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This course will expire or be updated on or before September 1, 2014.
ABOUT THIS COURSE
You must score 70% or better on the test and complete the course evaluation to earn a certificate of completion for this CE activity.
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Wild Iris Medical Education, Inc. is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation.
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COURSE OBJECTIVE: The purpose of this course is to provide healthcare workers with information on the assessment, diagnosis, treatment, and prevention of pertussis.
Upon completion of this course, you will be able to:
CASE: Grace's Story
Grace is an 8-month-old infant, the youngest of three children. Developmentally, she has had a normal, healthy infancy, and thus far, she has received all of the immunizations recommended by the American Academy of Pediatrics. When Grace wakes one morning with sniffles and a runny nose, her mother, Maria, assumes that Grace has caught a cold from one of her siblings. Maria has been feeling congested herself for the last few days. After a week with a low-grade fever and a runny nose, Grace develops a slight cough, and every now and then, it seems like she stops breathing. Cautious but not overly concerned, Maria takes her daughter to the doctor. Expecting to be told that Grace has a common respiratory ailment, Maria never anticipates that both she and her daughter will be diagnosed with pertussis.
Pertussis, also known as whooping cough, is a highly contagious respiratory disease caused by the bacterium Bordatella pertussis. It is a toxin-mediated illness: bacteria attach themselves to cilia in the upper respiratory system and then release toxins that paralyze the cilia and cause inflammation. This inflammation interferes with the clearing of pulmonary secretions. Recent studies suggest that the bacteria also invade tissue via alveolar macrophages in the pulmonary alveoli (CDC, 2005a).
The most identifiable symptom of pertussis is violent fits of uncontrollable coughing. In children, the coughing is typically followed by a “whooping” sound as air is sucked back into the lungs. (Visit http://www.pkids.org/dis_pert_stsop.php to hear a recording of “whooping.”) Pertussis most commonly affects children and infants, but adolescents and adults are also susceptible. Called the “cough of a 100 days” by the Chinese, the disease can be fatal, particularly for infants under one year of age.
Pertussis is spread via aerosolized droplets of respiratory secretions (coughing, sneezing) or by direct contact with secretions (saliva, mucus) from an infected person. Once a person has been exposed to pertussis bacteria, symptoms may develop within 7 to 10 days, but the disease can incubate for up to 6 weeks.
The course of the disease follows three stages: catarrhal, paroxysmal, and convalescent.
As pertussis progresses, it may lead to related complications that can pose serious health risks. Incidence of complications varies depending on the age of the patient, but an estimated 6% of children and as many as 24% of infants who contract pertussis can experience related health problems (WHO, 2010). According to the Centers for Disease Control and Prevention (2011), “More than half of infants younger than 1 year of age who get the disease must be hospitalized.” The disease can be particularly harmful for babies when coughing is so severe that they cannot eat, drink, or breathe.
Common complications for hospitalized infants include pneumonia, convulsions, apnea, encephalopathy (as a result of hypoxia from coughing or possibly from toxin), and death. For infants who die, refractory pulmonary hypertension is common and encephalopathy occurs in 20% of cases. “Other complications can include anorexia, dehydration, difficulty sleeping, epistaxis, hernias, otitis media, and urinary incontinence. More severe complications can include pneumothorax, rectal prolapse, and subdural hematomas” (CDC, 2011).
For teens and adults, the kinds of complications stemming form pertussis tend to be more directly related to the physical effects of the cough, and less than 5% of patients require hospitalization. Complications in those who do require hospital care are listed in the table below. Other complications can include “anorexia, dehydration, epistaxis, hernias, and otitis media. More severe complications can include encephalopathy as a result of hypoxia from coughing or possibly from toxin, pneumothorax, rectal prolapse, subdural hematomas, and seizures” (CDC, 2011).
|Source: CDC, 2011.|
|Pneumonia (2%)||Pneumonia (20%)|
|Convulsions (1%)||Weight loss (33%)|
|Apnea (50%)||Urinary incontinence (28%)|
|Encephalopathy (3%)||Syncope (6%)|
|Death (1%)||Rib fractures (4%)|
Before vaccinations were widely available, pertussis was one of the most common childhood illnesses around the globe. “Following large-scale vaccination during the 1950s and 1960s, a dramatic reduction (>90%) in incidence and mortality of pertussis was observed in the industrialized world” (WHO, 2010).
Unlike some other childhood diseases that have been nearly or fully eradicated, however, pertussis has been on the rise since the mid-1990s. Perhaps the most notable point about this increase is a shift in the age of affected individuals. Among newly vaccinated children, increase in the incidence of pertussis remains small: the greatest increase has been documented in young people between the ages of 10 and 19 (CDC, 2005a). (See the figures below, which demonstrate this increase by age group as well as U.S. region.)
