title: Radiological cavitation, sputum mycobacterial load and treatment response in pulmonary tuberculosis.
abstract: METHODS
  Royal Free Hospital, London.
  
  
  OBJECTIVE
  To investigate the relationship between sputum mycobacterial load, assessed by time to positivity (TTP) in liquid culture, radiological cavitation and change in sputum bacterial load in response to anti-tuberculosis treatment.
  
  
  METHODS
  The study was conducted on 95 patients treated for sputum culture-positive pulmonary tuberculosis (TB), with pre-treatment TTP and baseline chest X-ray (CXR). Of these, 31 had chest computed tomography scans assessed for number and volume of cavities. The microbiological treatment response was measured in 56 patients with serial TTP, and related to baseline radiological cavitation.
  
  
  RESULTS
  Cavitation was present in 48% of patients, and was associated with a shorter TTP at baseline (P < 0.001). Patients with more cavities and greater total cavitary volume had a shorter TTP (P < 0.001 for both). No difference was demonstrated in the rate of change in TTP on treatment (P = 0.36) between patients with and without cavities.
  
  
  CONCLUSIONS
  This study confirms that cavitation is associated with higher baseline sputum mycobacterial load. The rate of decline in bacterial load in response to treatment is similar in patients with and without radiologically demonstrable cavities, suggesting that response to, and hence duration of, effective treatment may be predicted by the initial number of organisms present in the sputum.
authors.affiliation: Department of Infection, Royal Free Campus, University College London, London, UK.
authors.forename: F M R
authors.initials: FM
authors.lastname: Perrin
authors.forename: N
authors.initials: N
authors.lastname: Woodward
authors.forename: P P J
authors.initials: PP
authors.lastname: Phillips
authors.forename: T D
authors.initials: TD
authors.lastname: McHugh
authors.forename: A J
authors.initials: AJ
authors.lastname: Nunn
authors.forename: M C I
authors.initials: MC
authors.lastname: Lipman
authors.forename: S H
authors.initials: SH
authors.lastname: Gillespie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000627:therapeutic use*; D058491:Bacterial Load / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D013997:Time Factors; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents