Digital Laser-Sintered Expander in Adolescent Patient with Hyperdontia and Molar Impaction.

Supernumerary teeth can have normal or abnormal morphologic structure and characteristics, and their impacted form is diagnosed usually during X-ray examinations. In this case report, the presented patient is a 16-year-old female with anterior and right posterior open bite and bilateral posterior crossbite, upper right supernumerary paramolar, and impacted second and third molars. The paramolar development was the reason for the asymmetric growth of the alveolar bone in the upper jaw. The development of the bone is connected with the development of the teeth, and one additional tooth leads to extensive development in the maxilla. There is a risk of gingival recession occurrence when leveling the lower incisors due to the thin gingival biotype. A combined surgical-orthodontic treatment was done according to the following plan: extraction of supernumerary paramolar, germectomy of the upper right third molar (18) and at the same time periodontal graft in the lower anterior segment. A digitally three-dimensional (3D) printed appliance for rapid maxillary expansion was used for the transverse insufficiency of the upper jaw. The upper dental arch expander was designed with distal extension in the area of the upper right second molar (17). The extension was used as an anchorage during the orthodontic traction of the second molar. The treatment continued with a fixed orthodontic appliance-braces in the upper and lower jaw. With the extraction of the impacted and supernumerary teeth in the right maxillary segment, the eruption of 17 was stimulated and a change in the height of the alveolar bone was achieved. This favored the vertical changes and normalization of the occlusion. The maxillary expansion was also a significant factor in normalizing the occlusion. Observations on paramolar behavior showed that more often they develop in the bone and do not erupt. Each clinical case is highly individual, and patients seek orthodontic treatment at different stages of dentition development and corresponding development of the supernumerary teeth.

Visualization of the individual blood microbiome to study the etiology of sarcoidosis.

Introduction: Single microbial pathogens or host-microbiome dysbiosis are the causes of lung diseases with suspected infectious etiology. Metagenome sequencing provides an overview of the microbiome content. Due to the rarity of most granulomatous lung diseases collecting large systematic datasets is challenging. Thus, single-patient data often can only be summarized visually. Objective: To increase the information gain from a single-case metagenome analysis we suggest a quantitative and qualitative approach. Results: The 16S metagenomic results of 7 patients with pulmonary sarcoidosis were compared with those of 22 healthy individuals. From lysed blood, total microbial DNA was extracted and sequenced. Cleaned data reads were identified taxonomically using Kraken 2 software. Individual metagenomic data were visualized with a Sankey diagram, Krona chart, and a heat-map. We identified five genera that were exclusively present or significantly enhanced in patients with sarcoidosis - Veillonella, Prevotella, Cutibacterium, Corynebacterium, and Streptococcus. Conclusions: Our approach can characterize the blood microbiome composition and diversity in rare diseases at an individual level. Investigation of the blood microbiome in patients with granulomatous lung diseases of unknown etiology, such as sarcoidosis could enhance our comprehension of their origin and pathogenesis and potentially uncover novel personalized therapeutics.

Statistical modelling of COVID-19 pandemic development applying branching processes.

In this paper, a statistical model for COVID-19 infection dynamics is described, using only the observed daily statistics of infected individuals. For this purpose, two special classes of branching processes without or with an immigration component are considered. These models are intended to estimate the main parameter of the infection and to give a prediction of the mean value of the non-observed population of the infected individuals. This is a serious advantage in comparison with other more complicated models where the officially reported data are not sufficient for estimation of the model parameters. The model is applied for different regions in the world and the corresponding parameters of the infection dynamics are estimated.

Study on the Prevalence of Pneumocystis jirovecii as a Causative Agent of Lung Pathology in People with Different Immune Status.

