After an outbreak of H1N1 influenza A virus infection in Mexico in late March 2009, the World Health Organization raised its pandemic alert level to phase 6, and to the highest level in June 2009. The pandemic H1N1/A influenza was caused by an H1N1 influenza A virus that represents a quadruple reassortment of two swine strains, one human strain, and one avian strain of influenza. After the first case report of H1N1/A infection in early May 2009, South Korea was overwhelmed by this new kind of influenza H1N1/A pandemic, which resulted in a total of 700,000 formally reported cases and 252 deaths. In this article, clinical characteristics of victims of H1N1/A influenza infection, especially those who developed pneumonia and those who were cared for in the intensive care unit, are described. In addition, guidelines for the treatment of H1N1/A influenza virus infection victims in the ICU, which was suggested by the Korean Society of Critical Care Medicine, are introduced.

Chronic obstructive pulmonary disease (COPD) is a substantially under-diagnosed disorder, and the diagnosis is usually delayed until the disease is advanced. However, the benefit of early diagnosis is not yet clear, and there are no guidelines in Korea for doing early diagnosis. This review highlights several issues regarding early diagnosis of COPD. On the basis of several lines of evidence, early diagnosis seems quite necessary and beneficial to patients. Early diagnosis can be approached by several methods, but it should be confirmed by quality-controlled spirometry. Compared with its potential benefit, the adverse effects of spirometry or pharmacotherapy appear relatively small. Although it is difficult to evaluate the benefit of early diagnosis by well-designed trials, several lines of evidence suggest that we should try to diagnose and manage patients with COPD at early stages of the disease.

Background: It is well-known that cell-free nucleic acids rise in patients with many types of malignancies. Several recent experimental studies using cancer cell lines have shown that changes in cell-free RNA are predictive of the response to chemotherapy. The objective of this study was to determine whether quantification of free RNA can be used as a biomarker for clinical responses to chemotherapy in patients with lung cancer. Methods: Thirty-two patients with lung cancer (non-small cell lung cancer, n=24; small cell lung cancer, n=8) were divided into 2 groups according to their responses to chemotherapy (response group, n=19; non-response group, n=13). Blood samples were collected before and after two cycles of chemotherapy. Real-time quantitative RT-PCR was used for transcript quantification of the glyceraldehyde-3-phosphate dehydrogenase gene. Results: The pre chemotherapy values (Response group $41.36{\pm}1.72$ vs. Non-response group $41.33{\pm}1.54$, p=0.78) and post chemotherapy values (Response group $39.92{\pm}1.81$ vs. Non-response group $40.41{\pm}1.47$, p=0.40) for cell free RNA concentrations, expressed as Ct GAPDH (threshold cycle glyceraldehyde-3-phosphate dehydrogenase gene) levels, was not different between the two groups. There was no significant relationship between changes in the cell free RNA level clinical responses after chemotherapy (p=0.43). Conclusion: We did not find a correlation between quantification of serum cell free RNA levels and clinical responses to chemotherapy in patients with lung cancer. Further investigations are needed to determine whether the cell free RNA level is a useful predictor of responses to chemotherapy in patients with lung cancer.

Background: Chronic obstructive pulmonary disease (COPD) is a major cause of death and disability worldwide and one of the most prevalent diseases in Korea. We examined trends and risk factors of health care utilization for COPD in Korea. Methods: We retrospectively analyzed the database of Patient Surveys from 1990 through 2008, which were nationwide surveys of health services utilization through outpatient department (OPD) visits and hospitalization. Physician-diagnosed COPD patients whose ages were 45 years and older were included. Results: OPD visits and hospitalization of COPD patients between 1990 and 2008 were estimated to be 68,552 and 17,774 persons, respectively. Trends in OPD visits and hospitalization for COPD significantly increased from 1990 through 2008 (p=0.019, p=0.001, respectively). The increment rate for OPD visits was 2.0 fold over those years; for hospitalization it was 3.3 fold. Risk factors for OPD visits for COPD were male gender (odd ration [OR], 1.41; 95% confidence interval [CI], 1.39~1.43), those aged 65 years and older (OR, 1.50; 95% CI, 1.47~1.53), residential area other than a metropolis (OR, 1.08; 95% CI, 1.07~1.010) and access to a physician's office (OR, 1.17; 95% CI, 1.14~1.21). Risk factors for hospitalization were male gender (OR, 2.15; 95% CI, 2.07~2.23), those aged 65 year and older (OR, 2.86; 95% CI, 2.72~3.00), residential area other than a metropolis (OR, 1.98; 95% CI, 1.90~2.07) and access to a hospital (OR, 2.88; 95% CI, 2.59~3.22) (p<0.001, both). Conclusion: Health care utilization for COPD subjects increased from 1990 to 2008. Risk factors for the utilization were male gender, older age, and residential area other than a metropolis.