Number of reported pertussis cases (confirmed and probable) in the United States, by year and age group. (Source: CDC, 2005a.)
Average annual incidence per 100,000 state population for this age group, by quartile (indicated by shading) of reported pertussis cases, and total number of reported cases in persons aged 10–19 years (confirmed and probable), by state, 2001–2003. Overall U.S. incidence rates were 5.5, 6.7, and 10.9 per 100,000 U.S. population for this age group during 2001, 2002, and 2003, respectively. (Source: CDC, 2005a.)
What is causing this upward shift in the incidence of pertussis cases? There are a number of possibilities worth noting:
CASE: Grace's Story (continued)
At the doctor’s office, RN Kathy interviews Maria to find out what symptoms Grace has been experiencing, for how long, of what severity, and so on. The fact that Grace has been suffering from apnea immediately arouses Kathy’s suspicions that this illness is more than a common cold. Noting that Maria is also sniffling, Kathy asks for a recent family health history and learns that Maria herself has been experiencing respiratory infection symptoms for the past 7 days. Because she knows that previously immunized adults may manifest only mild symptoms of pertussis, and because she understands that waning immunity in adults can lead to the accidental spread of the disease, Kathy suspects that Maria’s illness may be connected to Grace’s apnea. She recommends that both mother and daughter undergo diagnostic tests for pertussis.
When a patient comes into the office with common respiratory complaints, the medical staff should first conduct an interview to ascertain what symptoms are being experienced, the time of onset, and the duration and severity of the illness. During this interview, the patient’s personal history and family health history may also be solicited. Next, a physical examination is performed, vitals taken, and observations made about the patient’s status. Specifically, nurses will check for coughing (with or without a whoop), nasal congestion, apnea (in infants), fatigue, and a low-grade fever as potential signs of pertussis.
If enough evidence exists to suggest that pertussis may be present, then diagnostic tests are recommended. There are three main diagnostic tests for pertussis: culture, polymerase chain reaction (PCR), and serology. Of the three, a culture is the only 100% specific method and will identify which strands of Bordatella pertussis are responsible for illness; however, it takes up to 7 days to get results back. PCR is faster and does not require live bacteria, although it can deliver false results. Serology is most useful once the disease is in later stages: 2–8 weeks following cough onset, when antibody titers are at their highest. Specimens can be tested via serology up to 12 weeks after coughing begins (CDC, 2011).
Depending on when a patient visits the doctor’s office, different tests are more effective: within the first 2 weeks, when viable bacteria levels are highest, a culture or PCR would provide the most accurate reading. However, many patients do not seek medical treatment until they are well into the paroxysmal stage of the illness, when coughing has become increasingly disruptive. From about 3 weeks on, serology is the most accurate diagnostic tool.
(Source: CDC, 2011)
For both PCR and cultures of suspected pertussis cases, a nasopharyngeal (NP) swab or aspirate must be obtained. According to the CDC (2011), “Once an NP swab has been collected, it should be plated directly or placed into transport medium immediately. NP aspirates should be dispensed and plated within 24 hours of collection.” The same specimen can be used for both a culture and PCR. (See the figures below for examples of how to successfully obtain an NP swab or aspirate. For a video demonstrating proper NP techniques, go to http://www.cdc.gov/pertussis/clinical/diagnostic-testing/diagnosis-confirmation.html.)
Proper technique for obtaining a nasopharyngeal specimen for isolation of Bordetella pertussis. (Source: CDC, 2011.)
BEST PRACTICES TO ACHIEVE ACCURATE PCR RESULTS
The CDC recommends a series of PCR best practices to avoid inaccurate diagnosis of pertussis specimens. Specifically, the following guidelines are suggested:
Source: CDC, 2011.
|Test||Sensitivity2, 3||Specificity2, 3||Optimal Timing||Advantages||Disadvantages|
|Source: CDC, 2009.|
|Culture||12%–60%||100%||< 2 weeks post-cough onset||Very specific (100%)||Low sensitivity; 7–10 day delay between specimen collection and diagnosis|
|PCR||70%–99%||86%–100%||< 4 weeks post-cough onset||Rapid test; more sensitive than culture; organisms do not need to be viable; positive post-antibiotics||No FDA approved tests or standardization; potential for false positives; DNA cross-contamination can be problematic|
|Paired Sera1||90%–92%||72%–100%||At symptom onset and 4–6 weeks later||Effective indication of mounting antibody titers||Late diagnosis; no FDA approved tests or standardization|
|Single Sera1||36%–76%||99%||At least 2 weeks post-cough onset; ideally 4–8 weeks post-cough||Useful for late diagnosis or post-antibiotics||No FDA approved test or standardization; possibly confounded by recent vaccination; diagnostic cut-offs not validated|
|1 Not part of CDC/CSTE case definition (Exception: MA single point ELISA assay).
