Pulmonary sclerosing hemangioma presenting as solitary pulmonary nodule: dynamic CT findings and histopathologic comparisons

OBJECTIVE

The purpose of this study was to describe the dynamic CT findings of pulmonary sclerosing hemangioma presenting as a solitary pulmonary nodule and to compare these findings with histopathologic findings.

CONCLUSION

On dynamic CT, sclerosing hemangioma has strong and rapid enhancement attributed histopathologically to the presence of hemangiomatous or papillary components in the tumor.

A Peptide with anti-transglutaminase activity decreases lipopolysaccharide-induced lung inflammation in mice

Octapeptide R2 (KVLDGQDP), which has anti-transglutaminas (TGase) activity, decreases inflammation in allergic conjunctivitis model in guinea pigs. The authors examined the effect of R2 on lipopolysaccharide (LPS)-induced lung injury in BALB/c mice. R2 inhalation significantly decreased neutrophil count and cytokine mRNA expression in the lungs of LPS (25 mg/kg)-treated mice (P < .05). It also showed a tendency for decreased tumor necrosis factor (TNF)-alpha-immunoreactive protein in lung homogenates and significantly decreased TNF-alpha-immunoreactive protein in the serum of LPS-injected mice (P < .05). These results indicate that TGase may be a new therapeutic target in LPS-induced lung inflammation.

Acute respiratory distress syndrome. Computed tomography findings and their applications to mechanical ventilation therapy

In acute respiratory distress syndrome, computed tomography (CT) typically demonstrates symmetric ground-glass opacity and gravity-dependent consolidation when patients are positioned supine. Moreover, CT findings may vary according to the evolutional stage of the disease over time. The slope of the pressure-volume curve, which is a direct or indirect measure of lung recruitment rather than a measure of the characteristics of the respiratory mechanics of a portion of the aerated lung, indicates the potential for recruitment. The lung recruitment maneuver is performed by maintaining a sustained increase in airway pressure with the goal of opening collapsed alveoli, after which sufficient positive end-expiratory pressure is applied to maintain the alveoli in an open state. Alveolar recruitment resulting from continuous positive airway pressure occurs predominantly in nondependent and cephalic lung regions and is more limited in the diaphragmatic region or even negative (alveolar derecruitment) caudal to the diaphragmatic cupola. By partially relieving cardiac and abdominal compression, positioning patients in prone and semirecumbent positions may reopen dependent and caudal lung regions and improve gas exchange. The mean CT attenuation of a given region is equivalent to its aeration. Computed tomography, especially helical CT, may help to assess alveolar recruitment and lung overinflation by providing information on whole-lung attenuation.

Rigid bronchoscopic intervention in patients with respiratory failure caused by malignant central airway obstruction

INTRODUCTION

Bronchoscopic intervention in patients with malignant central airway obstruction provides initial palliation and stabilization of the airway, allowing the possibility of other effective therapeutic modalities, such as surgery, radiation, or chemotherapy. In critically ill patients, however, the only studies of bronchoscopic intervention are relatively small series.

METHODS

To describe the advantages and limitations of rigid bronchoscopic intervention in critically ill patients, we reviewed the medical records of 36 patients (26 men; median age, 62 years; range, 29 to 76 years) who underwent emergency airway intervention for malignant central airway obstruction.

RESULTS

Dyspnea was relieved in 34 of 36 patients (94.4%). After the airway was widened, additional definitive therapeutic modalities were used for 21 of 34 patients (61.8%). Patients who underwent additional definitive therapy after bronchoscopic intervention survived longer (median, 38.2 months; range 1.7 to 57.0 months) than those who did not (median, 6.2 months; range, 0.1 to 33.7 months; p < 0.001).

CONCLUSIONS

These data show that rigid bronchoscopic intervention in critically ill patients with malignant central airway obstruction may be temporarily life-saving and, in some patients, may serve as a "bridge" to allow time for additional therapies for longer survival.

Early intervention can improve clinical outcome of acute interstitial pneumonia

Study objectives:

To report on our experience with acute interstitial pneumonia (AIP) in which patients underwent early diagnostic procedures and received mechanical ventilation with a “lung-protective” strategy and early institution of immunosuppressive therapy.

