella pertussis. B. pertussis causes its most severe symptoms by attaching itself to those cells in the respiratory tract that 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 that exists throughout the world. While persons 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 including death. Apparently, exposure to B. pertussis bacteria earlier in life gives a person some, but not complete, immunity against infection with it later on. Subsequent infections resemble the common cold .

It is estimated that as many as 120,000 persons in the United States get whooping cough each year. The number of cases has been increasing, with the largest increases found in older children and adults. Between 1993 and 1996, the number of cases increased by 40% in five- to nine-year-old children, 106% in 10–19 year olds, and 93% for persons aged 20 years and older.

Causes & symptoms

Whooping cough has four stages that partially overlap: incubation, catarrhal stage, paroxysmal stage, and convalescent stage.

A person usually acquires B. pertussis by inhaling droplets carrying the bacteria that were coughed into the air by someone already suffering with the infection. Incubation is the symptomless period of seven to 14 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 mucus that 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 overactivity, feeding, crying, or even overhearing someone else cough.

The mucus that 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, which takes hold due to the patient's 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 only 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 pertussis-like viruses. The most accurate method of diagnosis is to culture (grow in the laboratory) 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.

Researchers believe that as many as 90% of the cases are not diagnosed, mainly because of the nonspecific symptoms displayed by adults. An adult who has been coughing for months may have whooping cough.

Recent advances in the accuracy of diagnostic tests based on polymerase chain reactions (PCR) are now being applied to whooping cough. Researchers in Seattle are presently working on a PCR-based test for Bordetella pertussis that will improve the speed as well as the accuracy of diagnosing whooping cough.

Treatment

Whooping cough should always be treated with antibiotics and never with only alternative therapies. The following complementary therapies may reduce symptoms and speed recovery. Supportive treatment involves careful monitoring of fluids to prevent dehydration, rest in a quiet, dark room to decrease paroxysms, and suctioning of mucus. Sitting up during coughing attacks may help.

Herbals

The following herbal remedies may help to support antibiotic treatment of whooping cough:

• bryonia (Bryonia alba ) tea: spasmodic coughing
• butterbur (Pinguicula vulgaris ) infusion: infection and spasms
• evening primrose (Oenothera biennis ) oil
• jamaican dogwood (Piscidia erythrina ) root or bark: spasms
• lobelia (Lobelia inflata ) tea or tincture: spasmodic coughing
• pansy (Viola tricolor ) tea or tincture: spasms
• red clover (Trifolium pratense ) tea
• santonica (Artemisia cina ) powder, tablets, or lozenges
• sea holly (Eryngium planum ) infusion: infection and spasms
• skunk cabbage (Symplocarpus foetidus ) powder, extract, or tincture
• sundew (Drosera rotundifolia ) infusion: infection and spasms
• thyme (Thymus vulgaris ) infusion: infection and spasms
• wild cherry (Prunus serotina ) bark infusion or syrup: infection, and spasmodic coughing

Homeopathy

Homeopathic remedies are chosen based upon the family of symptoms displayed by each patient. Remedies for symptom families include:

• Drosera: dry and tickly feeling in throat; violent coughing that induces vomiting; symptoms worse after midnight.
• Kali carbonicum: dry, hard, hacking cough at 3 a.m.; puffy eyelids; exhaustion; chilly feeling.
• Coccus: coughing worse when warm; drinking cold water brings relief; vomiting stringy, transparent mucus.
• Cuprum: coughing spasms cause breathlessness and exhaustion; blue lips; toe and finger cramping; drinking cold water brings relief.
• Kali bichromicum: coughing up yellow, stringy mucus.
• Belladonna: stomach pain before coughing; coughing worse at night; retching with coughing attacks; red face; puffy eyelids.
• Ipecac: sick feeling most of the time; paleness, rigidity, breathlessness, and then relaxation precede vomiting.

Chinese medicine

Traditional Chinese medicine (TCM) practitioners use a combination of herbals, acupuncture , and ear acupuncture to treat whooping cough during each stage. Yi Zhi Huang Hua (Herba solidaginis ) decoction or a decoction of Bai Mao Gen (Rhizoma imperatae), Lu Gen (Rhizoma phragmitis ), and Si Gua Gen (Radix vascularis luffae ) may be taken for the early stage of whooping cough. Gasping cough can be treated with a mixture of Wu Gong (Scolopendra ) and Gan Cao (Radix glycyrrhizae ).

Other remedies

Other remedies may assist in the treatment of whooping cough.