Background: A variety of diagnostic modalities for lung cancer have been developed. To achieve efficient and early detection of lung cancer, we tried to measure the expression rates of the melanoma associated gene (MAGE) and synovial sarcoma on X chromosome (SSX) genes. Methods: We designed primers for the SSX gene. In addition to the pre-developed MAGE A primer, using an SSX gene primer was attempted to increase the detection rate. We obtained cancer tissues and cancer-free lung tissues from resected lung, sputum from lung cancer patients who had not undergone surgery, and sputum from healthy people and patients with benign intrathoracic diseases. Results: The sensitivity of the MAGE or SSX gene RT-PCR to identifying cancer tissue of the 69 lung cancer patients was 95.2% for squamous cell carcinoma (scc), 87.0% for adenocarcinoma, and 100% for small cell carcinoma. The mean sensitivity value was 94.2% (p=0.001). For adenocarcinoma, the additional use of the SSX gene resulted in a higher expression rate than MAGE alone (87% vs. 69.6%). The expression rate for the cancer-free lung tissue was 14.3% in scc, 17.4% in adenocarcinoma, and 25.0% in small cell carcinoma. In the induced sputum of 49 lung cancer patients who had not undergone surgery, the expression rate for one of the two genes was 65.5%. The expression rate for the sputum of healthy people and benign intrathoracic diseases by MAGE or SSX gene reverse transcription polymerase chain reaction (RT-PCR) was 3.8% and 17.7%. Conclusion: Detecting lung cancer using the expression of MAGE and SSX genes in lung cancer tissue has high sensitivity.

Background: Although patients with tuberculous-destroyed lung (TDL) account for a significant proportion of those with chronic airflow obstruction, it is difficult to distinguish patients with airway obstruction due to TDL from patients with pure chronic obstructive pulmonary disease (COPD) on initial presentation with dyspnea. We investigated clinical features differing between (i) patients with TDL and airway obstruction and (ii) those with COPD admitted to the intensive care unit (ICU) due to dyspnea. Methods: We reviewed the medical records of patients with TDL who had a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of <70% on a pulmonary function test (PFT; best value closest to admission) and patients with COPD without a history of pulmonary tuberculosis (TB) who were admitted to the ICU. Ultimately, 16 patients with TDL and 16 with COPD were compared, excluding patients with co-morbidities. Results: The mean ages of the patients with TDL and COPD were 63.7 and 71.2 years, respectively. Mean FVC% (50.4% vs. 71.9%; p<0.01) and mean FEV1% (39.1% vs. 58.4%; p<0.01) were significantly lower in the TDL group than in the COPD group. More frequent consolidation with TB (68.8% vs. 31.3%; p=0.03) and more tracheostomies (50.0% vs. 0.0%; p=0.02) were observed in the TDL than in the COPD group. Conclusion: Upon ICU admission, patients with TDL had TB pneumonia more frequently, more diminished PFT results, and more tracheostomies than patients with COPD.

