respiratory health

Pertussis

Generality

Pertussis is an acute and highly contagious infectious disease caused by a Gram negative bacterium called Bordetella Pertussis .

Also known as whooping cough, killer cough or canine cough, the disease is responsible for a persistent cough, which, in the central phase of the infection (paroxysmal phase), becomes the protagonist of real tussive crises .

Pertussis is an infection that - when it affects infants and very young children - can cause serious complications, up to and including death; in adults, on the other hand, it rarely causes severe consequences.

The treatment of pertussis varies according to the age of the patient and the stage in which the infection is diagnosed.

The most effective method to prevent the disease is to resort to vaccination, a vaccination which, in Italy, is now mandatory.

What is pertussis?

Pertussis is an infectious disease of bacterial origin, with an acute and extremely contagious character, which affects the respiratory tract and the lungs.

Pertussis owes its name to the symptom that most characterizes it: cough.

In infected patients, the cough disorder is so persistent that it can last up to 10 weeks; this explains, moreover, the reason why pertussis is also called " 100-day cough ".

Other synonyms of pertussis

In addition to "100-day cough", other synonyms of pertussis are: canine cough, whooping cough and killer cough .

Epidemiology

With the advent of the vaccine (40s of the twentieth century), pertussis has gone from being a widely spread infection all over the world and the main cause of death among children, to representing a major health problem only in countries developing countries, where vaccination programs are still underdeveloped.

In other words, the realization of the anti-pertussis vaccine represents an epochal turning point, greatly reducing the cases of pertussis in the most industrialized countries of the globe.

Today, worldwide, pertussis is an infectious disease that, annually, affects around 16 million people (2015) and is the cause of death for 58.700 patients (2015).

Some numbers on whooping cough:

  • According to a 2008 global statistics, pertussis is the cause of death for 195, 000 people.
  • According to some estimates, around 90% of all pertussis cases would take place in developing countries.
  • In a country like the United States, the number of pertussis annual cases has increased from just over 178, 000 units, in the period preceding the construction of the vaccine, to just under 21, 000 units in 2015 (that is, after almost 70 years since the advent of vaccination).

Causes

"Infectious disease of bacterial origin" means an affection that appears due to a bacterium.

In the specific case of pertussis, the bacterium responsible for the infectious disease (or infection) is the so-called Bordetella Pertussis .

Bordetella Pertussis

Bordetella Pertussis is a Gram-negative, aerobic and morphologically similar egg to an egg (cocco-bacillus), which has various weapons of virulence, including an exotoxin, filamentous hemagglutinin, tracheal cytotoxin, pertactin, etc.

When it infects a human being, Bordetella Pertussis settles at the level of the epithelial cells of the lungs and colonizes them; the colonizing action of this bacterium involves an impediment to the movement of the eyelashes (which cover the pulmonary epithelium and have the important function of eliminating the debris entering the lungs, through the inhaled air).

Therefore, the obstruction of the movement of the eyelashes, by Bordetella Pertussis, determines the accumulation of debris along the airways and in the lungs of the host, and this is responsible for part of the symptoms of pertussis.

To complete the infection process of Bordetella Pertussis is the inhibitory action that this bacterium has against the host's immune system; entering in more detail, the weapon used by Bordetella Pertussis to attack the immune system is its exotoxin, simply called pertussis toxin .

Incubation times

The incubation period that characterizes Bordetella Pertussis (that is the time that must pass from the first exposure to the bacterium until the appearance of the first symptoms) has an average duration of 9-10 days; it is good, however, to specify that its range goes from a minimum of 6 to a maximum of 20 days.

Contagion

How Bordetella Pertussis transmits

The transmission of pertussis (and of Bordetella Pertussis ) to a new host occurs exclusively through the inhalation of droplets of infected saliva, emitted by a carrier of the infection, during sneezing, coughing or when speaking.

The degree of infectivity of the droplets containing Bordetella Pertussis is particularly high; according to some medical studies, the probability that these droplets have to transmit pertussis to a susceptible individual (who clearly inhales them) is more than 90%.