BACKGROUND: Pneumocystis pneumonia (PCP) commonly affects immunocompromised individuals, whereas in immunocompetent persons, it occurs relatively rarely, and in most cases, the Pneumocystis infection is detected as an asymptomatic colonization. The present study aimed to establish the prevalence of Pneumocystis jirovecii infection in human hosts with different immune status (immunocompromised and immunocompetent), using molecular diagnostic methods, and to compare their diagnostic value with that of classical staining methods. METHODS: We used the collected-to-this-moment data from a prospective study on the prevalence of pneumocystosis among the Bulgarian population. Clinical specimens (including throat secretions, induced sputum, tracheal aspirates, and bronchoalveolar lavage) collected from 220 patients suspected of PCP (153 immunocompetent and 67 immunocompromised patients) were examined with microscopic staining methods and real-time PCR for detection of P. jirovecii. Results: DNA of the pathogen was detected in 38 (17%) specimens (32 immunocompromised patients and 6 immunocompetent subjects). From all 220 clinical samples examined by staining methods, only five (2%) P. jirovecii cysts were detected by the Gomori stain. All patients with PCP were treated with trimethoprim-sulfamethoxazole, but in ten of them (HIV-positive patients), the disease had a fatal outcome. CONCLUSIONS: This study is the first in Bulgaria including the main available laboratory methods for diagnosis of human pneumocystosis. Regarding the etiological diagnosis of PCP, in our study the sensitivity of real-time PCR was higher compared to the staining methods. The choice of a method for sample collection and examination has an important role in the efficiency of the laboratory diagnostics.

Two cases with postintubation tracheal stenosis after COVID-19 pneumonia.

Only a small percent of all intubated SARS-CoV-2-positive patients survive because of the development of severe respiratory and multiorgan failure. The development of tracheal stenosis after orotracheal intubation or tracheostomy is a dangerous complication with gross consequences for the patient and medical staff. Endoscopic interventional procedures could be used in simple tracheal stenosis and surgical resection and anastomosis are reserved for complex stenosis or after unsuccessful endoscopic treatment. We present two cases with tracheal stenosis as a complication of prolonged intubation in COVID-19 survivors which was diagnosed up to 6 months after discharge. Clinical management and surgical techniques are also discussed.

A rare case of recurrent mediastinal malignant paraganglioma of thyroid origin: a case report.

Paraganglioma is a neuroendocrine tumor that originates from extraadrenal chromaffin cells. Primary thyroid paraganglioma is an extremely rare neoplasm. In this study, an exceptionally uncommon case of recurrent mediastinal malignant paraganglioma with primary origin from thyroid gland is presented. Median resternotomy, resection of left brachiocephalic vein, and extirpation of the mediastinal tumor were performed successfully. Commonly, it is preoperatively misdiagnosed and has unpredictable biological behavior. Incorrect diagnosis results in disastrous consequences for the patient, and consequently, correct pre- and postoperative diagnoses promise an optimal treatment plan and good prognosis. Long-term follow-up is indicated in all patients due to the risk of recurrence and distant metastases.

Tuberculosis in Adolescents in Bulgaria for a Three-Year Period: 2018-2020.

Background: Each year, approximately two million adolescents and young adults in the world become infected with tuberculosis (TB). The problem is that the classification of the disease includes children in the age group 0−14 years and young adults aged 15 and over. The present study aims to analyze and compare the epidemiology and clinical presentation of TB in Bulgaria in the different age subgroups of childhood. Methods: A retrospective study was undertaken of the newly diagnosed children (n = 80) with TB treated onsite from January 2018 to December 2020 at the Multiprofile Hospital for Active Treatment of Pulmonary Diseases ("St. Sofia"). They were distributed into three age groups: aged 8−11 (prepuberty), aged 12−14 (younger adolescents), and aged above 15 (older adolescents). Results: A clear finding of the research indicated that adolescent children develop TB both as primary and secondary infections. In a large number of cases with the children under our care, we found enlarged intrathoracic lymph nodes as well as infiltrative changes in the lungs, i.e., we observed transitional forms. There were statistically significant differences between the age group >15 years old and each of the other two younger groups for diagnosis, the severity of intoxication, and BK spreading status. Conclusion: The course of tuberculosis in adolescence has its own specifics and differences between the three age groups in the current study.

Diaphragmatic Movement at Rest and After Exertion: A Non-Invasive and Easy to Obtain Prognostic Marker in COPD.

