Pleural Infection in Finland

Pleural infection is a severe disease associated with high mortality and morbidity. Approximately 70% of all pleural infections are caused by previous pneumonia. Other possible causes include thoracic trauma, malignancies, and procedural complications. Pleural infections may be treated conservatively with antibiotics and pleural drainage, possibly combined with intra-pleural fibrinolysis, but surgery is often required for optimal patient recovery. The objective of surgical treatment is to evacuate the infection-related effusions from the pleura and to facilitate lung re- expansion. Video-assisted thoracic surgery (VATS) is the preferred surgical method, but traditional open surgery is sometimes useful in later disease stages. Less invasive surgery enables faster patient recovery without compromising the treatment results.

The incidence of pleural infections has increased in the developed countries for unknown reasons. Patients with a pleural infection are more often elderly with several comorbidities, impaired immunity, and/or substance abuse problems. No national guideline for the treatment of the disease exists in Finland, and only a few published studies are available regarding pleural infections in Northern Europe.

This thesis is composed of four separate studies, and the primary objective was to investigate the background, incidence, prognosis, and trends of pleural infections in Finland.

The first study analyzed the prognosis after pleural infections and reported significantly inferior long-term survival in patients with pleural infections when compared to a control group. The second study explored possible changes in the etiology, incidence, treatment, and outcomes of pleural infections in Tampere University Hospital over ten years. The study demonstrated that the incidence of pleural infections increased without any significant changes in the distributions of etiologic factors or causative pathogens. The prevalence of comorbidities and the rate of patients treated by VATS increased during the study period. The aim of the third study was to ascertain the overall need for medical care following pleural infections during a five-year follow-up and reported significantly higher rates of later hospitalizations, emergency room admissions, and outpatient clinic visits when compared to controls. The fourth study surveyed the incidence of pleural infections in Finland over three decades. The study reported a significant overall increase in the disease, with higher than previously reported incidence rates, particularly among elderly men.

The incidence of pleural infections will most likely continue to grow in the future due to the aging of the population, increasing the costs of and burden on health care. Hopefully, the present study entity increases the knowledge of this serious disease and helps health care professionals to diagnose and treat these patients, who are frequently seriously ill and fragile.