Tuberculosis: Implications for Dentistry

Tuberculosis (TB) is an airborne infection caused by Mycobacterium tuberculosis complex and can be described as active or latent.¹Mycobacterium tuberculosis mainly affects the lungs, making pulmonary TB the most common presentation. Pulmonary TB is described as TB that affects the lung parenchyma and tracheobronchial tree.² Although Mycobacterium tuberculosis is primarily a pulmonary pathogen, it also affects other organ systems such as the gastrointestinal, lymphoreticular, musculoskeletal and reproductive systems, as well as the skin.³

Globally, 1.5 million people died from TB in 2020, with TB being the 13th leading cause of death, and one of the leading infectious killers.⁴ The UK is a low incidence country, but higher rates are found in larger urban areas and are highest in people born outside the UK and in deprived populations, particularly in people with a history of imprisonment, drug and alcohol misuse, homelessness and asylum seekers. TB incidence in England was 7.8 per 100,000, which is below the World Health Organization (WHO) threshold for a low incidence country (less than or equal to 10 per 100,000 population).⁵ Data from the UK Health Security Agency (UKHSA) reveals that the number of notifications increased by 7% in the first half of 2023 compared with the first half of 2022. TB notification rates varied widely across the country, with the highest in London and the lowest in the north-east. Despite an overall downward trend in the number and rate of TB notifications in England over the past 10 years, the rate of decline is slowing.

TB is a highly infectious, but curable and preventable disease. Therefore, it is crucial for all healthcare professionals to recognize the signs of TB and manage them promptly. Progression of disease can be more rapid in children, thereby highlighting the significance of making urgent referral to a paediatric infectious diseases specialist.

Clinical features

Latent TB describes a situation where the bacteria become dormant, and the affected individuals do not transmit the disease to others. Patients with latent TB are asymptomatic. Approximately 5–10% of latent TB cases may progress to develop active TB, which is infectious, and immunocompromised patients, such as those who are diagnosed with HIV, diabetes or cancer, are more prone to develop active TB.^4,6 It is of utmost importance that the symptoms of pulmonary TB should be recognized and addressed accordingly because patients with active pulmonary or laryngeal TB are infectious.

The typical clinical features of pulmonary TB include haemoptysis, loss of appetite, weight loss, fever, night sweats, chronic cough that persists for more than 3 weeks and sputum production.² The symptoms of pulmonary TB may remain mild for a few months. This may lead to transmission of the disease to others and a delay in seeking care. It has been shown that, on average, people with active TB transmit their infection to 5–15 other people via close contact over the course of a year.⁴ Active TB disease is 18 times more likely in individuals living with HIV than those who are HIV negative. TB carries a high risk of mortality without treatment, particularly in patients living with HIV. This stresses the importance of raising awareness of TB symptoms among the general population to ensure timely treatment.

Oral manifestations

TB can manifest in a variety of forms, and it is important that GDPs are aware of its oral manifestations. Superficial ulcers, patches, indurated soft tissue lesions, peri-apical granulomas or jaw lesions, tooth mobility and displacement of tooth buds are some of the different forms in which it may present.^7,8,9,10,11

Oral TB lesions can be categorized into primary and secondary lesions. Primary lesions are rare and younger patients are more frequently affected. The lesions are usually single painless ulcers of long duration and are associated with regional lymph node enlargement.^12,13,14 Dentists should examine for cervical lymphadenopathy, particularly in the presence of a history of risk of TB or presence of ulcer. Most commonly affected are the submandibular nodes (jugulo-digastric and supra-clavicular). Primary gingival involvement is common, and the ulcers usually extend from the gingival margin to the depths of the adjacent vestibule. The ulcers are often non-indurated, irregular with well-defined margins and surrounding erythema. They may be single or multiple, painful or painless and satellite lesions are common findings.¹⁵ The lesions can also develop on the lateral border of the tongue and are often traumatic because areas of chronic irritation or inflammation may favour localization of the Mycobacterium tuberculosis within the affected areas.¹⁶

Secondary TB lesions are more common and usually present as single, indurated, irregular, painful ulcers covered by inflammatory exudates. Although secondary lesions can affect patients of any age group, it is more common in middle-aged and elderly patients. There is often an association between pulmonary disease and secondary oral TB lesions. Because cancerous lesions may present as chronic indurated lesions, which resemble oral TB lesions, it is important for the dentists to consider both causes in the differential diagnosis. Both cancerous and oral TB lesions may also co-exist.

