Phenotyping empyema by pleural fluid culture results and macroscopic appearance: an 8-year retrospective study

Prognostic significance of pleural fluid microbiological positivity in pleural infection: a bicentric 10-year retrospective observational study

BACKGROUND

Despite its heterogeneity, there is currently limited data in pleural infection phenotyping. Using pleural fluid characteristics, pleural infection can be classified into microbiological-positive pleural infection (MPPI) and microbiological-negative pleural infection (MNPI). This study aimed to evaluate the prognostic significance of microbiological positivity in pleural infection, and to evaluate the performance of RAPID (renal, age, purulence, infection source, dietary factor) score in these subgroups.

METHODS

Consecutive patients hospitalized for pleural infection over a 10-year period in two acute-care hospitals in Hong Kong were evaluated. According to the pleural fluid characteristics, they were classified into MPPI and MNPI, respectively. Survival was evaluated using multivariate Cox regression analysis. Performance of RAPID score to predict mortality at 3-month and 1-year was evaluated using C-statistics.

RESULTS

In total, 381 patients with pleural infection were included. They were classified into MPPI (n = 169) and MNPI (n = 212), respectively. The MPPI group had more elderly home residence and use of large-bore chest tube, and higher Charlson comorbidity index and RAPID score, compared to the MNPI group. Length-of-stay, the need of surgery and intensive care were similar between the two groups. MPPI was associated with significantly increased risk of mortality (adjusted hazard ratio [aHR] 1.46, 95% CI 1.08-1.98). Three-month mortality was significantly higher in MPPI compared to MNPI (24.9% vs. 10.4%, p < 0.001; adjusted odd ratio 2.05, 95% CI 1.11-3.80). The trend continued at 1, 3, 5 and 7 years. RAPID score predicted 3-month and 1-year mortality in both groups (C-statistics, MPPI 0.71, 0.75; MNPI 0.84, 0.81). In the MPPI group, presence of Staphylococcus aureus (aHR 2.26, 95% CI 1.43-3.57) and Gram-negative organisms other than Enterobacteriaceae (aHR 2.00, 95% CI 1.10-3.61) were associated with worse survival, while presence of Streptococcus anginosus group was associated better survival (aHR 0.50, 95% CI 0.32-0.78), when compared to their absence.

CONCLUSIONS

Pleural fluid microbiological positivity is independently associated with increased mortality in patients with pleural infections. This finding should complement the RAPID score in risk stratification and inform future research aimed at improving outcomes in this patient population.

Silicosis initially presenting with empyema

The current global outbreak of artificial stone silicosis is a recrudescence of a major occupational disease in the context of a novel exposure source. Respirable crystalline silica exposure, even without frank pneumoconiosis, is associated with an increased risk of respiratory infection. Empyema is a well-recognized complication of bacterial pneumonia; pneumonia among working-age adults, in turn, has been epidemiologically linked to occupational exposure to fumes and dust, including silica. A connection between empyema and silica dust inhalation has not been reported, however, whether through antecedent pneumonia or another mechanism. We describe a case of silicosis initially presenting with empyema in a 31-year-old Computerized Numerical Control stone-cutting machine operator who had heavy exposure to artificial stone and other rock dust.

Infective Pleural Effusions-A Comprehensive Narrative Review Article

Infective pleural effusions are mainly represented by parapneumonic effusions and empyema. These conditions are a spectrum of pleural diseases that are commonly encountered and carry significant mortality and morbidity rates reaching upwards of 50%. The causative etiology is usually an underlying bacterial pneumonia with the subsequent seeding of the infectious culprit and inflammatory agents to the pleural space leading to an inflammatory response and fibrin deposition. Radiographical evaluation through a CT scan or ultrasound yields high specificity and sensitivity, with features such as septations or pleural thickening indicating worse outcomes. Although microbiological yields from pleural studies are around 56% only, fluid analysis assists in both diagnosis and prognosis by evaluating pH, glucose, and other biomarkers such as lactate dehydrogenase. Management centers around antibiotic therapy for 2-6 weeks and the drainage of the infected pleural space when the effusion is complicated through tube thoracostomies or surgical intervention. Intrapleural enzymatic therapy, used to increase drainage, significantly decreases treatment failure rates, length of hospital stay, and surgical referrals but carries a risk of pleural hemorrhage. This comprehensive review article aims to define and delineate the progression of parapneumonic effusions and empyema as well as discuss pathophysiology, diagnostic, and treatment modalities with aims of broadening the generalist's understanding of such complex disease by reviewing the most recent and relevant high-quality evidence.

Tuberculous pleuritis: clinical presentations and diagnostic challenges

PURPOSE OF REVIEW

Tuberculous pleuritis (TBP) is one of the most common types of extrapulmonary tuberculosis. We highlight the latest epidemiology of TBP, the heterogeneity of its presentation and the performance of different diagnostic strategies.

RECENT FINDINGS

There are differential trends in the incidences of TBP worldwide. Its incidence increased in China but decreased in the United States in the past decade. The presentation of TBP is heterogeneous regarding clinical symptoms, radiological findings and pleural fluid analysis results. Conventional microbiological tests have low sensitivities to diagnose TBP. Recent research focused on various diagnostic tools with better yield. The sensitivity of nucleic acid amplification tests (NAAT) in pleural fluid, including the latest generation of PCR and sequencing-based techniques for detecting tuberculosis, remains suboptimal. Various pleural fluid biomarkers have been explored, but there is a lack of consensus on their clinical utility and cutoff levels.

SUMMARY

The heterogeneity of clinical presentation poses obstacles to diagnosing TBP. Further development of diagnostic tools, including more robust NAAT and biomarkers with additional validation, is needed before incorporation into routine clinical practice.