Unwelcome Return
Former foe pertussis on the rise again
By Barbara Barzoloski-O’Connor, RN, MSN
November 1, 2004
Most nurses know about pertussis from the stories their parents have told them about the breathtaking whooping cough that accompanies the disease. When respiratory illness season peaks, nurses pay more attention to common ailments like influenza and respiratory syncytial virus (RSV). For many practitioners, pertussis is a non-issue. They know that children receive a vaccine to prevent it, and that’s where their knowledge ends.
What they don’t know is, despite high vaccination rates, immunity wanes after five to 10 years, leaving adolescents, adults, and unimmunized infants open to contracting the infection.1 When they care for patients with an illness characterized by a prolonged cough, they should explore the possibility of pertussis.
Pertussis was first described in the early 16th century and was a major cause of childhood mortality in the United States during the 20th century. Incidence has decreased more than 98% since widespread vaccinations, but pertussis continues to be a problem in developing countries.2
The frequency of reported pertussis has been on the rise in the United States since the 1980s, with an epidemic every three to five years.1
Whooping cough
Pertussis, caused by the bacterium Bordetella pertussis, is commonly called “whooping cough.” The characteristic paroxysm of coughs followed by a long inspiratory effort sounding like a high-pitched whoop points to the possibility that pertussis has been on board for several weeks. Pertussis is spread through contact with respiratory droplets or airborne droplets of respiratory secretions of an infected individual. Secondary attack rates in susceptible household contacts have been as high as 80%, but, unfortunately, it is most communicable before the onset of the paroxysmal coughing stage.1
After exposure, the incubation period is seven to 10 days, with a range of four to 21 days, but it may extend as long as 42 days. At the onset, or catarrhal stage, symptoms are similar to the common cold with coryza (runny nose), sneezing, low-grade fever, and mild unproductive cough. These symptoms last one to two weeks, after which the paroxysmal stage begins.
The paroxysmal stage often lasts from one to six weeks, but it can last up to 10 weeks. Although the patient may appear normal between coughing episodes, cyanosis may occur during a spell, followed by post-tussive vomiting and exhaustion, which can lead to anorexia and dehydration. Attacks of paroxysmal coughing caused by efforts to expel thick mucus from the tracheobronchial tree are often nocturnal and may hit as frequently as 15 times in a 24-hour period. Paroxysmal coughing may be absent in infants but may show up in episodes of apnea instead.1
Secondary bacterial pneumonia is the most common and deadly complication of pertussis. Seizures and encephalopathy also may occur as a result of apnea. Sleep disturbance accompanies the nocturnal attacks. The forceful coughing may result in pneumothorax, epistaxis, subdural hematomas, hernias, and rectal prolapse.2
Recovery during the convalescent stage can take weeks to months, and subsequent respiratory infections can lead to paroxysmal coughing. Adolescents and adults often have milder disease without the characteristic whoop and can transmit the illness undetected to the unimmunized or underimmunized.2
Laboratory confirmation of B. pertussis can be difficult, because it doesn’t grow in a standard culture medium, and a specific request for testing is required.
A nasopharyngeal swab obtained with a Dacron or calcium alginate swab is optimal. The organism rarely is isolated in the blood.3
Prevention priorities
Although pertussis can occur at any age regardless of immunization history, primary prevention through vaccination is the most effective strategy in controlling the disease.
In the early 1940s when the vaccine was first introduced, an average of 175,000 cases were reported per year in the United States. Annual incidence gradually decreased to an average of 2,900 from 1980 to 1990. By 2002, however, case numbers increased to 9,771. This was the highest number of reported cases since 1964. This number may be influenced by advancing laboratory technologies, better recognition of the illness among older age groups, improved reporting to public health entities, and the apparent three- to five-year cycle that has been observed with pertussis.2
The DTP vaccine, which protects against diphtheria, tetanus, and pertussis, has been a pediatric mainstay since the 1940s. In the 1970s, it came under scrutiny as a possible precursor to adverse events, such as brain damage. Countries that have decreased vaccination efforts have experienced a resurgence of pertussis. (See “Impact of Antivaccine Movements” sidebar.) Although the presumptions of toxicity are not supported by data, the whole cell vaccine composed of formalin-inactivated B. pertussis was replaced by a more purified acellular vaccine (DTaP), which has been available since 1991.3,4
The vaccination is part of a series and is licensed only for children younger than age 7.4
Contraindications to the vaccine include an immediate anaphylactic reaction to the initial dose or an acute, severe neurologic reaction to the first dose occurring within seven days that does not resolve in 24 hours.
