Tuberculosis

Opening statement

Tuberculosis is a chronic granulomatous infection caused by Mycobacterium tuberculosis complex. It kills more people than any other single infectious agent — approximately 1.25 million in 2023 alone — and is the leading killer of people living with HIV (WHO Global tuberculosis report 2024). ^[12] For the registrar it behaves like three diseases in one body: a droplet-spread pulmonary infection demanding airborne isolation, a multisystem granulomatous disease that can seed any organ, and a latent infection that can reactivate decades later under immunosuppression. The decisive moves are simple and the same in every case — isolate the patient, prove the organism (smear plus nucleic acid amplification plus culture), ask about HIV and drug resistance before choosing a regimen, and complete a full six-month course under observation. ^[1]

Three examiner facts anchor every TB question. First, rifampicin resistance detected on GeneXpert changes the regimen before culture returns — never start standard RIPE therapy in a rifampicin-resistant case. Second, rifampicin is one of the most potent enzyme inducers in clinical medicine; it lowers the level of the oral contraceptive pill, warfarin, DOACs, corticosteroids, anticonvulsants and many antiretrovirals, and an unexpected loss of efficacy of a concomitant drug in a TB patient is usually rifampicin until proven otherwise. Third, ethambutol optic neuritis is irreversible if the drug is continued — test colour vision at baseline and educate every patient to stop and report visual change. ^[1]

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References14ShowHide

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