Curiosity

In the medical field, this route of transmission mentioned above, which assigns the role of pertussis vehicles to the droplets of saliva emitted by the sick, is called via aerosol .

Infectious diseases transmissible by aerosol make overcrowded places ideal for the spread of the causative pathogen.

Who can get sick with whooping cough?

Pertussis can affect anyone who has not received the vaccine; however, statistics in hand, has a predilection for infants and very young children, on which, however, it can have the worst consequences.

Symptoms and complications

To learn more: Symptoms Pertussis

After the incubation period - which as a rule is said to last 9-10 days - pertussis begins with the so-called catarral phase, during which the symptoms of the disease in question are common to those of a trivial respiratory disease (therefore cough snappy and phlegm, associated with a slight rise in body temperature).

The catarral phase is followed, after 1-3 weeks, by the so-called paroxysmal phase or accessory phase, in which, especially at night, there is an exacerbation (sudden aggravation) of the cough, which gives rise to real crises .

The paroxysmal phase lasts from 2 to 6 weeks; after which, the last phase of pertussis begins, namely the phase of convalescence .

Characterized by a gradual shutdown of the severe cough, typical of the previous pathological phase, the phase or period of convalescence has a variable duration, which can fluctuate from one to even 3 weeks.

Pertussis phasesCanonical duration (maximum duration)
Catarrhal phase7-14 days (4-21 days)
Paroxysmal phase1-6 weeks (10 weeks)
Phase of convalescence7-14 days (4-21 days)

Catarrhal phase

The characteristic symptoms of pertussis, when it is in its catarral phase, are:

  • Catarrhous cough. Resistant to common sedatives, as the days go by, it becomes increasingly irritated and frequent;
  • Temperature;
  • Runny nose (rhinorrhea);
  • Temperature;
  • Nasal congestion;
  • Sore throat;
  • Eyes red and watery;
  • Weakness and general malaise.

Together with the incubation period, the catarral phase of pertussis represents the pathological period in which infectivity (or contagiousness) is maximum .

Paroxysmal phase

The paroxysmal phase of pertussis begins when the mucus accumulating in the respiratory tract is so much that the need for the body to release the airways produces real coughing crises (readers are reminded that the cough it is a defensive reflex, implemented by the organism to protect the airways and make them visible).

More frequent during the night, paroxysmal phase coughs have a canonical duration of a few minutes and are characterized by short and contiguous coughing strokes. Their repetition in close sequence - the latter a very common phenomenon - has the tendency to end with a retching or expectoration of dense, vitreous and stringy mucous material; furthermore, he is responsible for:

  • Reddened face or blue (if blue, it is called cyanosis);
  • Sense of intense fatigue;
  • Production of a typical shrill rattle at the first inspiratory act following the end of the cough crisis.

The number of cough crises, over a whole day, can range from 5 to even 40.

As the paroxysmal phase progresses, the patient's level of infectiousness gradually decays, until it is canceled.

Phase of convalescence

In pertussis, the phase of convalescence represents the moment in which the symptoms of the paroxysmal phase begin to gradually diminish, until the complete disappearance.

In other words, the patient with pertussis who enters the convalescence phase sees progressively improve his state of health and can be considered on the road to recovery.

Pertussis in the newborn and small child

In the infant with pertussis, seizures are far more forgiving than in the child or in the larger subject; however, in the sick newborn, it is possible to witness apnea phenomena, which can, in the most unfortunate cases, result in serious complications.

Pertussis in large children, adolescents and adults

The more the pertussis patient is an adult, the more likely it is that the cough is the only symptom present.

In other words, in large children and adolescents it is easier to observe an articulated symptom picture, compared to what happens in adults, who, in general, exhibit only cough.

