Primary Tuberculous Pleural Effusion: A Retrospective Study of 32 Patients from Tripoli-Libya

الملخص

Involvement of the pleura is one of the most common sites of extra-pulmonary tuberculosis. In the absence of
lung parenchymal lesions, tuberculous pleural effusion (TBE) can present a diagnostic challenge, especially in
developing countries. Our objective was to describe the characteristics of a series of 32 Libyan patients who
presented with isolated pleural effusion and were diagnosed with primary type tuberculous pleural effusion (TPE).
A retrospective study of 32 patients recruited from three respiratory clinics in Tripoli (Abusetta Hospital, Tripoli
Central Hospital and Tripoli Medical Center) during the period from January 2007 to December 2009.
The patients presented acutely with fever, non-productive cough, chest pain, shortness of breath and unilateral
pleural effusion without radiological evidence of lung parenchymal lesions. They failed to respond to empirical
antibiotic therapy (Amoxicillin plus Clarithromycin). They had no past history of TB, their tuberculin skin test
readings were highly positive and pleural aspiration showedan exudative lymphocytic fluid. The diagnosis of TPE
was based ondetection of acid fast bacilli (AFB) in the pleural fluid. When the latter was negative, blind pleural
biopsy using Abraham’ needle was underaken and the diagnosis was based on detection of caseating granuloma in
the biopsy specimens. Data was analyzed by using statistical package for social sciences (SPSS) version 16.
The mean age of the patients was 40.4 years and there was an almost equal representation of males and females.
The mean duration of clinical symptoms was 14 days. They all presented with fever, dry cough, chest pain and
shortness of breath. The mean values of peripheral white blood cells, the C-reactive protein (CRP) and erythrocyte
sedimentation rate (ESR) were 14,000 cells/mm3
, 180 mg/L, and 118 mm/hr. respectively. Their chest radiography
showed unilateral pleural effusions with no apparent lung parynchymal lesions. Pleural fluid analysis showed
exudative lymphocytic pleural effusions, and tuberculin skin test readings were positive (≥ 15 mm induration).
Pleural fluid smear was positive for AFB in 11 patients (34.4%). Histopathologic examination of pleural biopsy
specimens from the 21 patients who had pleural fluid AFB negative results confirmed the presence of tuberculous
caseating granuloma. Five of the 32 studied patients (15.6%) were doctors from Tripoli Central Hospital working
at the medical and emergency department.
The studied patients had a classic acute presentation of primary TPE. Compared with reports from other developing
countries, they were older and both genders were equally affected. The diagnostic yield of pleural fluid AFB was
high (34.4%) and caseating granuloma was detected in all of the patients who underwent blind pleural biopsy. The
significant number of hospital doctors involved suggested that TB infection control measures need to be revised in
our hospitals.