Situation: A public health nurse at a Rural Health Unit (RHU) manages clients enrolled in the National Tuberculosis Program (NTP). Many of them live in crowded urban households. A 15-year-old girl is diagnosed with drug-susceptible pulmonary tuberculosis (TB). Her chest X-ray shows non-cavitary disease confined to one lobe, and the physician classifies it as non-severe. Which regimen should the nurse expect her to receive under the NTP? (H = isoniazid, R = rifampicin, Z = pyrazinamide, E = ethambutol)

Children and adolescents aged 3 months to 16 years with non-severe, drug-susceptible TB are treated for 4 months: 2 months of isoniazid, rifampicin, and pyrazinamide (with ethambutol in some cases), then 2 months of isoniazid and rifampicin. At 15 years she is still within this age band, so the adult 6-month regimen is not needed. The 12-month regimen is for TB of the central nervous system, bones, or joints, and 3HP is TB preventive treatment, not treatment of disease.

Core issue
A 15-year-old adolescent with drug-susceptible pulmonary TB classified as non-severe and non-cavitary, confined to one lobe, falls squarely under the shortened 4-month regimen recommended for children and adolescents. The expected regimen is 2HRZ(E) followed by 2HR, for 4 months in all.

Why the 4-month regimen applies here
The WHO-aligned clinical standards for pediatric drug-susceptible TB define the eligible age band as 3 months to 16 years ^[1]. A 15-year-old is still within this range, so the adult 6-month regimen is not automatically required. The key eligibility criterion is disease severity: non-severe pulmonary TB includes disease that is non-cavitary and limited in extent, such as involvement confined to one lobe ^[1][4]. The chest X-ray findings in this case match that definition.

The shortened regimen consists of an intensive phase of isoniazid, rifampicin, and pyrazinamide for 2 months, with ethambutol added when clinically indicated, followed by a continuation phase of isoniazid and rifampicin for 2 months. This totals 4 months of treatment, which is now the standard for non-severe drug-susceptible TB in this age group ^[1][2].

Why the other options are incorrect

Option	Regimen	Why it does not fit
1	Weekly isoniazid-rifapentine for 12 doses (3HP)	This is TB preventive treatment for latent TB infection, not treatment of active TB disease.
2	2HRZE followed by 10HR, for 12 months	The 12-month regimen is reserved for TB involving the central nervous system, bones, or joints, not for non-severe pulmonary disease.
3	2HRZE followed by 4HR, for 6 months	This is the standard adult regimen. It is not needed for a 15-year-old with non-severe, non-cavitary, single-lobe disease because the shorter pediatric regimen is equally effective and reduces treatment burden [1][2].

Pathophysiology and clinical reasoning
Non-severe pulmonary TB in children and adolescents typically reflects a paucibacillary disease state. The bacterial load is lower than in cavitary adult-type disease, which allows a shorter continuation phase to achieve durable cure without increasing relapse risk ^[2]. Cavitation indicates high bacillary burden and tissue destruction, which is why cavitary disease is excluded from the shortened regimen. In this case, the absence of cavitation and the confinement to one lobe signal a lower burden that responds well to 4 months of therapy.

Key point! Age alone does not determine regimen length; severity classification does. A 15-year-old with non-severe disease receives the 4-month regimen, while the same adolescent with cavitary or extensive disease would require the 6-month regimen.

Watch out! Ethambutol is included in the intensive phase only when clinically indicated, such as when there is concern for drug resistance, extensive disease, or HIV co-infection. In a straightforward non-severe case, 2HRZ may be sufficient for the first 2 months ^[1].

Nursing and program implications
Under the National Tuberculosis Program, the nurse must verify that the prescribed regimen matches the disease classification documented on the treatment card. For this client, the expected entry is 2HRZ(E)/2HR with a total treatment duration of 4 months. Adherence support should emphasize that the shorter duration is intentional and evidence-based, not a sign of undertreatment. The nurse should also monitor for medication adverse effects during the intensive phase, particularly hepatotoxicity from isoniazid and rifampicin, and reinforce that sputum monitoring and clinical follow-up continue through the full course ^[1][2].