Complications in the newborn

In the newborn - especially in those under 6 months - pertussis is an important health hazard, as it can degenerate into serious complications and sometimes fatal outcomes, such as:

  • Dehydration;
  • Severe breathing difficulties, neurological damage caused by hypoxia and suffocation. These are the possible complications referred to previously when there was talk of whooping cough in the newborn and the possibility of apnea;
  • Weight loss;
  • Pneumonia;
  • Epilepsy;
  • Kidney dysfunctions.

The newborn with pertussis who develops one of these complications needs immediate hospitalization.

Complications in the big child and the adult

In adolescents and adults with a good immune system, pertussis tends to resolve itself without problems.

However, in some situations, cough attacks have an intensity that causes:

  • The rupture of a rib;
  • Formation of an abdominal hernia;
  • Episodes of nosebleeds;
  • The rupture of some blood vessels present on the ocular sclerae.

When should I go to the doctor?

It represents a more than valid reason to address to the doctor the presence, in an individual, of a persistent cough, on which depend gag of vomit, red face, cyanosis, episodes of apnea and shrill rattles during the inspiration.

Diagnosis

In general, the diagnostic procedure for the detection of a disease such as pertussis includes: a thorough physical examination, a thorough medical history, a culture test on a nasopharyngeal swab and blood tests.

Physical examination and medical history

Physical examination and anamnesis are, as a rule, the first step in the path leading to the diagnosis of pertussis.

Briefly, they consist of observation and critical evaluation of the symptoms manifested by the patients.

In some situations (eg: when pertussis is in the paroxysmal phase), they may be sufficient for a correct diagnosis; in other circumstances (eg: when pertussis is in the catarrhal phase), they can only supply incomplete information.

Curiosity

Pertussis is an infectious disease which, when it is in its onset (catarrhal phase), is difficult to diagnose, as it produces the same symptoms as a simple cold.

Things change completely when the aforementioned infection is in its acute phase (paroxysmal phase): in these situations, the symptomatology is so to speak unequivocal and the diagnosis is very simple.

Culture test on a nasopharyngeal swab

The culture test on a nasopharyngeal swab - that is on a sample of tissue coming from the nose and throat - represents the confirmation diagnostic test, as it allows to trace Bordetella Pertussis and to demonstrate that the infection in progress is pertussis.

Blood analysis

Blood tests show that an infection with Bordetella Pertussis is in progress, as this bacterium triggers the production, by the infected organism, of particular antibodies found in the circulatory stream.

Therapy

Pertussis therapy varies according to the patient's age, the intensity of the symptoms and the stage in which the infection is diagnosed. This statement is justified in the following four points:

  • Patients of very young age (infants under 6 months) and individuals with very severe symptoms need "aggressive" care, which only hospitalization is able to provide;
  • Patients of young age and adulthood with normal symptoms can easily recover from home, as the infection is not serious;
  • For patients in whom the infection has been ongoing for less than 3 weeks (so when the diagnosis occurred before the paroxysmal phase), a treatment based on antibiotics is envisaged, the purpose of which is to stop the infection and prevent its spread. of the latter to other persons;
  • For patients in whom the infection has been in progress for more than 3 weeks (so when the diagnosis occurred after the start of the paroxysmal phase), no antibiotic treatment is foreseen, as it would be unprofitable; at this point of the disease, in fact, the bacterium has already acted and the patient is no longer contagious to others.

Antibiotics are substances processed by living organisms or produced in the laboratory, capable of determining the death of bacteria or preventing their growth.

Hospitalization: what does it consist of?

Taking place in intensive care, the hospitalization of a newborn with pertussis or a person with a severe form of pertussis includes:

  • The administration of intravenous fluids, in order to prevent / treat dehydration. The use of the intravenous route is linked to the fact that the patient may have difficulty ingesting fluids;
  • Periodic monitoring of respiratory function. This allows doctors to intervene promptly if the patient needs breathing support and treatment such as oxygen therapy;
  • Adequate antibiotic therapy, in order to eliminate the bacterium responsible for the infection from the infected organism.