Design:

A retrospective chart review.

Setting:

A tertiary referral hospital.

Participants:

Ten patients with AIP who presented with idiopathic ARDS and showed diffuse alveolar damage on surgical lung biopsy specimens from July 1995 to March 2004.

Measurements and results:

The median age of patients was 65.5 years (age range, 38 to 73 years). Patients presented with a median duration of severe dyspnea of 9.5 days (range, 2 to 34 days) at the hospital visit. All patients required mechanical ventilation beginning at median time of hospital day 1 (range, hospital day 0 to 5), which continued for a median duration of 9.5 days (range, 4 to 98 days). Patients received ventilation in the pressure assist-control mode with a median tidal volume of 6.97 mL/kg (range, 6.05 to 8.86 mL/kg) and median positive end-expiratory pressure of 11 cm H₂O (range, 8 to 16 cm H₂O). An aggressive diagnostic workup for respiratory infection, including BAL at a median time of hospital day 2 (range, hospital day 1 to 5) was performed. High-dose steroid pulse therapy was initiated on median hospital day 3.5 (range, hospital day 1 to 8), while surgical lung biopsy was performed on median hospital day 4 (range, hospital day 2 to 7). Eight patients (80%) survived to hospital discharge.

Conclusion:

Earlier intervention, such as an aggressive diagnostic approach, mechanical ventilation with lung-protective strategy, and the early institution of immunosuppressive may improve clinical outcome in patients with AIP.

Bronchial and nonbronchial systemic arteries in patients with hemoptysis: depiction on MDCT angiography

OBJECTIVE

In this pictorial essay, we show the usefulness of MDCT angiography for visualization of the bronchial and nonbronchial systemic feeder vessels responsible for hemoptysis.

CONCLUSION

By providing thin-section transaxial, multiplanar reconstruction, and 3D images, CT angiography using MDCT allows comparable or better images than conventional angiography with respect to the depiction of bronchial or nonbronchial systemic arteries. CT angiography is particularly useful for visualizing the ectopic origin of bronchial arteries and nonbronchial systemic collateral arteries.

Do Hemodynamic Studies of Stage T1 Lung Cancer Enable the Prediction of Hilar or Mediastinal Nodal Metastasis?

OBJECTIVE

We aimed to identify CT enhancement characteristics that predict hilar or mediastinal nodal metastasis in patients with stage T1 lung cancer.

SUBJECTS AND METHODS

Eighty-four patients (50 men and 34 women; age range, 39-80 years; mean age, 61 years) with stage T1 lung cancer underwent a hemodynamic and a conventional morphologic CT study before curative surgical resection. Peak enhancement (maximum attenuation over the entire time course), net enhancement (peak enhancement minus preenhancement attenuation), maximum enhancement ratio (MER), time to peak enhancement, slope of enhancement on dynamic studies, nodule size, presence of tumor necrosis or thickening of bronchovascular bundles, and marginal characteristics on morphologic studies were analyzed and correlated with the presence of histologically determined mediastinal or hilar nodal metastasis.

RESULTS

Mediastinal or hilar nodal metastases were found at surgery in 26 (31%) of 84 patients: mediastinal nodes in 13 (15%) and hilar nodes in 19 (23%). Six (7%) had both mediastinal and hilar nodal metastasis. Peak enhancement, net enhancement, and MER were significantly associated (p = 0.001, 0.002, and 0.008, respectively) with the presence of mediastinal or hilar nodal metastasis. A peak attenuation of 110 H or greater and a net enhancement of 60 H or greater predicted nodal metastasis with accuracies of 73% (61/84 nodules) and 73% (61/84 nodules) and odd ratios of 4.98 and 5.94, respectively.

CONCLUSION

Stage T1 lung cancers showing peak enhancement of 110 H or greater or net enhancement of 60 H or greater on dynamic CT indicate a high likelihood of hilar or mediastinal nodal metastasis.

Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterization

In this retrospective study, we investigated whether the (18)F-FDG uptake pattern and CT findings improved the accuracy over the standardized uptake value (SUV) for differentiating benign from malignant focal thyroid lesions incidentally found on (18)F-FDG PET/CT. We also defined the prevalence of these lesions and their risk for cancer.

METHODS

(18)F-FDG PET/CT was performed on 1,763 subjects without a previous history of thyroid cancer from May 2003 to June 2004. Two nuclear medicine physicians and 1 radiologist interpreted PET/CT images, concentrating on the presence of focal thyroid lesions, the maximum SUV of the thyroid lesion, the pattern of background thyroid (18)F-FDG uptake, and the CT attenuation pattern of the thyroid lesion.

RESULTS

The prevalence of focal thyroid lesions on PET/CT was 4.0% (70/1,763). Diagnostic confirmation was done on 44 subjects by ultrasonography (US)-guided fine-needle aspiration (n = 29) or US with clinical follow-up (n = 15). Among 49 focal thyroid lesions in these 44 subjects, 18 focal thyroid lesions of 17 subjects were histologically proven to be malignant (papillary cancer in 16, metastasis from esophageal cancer in 1, non-Hodgkin's lymphoma in 1). Therefore, the cancer risk of focal thyroid lesions was 36.7% on a lesion-by-lesion basis or 38.6% on a subject-by-subject basis. The maximum SUV of malignant thyroid lesions was significantly higher than that of benign lesions (6.7 +/- 5.5 vs. 10.7 +/- 7.8; P < 0.05). When only the maximum SUV was applied to differentiate benign from malignant focal thyroid lesions for the receiver-operating-characteristic curve analysis, the area under the curve (AUC) of PET was 0.701. All 16 focal thyroid lesions with very low attenuation or nonlocalization on CT images, or with accompanying diffusely increased thyroid (18)F-FDG uptake, were benign. When those lesions were regarded as benign lesions, irrespective of the maximum SUV, the AUC of PET/CT was significantly improved to 0.878 (P < 0.01).

CONCLUSION

Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Image interpretation that includes (18)F-FDG uptake and the CT attenuation pattern, along with the SUV, significantly improves the accuracy of PET/CT for differentiating benign from malignant focal thyroid lesions.

Pneumoconiosis: comparison of imaging and pathologic findings

Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coal worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.

Neuroendocrine tumors of the lung: clinical, pathologic, and imaging findings

Neuroendocrine tumors of the lung arise from Kulchitzky cells of the bronchial mucosa and comprise typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC). At histopathologic analysis, these tumors demonstrate a progressive increase in the number of mitotic figures per 10 high-power fields of viable tumor and in the extent of necrosis, with typical carcinoid having the lowest values and SCLC having the highest. Typical carcinoid is less aggressive than atypical carcinoid, although these tumors have similar gross pathologic and radiologic features; LCNEC has a prognosis between that of atypical carcinoid and that of SCLC. SCLC is the most aggressive pulmonary neuroendocrine tumor and has the most specific imaging feature: mediastinal or hilar lymphadenopathy. At CT, carcinoid tumors appear as a spherical or ovoid nodule or mass with a well-defined and slightly lobulated border. When nonspherical, the tumor is elongated with its long axis parallel to adjacent bronchi. Calcification or ossification is seen in up to 30% of cases. The CT findings of LCNEC are nonspecific and are similar to those of other non-small cell lung cancers. Although there are some overlapping features between these tumors, integration of the clinical and imaging features may be helpful in differentiation of pulmonary neuroendocrine tumors.

Clinical significance of nontuberculous mycobacteria isolated from respiratory specimens in Korea

STUDY OBJECTIVES

Precise epidemiologic data regarding nontuberculous mycobacterial (NTM) lung infection in many Asian countries have been relatively unavailable. In order to determine the clinical significance of NTM isolated from respiratory specimens, we reviewed medical records from all patients from whom NTM isolates were recovered within a 2-year period.