• Dietary supplements include vitamins A and C, beta carotene, acidophilus , lung glandulars, garlic , and zinc.
• Dietary changes include drinking plenty of fluids, eating fruits, vegetables, brown rice, whole grain toast, vegetable broth, and potatoes, and avoiding dairy products.
• Juice therapists recommend orange and lemon juice or carrot and watercress juice.
• Hydrotherapy treatment consists of wet clothes or other material applied to the head or chest to relieve congestion.
• Aromatherapy uses essential oils of tea tree, chamomile , basil, camphor, eucalyptus, lavender, peppermint , or thyme.
• Osteopathic manipulation can reduce cough severity and make the patient feel more comfortable.

Allopathic treatment

Treatment with the antibiotic erythromycin is clearly helpful only in the very early stages of whooping cough, during incubation and early in the catarrhal stage. In general, however, physicians have used this antibiotic both for treatment of whooping cough itself and to prevent its spread to others in the patient's community. This type of preventive measure is known as prophylaxis.

Unfortunately, the benefits of antibiotic prophylaxis and treatment for whooping cough are limited because erythromycin-resistant strains of B. pertussis have spread throughout the United States since the first case of erythromycin resistance was identified in Arizona in 1994. Although erythromycin is still used as of 2003 for both treatment and prophylaxis of whooping cough, the Centers for Disease Control (CDC) is monitoring the five resistant strains of B. pertussis that have been identified so far.

Expected results

Just under 1% of all cases of whooping cough cause death; in 2000, only two deaths from whooping cough were reported in the United States. Children who die of whooping cough usually have one or more of the following three conditions:

• Severe pneumonia, perhaps with accompanying encephalopathy.
• Extreme weight loss, weakness, and metabolic abnormalities due to persistent vomiting during paroxysms of coughing.
• Other preexisting 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 the immunization program. In the United States, inoculations begin at two months of age. The pertussis vaccine, most often given as one immunization together with diphtheria and tetanus (called DTP), has greatly reduced the incidence of whooping cough. With one shot backed with a 70% immunization rate, two shots increase it to 75–80%, and three to only 85%, it is not a guarantee.

A new formulation of the pertussis vaccine is available. Unlike DTP, which is composed of dead bacterial cells, the newer acellular pertussis vaccine is made up of two to five chemical components of the B. pertussis bacteria. The acellular pertussis vaccine (called DTaP; when combined with diphtheria and tetanus vaccines) greatly reduces the risk of unpleasant reactions, including high fever and discomfort at the injection site.

Because adults are the primary source of infection for children, there has been some talk in the medical community about vaccinating or giving booster vaccinations to adults. A recent increase of pertussis cases among adults in France has led several French medical schools to recommend booster doses of vaccine for adults.

Resources

BOOKS

Fetrow, Charles W. The Complete Guide to Herbal Medicines. Springhouse, PA: Springhouse Corporation, 1999.

Lockie, Andrew and Nicola Geddes. The Women's Guide to Homeopathy. New York: St. Martin's Press, 1994.

Pertussis in Adults: Epidemiology, Signs, Symptoms, and Implications for Vaccination, edited by Sydney M. Finegold, et al. Chicago: The University of Chicago Press, 1999.

Ryan, Kenneth J., and Stanley Falkour. "Pertussis." In Sherris Medical Microbiology: An Introduction to Infectious Diseases. edited by Kenneth J. Ryan. Norwalk, CT: Appleton and Lange, 1994.

Stoffman, Phyllis. The Family Guide to Preventing and Treating 100 Infectious Diseases. New York: John Wiley and Sons, Inc., 1995.

Ying, Zhou Zhong and Jin Hui De. "Whooping Cough." In Clinical Manual of Chinese Herbal Medicine and Acupuncture. New York: Churchill Livingstone, 1997.

PERIODICALS

Decker, Michael D. and Kathryn M. Edwards. "Acellular Pertussis Vaccines." Pediatric Clinics of North America 47 (April 2000): 309-335.

Gilberg, S., E. Njamkepo, I. P. Du Chatelet, et al. "Evidence of Bordetella pertussis Infection in Adults Presenting with Persistent Cough in a French Area with Very High Whole-Cell Vaccine Coverage." Journal of Infectious Diseases 186 (August 2002): 415-418.

Henderson, C.W. "Disease Still Potentially Deadly." World Disease Weekly (11/29/99-12/6/99): 17+.

Jenkinson, Douglas. "Natural Course of 500 Consecutive Cases of Whooping Cough: A General Practice Population Study." British Medical Journal 310 (6975)(February 4, 1995): 299+.