Introduction: Diaphragmatic dysfunction is common in patients with chronic obstructive pulmonary disease (COPD). This study aimed to assess the prognostic significance of impaired diaphragmatic movement at rest and after exercise. Methods: This was a prospective study of patients with stable COPD. Diaphragmatic movements were examined at rest and after a 6-minute walking test (6MWT) with a convex transducer with a frequency of 3.5-5-7.5 MHz. Maximal movement of the diaphragm was measured in both right and left diaphragm, and the side with higher amplitude was selected for further analysis. Measurements obtained were evaluated for their prognostic value for a composite endpoint of moderate and severe COPD exacerbations and death in 1 year time period was assessed. In addition, postbronchodilator spirometry, symptoms, quality of life, and demographic and clinical information were collected. Results: A total of 96 patients were analyzed (62.5% male, mean age 65.1 years (standard deviation (SD): 8.1), mean FEV1 (% predicted): 55.8%, SD: 18.3%, mean CAT: 15.6 units, SD: 9.2). Sixty-four patients (67%) presented the composite endpoint. In the multivariate Cox analysis, FVC (HR = 0.944, p = 0.005), CAT score (HR = 1.133, p = 0.011), previous severe exacerbations (HR = 5.446, p = 0.004) and diaphragmatic movement at rest (HR = 0.932, p = 0.033) were found to be predictors of the composite endpoint. This model correctly classified 86.5% (83/96) of the patients. Conclusion: Non-invasive assessment of diaphragmatic movement by ultrasound measurement both at rest and after exercise could contribute to the assessment of disease severity and prognosis of COPD.

Recommendations for COPD management in Central and Eastern Europe.

INTRODUCTION: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy report provides guidance on effective management of chronic obstructive pulmonary disease (COPD) according to local healthcare systems. However, COPD is a heterogenous disease and certain aspects, including prevalence, disease-time course and phenotype distribution, can differ between countries. Moreover, features of clinical practice and healthcare systems for patients with COPD can vary widely, even in geographically close and economically similar countries. AREAS COVERED: Based on an initial workshop of respiratory physicians from eleven countries across Central and Eastern Europe (CEE) in December 2018 and subsequent discussions, this article offers region-specific insights from clinical practice and healthcare systems in CEE. Taking recommendations from the GOLD 2022 report into account, we suggest approaches to adapt these into national clinical guidelines for COPD management in CEE. EXPERT OPINION: Several factors should be considered when optimizing management of COPD in CEE compared with other regions, including differences in smoking status, vaccination uptake, prevalence of tuberculosis and nontuberculous mycobacteria, and variations in healthcare systems. We provide guidance and algorithms for pharmacologic and non-pharmacologic management of COPD for the following scenarios: initial and follow-up treatment, treatment of patients with frequent exacerbations, and withdrawal of inhaled corticosteroids where appropriate.

Chronic obstructive pulmonary disease (COPD) is a common disease of the lungs. It causes symptoms such as breathlessness, cough, and production of phlegm. In people with COPD, these symptoms often reduce the quality of their lives. From time to time, symptoms may get worse in people with the disease. This worsening is known as 'exacerbation'. Exacerbations of COPD can be so bad that they lead to hospital admissions. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) regularly gives advice to doctors around the world. This can help them to provide their patients with the best possible treatment for COPD. However, people with the disease and healthcare systems vary from country to country. This means that the guidance may need to be adjusted to the needs and available resources of different regions. This review looks at how COPD is treated in Central and Eastern Europe. We suggest how to adapt the GOLD recommendations to best suit the Central and Eastern European region.

A mediastinal malignant thyroid paraganglioma: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Thyroid cancer is the most common endocrine malignancy, while primary paraganglioma of the thyroid gland (TP) is an unusual tumour and in rare cases, this disease tends to mimic thyroid cancer. They are rare extra-adrenal neuroendocrine tumours originating from the neural crest, and are found almost exclusively in the head and neck area. CASE PRESENTATION: We present a case of a 53-year-old man, in whom a mediastinal lesion originating from the left lobe of the thyroid gland was found on routine ultrasound and subsequent computed tomography (CT). CLINICAL DISCUSSION: Total thyroidectomy and lymph dissection were performed. A review of the literature was made and a discussion was held regarding the diagnosis, the importance of surgical treatment and further behaviour. CONCLUSION: Surgical removal of the thyroid gland is the main treatment, followed by radiation therapy. The diagnosis and differential diagnosis with other thyroid tumours is extremely important in terms of subsequent behaviour and prognosis.

A Case of Tracheal Stenosis as an Isolated Form of Immunoproliferative Hyper-IgG4 Disease in a 17-Year-Old Girl.

Immunoglobulin G4-related disease (IgG4-RD) is a lymphoproliferative disease which is described almost exclusively in adults. There are only a few pediatric patients who have been observed with this disorder. Here, we describe a rare case of IgG4-RD in a 17-year-old girl with a single manifestation-tracheal stenosis without previous intubation or other inciting event. She had mixed dyspnea and noisy and weakened breathing. Immunoproliferative hyper-IgG4 disease was diagnosed, based on elevated serum IgG4 and histological findings. Until now we have chosen to treat the girl only with corticosteroids with a good response so far. The general condition as well as the respiratory function are regularly monitored. The tracheal involvement of IgG4-RD is uncommon. Nonetheless, it is a manifestation that should be included in the differential diagnosis of tracheal stenosis.