MATERIALS AND METHODS

We identified all NTM isolates from respiratory specimens at the Samsung Medical Center (Seoul, South Korea) obtained from January 2002 to December 2003. We then reviewed the clinical and radiologic characteristics of the patients from whom NTM was isolated. Patients were classified as having either definite, probable, or unlikely NTM lung disease, as defined by the guidelines of both the American Thoracic Society and the British Thoracic Society.

RESULTS

During the study period, 1,548 NTM isolates were recovered from 794 patients. Of these 794 patients, 131 patients (17%) were determined to have definite NTM lung disease, and 64 patients (8%) were designated as probable disease candidates. The most commonly involved organisms in the definite and probable NTM lung disease cases were Mycobacterium avium complex (n = 94, 48%) and Mycobacterium abscessus (n = 64, 33%). In 195 patients with NTM lung disease, 82 patients (42%) manifested the upper lobe cavitary form, 101 patients (52%) exhibited the nodular bronchiectatic form, and 12 patients (6%) exhibited the unclassifiable form.

CONCLUSIONS

About one fourth of the patients in whom NTM was isolated from respiratory specimens were found to have clinically significant NTM lung infections. The spectrum of organisms responsible for the NTM lung disease in these Korean patients differed from those reported in other regions of the world. However, the estimates of clinical significance in this study may be underestimates due to the retrospective analysis. Some of the patients might have "true" NTM lung disease that could be diagnosed with continued evaluation and follow-up.

Prognostic factors and causes of death in Korean patients with idiopathic pulmonary fibrosis

The purpose of this study was to investigate the prognostic factors at initial presentation and the causes of death in Korean patients with idiopathic pulmonary fibrosis (IPF), which might be different report wise, in comparison to the western countries. A retrospective review of 88 patients (mean 60.3 years, 69 male) was carried out and they were diagnosed as IPF positive. After diagnosis, the survival rate was 57% and 41% for third and fifth year, respectively (mean follow-up 39.1 months). Mortality was closely correlated with severe dyspnea at presentation (Hazard Ratio [HR], 2.6 per grade; p=0.015), lower initial forced vital capacity (HR, 1.7 per 10% predicted; p=0.004) and lower initial diffusing capacity of the lung (HR, 1.5 per 10% predicted; p=0.033). Treatment with specific drugs was ineffective against the survival when compared with symptomatic supportive care. Thirty-four patients (68%) died of worsened respiratory failure, seven (14%) died of infection and only one patient showed cardiovascular death. In conclusion, our study suggests that the severity of dyspnea and lung function tests at the time of diagnosis are the predictive factors for the survival of patients with IPF. In comparison to the reports from western countries, we observed that respiratory failure and pulmonary infection were more frequent causes of death, while cardiovascular death was rare in Korean patients with IPF.

Tissue characterization of solitary pulmonary nodule: comparative study between helical dynamic CT and integrated PET/CT

Recent advances in the technology of helical multidetector CT allow precise evaluations of nodule hemodynamics. In addition, the efficacy of tissue characterization has improved, and now sensitivity and specificity of >90% are achieved. Moreover, the efficacy of PET for the tissue characterization of solitary pulmonary nodules (SPNs) has also become of importance. The purpose of this study was to compare the diagnostic accuracy of helical dynamic (HD) CT (HDCT) and integrated PET/CT for pulmonary nodule characterization.

METHODS

One hundred nineteen patients with an SPN underwent both HDCT (unenhanced scans, followed by series of images at 30, 60, 90, 120 s and at 5 and 15 min after intravenous injection of contrast medium) and integrated PET/CT. On HDCT, a nodule was regarded as malignant with a net enhancement of > or =25 Hounsfield units (HU) and a washout of 5-31 HU. On integrated PET/CT, nodules were considered malignant with a > or =3.5 maximum standardized uptake value and an 18F-FDG uptake greater than that of mediastinal structures. The sensitivity, specificity, and accuracy of the 2 modalities for malignancy were compared using the McNemar test.

RESULTS

There were 79 malignant and 40 benign nodules. The sensitivity, specificity, and accuracy for malignancy on HDCT were 81% (64/79 nodules), 93% (37/40), and 85% (101/119), respectively, whereas those on integrated PET/CT were 96% (76/79), 88% (35/40), and 93% (111/119), respectively (P = 0.008, 0.727, and 0.011, respectively). All malignant nodules were interpreted correctly on either HDCT or PET/CT.

