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Biomedical subjects

Atul C Mehta

Publications and source records attributed to Atul C Mehta.

At least 19 recordsLinked to original sources

Endobronchial fungal disease: an under-recognized entity.

Most fungi enter the human body via inhalation; however, endobronchial fungal infection (EBFI) seems to be a rare manifestation compared to pulmonary or systemic disease. This presentation seems to be related to environmental factors as well as to the host status. With the increasing popularity of flexible bronchoscopy, it is being recognized with a higher frequency. Bronchoscopic findings in EBFI vary from mild mucosal inflammation to central airway obstruction. We searched English literature related to the topic and found 228 total cases of EBFI: Aspergillus species (121), Coccidioides immitis (38), Zygomycetes (31), Candida species (14) Cryptococcus neoformans (13), and Histoplasma capsulatum (11). We have also included a single case of endobronchial Pseudallescheria boydii infection in a lung transplant recipient that has not been reported previously. Most patients were immunocompromised, exhibited systemic manifestations of the primary infection, and responded to appropriate therapy. EBFI should be included in the differential diagnosis of any form of airway lesions in immunocompromised patients, especially among residents from the endemic areas.

Bronchitis↗

Short-term deployment of self-expanding metallic stents facilitates healing of bronchial dehiscence.

Bronchial dehiscence after lung transplantation is difficult to treat and associated with high mortality. We describe our experience using self-expanding metallic stents to treat post-lung transplant bronchial dehiscence. From January 1995 to June 2004, 189 single and 118 double lung transplants were performed in our institution, totaling 425 at-risk bronchial anastomoses. Seven (1.6%) incidents of life-threatening bronchial dehiscence were treated with self-expanding metallic stents. The interval between transplant and diagnosis of dehiscence was 29.1 +/- 18.5 days. All patients presented with respiratory distress, and three required mechanical ventilation. Self-expanding metallic stent placement resulted in complete bronchial healing. All three patients with respiratory failure requiring mechanical ventilation were successfully weaned after stent placement. In two later cases, the stents were electively removed after adequate healing of the dehiscence. Complications included stent migration (one patient) and in-stent stenosis (three patients). Two of these patients required repeat stent insertion after removal, due to bronchomalacia. In patients with life-threatening bronchial dehiscence, self-expanding metallic stents offer prospects for a successful outcome. Self-expanding metallic stents are known to be associated with significant granulation tissue formation, and this property provides a platform for healing of dehiscence and, in time, peribronchial soft tissue grows in to cover the defect, allowing stent removal.

Anastomosis, Surgical↗

Central airway obstruction.

Central airway obstruction is a problem facing all medical and surgical subspecialists caring for patients with chest diseases. The incidence of this disorder appears to be rising because of the epidemic of lung cancer; however, benign causes of central airway obstruction are being seen more frequently as well. The morbidity is significant and if left untreated, death from suffocation is a frequent outcome. Management of these patients is difficult, but therapeutic and diagnostic tools are now available that are beneficial to most patients and almost all airway obstruction can be relieved expeditiously. This review examines current approaches in the workup and treatment of patients suffering from airway impairment. Although large, randomized, comparative studies are not available, data show significant improvement in patient outcomes and quality of life with treatment of central airway obstruction. Clearly, more studies assessing the relative utility of specific airway interventions and their impact on morbidity and mortality are needed. Currently, the most comprehensive approach can be offered at centers with expertise in the management of complex airway disorders and availability of all endoscopic and surgical options.

Airway Obstruction↗

Cell-mediated immune response to influenza vaccination in lung transplant recipients.

BACKGROUND: Lung transplant recipients are susceptible to complications from influenza infection. Antibody responses to influenza vaccination have been shown to be decreased in lung transplant recipients. Cellular immune mechanisms serve an important role in influenza clearance. The cellular immune response to influenza vaccination has not been studied in transplant populations. METHODS: Interleukin-2, interleukin-10, interferon-gamma, and granzyme B levels to the three viral antigens included in the 1999 to 2000 influenza vaccine were measured before and 4 weeks post-vaccination in 43 lung transplant recipients and 21 healthy adult controls. RESULTS: Interleukin-2, interleukin-10, interferon-gamma, and granzyme B levels did not increase from pre- to post-vaccination in the lung transplant group. Both pre- and post-cytokine levels were lower in the transplant group compared to the control group. Pre- and post-granzyme B levels did not differ significantly between the groups. The T-helper response in the control group varied with the different viral strains. A correlation between acute rejection episodes and the absence of both azathioprine and mycophenolate was found. CONCLUSIONS: Influenza vaccination does not stimulate a cell-mediated immune response in lung transplant recipients as judged by interleukin-2, interleukin-10, interferon-gamma, and granzyme B levels. Alternative prevention strategies may be needed.

