Pulmonary tuberculosis

One third of the world's population, about 1.8 billion people, are infected with the tuberculosis bacillus, of which 30 million suffer from the disease. There is a clear relationship between tuberculosis and poverty, the disease being considered one of the causes of preventable death in poor countries, where only a quarter of sick people receive treatment.

There are specific detection and treatment programs both at the international level - carried out by the WHO - and at the national level, which insist on the need to create special units that guarantee the treatment, control and study of patient contacts, given that therapeutic compliance is necessary to achieve a cure.

How is it produced?

The contagion form of the disease is almost always by inhalation route (exceptionally by digestive or cutaneous route).

Lack of ventilation and overcrowding favor contagion, and this increases in people who live in the same room, contagion through sporadic contact being exceptional.

Once contagious, the tuberculosis bacillus can remain dormant (asleep) or cause disease. Most cases of clinical tuberculosis occur months or years after infection. The decrease in immunological defenses can reactivate tuberculosis that was in a latent state, with pulmonary involvement being the most frequent.

It is for this reason that HIV (AIDS) cases increase among the population, constituting a diagnostic criterion for AIDS, and it is also the most frequent opportunistic disease in people affected by.

Symptoms

General symptoms such as asthenia (tiredness), anorexia (loss of appetite), weight loss, evening fever and night sweats are the earliest, but given their insidious onset they may go unnoticed.

Among the respiratory symptoms, the most common is cough. Hemoptysis can also appear, but is less frequent, as well as thoracalgia or dyspnea.

10% -20% of those infected are asymptomatic and are detected by contact study or by chance.

Tuberculous infection should be ruled out in the presence of a cough that persists for more than 3 weeks, especially in those groups with higher risk, eg: immunosuppressed or in case of overcrowding of people.

Diagnosis

Sputum culture in Löwenstein-Jensen medium is the certainty diagnostic method, but it takes between 2-8 weeks to obtain the result, so other diagnostic methods are used such as smear microscopy (direct microscopic examination) which is the method used for a rapid diagnosis being able to obtain a probability diagnosis if it is accompanied by a compatible clinic and / or radiology.

The tuberculin test (Mantoux) consists of the intradermal inoculation of a purified derivative of proteins called PPD and the reading of the dermoreaction that occurs between 48 and 72 hours later. Tuberculous infection is considered when induration is greater than or equal to 5 mm (15 mm if there has been previous BCG vaccination). The tuberculin test does not distinguish between infection and disease. In both cases, a positive result is required, although no proven clinical disease coexists with the infection.

This test is not recommended for people who have not been exposed to the tuberculosis bacillus.

Other diagnostic methods include chest radiography and newer nucleic acid amplification techniques using genetic DNA and polymerase chain reaction (PCR) probes. The latter approved to confirm the diagnosis with a positive smear microscopy and awaiting the result of the cultures.

Treatment

It is based on the administration of three anti-tuberculosis drugs over a prolonged period, which is usually 6 months. The use of three drugs and the duration of treatment are due to the appearance of resistance to the bacillus to the different drugs administered. In the HIV population, treatment lasts up to 9 months.

Treatment begins while awaiting confirmation of the sputum culture, when clinical, radiological and bacteriological data so suspect.

Currently, with this treatment, cure rates of 96% are achieved

The most frequent cause of therapeutic failure is the lack of correct compliance with it.

Treatment can be carried out at home if proper isolation is carried out during the first 15 days of the same. In general, the patient can return to work after 2 months.

Monthly monitoring of the patient by the medical staff is important to assess the patient's clinical status, the possible side effects of the medication and its compliance. It is advisable to perform bimonthly smears and cultures until they become negative and at the end of treatment, as well as a chest X-ray at two months and at the end of treatment.

Preventive treatment

There are two types of preventive treatment:

• Preventive treatment of tuberculosis infection (primary chemoprophylaxis). It is based on the treatment of people with PPD-, living with smear-positive patients, especially in children and young people. If after 2 months of treatment, a new PPD is negative, the treatment is suspended. In the case of the appearance of PPD + -in the absence of radiological lesion- treatment is maintained until completing 6 months.
• Treatment of latent tuberculosis infection (secondary chemoprophylaxis). It is based on the treatment of PPD + tuberculosis infection and a normal chest X-ray- in the absence of disease, to avoid its appearance. It lasts for 6 months (12m in HIV) and is performed only once in a lifetime.

In both cases, the aim is to stop the epidemiological chain of tuberculosis.

BCG vaccination: Currently not recommended in developed countries, due to a controversial efficacy. It consists of the administration of live attenuated bacteria, which is why it is contraindicated in immunosuppressed and pregnant women.

It can be useful in children and young people who are in contact with chronic smear-bearing patients and among healthcare personnel in frequent contact with tuberculosis patients or with their biological samples. In both cases, you need a previous negative turberculin test.

Before any symptoms it is best to go to a specialist. They include a complete Preventive Medicine Proframa oriented to take care of your health (Consultation, exploration and diagnostic tests carried out by a specialist who will offer you an assessment of your state of health and recommendations to take care of yourself).

Dra. Laura Cristel Ferrer Family and Community Medicine Specialist