CONCLUSION

Integrated PET/CT is more sensitive and accurate than HDCT for the malignant nodule characterization; therefore, PET/CT may be performed as the first-line evaluation tool for SPN characterization. Because HDCT has high specificity and acceptable sensitivity and accuracy, it may be a reasonable alternative for nodule characterization when PET/CT is unavailable.

The role of endoscopic surgery for completely obstructive endobronchial benign tumor

BACKGROUND

The improving techniques of therapeutic bronchoscopy have been replacing conventional surgery for resecting endobronchial benign tumor. However, there could be some limitation for performing bronchoscopic intervention for the patients with complete bronchial obstruction. To evaluate the role of endoscopic surgery for completely obstructive endobronchial benign tumor, we retrospectively reviewed the medical records of 7 patients who underwent bronchoscopic resection due to completely obstructive benign tumor.

METHODS

Rigid bronchoscopy was performed under general anesthesia. After the stalk of tumor was identified with using a 1 mm biopsy forceps as a probe, a Nd-YAG laser was used to coagulate the stalk of tumor. The tumor was then removed.

RESULTS

Bronchoscopic resection was successful in 6 out of 7 patients. The histological diagnoses were 3 leiomyomas, 3 harmatomas and 1 lipoma. There was no mortality in our study. Pneumomediastinum developed in 1 patient, and this patient was treated with 3 days of oxygen therapy. In 5 out of the 6 successful patients, there was no recurrence for a median of 35 months. In 1 patient, leiomyoma recurred after 17 months, and this was treated by pneumonectomy.

CONCLUSIONS

Endoscopic surgery could be applied to the patients with completely obstructive endobronchial benign tumor.

Drug-sensitive tuberculosis, multidrug-resistant tuberculosis, and nontuberculous mycobacterial pulmonary disease in nonAIDS adults: comparisons of thin-section CT findings

The aim of this work was to compare thin-section CT (TSCT) findings of drug-sensitive (DS) tuberculosis (TB), multidrug-resistant (MDR) TB, and nontuberculous mycobacterial (NTM) pulmonary disease in nonAIDS adults. During 2003, 216 (113 DS TB, 35 MDR TB, and 68 NTM) patients with smear-positive sputum for acid-fast bacilli (AFB), and who were subsequently confirmed to have mycobacterial pulmonary disease, underwent thoracic TSCT. The frequency of lung lesion patterns on TSCT and patients' demographic data were compared. The commonest TSCT findings were tree-in-bud opacities and nodules. On a per-person basis, significant differences were found in the frequency of multiple cavities and bronchiectasis (P < 0.001, chi-square test and multiple logistic regression analysis). Multiple cavities were more frequent in MDR TB than in the other two groups and extensive bronchiectasis in NTM disease (multiple logistic regression analysis). Patients with MDR TB were younger than those with DS TB or NTM disease (P < 0.001, multiple logistic regression analysis). Previous tuberculosis treatment history was significantly more frequent in patients with MDR TB or NTM disease (P < 0.001, chi-square test and multiple logistic regression analysis). In patients with positive sputum AFB, multiple cavities, young age, and previous tuberculosis treatment history imply MDR TB, whereas extensive bronchiectasis, old age, and previous tuberculosis treatment history NTM disease.

Acute pneumonia and empyema caused by Mycobacterium intracellulare

Nontuberculous mycobacterial infection is rarely accompanied by pleural involvement. We report a very rare case of M. intracellulare pulmonary disease with pleural empyema. A 56-year-old man was admitted to our hospital because of fever, purulent sputum and pleuritic chest pain. A chest radiograph and CT revealed pneumonic consolidation in the left lower lobe and loculated hydropneumothorax. The sputum smear was positive for acid fast bacilli. The aspirated pleural fluid was grossly purulent and the smear of the pleural effusion was also positive for acid fast bacilli. M. intracellulare was identified by culture and PCR from sputum and pleural fluid specimens. The patient improved with percutaneous tube drainage of the purulent effusion and antibiotic treatment including clarithromycin, rifampicin, ethambutol and streptomycin.