Case-Control Studies↗

Removal of self-expandable metallic stents: is it possible?

Self-expandable metallic stents (SEMS) have become an important component of the management of central airway disease. These stents are not, however, without problems and stent-related complications (SRCs) can be more formidable to treat than the original indication for SEMS placement. As use of SEMS has increased, the number of patients returning to hospital for management of SRCs has similarly risen. A small group of these patients will have, as their only therapeutic option, stent removal Thus far limited experience exists with late stent removal. Stent extraction is difficult and requires expertise in a variety of techniques. A multidisciplinary approach to both SEMS placement and extraction is strongly advocated.

Journal Article↗

Reprocessing the bronchoscope: the challenges.

Spread of infection through the flexible bronchoscope is underrecognized and underreported. Prevention of bronchoscopy-induced infection requires increased vigilance by the physician, assiduous implementation of reprocessing protocols, and closer collaboration between bronchoscopy personnel, infection control practitioners, and instrument manufacturers. Patient safety depends on adequate disinfection of bronchoscopes and accessories used, as well as proper training of bronchoscopists, nurses, and ancillary staff. It is important to recognize that microbial transmission may occur via any part of instruments or anything in contact with the instruments including cleaning solutions, automated washers, and rinsing water. Numerous surveys have suggested poor adherence to published preventive guidelines. To address the challenges of reprocessing bronchoscopes, all users must comply with guidelines for cleaning and disinfection and each procedure should be performed with a clean, disinfected bronchoscope.

Journal Article↗

Pulmonary nodules in lung transplant recipients: etiology and outcome.

BACKGROUND: The pulmonary nodule (PN) poses a diagnostic and therapeutic challenge in the immunocompromised host. Common causes of PNs in lung transplant (LT) recipients include bacterial or fungal infections and posttransplant lymphoproliferative disorder (PTLD). However, experience in diagnosis and management of PNs is limited. METHODS: Two hundred thirty-four LTs were performed between February 1990 and December 2000. Medical records of all patients with PNs were reviewed retrospectively. Data on presentation, radiographic features, diagnostic methods, therapy, and outcome were collected and analyzed. RESULTS: Twenty-three patients had PNs after a follow-up of 20.1 +/- 20.1 months (mean +/- SD). The mean age was 45.5 +/- 14.4 years, with a male:female ratio of 17:6. Thirteen patients received single LT, 9 patients received bilateral LT, and 1 patient received heart-LT. Cough and dyspnea were the most common symptoms at presentation, and PNs were better detected by CT than chest radiography. Solitary PNs were due to bronchogenic carcinoma and PTLD, while multiple PNs were due to invasive pulmonary aspergillosis (IPA), cytomegalovirus pneumonitis, bronchiolitis obliterans, and metastatic carcinoma. Bronchoscopy with BAL and transbronchial lung biopsy was the usual method of diagnosis (n = 17, 74%), and our mortality rate was 70%. CONCLUSION: PNs are not uncommon in patients following LT. The majority were due to IPA and PTLD. Prophylaxis with itraconazole against Aspergillus, and acyclovir for Epstein-Barr virus-negative LT recipients, serial CT and surveillance bronchoscopy for early detection of Aspergillus infections, and rituximab therapy for PTLD could improve the outcome of these patients.

Aspergillosis↗

Role of flexible bronchoscopy in immunocompromised patients with lung infiltrates.