Laliberte, Richard. "The Threat of Whooping Cough." Parents 74 (January 1999): 45+.

"Pertussis Deaths—United States, 2000." Morbidity and Mortality Weekly Report 51 (July 19, 2002): 616-618.

Qin, X., D. K. Turgeon, B. P. Ingersoll, et al. "Bordetella pertussis PCR: Simultaneous Targeting of Signature Sequences." Diagnostic Microbiology and Infectious Disease 43 (August 2002): 269-275.

Wilson, K. E., P. K. Cassiday, T. Popovic, and G. N. Sanden. "Bordetella pertussis Isolates with a Heterogeneous Phenotype for Erythromycin Resistance." Journal of Clinical Microbiology 40 (August 2002): 2942-2944.

ORGANIZATIONS

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007. (847) 434-4000. <www.aap.org>

Centers for Disease Control and Prevention (CDC). 1600 Clifton Road, Atlanta, GA 30333. (404) 639-3311. <www.cdc.gov>.

Food and Drug Administration (FDA), Center for Biologics Evaluation and Research (CBER), 1401 Rockville Pike, Suite 200-N, Rockville, MD 20852. <www.fda.gov/cber>.

Belinda Rowland

Rebecca J. Frey, PhD

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 that is reflected in the disease's name.

Description

Whooping cough is caused by a bacteria called Bordetella pertussis. B. pertussis causes its most severe symptoms by attaching itself to those cells in the respiratory tract that 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, cleansing function, mucus and cellular debris accumulate and cause constant irritation to the respiratory tract, triggering coughing and increasing further mucus production.

Whooping cough exists throughout the world. While people of any age can contract the disease, 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 individuals some immunity against infection with it later on. Subsequent infections resemble the common cold .

Demographics

According to the Centers for Disease Control and Prevention, since 1990, the reported incidence of pertussis has increased in the United States. Peaks occur at three to four year intervals. Since 1990, 14 states reported the number of cases of whooping cough to be more than two per 100,000 in the population. A high proportion of those cases occurred in persons aged ten years or older.

Nearly 75 percent of pertussis cases reported worldwide are in children; half of those children affected require hospitalization . Prior to effective immunization programs in the United States, pertussis was the major cause of death from infectious disease among individuals under the age of 14. Because developing countries as of 2004 did not have widespread immunization available, there continue to be about 50 million cases of pertussis every year across the globe, with 300,000 leading to death. About 38 percent of all hospitalizations from pertussis are in babies under the age of six months.

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 asymptomatic period (time when no evidence of disease is present) of seven to 14 days after breathing in the B. pertussis bacteria, 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. People have teary eyes, sneezing, fatigue, poor appetite, and an extremely runny nose (rhinorrhea). This stage lasts approximately ten days to two weeks.

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 increased mucus, which narrow the breathing tubes, causing people to struggle to get air into their 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 that is produced during the paroxysmal stage is thicker and more difficult to clear than the more watery mucus of the catarrhal stage. Affected persons become increasingly exhausted when attempting to clear the respiratory tract through coughing. 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 swelling and degeneration of the brain (encephalopathy), which is believed to be caused both by lack of oxygen to the brain during paroxysms and 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. Another complicating factor during this phase is the development of pneumonia from infection with another agent. The second pathogen successfully invades due to the person's already-weakened condition.

If individuals survive 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 person contracts a cold, or other respiratory infection.

When to call the doctor

A physician or other healthcare professional should be contacted during the first two months of life to arrange for immunization. Otherwise, a person with a cough that lasts for more than a few days should be seen by a healthcare professional.

Diagnosis

A diagnosis that is based solely on a person's symptoms is not particularly accurate, as the catarrhal stage may appear to be a heavy cold, a case of the flu, or a case of 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 person experiences the full progression of whooping cough symptoms; symptoms 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 in which an individual 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 from the lungs.

Prognosis

Just under 1 percent of all cases of whooping cough in the United States result in 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 person 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 that 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. Three injections (a primary and two booster shots) during early infancy confer complete immunity. Unfortunately, in the 1990s, there has been some concern about serious neurologic side effects from the vaccine itself. This concern led significant numbers of parents in England, Japan, and Sweden to avoid immunizing their children. Such actions led to major epidemics of the disease in those countries. However, several carefully constructed research studies disproved the idea that the pertussis vaccine is the cause of neurologic damage. Furthermore, a subsequent formulation of the pertussis vaccine became available. Unlike the former whole cell pertussis vaccine, which was composed of the entire bacterial cell that has been deactivated (and therefore unable to cause infection), the subsequent acellular pertussis vaccine does not use a whole cell of the bacteria but is comprised 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 .

