When there is extensive caseation and the granulomas involve a larger bronchus, it is possible for much of the soft, necrotic center to drain out and leave behind a cavity. Cavitation is typical for large granulomas with tuberculosis. Cavitation is more common in the upper lobes.

Question: How long will the patient remain infectious to others?

AnswerFollowing initiation of anti-tubercular therapy, the sputum may become clear of organisms after a week, but may take 2 to 4 weeks, confirmed by 3 consecutive negative sputum smears. Continuing infectivity can occur with inadequate treatment or resistant organisms.