STUDY OBJECTIVE: To study the diagnostic role of flexible bronchoscopy (FB) in immunocompromised patients with pulmonary infiltrates. DESIGN: Prospective, observational study. SETTING: Tertiary care hospital. PATIENTS: A total of 104 consecutive non-HIV-infected immunocompromised patients with lung infiltrates in whom FB was performed. METHODS: The primary outcome measure was the diagnostic yield of FB, which was derived as the number of the diagnoses made using FB results divided by all final diagnoses. Final diagnoses were established using data from FB, surgical lung biopsy (SLB), and microbiology and serology testing, and by the clinical response to empiric therapy. We also studied the diagnostic yields of individual sampling procedures such as BAL, transbronchial biopsy (TBB), and protected-specimen brush (PSB) sampling. RESULTS: Overall, 128 diagnoses were made in 104 patients. The overall diagnostic yield of FB was 56.2% (95% confidence interval [CI], 47 to 64%). FB provided at least one diagnosis in 53 of 104 patients (51%; 95% CI, 40 to 62%). FB was more likely to establish the diagnosis when the lung infiltrate was due to an infectious agent (81%; 95% CI, 67 to 90%) than to a noninfectious process (56%; 95% CI, 43 to 67%; p = 0.011). The diagnostic yields of BAL (38%; 95% CI, 30 to 47%) and TBB (38%; 95% CI, 27 to 51%) were similar (p = 0.94). The diagnostic yield of PSB sampling was lower (13%; 95% CI 6 to 24%; p = 0.001) than that of BAL. The combined diagnostic yield of BAL and TBB (70%; 95% CI, 57 to 80%) was higher than that of BAL alone (p < 0.001). Finally, the diagnostic yield of FB with PSB sampling, BAL, and TBB was similar to that of FB with BAL and TBB. The complication rate from FB was 21% (95% CI, 15 to 31%). Minor bleeding (13%) and pneumothorax (4%) were the most common complications. CONCLUSIONS: FB has a high diagnostic yield in immunocompromised patients with pulmonary infiltrates. Based on our results, we recommend performing TBB in these patients, whenever possible.

Adult↗

Transbronchial needle aspiration in diagnosing intrathoracic tuberculous lymphadenitis.

STUDY OBJECTIVE: To assess the role of transbronchial needle aspiration (TBNA) in diagnosing intrathoracic tuberculous lymphadenitis (TB-LA). METHODS: In a tertiary referral center for thoracic medicine and surgery, using a CT scan as a guide, transbronchial aspirates were obtained with a 19-gauge flexible histology needle in consecutively enrolled patients with sputum smears negative for acid-fast bacilli, and with isolated mediastinal or hilar adenopathy suspicious for tuberculosis (TB). RESULTS: Of 84 eligible patients who were all found to be HIV-negative, 63 (75%) cases of TB were diagnosed by TBNA (histology, 48 patients [76%]; cytology, 9 patients [14%]; and bacteriologic studies, 21 patients [33%; smear, 8 patients; culture, 17 patients]). TBNA was used to diagnose sarcoidosis in two patients, angioimmunoblastic lymphadenopathy in one patient, and Hodgkin lymphoma in one patient. In the 17 TBNA-negative patients, the results of transthoracic needle aspiration were positive in 12 patients (TB, nine patients; lung cancer, two patients; sarcoidosis, one patient), the results of mediastinoscopy were positive in three patients (TB, two patients; Hodgkin lymphoma, one patient), and the results of thoracotomy were positive in two patients (TB, two patients). Thus, 76 patients had TB, and all responded to anti-TB treatment. TB was corroborated by culture or histology of another specimen obtained from subsequently developed lesions in 40 patients (53%) during anti-TB treatment or posttreatment follow-up. TBNA was immediately diagnostic in 59 patients (78%), and exclusively in 52 patients (68%), among all bronchoscopic procedures and prebronchoscopic sputum studies. Sensitivity, specificity, positive and negative predictive values, and accuracy of TBNA for TB were 83%, 100%, 100%, 38%, and 85%, respectively. The only complication, self-limiting hemorrhage of < 30 mL volume, occurred in 65 patients (77%), with a volume of < 5 mL in 59 patients (70%). CONCLUSION: TBNA is efficient and safe in the bacteriologic and pathologic diagnosis of intrathoracic TB-LA in HIV-negative and sputum smear-negative patients.

Adolescent↗