Nutritional concerns

Persons with whooping cough should be given adequate nutrition to assist their bodies in recovering from the infective agent.

KEY TERMS

Cilia —Tiny hairlike projections on certain cells within the body. Cilia produce lashing or whipping movements to direct or cause motion of substances or fluids within the body. Within the respiratory tract, the cilia act to move mucus along, in an effort to continually flush out and clean the respiratory tract.

Encephalopathy —Any abnormality in the structure or function of brain tissues.

Hernia —A rupture in the wall of a body cavity, through which an organ may protrude.

Parental concerns

Parents should ensure that their children receive a complete series of immunizations (three injections) against whooping cough. Children who are suspected of having whooping cough should be seen by a healthcare professional. Early treatment is essential to limit the progression of the disease.

Resources

BOOKS

Halperin, Scott A. "Pertussis and Other Bordetella Infections." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 949–52.

Johnston, Richard B. "Whooping Cough (Pertussis)." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1829–30.

Lasky, Elizabeth. Cecil Whooping Cough. Portsmouth, NH: Heinemann, 2002.

Long, Sarah S. "Pertussis (Bordetella pertussis and B. parapertussis)." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 908–11.

PERIODICALS

Andreae, M. C., et al. "Safety concerns regarding combination vaccines: the experience in Japan." Vaccine 22, no. 29–30 (2004): 3911–6.

Hviid, A., et al. "Impact of routine vaccination with a pertussis toxoid vaccine in Denmark." Vaccine 22, no. 27–28 (2004): 3530–4.

Steele, R. W. "Pertussis: is eradication achievable?" Pediatric Annals 33, no. 8 (2004): 525–34.

Zetterstrom, R. "Flawed reports of immunization complications: consequences for child health." Acta Paediatrica 93, no. 9 (2004): 1140–3.

WEB SITES

""Bordetella pertussis" and Whooping Cough." University of Wisconsin-Madison. Available online at <http://textbookofbacteriology.net/pertussis.html> (accessed January 9, 2005).

"Pertussis (Whooping Cough)." Nemours Foundation. Available online at <http://kidshealth.org/parent/infections/bacterial_viral/whooping_cough.html> (accessed January 9, 2005).

"Whooping Cough." National Library of Medicine. Available online at <www.nlm.nih.gov/medlineplus/whoopingcough.html> (accessed January 9, 2005).

"Whooping Cough, the DPT Vaccine, and Reducing Vaccine Reactions." National Vaccine Information Center. Available online at <www.909shot.com/Diseases/whooping.htm> (accessed January 9, 2005).

L. Fleming Fallon, Jr., MD, DrPH

Whooping Cough

Symptoms and progression of whooping cough

Diagnosis

Treatment

Prevention

Resources

Whooping cough, also known as pertussis, is a highly contagious disease caused by the bacteria Bordatella pertussis. It is characterized by classic paroxysms (spasms) of uncontrollable coughing, followed by a sharp intake of air that creates the characteristic “whoop” of the disease name.

B. pertussis is uniquely a human pathogen, meaning that it neither causes disease in other animals, nor survives in humans without resulting in disease. It exists worldwide as a disease-causing agent, and has caused epidemics cyclically in all locations.

B. pertussis causes its most severe symptoms by attacking specifically those cells in the respiratory tract which have cilia. Cilia are small, hair-like projections that beat constantly, 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 the cough reflex and increasing further mucus production.

Children under the age of two, particularly infants, are most at risk for serious infection, although the disease can occur at any age. However, once an individual has been exposed to B. pertussis, subsequent exposures result in mild illness similar to the common cold, and thus usually are not identifiable as resulting from B. pertussis.

Symptoms and progression of 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 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 thought 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 over-activity, feeding, crying, or even overhearing someone else cough.

The mucus that is produced during the paroxysmal stage is thicker and more difficult to clear than the waterier mucus of the catarrhal stage, and the person with pertussis becomes increasingly exhausted while attempting to clear the respiratory tract by coughing. Severely ill children may have 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 in their blood. These children may also suffer from encephalopathy, a swelling and degeneration of the brain which is thought 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 person’s weakened condition.

If the person with whooping cough 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 person 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).

Diagnosis

diagnosis based on symptomatology is not particularly accurate, as the catarrhal stage may appear to be a heavy cold, a case of the flu, or bronchitis. Other viruses and tuberculosis infections 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 B. pertussis infection, although it could occur with 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 during microscopic examination of the culture.

