100+ Free Cert Pulmonology(SA) Phys Practice Questions

Explanation: In individuals with no history of TB treatment within the preceding 5 years, a 'Trace' result on GeneXpert Ultra represents true low-bacillary load Mycobacterium tuberculosis infection. In persons living with HIV (PLHIV), this is classified as bacteriologically confirmed active TB, and full first-line anti-TB treatment should be initiated immediately.

Explanation: The BPaL regimen consists of Bedaquiline, Pretomanid, and Linezolid. South African National TB guidelines recommend this 6-month all-oral regimen for patients with RR-TB/MDR-TB without prior exposure (>1 month) to bedaquiline, linezolid, or pretomanid. If moxifloxacin/levofloxacin is added, it forms the BPaLM regimen.

Explanation: Linezolid toxicity (myelosuppression, peripheral neuropathy, optic neuritis) is dose- and duration-dependent. Per SA guidelines for BPaL/BPaLM, Linezolid should be held for significant toxicity (Hb <8 g/dL or symptomatic neuropathy) until recovery, then reinstated at a reduced dose of 300 mg daily.

Explanation: In HIV-infected patients with severe immunosuppression (CD4 < 50 cells/µL), ART should be initiated within 2 weeks of starting anti-TB treatment to significantly reduce overall mortality. The exception is TB meningitis, where ART initiation is delayed to 4-6 weeks to avoid life-threatening intracranial IRIS.

Explanation: This patient presents with paradoxical Immune Reconstitution Inflammatory Syndrome (IRIS). Management requires continuation of both ART and effective anti-TB therapy, combined with systemic corticosteroids (Prednisone 1.5 mg/kg/day tapered over 4 weeks) to suppress hyper-inflammatory responses.

Explanation: Per ATS/ERS/ESCMID/IDSA guidelines, nodular/bronchiectatic pulmonary MAC disease should be treated with a three-drug oral regimen of a macrolide (Azithromycin 500 mg or Clarithromycin 1000 mg), Rifampicin (600 mg), and Ethambutol (15 mg/kg) administered three times weekly until cultures are negative for at least 12 months.

Explanation: The inhA mutation confers low-level isoniazid resistance (and cross-resistance to ethionamide/prothionamide), while rpoB is wild-type (rifampicin sensitive). Per WHO and SA guidelines, isoniazid mono-resistant TB (Hr-TB) is treated with a 6-month regimen of Rifampicin, Ethambutol, Pyrazinamide, and Levofloxacin (6 REZ-Lfx).

Explanation: An intact erm(41) gene with a T28 sequevar confers inducible macrolide resistance in M. abscessus subsp. abscessus upon exposure to clarithromycin or azithromycin (evident after 14 days of incubation). Consequently, macrolides cannot be relied upon as the sole active oral agent in multi-drug multidirectional therapy.

Explanation: Drug-induced liver injury (DILI) criteria for stopping anti-TB drugs are ALT >= 3x ULN with symptoms (or ALT >= 5x ULN without symptoms) or total bilirubin > 2x ULN. All potential hepatotoxic drugs (Rifampicin, Isoniazid, Pyrazinamide) must be stopped immediately.

Explanation: 3HP consists of weekly high-dose Rifapentine plus Isoniazid for 12 weeks (3 months). It offers equivalent efficacy to 6-9 months of INH monotherapy with significantly higher completion rates and lower hepatotoxicity.