Page 63 - Demo

PERTUSSIS Patients are infectious in the early stages of the illness and may remain infectious up to 21 days from the onset of symptoms.3,5 Vaccination does not always protect from contracting pertussis, but the effect of the disease is usually reduced in vaccinated patients.5,6 The Australian Immunisation Handbook and National Immunisation Program recommend pertussis vaccination for all mothers-to-be, during each pregnancy. The vaccine is normally administered between 20 and 32 weeks but may be given up to the time of delivery.4,11 All close contacts of the newborn child should be vaccinated at least two weeks before their expected arrival date.4 The mother may pass some pertussis antibodies to the baby via the breast milk. The mother needs to have had the pertussis vaccination at least two weeks before her milk comes down, to allow her body to have produced the antibodies. Pertussis is a notifiable disease in all Australian states and territories.2 Symptoms Symptoms of whooping cough include:1 • Blocked or runny nose. • Sneezing. • Raised temperature. • Uncontrolled bouts of coughing that sound like a ‘whoop’ or are followed by a ‘whooping’ sound. • Vomiting after coughing. • Inability to catch the breath. Symptoms normally start seven to 20 days after contracting pertussis.1,3,6 The beginning may appear to be a typical cold/flu with a fever, cough, blocked or runny nose. This is called the catarrhal stage.6 The cough will worsen, especially at night, and can become so severe that patients may faint, vomit or break ribs when coughing (paroxysmal stage).1,6 A milder form of the cough may last for several months (the convalescent stage).1,6 In small infants there may be no cough, but they may stop breathing, turn blue or have trouble feeding.1 In some patients the symptoms may be mild, and they may not be aware that they have pertussis. Taking a history to identify possible cases of pertussis Criteria and symptoms that may indicate pertussis include:5 • Cough and coryza (catarrhal inflammation of the mucous membrane of the nose) for one week followed by a more pronounced cough in bouts or paroxysms. • A non-persistent cough. • Vomiting following a bout of coughing. CPD ACTIVITY 61 • Apnoea and/or cyanosis following a bout of coughing. • Close contact with a person who has been diagnosed with pertussis. • Fever is not common. • Children may be relatively well between bouts of coughing. Laboratory tests involved in diagnosing pertussis Infection control may require laboratory confirmation.5,6 However, the diagnosis doesn’t require laboratory testing in most cases.5 A nasopharyngeal aspirate/swab for polymerase chain reaction (PCR) is the normal test.5,6 After 21 days the test is normally negative.5 This test is usually performed only on those patients with symptoms who have been in direct contact with someone with pertussis.6 Direct contacts wouldn’t normally be tested if they are asymptomatic.6 A PCR test is the more common test performed as it amplifies the genetic material of the bacteria in the sample.6 Results are available in a few days, making this test more reliable and quicker than the former gold standard test of culturing.6 Once effective antibiotic therapy is begun, the test may become negative after five to seven days.5 A serology test (IgA) may be positive two weeks after the onset of illness.5 Other tests that may be undertaken include:6 Culture • Uses a nasopharyngeal swab or nasal aspirate. • Grown in nutrient rich media. • Takes one to two weeks to cultivate. • False negative tests can occur as the samples collected can be damaged during transport to the laboratory. Direct fluorescent antibody (DFA)-blood test • No longer used as is less sensitive and less specific than tissue culture. Normally a tissue culture and PCR test will be ordered as early into the illness as possible. The further into the illness the sample is taken, the less likely the culture will grow organisms, especially if antibiotic therapy has been commenced.6 Serology testing has limitations but is used in adults when the illness has been persisting for a length of time. If the patient has previously been immunised against pertussis, they will have IgG antibodies. Pertussis IgM and IgA antibodies will be present for a short time after vaccination or infection. A serology test cannot differentiate between vaccine- and infection-induced TO PAGE 62 Karalyn Huxhagen Karalyn is a community pharmacist from Mackay, Queensland. Also an accredited consultant pharmacist, Karalyn performs medication reviews, delivers quality-use-of- medication programs and provides support services to groups such as the Mackay Regional Pain Support Group. Karalyn’s interests include pain management, asthma and COPD, aged care, wound care, travel medicine, chronic-disease programs and the health of Aboriginal, Torres Strait and South Sea Islander people. She is credentialled to provide Mental Health First Aid and immunisation services. In 2010 Karalyn was recognised with the Australia Day award for services to the health of the Mackay community. LEARNING OBJECTIVES After completing this CPD activity, pharmacists should be able to: • Outline the scope of pertussis infection in Australia, including in at-risk patient populations. • Describe the signs, symptoms and prognosis of pertussis infection. • Describe the treatment and prevention of pertussis, including the role of pharmacist vaccinators. 2016 Competency Standards: 3.1, 3.2, 3.6. Accreditation Number: A2102RP3 (exp: 31/01/2023). Background Pertussis is commonly called whooping cough due to the inspiratory ‘whoop’ sound made during/after a bout of coughing.1,2 The cough is persistent and can be quite uncontrollable, making it difficult for the patient to breathe.1,2 The bacteria responsible for pertussis is Bordetella pertussis.1,3,4,5,6 Pertussis is spread by airborne droplet transfer when patients cough or sneeze onto others, or via direct contact with secretions from the nose or throat.1,3 Pertussis is a contagious and potentially severe disease as it can lead to further complications, including encephalopathy (brain damage) and pneumonia.1,2 Pertussis does have a mortality rate.1 Young babies are the most at risk, but pertussis can lead to complications in all age groups.2 About one in 125 babies under the age of six months who contract pertussis will die from encephalopathy or pneumonia.2,5,6 2 CPD CREDITS RETAIL PHARMACY • JAN/FEB 2021