2 Sensitivity and specificity values obtained from Wendelboe & Van Rie, 2006.
3 Data currently being validated at CDC (except paired sera).
Because pertussis is also a public health issue, diagnosis for epidemiological reasons has a different goal from that in the doctor’s office. “In the clinical setting, the goal is to optimize sensitivity (not to miss cases) while providing rapid results. This ensures rapid diagnosis and appropriate treatment to prevent further transmission. In the public health setting, a high degree of specificity (not to over-diagnose cases) is needed to avoid unnecessary and ineffective public health interventions” (CDC, 2011).
Initial diagnosis of a patient is based on the case assessment (oral interview and physical examination). However, because pertussis presents like other common respiratory infections for the first few weeks, and because some patients may be asymptomatic, it can be difficult to make an initial pertussis diagnosis. Moreover, many patients often wait to visit the doctor until the disease has already progressed to the second stage, when diagnostic tests are limited to serological assays.
Thus, the CDC (2011) recommends that “clinicians strongly consider treating prior to test results if clinical history is strongly suggestive or if a patient is at risk for severe or complicated disease, e.g., infants.” Given the potential health risks associated with pertussis, its high degree of contagiousness, and the rise in incidence of the disease, treating suspected cases prior to receiving definitive results can be a responsible option for healthcare providers.
In some cases, there is little to prescribe beyond a regimen of rest, for pharmaceuticals are an effective treatment option for pertussis only if administered early on in the course of the disease. The decision to prescribe pharmaceuticals varies depending on the age of the patient, risk factors involved, severity of symptoms, how long a patient has already been ill, and so on. If drugs are prescribed, azithromycin, clarithromycin, and erythromycin are the antibiotics of choice.
The CDC presents specific recommendations for pharmacologic intervention:
Some negative side effects—gastrointestinal ailments or rashes—may result from the use of erythromycin and macrolides. When choosing what drug to administer, medical professionals should take into consideration its safety, effectiveness, cost, tolerability, and ease of regimen.
IHPS AND ERYTHROMYCIN
Infantile hypertrophic pyloric stenosis (IHPS) is a form of gastric outlet obstruction that occurs in about 3 in every 1,000 babies born in the United States. When an infant suffers from IHPS, the pylorus muscles of the stomach thicken abnormally and block the pyloric channel so that food is unable to leave the stomach and enter the small intestine. The condition can cause vomiting, dehydration, and fluid imbalances and must be surgically repaired. There is a causal link between use of erythromycin in the first 2 weeks of life and development of IHPS, so it should be avoided as a pertussis treatment in infants less than 1 month old (Cronan, 2011).
When a pertussis patient is experiencing extreme breathing difficulties or other complications, hospitalization is in order. Once admitted, patients may receive IV fluids to alleviate dehydration. An oxygen tent with high humidity or a ventilator is often used to assist with breathing. Prevention of secondary infections and attentive nursing care are important components of hospitalization.
CASE: Grace's Story (continued)
Strongly suspecting that Grace and Maria will test positive for pertussis based on clinical history, their physician begins treating both with antibiotics. They are placed on a regimen of azithromycin, from which Grace develops gastrointestinal side effects. After a day on the medication, Grace, who is now suffering from both diarrhea and a more severe cough that keeps her from nursing effectively, becomes dehydrated. Maria, noting her daughter’s listlessness and inability to ingest liquids, calls the doctor. He advises her to take Grace to the hospital, where she is admitted, given IV fluids to alleviate her dehydration, and is closely monitored for emergence of other complications.
Home treatment for diagnosed pertussis patients typically involves administering antibiotics according to the prescribed regimen and providing supportive care to alleviate discomfort and monitor progression of the illness. Over-the-counter cough medicines are ineffective in treating pertussis and should not be given. Caregivers should also limit close physical contact between themselves and the patient and take precautions to minimize germ transmission (Schoenstadt, 2011).
In addition to treating a positively diagnosed patient, doctors may choose to provide a macrolide as a prophylaxis for people in close contact with the patient. Deciding whether to proceed with prophylaxis depends on the intensity of exposure, the infectiousness of the patient, and the risk of contracting pertussis for the individual coming into contact with the disease (CDC, 2005b).