EGFR mutation status yield from bronchoalveolar lavage in patients with primary pulmonary adenocarcinoma compared to a venous blood sample and tissue biopsy.

BACKGROUND: In recent years, there has been a revolution in the genomic profiling and molecular typing of lung cancer. A key oncogene is the epidermal growth factor receptor (EGFR). The gold standard for determining EGFR mutation status is tissue biopsy, where a histological specimen is taken by a bronchoscopic or surgical method (transbronchial biopsy, forceps biopsy, etc.). However, in clinical practice the tissue sample is often insufficient for morphological and molecular analysis. Bronchoalveolar lavage is a validated diagnostic method for pathogenic infections in the lower respiratory tract, yet its diagnostic value for oncogenic mutation testing in lung cancer has not been extensively investigated. This study aims to compare the prevalence of EGFR mutation status in bronchoalveolar lavage and peripheral blood referring to the gold standard - tissue biopsy in patients with primary lung adenocarcinoma. METHODS: Twenty-six patients with adenocarcinoma were examined for EGFR mutation from tissue biopsy, peripheral blood sample and bronchoalveolar lavage. RESULTS: Thirteen patients had wild type EGFR and the other 13 had EGFR mutation. EGFR mutation from a peripheral blood sample was identified in 38.5% (5/13) of patients, whereas EGFR mutation obtained from bronchoalveolar lavage (BAL) was identified in 92.3% (12/13). This study demonstrates that a liquid biopsy sample for EGFR status from BAL has a higher sensitivity compared to a venous blood sample.

Clinical and spirometric variables are better predictors of COPD exacerbations than routine blood biomarkers.

BACKGROUND: Understanding the risk factors for exacerbations of COPD may help provide a more personalised approach to exacerbation prevention. METHOD: Observational, prospective, international, multicentre study aimed at identifying risk factors for exacerbations of COPD. Clinical variables, lung function and CAT scores were collected at baseline. In addition, routine blood biomarkers were also obtained, and patients were followed for 12 months. RESULTS: A total of 326 patients were included. Of these, 155 (47.5%) presented at least one exacerbation. The median time to the first exacerbation was 147 days. Exacerbators had more respiratory symptoms, more impairment in FEV1(%), FVC(%) and a worse CAT score. Regarding biomarkers, only C-reactive protein was significantly higher in exacerbators (2.8 (standard deviation (SD):3.8) mg/dL vs. 1.9 (SD:2.6) mg/dL; p = 0.037). In multivariate analysis, only CAT scores, FEV1(%) and previous exacerbations were significantly associated with having an exacerbation during follow-up. In the equation of risk, patients with a CAT score ≥15, FEV1(%) <55% and at least one exacerbation the previous year had a probability of 76% of having an exacerbation during the next year, compared with 17% in patients who had none of the previous variables. No biomarkers showed a significant association in multivariate analysis. CONCLUSIONS: Less than half of the patients presented an exacerbation during the one-year follow-up. CAT scores, FEV1(%) and previous exacerbations were the only variables associated with increased risk of exacerbations. Routine biomarkers did not provide additional information to evaluate the risk of exacerbations.

Association Between Routine Blood Biomarkers and Clinical Phenotypes and Exacerbations in Chronic Obstructive Pulmonary Disease.