Oral TB lesions can affect any part of the oral mucosa, with the tongue being the most commonly affected area. Other sites that may become affected include the buccal mucosa, lips, palate, gingiva, salivary glands, uvula, tonsils including palatine tonsils and floor of mouth.¹⁷ Deep tubercular ulcers of the tongue are associated with severe and progressive pain, and may involve the tip, lateral borders, dorsum, the midline and base of the tongue. Classically, they are irregular and pale, with inverted margins and granulations at the base with sloughing tissues.

Tuberculous osteomyelitis is uncommon and occurs most often in bones of the extremities. Jaw involvement is very rare and usually affects older individuals. Chaudhary et al suggested the common route of infection can be the open pulp of a carious tooth, an extraction socket, perforation of an erupting tooth that can be exposed to infected sputum or an extension of the soft tissue lesion.¹⁸ Therefore, it is important to consider primary tuberculous osteomyelitis in the differential diagnosis of mandibular lesions.

It is also important to note that oral lesions of TB are often overlooked in differential diagnoses because they usually appear before systemic symptoms become apparent. These oral lesions are non-specific in their clinical presentation and can be similar to malignant lesions and for example, recurrent aphthous ulcers, traumatic ulcers and granulomatosis with polyangiitis. Therefore, this underlines the significance of carrying out a thorough history-taking and clinical assessment.

Treatment for TB

The management of oral TB lesions is essentially the same as for systemic TB. The standard treatment of active TB is completed in two phases (initial and continuation phases).^19,20 During the initial phase, rifampicin, isoniazid (with pyridoxine hydrochloride), pyrazinamide and ethambutol hydrochloride should be offered as standard therapy and continued for 2 months. The drug regimen should be modified according to the patient's drug susceptibility testing. Following the initial phase, the treatment should be continued with rifampicin and isoniazid (with pyridoxine hydrochloride) for 4 months provided that there are no signs of central nervous system involvement. Longer treatment for a further 10 months should be considered in patients with active TB of the central nervous system, or if there is spinal cord involvement.

NICE guidelines recommend two regimens for the treatment of tuberculosis: unsupervised and supervised treatment.²¹ Unsupervised treatment is for patients who are likely to have better adherence to the drug regimen. Alternatively, supervised treatment, also known as directly observed therapy (DOT), is provided as part of enhanced case management for patients from underserved groups who have a higher risk of non-adherence to the medical regimen. DOT is endorsed by the WHO, and aims to improve adherence by involving healthcare workers or community volunteers to monitor and record patients' compliance in taking the medications. The long duration of treatment may lead to poor patient adherence to the treatment regimen, which can cause detrimental complications, such as development of drug resistance and increased transmission of the bacteria. Consequently, this may result in relapse and even death.^22,23 Nonetheless, studies have revealed that DOT is not always an effective solution for poor adherence in TB treatment, and other cost-effective options should be considered.²⁴

Mycobacterium tuberculosis can develop resistance to the antimicrobial drugs that are used to treat TB. Rifampicin and isoniazid are the conventional first-lines for TB. Multidrug-resistant TB (MDR-TB) is defined as TB caused by M. tuberculosis that is resistant against rifampicin and isoniazid. WHO states that the main causes of MDR-TB are inappropriate or incomplete TB treatment and person-to-person transmission.²⁵ The treatment of MDR-TB requires medications for a longer period of time with less effective second-line drugs. The treatment is more difficult, expensive and has poor outcomes.²⁶ On a global scale, successful treatment completion rates were only 55% in a WHO report.²⁷

Dental management

Dentists may encounter patients with suspected or confirmed TB who require dental treatment. This highlights the significance of obtaining a comprehensive medical and social history, and documenting any signs and symptoms that may suggest TB. For suspected cases of active pulmonary TB, the patient should be referred urgently to the local infectious diseases team.

