What should be done if a patient presents with symptoms of tuberculosis while on INH?

When a patient presents with symptoms of tuberculosis while on isoniazid (INH), conducting diagnostic testing to rule out active TB disease is crucial. INH is often prescribed as a treatment for latent tuberculosis infection (LTBI) or as part of a multi-drug regimen for active TB. However, the development of symptoms indicative of tuberculosis—such as a persistent cough, fever, night sweats, and weight loss—raises the possibility that the patient may actually have active TB rather than latent TB that is being treated.

Diagnostic testing, which may include a chest X-ray, sputum tests, or other relevant laboratory investigations, is necessary to confirm whether the patient has transitioned from latent to active TB. Timely detection of active TB is essential to initiate appropriate treatment strategies, prevent transmission to others, and ensure the patient's health is safeguarded. Continuing INH therapy without further investigation could lead to worsening of the patient's condition if they indeed have active tuberculosis.

Waiting for symptoms to resolve or simply assessing for side effects would ignore the potential severity of active TB and could delay critical intervention. Thus, performing thorough diagnostic testing is the appropriate and responsible action in this scenario.