Final answer:
A positive PPD with a negative CXR typically leads to a prescription of Isoniazid (INH) therapy for latent TB infection. INH disrupts the synthesis of mycolic acids in mycobacterial cell walls, and adherence to treatment is essential to prevent drug-resistant TB strains.
Step-by-step explanation:
If a patient has a positive PPD (Purified Protein Derivative) test but a negative Chest X-Ray (CXR), the treatment option is typically a course of Isoniazid (INH) therapy. This indicates that the patient may have a latent TB infection, for which INH is a standard treatment. The negative CXR suggests that there is no active TB disease present, hence the absence of symptoms like a cough or fever that would normally be detected on the radiograph.
Isoniazid is a cornerstone drug in the prevention and treatment of TB and works by preventing the synthesis of mycolic acid, essential for mycobacterial cell walls. Completing the full course of medication is crucial to prevent developing drug-resistant strains of tuberculosis, such as MDR-TB or XDR-TB, and ensure effective management of the disease. Directly observed therapy (DOT) is often used to ensure adherence to the treatment regimen.