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Pertussis or Whooping cough |
Whooping cough, also known as Pertussis, is an infectious disease caused by bacteria called Bordetella Pertussis.
Summary
Pertussis causes coughing fits that may end with a high-pitched whooping sound when taking a breath in. The cough sometimes causes vomiting. In older children and adults the symptoms may be milder. In adults there is often no whoop, just a persistent cough. Pertussis is highly infectious regardless of the severity of the cough.
Antibiotics can decrease the infectious period, but have no effect on the duration or severity of disease. Antibiotic may be used for family contacts to prevent Pertussis.
Symptomatic treatment of cough has not been proven to be significantly helpful in decreasing the cough of Pertussis.
Immunisation remains the mainstay of prevention of Pertussis infection.
Most people in Australia have been immunised against whooping cough, however the protective effects of the vaccine can wear off in later childhood. All babies should receive a course of vaccinations before they are one year of age, and children should have a booster injection at four and during the teenage years. The vaccine is usually given in combination with diphtheria and tetanus vaccinations.
Adolescent and adult booster immunisation remains critical for preventing disease outbreaks.
Household members such as grandparents or carers should also be vaccinated.
Remembers high fever rapid breathing and cough may also be symptoms of pneumonia so early medical review is appropriate. If you are presenting to the practice please call ahead as we may recommend you wear a mask in the waiting room to reduce the risk of spread to others.
Clinical presentation
The classic presentation of Pertussis is one of spasms of coughing with a characteristic inspiratory whoop. However, this is less common in older children and adults. The first 1–2 weeks of illness with Pertussis resembles other upper respiratory tract infections, with runny nose and mild cough. This is followed by the coughing phase in the second and third weeks.
Diagnosis
A number of investigations can be performed to support the diagnosis of Pertussis.
For patients presenting early (within the first three weeks) polymerase chain reaction (PCR), testing of nose and throat swabs may be useful.
For patients who present later, blood testing − which is reliant on an immune response − is often more helpful.
The PCR tests amplify the Pertussis DNA to make testing more reliable. PCR tests detect Pertussis for longer than culture and are less likely to be affected by antibiotic treatment
The blood tests look for Pertussis-specific IgA which is part of the body’s response to the Pertussis infection. Pertussis-specific IgA is only produced after natural infection, whereas Pertussis IgG rises with vaccination and also with natural infection.
While a positive IgA test confirms the diagnosis of Pertussis, a negative result does not exclude the possibility of infection.
Antibiotic treatment
Antibiotics are recommended to reduce the spread of the infection to others. However, after three weeks of coughing, antibiotics have no measurable effect on reducing the infectious period and are not recommended.
Patients should avoid contact with susceptible individuals until at least five days of antibiotics have been taken.
Managing household contacts
Pertussis is highly contagious and a significant proportion of contacts become infected (70–100% of household members). The incubation period is typically 7–10 days (range of 4–21 days). Antibiotics are often offered to family contacts before they get sick to prevent complication of Pertussis
It is suggested that if prophylaxis is indicated it should be given as soon as possible, within the first three weeks of symptom onset in the infected contact.
As three or more injections are required to confer protection, infant vaccination is not helpful in controlling a Pertussis outbreak. However, unvaccinated contacts aged eight years or older can be offered a diphtheria, tetanus and acellular Pertussis vaccine and younger contacts can be given a catch-up course if needed
Important role of immunisation in adults
Immunisation remains the mainstay of prevention of Pertussis infection.
The current Australian immunisation schedule recommends that a child formulation of a diphtheria, tetanus and acellular Pertussis vaccine is given at two, four and six months of age with a booster at four years. Another booster is recommended at 12–17 years of age using the adolescent/adult formulation which has a lower concentration of Pertussis antigens than childhood vaccinations.
Adult and adolescent vaccination is an effective means of controlling Pertussis and will have positive health benefits.
Household members such as grandparents or carers should also be vaccinated. Likewise, adults working in health care or childcare should be given a booster vaccination. Pertussis booster vaccination can also be considered along with a routine diphtheria and tetanus booster at age 50.
Reference Managing Pertussis by Julie Marchant, Australian Prescriber 2009
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