Melomed Articles


14 February 2019 - Dr. Naeema Sheik

Pertussis


What is Pertussis?
Pertussis is a bacterial infection caused by the organism Bordatella Pertussis. This organism releases toxins causing the airway lining to swell.

How does one contract the disease?
Pertussis is highly contagious and is spread via coughing, sneezing, being in close proximity to one another and sharing the same breathing space. Infants can easily contract the disease from siblings, parents, or caregivers who may not even know they are infected.

Who can get pertussis?
This infection can occur in all ages but is serious for infants and children, and can be fatal especially amongst infants who have not begun or completed their series of vaccines. The infection appeared to have become a disease of the past but is now once again a major public health challenge. 

Why the recent resurgence of Pertussis?
It is thought that this may be due to: -
1) The testing mechanisms which have become more advanced -higher sensitivity and specificity
2) A greater awareness and more reporting amongst practitioners.
3) Genetic changes to the organism over the years.

How is the Diagnosis of Pertussis made?
Diagnosis is based on history of signs and symptoms, physical examination and laboratory investigations. However, if clinical signs and symptoms are suggestive, treatment can be commenced whilst awaiting diagnostic confirmation.

How does Pertussis present?
Within the first 2 weeks, symptoms are similar to that of the common cold - runny nose, low-grade fever. A cough may not be present; or it may be a mild, occasional cough.
Infants may also present with vomiting, apnoea (cessation of breathing for longer than 20 seconds), with resultant cyanosis (Blue colour on the lips and tongue due to lack of oxygen in the blood). In young infants, apnoea may be the only sign that they are infected. They may never develop the cough.

The Cough
Initially the SOUND of the cough is not different from the sound of cough of other origin, but with Pertussis the cough generally becomes paroxysmal (sudden attack of bouts of coughing) with numerous RAPID coughs due to difficulty expelling thick mucus from the tracheo-bronchial tree.

This paroxysmal stage lasts from 1 to 6 weeks.

In China it is known as the 100 days Cough and is associated with a wide range of Severe Complications such as: - 
Apnoea (60%)
Pneumonia (Lung infection)
Convulsions (seizures) 
Encephalopathy (abnormal brain functioning)
Death 

Adolescents and adults can also experience complications of pertussis, but they are less serious especially if they were vaccinated. The most common complications requiring hospitalisation are: -
Loss of weight
Loss of bladder control
Loss of consciousness
Rib fractures, ruptured eardrum or hearing loss due to severe coughing

Impact on family life
The cough of pertussis lasts for several weeks. This may result in missed time from school, work and other activities.
The infected person is also a reservoir of disease for infecting infants and young children with whom they may come into contact.

How is Pertussis Treated?
Early treatment before the cough paroxysms begin minimises the symptoms, and the risk of transferring bacteria to others will also be decreased.

The historical management with 14 days of Erythromycin has now been superseded with the more patient-friendly regimen of shorter courses with Azithromycin or Clarithromycin.

If an infected person is coughing for longer than 3 weeks, then treatment is unlikely to improve the symptoms. Nevertheless, antibiotic therapy should be recommended to decrease contagiousness.

Symptoms may persist after this period, but this does not mean there is active infection. The symptoms are due to damage to the respiratory tract that is already been caused by the bacteria.

All close contacts of a person infected with pertussis needs to be put onto chemoprophylaxis. The same antibiotic regimens that are used for the treatment of Pertussis are used as chemoprophylaxis.

Important to note
Protective immunity against Pertussis wanes over time, and there is concern about how this may be contributing to the increased incidence of infection. Immunity following NATURAL infection lasts maybe 7 to 15 years.

The duration of immunity following vaccination is even shorter - with protection lasting about 6 years. Therefore, those that received the immunisation in childhood only are no longer protected as their immunity from the initial childhood vaccination has waned, and they are therefore now susceptible to the infection.

They can become asymptomatic carriers, and carry and infect infants who can become seriously ill, especially those who have not received their complete immunisation series.

All pregnant women should be vaccinated against Pertussis- between 27- and 36-weeks' gestation, irrespective of the mothers' previous vaccination status.

Pertussis in the Immunisation Schedule:
Pertussis vaccine is usually given in combination with other vaccines viz: Diphtheria, Tetanus, Haemophilus influenza type B and Hepatitis B vaccines at:
6 weeks, 10 weeks, and 14 weeks, with a booster given at 18 months of age. 
Take home message
Prevention is better than cure - VACCINATE
Testing is quick, simple, pain-free and effective
If you are unsure about the type of cough you or your loved ones present with, a visit to your healthcare provider will be able to put your minds at ease.


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