Pulmonary tuberculosis--a review of clinical features and diagnosis in 232 cases

The diagnosis of pulmonary tuberculosis is often delayed due to atypical clinical features and difficulty in obtaining positive bacteriology. We reviewed 232 cases of pulmonary tuberculosis diagnosed in Kedah Medical Centre, Alor Setar from January 1998 to December 2002. All age groups were affected with a male predominance (Male:Female ratio = 60:40). Risk factors include underlying diabetes mellitus (17.7%), positive family history (16.8%) and previous tuberculosis (5.2%). Nearly half (45.3%) of patients had symptoms for more than one year. Only 22% of patients had typical symptoms of tuberculosis (prolonged recurrent fever, cough, anorexia and weight loss), whilst others presented with haemoptysis, chronic cough, COPD, bronchiectasis, general ill-health, pyrexia of unknown origin or pleural effusion without other systemic symptoms. Fifteen percent of the patients presented with extrapulmonary diagnosis. Ninety percent of the patients had previous medical consultations but 40% had no chest radiograph or sputum examination done. The chest radiographs showed 'typical' changes of tuberculosis in 62% while in the other 38% the radiological features were 'not typical'. Sputum direct smear was positive for acid-fast bacilli in only 22.8% of patients and 11.2% were diagnosed base on positive sputum culture. Sputum may be negative even in patients with typical clinical presentations and chest radiograph changes. Bronchial washing improved the diagnosis rate being positive in 49.1% of cases (24.1% by direct smear and the other 25.0% by culture). In 16.8% of cases, the diagnosis was based on a good response to empirical anti-tuberculosis therapy in patients with clinical and radiological features characteristic of tuberculosis. In conclusions, the clinical and radiological manifestations of pulmonary tuberculosis may be atypical. Sputum is often negative and bronchoscopy with washings for Mycobacterium culture gives a higher yield for diagnosis. In highly probable cases, empirical therapy with antituberculosis drugs should be considered because it is safe and beneficial.