Mycobacterium abscessus pulmonary infection presenting as a solitary pulmonary nodule

Nontuberculous mycobacterial pulmonary infection is a rare cause of a solitary pulmonary nodule. All previously reported cases were caused by Mycobacterium avium complex, and a solitary pulmonary nodule caused by other NTM species has been very rarely reported. We describe the first case of Mycobacterium abscessus infection presenting as a solitary pulmonary nodule in a 51-year-old asymptomatic adult patient.

Integrated PET/CT and the Dry Pleural Dissemination of Peripheral Adenocarcinoma of the Lung

OBJECTIVE

The aim of this study was to describe retrospectively the CT findings of dry pleural dissemination of peripheral lung adenocarcinoma, and to compare the mutual roles of PET and CT components of integrated PET/CT in the diagnosis of the disease.

METHODS

The authors analyzed retrospectively the CT findings of pathologically proved dry pleural dissemination in 8 of 172 patients with peripheral adenocarcinoma of the lung. Subsequently, one radiologist and one nuclear medicine physician (unaware of the CT and pathologic results) evaluated together in a random order the integrated PET/CT of 172 adenocarcinoma patients (8 with dry pleural dissemination and 164 without). They recorded the presence of pleural dissemination using PET images only and using both PET and CT images. The diagnostic accuracies with respect to the presence of pleural dissemination were evaluated.

RESULTS

The CT findings of dry pleural dissemination were pleural small nodules (n=8, 100%) (>or=6 in number in all patients; 198/204 nodules were <5 mm in diameter and 6/204 were 5-10 mm) and uneven (n=4, 50%) or band-like (n=3, 38%) fissural thickening. By PET only, the sensitivity, specificity, and accuracy of dry pleural dissemination were 25% (2/8), 90% (147/164), and 87% (149/172), respectively; by PET plus CT these were 100% (8/8), 100% (164/164), and 100% (172/172), respectively.

CONCLUSIONS

The CT findings of dry pleural dissemination are multiple small pleural nodules and uneven pleural thickening. Dry pleural dissemination should be diagnosed using CT findings at integrated PET/CT because lesions causing pleural dissemination without pleural effusion are usually beyond PET resolution.

T1 non-small cell lung cancer: imaging and histopathologic findings and their prognostic implications

About 5% of T1 non-small cell lung cancers (ie, lung cancers less than 3 cm in diameter), mostly focal nodular bronchioloalveolar carcinomas and carcinoid tumors, demonstrate no uptake at fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and appear to be indolent in growth; consequently, they are associated with long-term patient survival. About 21% of T1 lung cancers show mediastinal nodal metastasis at the time of diagnosis and about 24% show extrathoracic metastasis, mostly brain metastasis, either at the time of diagnosis or at 1-year follow-up. T1 lung cancers with a large ground-glass attenuation component (50% of tumor volume) at thin-section computed tomography (CT) have a good prognosis with less likelihood of mediastinal nodal or extrathoracic metastasis. On the other hand, solid cancer lesions, especially those with a spiculated margin or with bronchovascular bundle thickening in the surrounding lung, more frequently demonstrate local vessel invasion, lymph node metastasis, and extrathoracic metastasis. In these tumors, work-up for extrathoracic metastases (including whole-body FDG PET or brain magnetic resonance imaging and mediastinoscopy for mediastinal nodes) may be needed, even when CT demonstrates no enlarged nodes in the mediastinum.

