Pulmonary Mycobacterium kansasii Infection in Israel, 1999-2004: Statistical Analysis
Data on clinical features of the patients (including systemic comorbid disease and smoking status), radiologic findings, treatment, and outcome were obtained from the case notes and laboratory records by a single investigator. Chest radiographs obtained within 2 weeks of diagnosis of mycobacterial disease were read by an independent investigator who was blinded to the clinical findings. All the patients had been tested for HIV. The study was approved by the Ethics Committee of Rabin Medical Center.
Results are shown as mean ± SD. To statistically analyze differences between categorical variables, a x2 test or Fisher exact test were used, as appropriate. The Pearson correlation coefficient (r) and the significance for it (p value) were calculated between the variables; p < 0.05 was considered statistically significant.
The background features of the patients are summarized in Table 1. Mean age (± SD) was 58 ± 18 years; 24 patients (64%) were men, 22 patients (39%) were smokers, and 10 patients (18%) had environmental exposure to heavy air pollution or dusty environment. None had pneumoconiosis. Associated lung diseases included COPD in 19 patients (36%), previous tuberculosis in 7 patients (13%), and bronchiectasis in 7 patients (13%). Twenty-three patients (41%) had no underlying lung disease. Systemic comorbid nonpulmonary diseases included diabetes in seven patients (13%), nonpulmonary malignancy in three patients (5%), cardiac disease in four patients (7%), and a history of alcohol abuse (> 14 U/wk) in two patients (4%). Eight patients (14%) were receiving immunosuppressive agents, including steroids. None had HIV infection. The most common presenting symptoms were nonspecific chest pain and cough in 47 patients (84%) each. Twenty-two patients (39%) had fever and night sweats, 21 patients (38%) had hemoptysis, and 18 patients (32%) had weight loss. Two patients (4%) presented with hoarseness due to vocal cord involvement.
M kansasii infection was an incidental finding on chest radiography in only one patient. All others had symptoms of mycobacterial infection. Cavitary disease was noted radiologically in 30 patients (54%), and noncavitary disease was found in 26 patients (46%); one patient had normal chest radiograph findings. M kansasii disease was confined to the upper lobes in 46 patients (82%): the right lobe in 27 patients (48%) and the left lobe in 19 (34%); 6 patients (11%) had bilateral disease. None of the patients presented with pleural effusions or lymph-adenopathy. Seven patients (13%) underwent bronchoscopy with BAL and transbronchial biopsy to confirm the diagnosis of tuberculosis after repeated negative sputum culture results.
Table 1—Clinical Characteristics of 56 Israeli Patients With M kansasii Infection
Characteristics | Data |
Age, yr | 45 ± 18 |
Sex | |
Male | 36 (64) |
Female | 20 (36) |
Smoking | 22 (39) |
Environmental exposure | 10 (18) |
Systemic comorbid illness | |
Diabetes | 7(13) |
Cardiac disease | 4(7) |
Malignancy | 3 (5) |
Alcohol intake 14 U/wk | 2 (6) |
Associated lung disease | 33 (59) |
Previous tuberculosis | 7 (13) |
COPD | 20 (36) |
Bronchiectasis | 7 (13) |
Use of immunosuppressive medication | 8 (14) |
Symptoms at presentation | |
Chest pain | 46 (82) |
Cough | 47 (84) |
Hemoptysis | 21 (38) |
Weight loss | 18 (32) |
Sweat/fever | 22 (39) |
Hoarseness | 2 (4) |
Radiologic findings | |
Normal | 1 (2) |
Cavitations | 30 (54) |
Location of radiologic findings | |
Right upper lobe | 27 (48) |
Left upper lobe | 19 (34) |
Lower lobes | 2 (4) |
Bilateral disease | 6(11) |
Pleural effusion | 0 |
Lymphadenopathy | 0 |
Unknown | 2 (4) |
Diagnosis by bronchoscopy | 7(11) |
Duration of positive culture results, mo | 8.9 ± 10.3 |
Rifampicin sensitivity | 56 (100) |
Ethambutol sensitivity | 42 of 43 (98) |
Outcome, alive | 56 (100) |