“Maintaining high vaccination coverage rates among preschool children, adolescents, and adults and minimizing exposures of infants and persons at high risk for pertussis is the most effective way to prevent pertussis” (CDC, 2005b). A universal vaccine for children has been recommended since the mid-1940s and has made great inroads in prevention of the disease.
There are two types of pertussis vaccine currently available:
Both kinds of vaccines are given in combination with diphtheria and tetanus immunizations. Children younger than 7 years of age should get five doses of DTaP (capital letters represent full-strength doses of vaccine), one dose at each of the following ages: 2, 4, 6, and 15–18 months, and 4–6 years. Tdap booster shots are recommended for adolescents 11–18 years of age and adults 19–64. Many school districts now require proof of up-to-date Tdap vaccination for attendance at middle or high schools in an effort to curb the disease.
Updated recommendations (AAP, 2011) state that Tdap should be given to adults 65 and older who have close contact with an infant and have not previously received Tdap. It should also be given to 7–10 year olds who were not fully immunized against pertussis. There is no longer a minimal interval required between receipt of a tetanus or diphtheria vaccine and Tdap. Tdap may also be given to pregnant mothers as indicated instead of waiting until after childbirth.
The Tdap contains smaller doses of diphtheria and pertussis components, because once an individual has been previously vaccinated, lower dosages are sufficient to maintain immunity.
CASE: School Nurse on the Front Lines
As the sole nurse for the Putnam County School District, Claudia is the one who must verify that each middle and high school student has received an up-to-date Tdap vaccination in order to attend school come fall. She makes phone calls home and sends reminder letters to keep parents apprised of the need to submit documentation prior to school’s start. Because Claudia’s district is one that provides a free vaccination clinic for local students, she also administers these injections to those who take advantage of the offer. Even with vaccinations verified, she has the additional responsibility of being the district’s pertussis “gatekeeper”: if a student turns up in her office with symptoms indicative of whooping cough, Claudia follows up with phone calls home to learn more case history and, when warranted, she advises a trip to the child’s doctor for further diagnosis. If antibiotics are prescribed for an infected student, Claudia administers the medication during school hours.
Because of the increased exposure healthcare workers face, they are at greater risk of contracting pertussis. “One Canadian study found that [healthcare workers] were 1.7 times more likely to contract pertussis than were people in the general adult population” (Zastrow, 2011). Pertussis outbreaks in the workplace are not only stressful for the individual, but they can be costly and disruptive for the place of employment.
To help counterbalance the increased risk for healthcare workers, the CDC recommends that all employees with direct patient contact receive a Tdap booster every 10 years or sooner. Moreover, taking precautions to prevent cross-contamination from sample collection, wearing protective gloves, disinfecting surfaces with a 10% bleach solution, and washing hands thoroughly and regularly can also help minimize chances of infection.
Pertussis is a nationally notable disease, and as such, clinical cases must be reported to local health departments. Tracking pertussis can help prevent its spread while also revealing patterns about how, when, and where the disease is manifesting itself. Both probable and confirmed cases should be reported.
To clarify the distinction between probable and positive cases, the CDC provides a clinical case definition that is crucial given the limitations of lab diagnostics and the underreporting of pertussis cases due to misdiagnosis. The clinical case definition for pertussis describes the illness as one in which a cough lasts 14 or more days with “paroxysms of coughing, inspiratory ‘whoop,’ or post-tussive vomiting, without other apparent cause, as reported by a health professional” (CDC, 2011).
What, then, is a “probable” case of pertussis? Simply put, it is one that meets the clinical definition above. A probable case is not confirmed by a lab, nor is it epidemiologically linked to a lab-confirmed case.
What is a “positive” case of pertussis? For a case to be classified with this terminology, “an acute cough illness of any duration is present. A case meets the clinical case definition and is confirmed by positive PCR; or a case meets the clinical case definition and is epidemiologically linked directly to a case confirmed by either culture or PCR” (CDC, 2011).
Different parts of the country have different guidelines for reporting pertussis cases. The Council of State and Territorial Epidemiologists (CSTE) website includes a state-by-state reportable conditions link that will provide specific details (see “Resources” below).
Pertussis is endemic in the United States, with epidemics cycling every 3–5 years and periodic outbreaks.
As defined by the World Health Organization, the primary goal of outbreak control is to prevent infant morbidity, and the secondary goal is to prevent overall morbidity (2010). Due to waning immunity during teenage years, outbreaks at middle and high schools are common; the best response for such situations is prophylaxis for contacts and booster shots, depending on the age of the students involved.
CASE: Grace's Story (conclusion)
With excellent hospital care, Grace survives the complications brought on by her pertussis infection. After seven days of treatment in which she receives IV antibiotics as well as fluids to combat her dehydration, Grace is released from the hospital and returns home to her family. She still has a cough that will linger for several more weeks, and her parents watch closely to make sure that she doesn’t develop a secondary infection as indicated by a fever.
Meanwhile, Maria is still taking her own antibiotics, and her husband, Greg, has also been given a prophylactic prescription, since he hasn’t received a Tdap booster and will be coming into close contact with both infected family members. With rest, fluids, and time, both Grace and Maria gradually return to good health.
Pertussis, or whooping cough, has traditionally been seen as a childhood disease, but in fact, it is potentially dangerous for people of all ages. Infants are the most vulnerable to the illness and often develop related complications that require hospitalization. Violent paroxysms of coughing and the extended duration of pertussis make it particularly challenging to endure, but if caught within the first few weeks of onset, the disease can be treated with antibiotics. Waning immunity in adolescents and adults has challenged efforts to eradicate the disease, and the incidence of pertussis is on the rise among young people ages 10–19. Childhood vaccination and subsequent booster shots for adolescents and adults are the best method for combatting the spread of this infectious disease.
Centers for Disease Control and Prevention (CDC)
CDC video demonstrating proper NP techniques
Council of State and Territorial Epidemiologists (CSTE): Links to state-by-state reportable conditions http://www.cste.org/dnn/ProgramsandActivities/PublicHealthInformatics/PHIStateReportableWebsites/tabid/136/
KidsHealth: Pyloric stenosis
National Institutes of Health – Medline Plus
National Network for Immunization Information
Parents of Kids with Infectious Diseases, including audio of “whooping”
World Health Organization
American Academy of Pediatrics (AAP). (2011). Additional recommendations for use of tetanus toxoid, reduced-content diphtheria toxoid, and acellular pertussis vaccine (Tdap). Retrieved October 24, 2011, from http://pediatrics.aappublications.org/content/early/2011/09/21/peds.2011-1752. Doi: 10.1542/peds.2011-1752.
Centers for Disease Control (CDC). (2011). Pertussis (whooping cough). Retrieved June 21, 2011, from http://www.cdc.gov/pertussis/.
Centers for Disease Control and Prevention (CDC). (2009). What’s all the WHOOP about? Retrieved June 20, 2011, from http://www.aphl.org/aphlprograms/infectious/Documents/Pertussis_Brochure-Final3.pdf.
Centers for Disease Control and Prevention (CDC). (2005a). Morbidity and Mortality Weekly Report (MMWR). Pertussis – United States, 2001-2003. Retrieved June 20, 2011, from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5450a3.htm.
Centers for Disease Control and Prevention (CDC). (2005b) Morbidity and Mortality Weekly Report (MMWR). Recommended antimicrobial agents for the treatment and postexposure prophylaxis of pertussis, 2002 CDC Guidelines. Retrieved June 20, 2011, from http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5414a1.htm?s_cid=rr5414a1_e.
Cronan KM. (2011). KidsHealth from Nemours: Pyloric stenosis. Retrieved July 10, 2011, from http://kidshealth.org/parent/medical/digestive/pyloric_stenosis.html.
Feikin DR, et al. (2000). Individual and community risks of measles and pertussis associated with personal exemptions to immunization. Journal American Medical Association, 284(24), 3145–50.
National Institutes of Health (NIH). (2011). Medline Plus, Pertussis. Retrieved June 20, 2011, from http://www.nlm.nih.gov/medlineplus/ency/article/001561.htm.
Schoenstadt A. (2011). Whooping cough treatment. Retrieved July 11, 2011, from http://diseases.emedtv.com/whooping-cough/whooping-cough-treatment-p2.html.
Wendelboe AM & Van Rie A. (2006). Diagnosis of pertussis: A historical review and recent developments. Expert Review of Molecular Diagnostics, 6(6), 857–64.
World Health Organization (WHO). (2010). Weekly Epidemiological Record, No. 40. Retrieved June 21, 2011, from http://www.who.int/wer/2010/wer8540.pdf.
World Health Organization (WHO), Department of Immunization, Vaccines, and Biologicals. (2007). Laboratory manual for the diagnosis of whooping cough caused by Bordetella pertussis/bordetella parapertussis. Geneva, Switzerland: World Health Organization. Retrieved June 21, 2011, from http://www.who.int/vaccines-documents/DocsPDF04/www788.pdf.
Zastrow R. (2011). Pertussis on the rise. American Journal of Nursing, 111(6), 51–56.
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