The cornerstones of home treatment

Provided for all non-newborn patients and with a normal symptomatology, home-based treatment of pertussis includes: the use of antibiotics (according to the methods described above), an absolute rest period, the consumption of a lot of water to avoid dehydration and the use of paracetamol or ibuprofen to reduce fever.

What are the best antibiotics?

The most indicated antibiotics for the treatment of pertussis include: erythromycin, clarithromycin and azithromycin .

How should a patient behave in order not to infect other people?

To avoid infecting other people, a person with pertussis should:

  • Avoid frequenting crowded places and any circumstances leading to contact with other people (school, work, etc.). This recommendation lapses after 48 hours from the start of any antibiotic therapy or 3 weeks after the start of the infection.
  • Cover your mouth or nose with sneezing or coughing. For the little ones, this recommendation is more difficult to put into practice.
  • Dispose of / wash as soon as possible any tissue used to cover the mouth and nose.
  • Wash your hands with warm water and soap.

Antibiotic prophylaxis: who needs it?

According to the doctors, it is a good rule that anyone who lives in close contact with a pertussis patient (in general, family members) resort to adequate antibiotic prophylaxis, in order to protect themselves from a possible infection.

Can cough medications be useful?

Cough medications are generally contraindicated in children and infants, while they could be used in adults.

In any case, with regard to this topic, it is better to rely on the instructions of the attending physician.

Vaccine and Prevention

The vaccine against the bacterium of pertussis is the main preventive measure against the aforementioned infectious disease.

The advantages of anti-pertussis vaccination

The advent of vaccination against pertussis has contributed to reducing not only the morbidity of the disease in question, but also its lethality linked to complications such as pneumonia, encephalitis, suffocation suffocation etc.

Does the pertussis vaccine last a lifetime?

Immunity induced by the pertussis vaccine tends to diminish over time (5-10 years). This means that, after a certain period of time, those who have received the vaccination can get sick in the same way as a person who has never been vaccinated.

This same possibility (immune protection from pertussis that fades with time) also applies to people who have developed pertussis and have developed natural immunity.

Pertussis vaccination in Italy before 2017

Until 2017, pertussis vaccination was not mandatory in Italy, but most doctors advised to have it vaccinated within the first year of the child's life according to different vaccination schemes (for example at the third, fifth and twelfth month of life, with a call to 3 years, before attending kindergarten).

Pertussis vaccination was usually associated with those against other diseases, such as diphtheria, tetanus, hepatitis B, polio and Haemophilus Influenzae meningitis types B (ve Infanrix Penta, Infanrix Hexa and Tritanrix HepB).

What changes since 2017

With the decree-law on vaccination prevention for minors from zero to 16 years, approved on 07/28/2017 , vaccination against pertussis has become mandatory .

This specific vaccination can be carried out with a single injection together with five other vaccination covers (the so-called hexavalent vaccination, which includes vaccines: anti-poliomyelitis, anti-diphtheria, anti-tetanus, anti-hepatitis B, anti-pertussis, anti - Haemophilus Influenzae type b).

  • The obligation of vaccination against pertussis is in force, in the context of the 10 mandatory vaccinations, for people born from 2017. Even those born after 2001 are subject to the obligation of vaccination against pertussis .
  • Immunized subjects due to the natural disease are exempt from the vaccination requirement, therefore children who have already had pertussis should not be vaccinated against this disease

Please note that compulsory vaccinations are a requirement for admission to nursery schools and kindergartens (for children from 0 to 6 years) and that the violation of the vaccination requirement implies the application of significant financial penalties .

For more information on mandatory vaccines in children, see this article.

Prognosis

In children older than one year of life, adolescents and adults, whooping cough tends to have a positive prognosis; in other words, in the subjects indicated above, the infection in question has the tendency to resolve itself completely and without complications.

The situation changes radically when the patient is a child under the year of life; in such circumstances, in fact, pertussis is a dangerous disease, which can lead to serious complications and, in the most unfortunate cases, cause death.

Curiosity

According to some studies, in a country like the USA, pertussis would be fatal for 1.6% of children under one year of life hospitalized.

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