Other events, such as temperature elevation of 105 F or more; a hypotonic-hyporesponsive episode (HHE), where there is an acute diminution of sensory awareness or unconsciousness accompanied by pallor and muscle hypotonicity; persistent crying for three or more hours; or short-lived convulsions within 48 hours of a first dose are no longer considered contraindications to further vaccination.
They are precautions to be considered, but the benefit-risk ratio should be carefully considered for each individual.4 A vaccine information sheet developed by the Centers for Disease Control and Prevention for parents can be found at www.cdc.gov/nip/publications/vis/vis-dtp.pdf. Local reactions at the site and mild systemic reactions such as fever, drowsiness, fretfulness, and anorexia are common but usually short-lived and manageable.
Treatment should be with an aspirin-free product to avoid the potential for the development of Reye’s syndrome.4
Treatment and protection
Treatment of pertussis generally is supportive care, along with erythromycin as the antibiotic of choice. It has varying effectiveness in reducing symptoms, but aids in eradication of B. pertussis from secretions, thus reducing infectivity. Because of the high degree of communicability, a 14-day course of the medication for household and close contacts of those with pertussis is recommended as chemoprophylaxis, even for those previously vaccinated.2 If erythromycin is not tolerated or contraindicated, trimethoprim-sulfamethoxazole is an alternative.1
Priorities
The reemergence of pertussis is another example of a contagious illness that can go undetected and spread quickly. Nurses must make it a priority to protect themselves and others from this and other respiratory illnesses. (See “Respiratory Etiquette” sidebar.)
Patients with suspected or confirmed pertussis should be placed on droplet precautions in addition to standard precautions. Public health officials should be notified as soon as possible to aid in tracing contacts and providing chemoprophylaxis.
Respiratory etiquette
To prevent the transmission of all respiratory infections in health care settings, including influenza, the following infection control measures should be implemented at the first point of contact with a potentially infected person or those with signs and symptoms of a respiratory infection.
During periods of increased respiratory infection activity in the community (e.g., when there is increased absenteeism in schools and work settings and increased medical office visits by persons complaining of respiratory illness), offer masks to people who are coughing. Either procedure masks (i.e., with ear loops) or surgical masks (i.e., with ties) may be used to contain respiratory secretions (respirators such as N-95 or above are not necessary for this purpose). When space and chair availability permit, encourage people who are coughing to sit at least 3 feet away from others in common waiting areas.
Source: These recommendations are based on the Draft Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee, CDC. Available at www.cdc.gov/flu. Accessed October 18, 2004.
Pertussis outbreaks
- 1982 Massachusetts & Maryland — Elementary and high school.
www.cdc.gov/mmwr/preview/mmwrhtml/00000094.htm - 1996 Vermont —
School-age children.
www.cdc.gov/mmwr/preview/mmwrhtml/00049244.htm - 2002 Illinois —
Adults in an oil refinery.
www.cdc.gov/mmwr/preview/mmwrhtml/mm5201a1.htm - 2003 Arizona — Middle school children.
www.cdc.gov/mmwr/preview/mmwrhtml/mm5310a4.htm
Impact of antivaccine movements
A study was undertaken to compare the prevalence of pertussis in countries that maintain high vaccination rates with those that have lower rates due to antivaccine movements. In the countries where vaccination has been maintained such as the United States, Hungary, Poland, and the former East Germany, the incidence of pertussis was 10 to 100 times lower than in countries where immunization has waned. These countries include Sweden, Japan, the United Kingdom, the Russian Federation, Ireland, Italy, the former West Germany, and Australia.
Barbara Barzoloski-O’Connor, RN, MSN, is a contributing writer to Nursing Spectrum.
References
1. Guidelines for the control of pertussis outbreaks. CDC website . Available at www.cdc.gov/nip/publications/ pertussis/guide.htm. Accessed October 11, 2004.
2. The Pink Book – Pertussis. CDC website. Available at: www.cdc.gov/nip/publications/pink/pert.pdf. Accessed October 11, 2004.
3. Fatal case of unsuspected pertussis diagnosed from a blood culture — Minnesota, 2003. CDC website. Available at www.cdc.gov/mmwr/ preview/mmwrhtml/mm5306a5.htm. Accessed October 11, 2004.
4. Diphtheria, tetanus, and pertussis: Recommendations for vaccine use and other preventive measures — Recommendations of the Immunization Practices Advisory Committee. CDC website. Available at www.cdc.gov/ mmwr/preview/mmwrhtml/00041645.htm. Accessed October 11, 2004.