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, which will only abate 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 in which a patient with whooping cough lives should be treated with erythromycin to prevent spread of B. pertussis throughout the community.

Other treatment is supportive, and includes careful monitoring of fluids, rest in a quiet, dark room to decrease paroxysms, and suctioning of mucus.

Prevention

the mainstay of prevention lies in the mass immunization program which begins in most developed countries when an infant is around 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 possible serious neurologic side effects from the vaccine itself. This concern led large numbers of parents in England, Japan, and Sweden to avoid immunizing their children in the 1990s, which in turn led to major outbreaks of disease in those countries. Multiple carefully constructed research studies, however, have disproved pertussis vaccine as the cause of neurologic damage. Over 26,000 cases of whooping cough were reported in the U.S. in 2004, continuing a pattern showing an increase in incidence of the disease. This increase is attributed to increased recognition of

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.

Encephalopathy —Any abnormality in the structure or function of the brain.

Pathogen —A disease causing agent, such as a bacteria, virus, fungus, etc.

whooping cough in older children and adults, along with physicians who are more often accurately diagnosing and reporting whooping cough in both its classic and milder forms.

See also Childhood diseases; Respiratory diseases; Respiratory system.

Resources

BOOKS

Gershon, Anne, et al. Krugman’s Infectious Diseases of Children. St. Louis: Mosby, 2003.

Kobayashi, G., Patrick R. Murray, Ken Rosenthal, and Michael Pfaller. Medical Microbiology. St. Louis, MO: Mosby, 2003.

OTHER

Centers for Disease Control and Prevention. “Pertussis.” <http://www.cdc.gov/niP/publications/pink/pert.pdf> (accessed on November 25, 2006).

Pertussis.com “See Pertussis.” <http://www.pertussis.com/> (accessed on November 25, 2006).

Rosalyn Carson-DeWitt

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 Journal 310, 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.

Encephalopathy— Swelling and degeneration of the brain.

Whooping cough

Whooping cough is a highly contagious disease caused by the bacteria Bordatella pertussis. It is characterized by classic paroxysms (spasms) of uncontrollable coughing, followed by a sharp intake of air which creates the characteristic "whoop" of the disease name.

B. pertussis is uniquely a human pathogen, meaning that it neither causes disease in other animals, nor survives in humans without resulting in disease. It exists worldwide as a disease-causing agent, and causes epidemics cyclically in all locations.

B. pertussis causes its most severe symptoms by attacking specifically those cells in the respiratory tract which have cilia. Cilia are small, hair-like projections which beat constantly, 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 the cough reflex and increasing further mucus production.

Children under the age of two, particularly infants, are most at risk for serious infection , although the disease can occur at any age. However, once an individual has been exposed to B. pertussis, subsequent exposures result in mild illness similar to the common cold, and thus usually not identifiable as resulting from B. pertussis.

Symptoms and progression of 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).

Diagnosis

Diagnosis based just on symptomatology is not particularly accurate, as the catarrhal stage may appear to be a heavy cold, a case of the flu, or bronchitis . Other viruses and tuberculosis infections 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 B. pertussis infection, although it could occur with 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 during microscopic examination of the culture.

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, which will only abate 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 in which a patient with whooping cough lives should be treated with erythromycin to prevent spread of B. pertussis throughout the community.

Other treatment is supportive, and includes careful monitoring of fluids, rest in a quiet, dark room to decrease paroxysms, and suctioning of mucus.

Prevention

The mainstay of prevention lies in the mass immunization program which begins in the United States when an infant is 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 led to major epidemics of disease in those countries. Multiple carefully constructed research studies, however, have disproved pertussis vaccine as the cause of neurologic damage.

See also Childhood diseases; Respiratory diseases; Respiratory system.

Resources

books

Berkow, Robert, and Andrew J. Fletcher. The Merck Manual of Diagnosis and Therapy. Rahway, NJ: Merck Research Laboratories, 1992.

Kobayashi, G., Patrick R. Murray, Ken Rosenthal, and Michael Pfaller. Medical Microbiology. St. Louis: Mosby, 2003.

Krugman, Saul, et al. Infectious Diseases of Children. St. Louis: Mosby-Year Book, Inc., 1992.

Rosalyn Carson-DeWitt

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.

Encephalopathy

—Any abnormality in the structure or function of the brain.

Pathogen

—A disease causing agent, such as a bacteria, virus, fungus, etc.