It is of paramount importance to ensure stringent infection control measures are in place to reduce the risk of transmission of TB within a dental setting. No evidence has shown that medical equipment contributes to transmission of TB.²⁸ Nevertheless, it is crucial for all the dental practices to clean and sterilize the dental instruments in compliance with the Decontamination Health Technical Memorandum 01-05 (HTM01-05) published by the Department of Health.²⁹ A clear protocol should be devised for managing dental patients with suspected or confirmed TB. In accordance with the NICE guidelines, care should be provided for patients with suspected infectious or confirmed pulmonary TB in a negative pressure and well-ventilated room where the air from the room is sucked out through a filter into the outside air.²¹ The pressure should be 10 Pascals below the ambient air pressure. This regimen is not readily available in a dental setting. Therefore, the urgency of the dental treatment should be assessed, and it is prudent to defer elective dental treatment until the patient is no longer infectious. Infection risk is significantly reduced following the completion of 2 weeks of TB therapy if appropriate for antimicrobial sensitivities.

Emergency dental treatment should be provided in an airborne infection isolation room (negative pressure, controlled ventilation, air filtration). The patient's waiting time in the public area should be kept to a minimum. All the healthcare professionals and visitors in the room should wear at least N95/FFP3 disposable respirators to minimize the risk of transmission of M tuberculosis²⁸ as standard surgical face masks do not offer sufficient protection against TB transmission. High-risk aerosol-generating procedures (AGPs) should be avoided where possible. The use of high-volume suction and rubber dam is recommended to minimize aerosol contact.

Dental treatment should ideally be limited to treatment under local anaesthetic only when emergency treatment is required for patients with active TB owing to the risk of respiratory depression, the need for increased oxygenation and potential drug interactions with concurrent TB therapy.³⁰ The medications for TB therapy can also affect the provision of dental treatment because some medications may lead to pancytopenia and hepatotoxicity.²¹ It is also vital to recognize that rifampicin increases cortisol metabolism and can cause adrenal insufficiency. It can trigger an adrenal crisis in patients with pre-existing adrenal insufficiency.³¹ The TB specialist should therefore be consulted to confirm the patient's suitability for dental treatment. Blood tests, such as a full blood count should also be carried out to identify any haematological abnormalities. It is also important to note that patients diagnosed with extrapulmonary TB with central nervous system or pericardial involvement will be given an initial high dose of dexamethasone or prednisolone with gradual withdrawal over a few weeks.^19,21 Dentists should take this into consideration, and discuss the need for steroid cover with the TB specialist prior to dental treatment. It may be appropriate for the treatment to be provided in a secondary or tertiary care environment.

Conclusion

TB is a highly contagious disease, but is preventable and treatable. It is imperative that the dentist carries out a detailed history-taking and clinical examination and, when TB is suspected, refer patients without delay.

For patients with a diagnosis of TB, elective dental treatment should be postponed until the patient is no longer infectious and has completed at least 2 weeks of TB treatment. In cases where emergency dental treatment is required, liaison with the TB specialists is essential, and precautionary measures should be implemented to reduce the risk of TB transmission. Emergency dental treatment in these cases should be provided in an appropriately engineered airborne infection isolation room with negative pressure and good ventilation. Dental professionals should be aware of the potential side effects of TB drugs and their impacts on delivery of dental care. They should be confident to provide routine dental treatment for patients diagnosed with latent TB following a standard protocol.

In conclusion, it is prudent for dentists to collaborate promptly with infectious diseases and respiratory specialists when managing patients with confirmed or suspected TB prior to any dental treatment.