Introduction: Chronic obstructive pulmonary disease (COPD) is associated with increased lung and systemic inflammation. We aimed to identify associations between easy-to-obtain blood biomarkers and the frequency and severity of exacerbations. Methods: Cross-sectional, multicentre study performed in four centres in Spain, Italy, Bulgaria, and Slovenia. Blood samples were obtained for blood cell count, C-reactive protein (CRP), alpha-1 antitrypsin (AAT) and fibrinogen analysis. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and eosinophil/basophil ratio (EBR) were calculated. Firstly, patients were divided into clinical phenotypes according to the Spanish guidelines of COPD, and secondly, patients were classified into 2 groups: non-exacerbators (≤1 ambulatory exacerbation in the previous year) and exacerbators (≥2 ambulatory exacerbations or 1 hospitalisation in the previous year). A multivariate stepwise logistic regression model was performed to identify laboratory parameters associated with exacerbators. Results: A total of 355 patients with a mean age 66 years (SD=8.9) were included, and 64% were male. The mean FEV1% (forced expiratory volume in the first second) was 55% (SD=20%), and the mean COPD Assessment Test (CAT) score was 15.6 (SD=7.9). One hundred ninety-six (55.2%) patients were classified in the non-exacerbator group, and 159 (44.8%) were exacerbators. Patients in the exacerbators group presented lower haemoglobin levels (p=0.019) and ERB (p= 0.023) but higher CRP levels (p=0.001). In the multivariate analysis, females, higher levels of CRP, lower FEV1% and low EBR were independently related to exacerbators. Conclusion: Female sex, having a more severe impairment of lung function, higher CRP levels and a lower EBR are associated with an exacerbator phenotype in COPD.

Endobronchial Ultrasound Transbronchial Needle Aspiration for the Diagnosis of Paratracheal and Peribronchial Central Parenchymal Lesions.

OBJECTIVES: Obtaining qualitative, sufficient material for the diagnosis of malignancies in cases with normal endoscopic findings in patients with suspected lung cancer and hilar and mediastinal lymphadenopathy is challenging. MATERIALS AND METHODS: Endobronchial ultrasound (EBUS) was used to control a transbronchial needle biopsy (ТBNA) for the first time in our country. From 2015 to 2018, TBNA with a convex probe EBUS was performed on 57 patients [41 men, 16 women, mean age 56.10 (range 37-77 years)] with mediastinal lesions found on CT scan. We used the Hitachi Aloka - ProSound Alpha 7 and BF-UC180F (Olympus) 21G and 22G needles Ultrasound System. In 22 of the cases, we performed a biopsy of hilum lesions (9 on the left and 13 on the right), in 13 - of subcarinal lesions, and in 4 - of lesions located on the right paratracheal lymphatic chain. RESULTS: EBUS-TBNA confirmed lung cancer in 48 patients (84.2%). In 33 of them, it was non-small cell lung cancer: spinocellular in 13 cases and adenocarcinoma in 17 cases; three cases were without accurate verification. Small cell lung cancer was found in 15 cases. In two cases, the biopsies were negative for tumor (3.5%), and in seven - non-specific inflammatory process (12.3%). CONCLUSIONS: This study confirms the high diagnostic success rate of EBUS-TBNA reported in similar studies developed on a daily routine basis without adhering to a specific protocol. EBUS-TBNA is an interventional procedure with high sensitivity in diagnosing hilar and mediastinal lesions in negative conventional bronchoscopy and thus is useful in patients with paratracheal and peribronchial lesions. The results could be improved with training and experience.

Autofluorescence and White Light Bronchoscopy in the Diagnosis of Endobronchial Malignant Lesions.

BACKGROUND: Autofluorescence bronchoscopy (AFB) allows a more sensitive approach to the diagnosis of premalignant and malignant endobronchial lesions than white light bronchoscopy (WLB) can do. AIM: To assess the autofluorescence bronchoscopy and white light bronchoscopy in diagnosing malignant endobronchial lesions. MATERIALS AND METHODS: The design of the study is a retrospective case-control study. Thirty-two parameters were entered into an Excel file and analysed with SPSS v. 21 for Mac book Pro. Endoscopy findings were graded in 4 options and morphological results - in 9 options according to WHO classification. The results are presented using McNemar's test and sensitivity, specificity and positive and negative predictive values as well. RESULTS: Three hundred and three patients were included in the study. Lung cancer was found in 38.3% of the patients using histology and in 35.6% - using cytology. McNemar's test for AFB finding for suspected and malignant lesions OR was 8.333 (95% CI 3.571-23.784) while for WLB OR was 0.128 (95% CI 0.045-0.299). For cytological results OR was 3.800 (95% CI 2.123-7.227) and 3.471 (95% CI 1.996-6.351), respectively. P value was <0.0001 for all tests. Sensitivity for AFB and WLB was 94.83% but specificity was 52.83% and 55.66% if histology was used. For cytology these numbers were respectively 86.11% and 84.26% for sensitivity, and 63.69% and 62.42% for specificity. CONCLUSION: AFB has an advantage over WLB in diagnosing endobronchial malignant lesions. Biopsying suspicious, not only visible malignant lesions, increased diagnostic sensitivity.

