Stage 3 — Prioritize hypotheses. Mr. R, 38, moved from the Philippines 14 months ago and was admitted six hours ago to a shared general medical room for presumed community-acquired pneumonia. He reports a three-week productive cough with intermittent blood-streaked sputum, a 12-pound weight loss over six weeks, drenching night sweats, and fatigue, and a coworker was diagnosed with pulmonary TB last month. Ceftriaxone and azithromycin were started and blood cultures collected overnight. Temperature is 38.1 C, heart rate 102/min, respirations 22/min, BP 118/72 mm Hg, SpO2 93% on 2 L/min, and WBC 12.4 x 10^9/L. The chest radiograph shows a right-upper-lobe cavity with surrounding infiltrate. His roommate is receiving chemotherapy, no airborne order is active, and staff wore surgical masks overnight. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

Quick answer
Condition: suspected active pulmonary tuberculosis. Actions: mask him and move him to an airborne isolation room, and send three sputum samples for AFB smear and NAAT (with culture). Monitor: serial sputum AFB smears and fever and cough pattern.

Why this is correct
Weeks of symptoms, constitutional signs (weight loss, night sweats), hemoptysis, a known contact, and an upper-lobe cavity together point to infectious pulmonary TB, which spreads by airborne droplet nuclei. The client wears a surgical mask as source control while moving to an airborne infection isolation room, and staff use fit-tested N95 respirators. Sputum specimens 8 to 24 hours apart (one early morning) with NAAT confirm the diagnosis and guide release from isolation. Smear conversion and fading fever and cough are the trends clinicians use to judge response and infectiousness.

Easy analogy or mental picture
TB in a cavity is like smoke in a room: a surgical mask on the smoker keeps some in, but everyone else needs a real respirator and the door needs to close on a negative-pressure room.

Memory hook
Cough 3 weeks + cavity + contact = airborne room, N95, and three sputums.

NCLEX decision rule
Begin isolation when a transmissible infection is suspected, collect diagnostic specimens before starting treatment, and monitor the markers that decide infectiousness.

Why the other choices are wrong
Community-acquired pneumonia is the admission label and shares fever, cough, and WBC elevation, but three weeks of cough, weight loss, night sweats, a TB contact, and a cavity do not fit, so blood cultures and procalcitonin track the wrong disease. Latent TB is excluded because he has symptoms and a cavity; a tuberculin skin test measures infection, not disease activity or response. Lung cancer shares weight loss and hemoptysis but not fever, night sweats, and an infectious contact at age 38. Surgical masks do not protect staff from droplet nuclei; fit-tested N95 respirators are needed. An IGRA cannot rule out active TB and must not delay isolation. Starting drugs before sputum collection can make smears and cultures harder to interpret.