Diagnosis and treatment of nontuberculous mycobacterial pulmonary diseases: a Korean perspective

The incidence of pulmonary disease caused by nontuberculous mycobacteria (NTM) appears to be increasing worldwide. In Korea, M. avium complex and M. abscessus account for most of the pathogens encountered, whilst M. kansasii is a relatively uncommon cause of NTM pulmonary diseases. NTM pulmonary disease is highly complex in terms of its clinical presentation and management. Because its clinical features are indistinguishable from those of pulmonary tuberculosis and NTMs are ubiquitous in the environment, the isolation and identification of causative organisms are mandatory for diagnosis, and some specific diagnostic criteria have been proposed. The treatment of NTM pulmonary disease depends on the infecting species, but decisions concerning the institution of treatment are never easy. Treatment requires the use of multiple drugs for 18 to 24 months. Thus, treatment is expensive, often has significant side effects, and is frequently not curative. Therefore, clinicians should be confident that there is sufficient pathology to warrant prolonged, multidrug treatment regimens. In all of the situations, outcomes can be best optimized only when clinicians, radiologists, and laboratories work cooperatively.

Comparison of drug resistance genotypes between Beijing and non-Beijing family strains of Mycobacterium tuberculosis in Korea

The frequency of resistance genotypes among Beijing and non-Beijing strains was compared using a reverse blot hybridization assay to detect mutations within genes associated with rifampicin (rpoB) and isoniazid (katG, inhA, and ahpC) resistance. Of the 743 Mycobacterium tuberculosis isolates, 569 (77%) belonged to Beijing family. The proportion of Beijing strains was significantly higher among MDR-TB isolates than among drug-susceptible strains (82% vs. 72%, p<0.01). Genotype analysis of the rpoB gene revealed significantly lower rates of the Ser531Leu mutation rate among Beijing vs. non-Beijing MDR-TB strains (41% vs. 66%, p<0.005). While the mutation for Ser315Thr in the katG gene was more common among Beijing vs. non-Beijing family strains (65% vs. 50%, p<0.01), the mutation rate of promoter region of the inhA gene was lower among Beijing strains compared with non-Beijing strains (14% vs. 25%, p<0.05). Reverse hybridization successfully detected over 80% of isoniazid-resistant strains and over 92% of rifampicin-resistant strains among Korean isolates. Significant differences in mutation rates in the rpoB, katG, and inhA genes between Beijing strains and non-Beijing strains could explain discrepancies in mutation rates of genotypes in different countries. Reverse hybridization was useful for rapid detection of isoniazid and rifampicin resistant strains.

Optimal duration of IV and oral antibiotics in the treatment of thoracic actinomycosis

STUDY OBJECTIVE

IV antibiotic therapy for 2 to 6 weeks followed by 6 to 12 months of oral antibiotic therapy is usually recommended for the treatment of thoracic actinomycosis. The objective of this study was to evaluate the duration of IV and oral antibiotic therapy for thoracic actinomycosis.

METHODS

We present a retrospective case series of 28 patients with thoracic actinomycosis as confirmed by histopathology from October 1994 through December 2003.

RESULTS

After diagnosis of actinomycosis, 54% (15 of 28 patients) received antibiotic therapy alone. The duration of IV antibiotic therapy ranged from 0 to 18 days (median, 2 days; interquartile range [IQR], 0 to 3 days), and the duration of oral antibiotic treatment ranged from 76 to 412 days (median, 167 days; IQR, 142 to 214 days) in patients who received antibiotics alone. Combination surgical and antibiotic therapy occurred in 46% (13 of 28 patients). The duration of IV antibiotic therapy ranged from 3 to 17 days (median, 8 days; IQR, 5 to 13 days), and the duration of oral antibiotic therapy ranged from 0 to 534 days (median, 150 days; IQR, 3.5 to 289 days) in these patients. Clinical cures were achieved in 96% (27 of 28 patients). There was no clinical evidence of recurrence during follow-up period at our hospital (median, 23 months; IQR, 9 to 44 months) in 21 patients, excluding 7 patients who were transferred to referring hospitals after completion of antibiotic therapy (n = 6) or during antibiotic therapy (n = 1).

CONCLUSIONS

Thoracic actinomycosis is best treated with individualized therapeutic modalities, depending on factors such as the initial burden of disease, the performance of resectional surgery, and the clinical and radiologic responses to therapy. The traditional recommendation of IV antibiotic therapy for 2 to 6 weeks followed by oral antibiotic therapy for 6 to 12 months is not always necessary for all thoracic actinomycosis patients.