Diagnosis and Treatment of Three Cases of Bronchial Carcinoma In Situ.

As part of a retrospective study on bronchoscopies performed at the Clinic of Pneumonology and Phthisiatry of the University Hospital - Pleven by autofluorescence bronchoscopy we found 3 cases diagnosed with carcinoma in situ. They were treated in different ways - endobronchial electrocoagulation, extraction by forceps biopsy and open surgery, but the result was the same - clinical healing. The paper presents the three clinical cases and the analysis of the treatment.

Stability of Frequent Exacerbator Phenotype in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: At present, there is little information in Bulgaria regarding the rate and stability of frequent-exacerbation phenotype in COPD patients. AIM: To study the rate and stability of frequent-exacerbation phenotype in COPD patients. MATERIALS AND METHODS: We followed up 465 COPD patients for exacerbations over a 3-year period. Exacerbations were defined as events that resulted in treatment with antibiotics and/or corticosteroids (moderate), or that led to hospitalization (severe). RESULT: Approximately 10% of the patients had two or more exacerbations per year (frequent-exacerbation phenotype), and this structure stayed stable over the study period. The exacerbation rate in the first year of follow up was 0.33 per stage I COPD patients (according to GOLD stages), 0.49 per stage II COPD patients; 0.69 - for stage III, and 1.06 for stage IV COPD patients. The frequent-exacerbation rate increased from stage I to stage IV by 4.35%, 9.17%, 10.79%, and 20.97%, respectively. A history of previous year exacerbations increased the risk of new exacerbations: with a history of one exacerbation - OR 2.1820 (95% CI: 1.4018 to 3.3965, p = 0.0005), and with a history of two exacerbations - OR 4.6460 (95% CI: 2.3286 to 9.2696; p < 0.0001). The frequent-exacerbation phenotype appeared to be unstable over the study period - up to 33% from those patients stayed in the phenotype for the next year. CONCLUSIONS: The exacerbation frequency and the rate of frequent-exacerbation phenotype increases with COPD progression. History of exacerbations in the previous year is a significant risk factor for exacerbations of COPD. The frequent-exacerbation phenotype appeared to be unstable over the study period. The pheno-type of non-exacerbators was more likely to remain stable over time.

Subcritical Sevastyanov branching processes with nonhomogeneous Poisson immigration.

We consider a class of Sevastyanov branching processes with non-homogeneous Poisson immigration. These processes relax the assumption required by the Bellman-Harris process which imposes the lifespan and offspring of each individual to be independent. They find applications in studies of the dynamics of cell populations. In this paper, we focus on the subcritical case and examine asymptotic properties of the process. We establish limit theorems, which generalize classical results due to Sevastyanov and others. Our key findings include novel LLN and CLT which emerge from the non-homogeneity of the immigration process.

Impact of Air Pollution and Outdoor Temperature on the Rate of Chronic Obstructive Pulmonary Disease Exacerbations.

BACKGROUND: Environmental pollution can be one of the main risk factors for acute exacerbations of chronic obstructive pulmonary disease (COPD). AIM: To study the relationship between air pollution, outdoor temperature and exacerbations of COPD. MATERIALS AND METHODS: COPD patients (n=1432) were followed up for one year. The levels of particulate matter up to 10 µm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2) and outside temperatures were collected from the Environmental Agency database. RESULTS: A total of 309 acute COPD exacerbations (AECOPD) were recorded in the analysis. The daily mean concentrations of PM10 were found to correlate significantly with the daily mean concentrations of NO2 and SO2 (ρ 0.34 and ρ 0.49, respectively; p=0.0001). The negative correlations between the daily mean temperature and the daily mean levels of PM10, NO2 and SO2 were also significant (ρ -0.44, ρ -0.11, and ρ -0.37, respectively; p=0.0001). The daily number of AECOPD correlated with the mean levels of PM10 in the previous six days (ρ 0.14; p=0.02) and the lower outdoor temperature (ρ -0.2; p=0.001). The negative correlation between the daily number of AECOPD and the mean daily temperature was stronger in days with levels of PM10 above 50 µg/m3 (ρ -0.3 p=0.02 vs. ρ -0.18 p= 0.01). CONCLUSION: Lower daily mean temperatures were associated with the levels of air pollutants. The level of PM10 correlated with the levels of the other air pollutants. The daily number of AECOPD was found to correlate weakly, but signifi cantly with the mean level of PM10 in the previous six days.