A Practical Approach to Special Care in Dentistry. Группа авторов

tuberculosis disease should be isolated, instructed to wear a surgical or procedure mask, and referred promptly for medical careFor those patients who require urgent dental treatment/who may be infectious, high‐efficiency particulate air (HEPA) filters, ultraviolet germicidal irradiation (UVGI) lamps and appropriate personal protective equipment should be available (FFP3)DuringThe use of sprays and the generation of aerosols (ultrasonic scaling equipment and high‐speed rotary instruments) should be reducedUse high‐volume suctionUse rubber damsUse facemasks with eye protection and change them if they get moistAfterSterilise the instruments with heat (mycobacteria are resistant to disinfectants)Ventilate the clinic after completing the session (open windows) Drug prescription Avoid paracetamol or recommend low doses (increased hepatic toxicity by rifampicin and isoniazid)It is prudent to avoid all drugs reliant on hepatic metabolismAvoid aspirin (increases the risk of ototoxicity by streptomycin, amikacin, kanamycin or capreomycin)Avoid clarithromycin and azole derivatives (they interact with rifampicin) Education/prevention All staff who provide dental care should undergo a Mantoux test when commencing employment, regardless of the setting's risk classification

      Aetiopathogenesis

       The most common infectious agent is M. tuberculosis

       The bacilli access the lungs (in the form of aerosol droplets), are phagocytised by macrophages and transferred to regional lymph nodes

       Haematogenous dissemination then occurs

       The granulomatous lesions (tubercles) contain living bacilli and develop by a delayed hypersensitivity mechanism

      Clinical Presentation

       Globally, tuberculosis notification data show a male‐to‐female ratio of 1.7:1 and higher, although the underlying reasons for the male bias remain unclear

       Latent tuberculosisThe initial infection is usually asymptomaticApproximately one‐quarter of the world's population has latent tuberculosis – at this stage, they cannot transmit the infection

       Active primary tuberculosis diseasePeople infected with tuberculosis bacteria have a 5–15% lifetime risk of progressing to develop tuberculosis diseasePersons with compromised immune systems, such as those living with HIV, malnutrition or diabetes, or people who use tobacco, have a higher risk of developing the diseaseSymptoms include fever, night sweats, cough, asthenia, anorexia and lymphadenopathyThe symptoms may be mild and persist for many months, leading to delays in seeking care, and in transmission of the bacteria to othersPulmonary impairment may progress, resulting in a productive cough, rales (abnormal rattling sound from the lungs) and, in highly advanced stages, haemoptysisOccasionally, there is extrapulmonary dissemination, which can affect the central nervous system, bones and cardiovascular, genitourinary and gastrointestinal systemsSome particularly prevalent conditions such as alcoholism, drug addiction, cancer, diabetes and HIV infection can alter the clinical presentation of tuberculosisWithout appropriate treatment, approximately 45% of HIV‐negative people with tuberculosis and nearly all HIV‐positive people with tuberculosis will die

       Tuberculosis recurrenceLatent tuberculosis is associated with 5–10% chance of reactivation, usually within the first 2 years of infectionRecurrence can be due to either reactivation of the same strain, i.e. relapse, or reinfection with a new strainRecurrence due to reinfection is more likely in endemic settings with high rates of HIV coinfection

      Diagnosis

       The acquisition of skin reactivity to the tuberculin purified protein derivative or Mantoux test is considered suggestive of tuberculosis (Figure 4.1.3)

       Chest radiography helps establish the suspected diagnosis for patients with symptoms (Figure 4.1.4)

       Sputum smears have poor sensitivityFigure 4.1.3 Positive Mantoux test (also known as tuberculin PPD test for purified protein derivative).Figure 4.1.4 Chest x‐ray showing cavitary lesions typically associated with active pulmonary tuberculosis.

       Sputum cultures provide the definitive diagnosis, but the results are not obtained for up to 4–8 weeks

       PCR provides a rapid and reliable diagnosis

       For extrapulmonary tuberculosis, a histopathological analysis of the infected organs should be conducted . It is characterised by the presence of caseating granulomas formed by epitheloid macrophages surrounging an acelluar necrotic region

      Management

       The most widely used regimen is the administration of 4 drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months, followed by 2 drugs (isoniazid and rifampicin) for another 4 months

       Multidrug‐resistant tuberculosis is an increasing concern – the disease does not respond to isoniazid and rifampicin, the 2 most powerful medications used to treat the disease

       Alternatives in this situation include diarylquinoline and nitroimidazole

       Treatment regimens can be prolonged, typically lasting 6–12 months

       Treating recurrent tuberculosis that is caused by relapse is challenging as often the bacteria have become resistant to treatment and a different combination of drugs, taken over a longer period of time, is required

       Hence recurrent tuberculosis disease is associated with poor treatment outcomes and higher mortality rates compared to primary tuberculosis infection

      Prognosis

       About 5% of patients infected by M. tuberculosis develop active tuberculosis in the first 2 years post exposure

       The incidence of drug‐resistant tuberculosis is increasing exponentially

       Although tuberculous mortality has fallen substantially in the past 20 years, it is estimated that 3 million individuals die annually due to complications from this disease

       About 25% of those who die have concurrent HIV infection

      A World/Transcultural View

       There is a strong association between the incidence of tuberculosis and a country's gross domestic product per capita

       Marginalised and socially disadvantaged populations, such as indigenous populations, ethnic minorities, immigrants and prisoners, also have a higher incidence of tuberculosis

       Poorer treatment results have been recorded in groups with low socio‐economic levels, probably because they have limited access to high‐quality care

       Although drug‐resistant strains have been previously diagnosed in highly endemic settings, resistance to numerous drugs constitutes a significant problem in the industrialised world

Recommended Reading

      1 Dheda, K., Barry, C.E. 3rd, and Maartens, G. (2016). Tuberculosis. Lancet 387: 1211–1226.

      2 Faecher, R.S., Thomas,