Background: The clinicopathologic characteristics of patients with non-small cell lung cancer (NSCLC) have been changing. Recently, Positron emission tomography-computed tomography (PET-CT) has usually been used for diagnosis, follow-up to treatment and surveillance of NSCLC. We studied the pattern of recurrence and prognosis in patients who underwent complete resection for NSCLC according to histologic subtype. Methods: All patients who underwent complete resection for pathological stage I or II NSCLC between January 2005 and June 2009 were identified and clinical records were reviewed retrospectively, especially the histologic subtype. Results: Recurrences were identified in 50 of 112 patients who had complete resection of an NSCLC. Sites of recurrence were locoregional in 15 (30%), locoregional and distant in 20 (40%), and distant in 15 (30%). Also, sites of recurrence were intra-thoracic in 29 (58%), extrathoracic and intra-thoracic recurrence in 15 (30%), and extrathoracic in 6 (12%). In locoregional recurrence, there was 37% recurrence for non-squamous cell carcinoma (non-SQC) and 25% for squamous cell carcinoma (SQC). In distant recurrence, there was 39% recurrence for non-SQC and 18% for SQC. Locoregional recurrence in the bronchial stump was more common in SQC than non-SQC (14% vs. 45%, p=0.025). Prognosis of recurrence was not influenced by histologic subtype and the recurrence-free survival curve showed that the non-SQC group did not differ from the SQC group according to stage. Conclusion: The prognosis for recurrence does not seem to be influenced by histologic types, but locoregional recurrence in the bronchial stump seems to be more common in SQC than non-SQC in completely resected stage I and II NSCLC.

Hydatid disease is caused by the larval stage of taenia $Echinococcus$, which endemic in the Mediterranean region. Recently, the prevalence of the disease has increased worldwide due to an increase in the frequency of travel and immigration. As the infested larvae migrate through the bloodstream, the final destination is most commonly the liver or lungs; direct pleural invasion is very rare. A 50-year-old diabetic Korean man presented with an incidentally noted 2 cm right pleural nodule. On follow up imaging after three months, its size had increased. To confirm the diagnosis of the lesion, surgical excision was performed. Histopathological examination showed the diagnosis of a hydatid cyst. The patient had no history of overseas travel, but lives in an urban area where many foreign workers from endemic countries reside. This is the first reported case of primary pleural hydatid disease in a non-endemic country.

Herein we report the case of a 71-year-old woman who complained of fatigue and enlarged right axillary lymph nodes for 18 months. At her first visit, her chest X-ray showed diffuse nodular opacities in both lung fields. Initial excisional biopsy of the axillary lymph nodes showed granulomatous lesions and acid fast bacilli were seen on Ziehl-Neelsen staining. However, even after 15 months of anti-tuberculosis (TB) medication, her right axillary lymph nodes were enlarged. We re-performed an excisional biopsy of the nodes, which showed Hodgkin's lymphoma (HL). A retrograde review of the biopsy before anti-tuberculous medication, revealed HL coexisting with TB. HL and TB cause difficulties in differential diagnosis due to similarities in clinical course, imaging procedures and histopathological analysis of the involved tissue. Therefore, it is important to consider the possibility of concurrent HL and TB when patients who undergo treatment for TB or chemotherapy for lymphoma complain of persistent systemic symptoms or enlarged lymph nodes.

We report here an unusual case of pericardial tuberculoma that was misdiagnosed as thymic carcinoma on an imaging study. A 48-year-old woman was referred for evaluation of an anterior mediastinal mass. Computed tomography (CT) scans of the chest displayed cystic masses mimicking thymic carcinoma at the anterior mediastinum. Pericardiotomy and surgical drainage of the cystic masses were done, and pathologic examination of the excised pericardial specimen showed a chronic granulomatous inflammation with necrosis, compatible with tuberculosis. Acid-fast bacilli were also identified in the specimen. After treatment with anti-tuberculosis drugs and steroids, the patient showed clinical improvement. Although tuberculous pericarditis usually presents as pericardial effusion or constrictive pericarditis, it can also present as a pericardial mass mimicking thymic carcinoma on CT. Therefore, we suggest that tuberculous pericardial abscess should be included in the differential diagnosis of a mediastinal mass in Korea, with intermediate tuberculosis prevalence.