Imaging of opportunistic fungal infections in immunocompromised patient

Opportunistic fungal infection is a common cause of serious morbidity and mortality in the immunocompromised host. Combination of pattern recognition with knowledge of the clinical setting is the best approach to pulmonary infectious processes. The aim of this article is to assess the chest radiographs and CT imaging features of different opportunistic fungal infections in immunocompromised patients.

Engraftment syndrome emerges as the main cause of transplant-related mortality in pediatric patients receiving autologous peripheral blood progenitor cell transplantation

The authors examined data from 166 children who received autologous peripheral blood progenitor cell (PBPC) transplantation to ascertain the incidence of early transplant-related mortality (TRM) and the contributing risk factors. Eleven patients (6.6%) (6 boys, 5 girls) died within 180 days following PBPC infusion. The median age was 4 years (range 2-17). The overall probability of TRM was 6.9 +/- 2% at day +180. On univariate analysis, the status of disease at transplantation (complete remission vs. not in complete remission) was identified as the only pretransplant significant predicting factor for TRM (14% of patients who were not in complete remission died within 180 days after PBPC infusion, whereas only 2% of patients in complete remission died) (relative risk [RR] 1.13, 95% confidence interval [CI] 1.01-1.26, P = 0.01). Age, gender, conditioning, and number of CD34+ cells infused were not significantly associated with TRM. In the postinfusion phase, patients who developed multiorgan dysfunction during the neutropenic period, especially when the lung was the first failing organ (RR 16.1, 95% CI 7.16-36.18, P = 0.0001), and those with engraftment syndrome (RR 2.81, 95% CI 1.49-5.24, P = 0.001) had an increased risk for TRM. On multivariate analysis, development of engraftment syndrome was the only significant variable that influenced TRM. In conclusion, the authors found for the first time that engraftment syndrome emerges as the main cause of TRM after autologous PBPC transplantation in children with malignancies.

[An unusual cause of acute respiratory distress: obstructive bronchial aspergillosis]

We report the case of a 77-Year-old immunocompetent woman who required intensive care for acute dyspnea revealing complete atelectasia of the left lung related to an aspergillus mycelium plug blocking the principal bronchus. The clinical course was favorable after deobstruction by thermocoagulation and oral itraconazole given for six Months. The patient was free of parenchymatous or endobronchial sequelae. Adjuvant oral corticoid therapy was given temporarily during the second Month of treatment when signs of transition towards allergic aspergillosis developed. Four Months after discontinuing the antifungal treatment, the patient developed a new episode of acute dyspnea caused by atelectasia limited to the right lower lobe. Treatment by itraconazole was resumed and continued as long-term therapy. No recurrence has been observed for eighteen Months. The diagnostic and therapeutic problems raised by Aspergillus fumigatus are well known in the immunocompromised subject, but can also be encountered in the immunocompetent subject.

Prospective study of respiratory viral infections in pediatric hemopoietic stem cell transplantation patients

BACKGROUND

Community-acquired respiratory viruses are an important cause of respiratory disease in pediatric patients undergoing hemopoietic stem cell transplantation. However, there are no studies examining the impact of more rapid and sensitive diagnosis by real time polymerase chain reaction (PCR) in this population. We performed a prospective study to assess the impact of real time PCR diagnosis as well as protective isolation for community-acquired respiratory virus infections in pediatric patients undergoing hemopoietic stem cell transplantation.

METHODS

During a 2-year period, 39 pediatric patients undergoing hemopoietic stem cell transplantation were analyzed for presence of respiratory viruses. Samples were taken at regular intervals and analyzed by culture and newly developed real time PCR methods. All patients were cared for in protective isolation.

RESULTS

Respiratory symptoms were observed in 10 of the 39 cases (26%) and a virus was identified in 8 and 6 of these cases by PCR and culture, respectively. The PCR detected the respiratory infection a median of 8 days before culture. However, the morbidity of the respiratory infections was generally mild, and no mortality was observed. Additionally all infections were observed pretransplant or after discharge; no nosocomial infections were observed.

CONCLUSIONS

The real time PCR assay is more rapid and sensitive than culture and could be used to screen patients before transplant or as respiratory symptoms present for timely diagnosis.

Levels of total fungus and Aspergillus on a pediatric hematopoietic stem cell transplant unit

The purpose of this descriptive study was to determine the levels of total fungus (TF) and Aspergillus in a pediatric hematopoietic stem cell transplant (HSCT) unit. One hundred twenty air samples and 120 floor samples were collected from the same locations in 10 patient rooms and bathrooms for 4 consecutive days. The count in colony-forming units of TF and Aspergillus from each of the samples was measured by the institution's mycology laboratory. Means, standard deviations, minimum values, and maximum values were determined for levels of TF and Aspergillus from different locations and on different days in the air and on the floor. Determination of a mean value of TF and Aspergillus for each room allowed for analysis of mean values of TF and Aspergillus for sample category, room side, room type, and room status. After visual examination of the mean values for the air samples collected, it was determined that the TF and Aspergillus in the air were less than the institution's acceptable air baseline standard. t tests and analysis of variance were used to verify the findings.

Pulmonary complications of solid organ and hematopoietic stem cell transplantation

The ability to successfully transplant solid organs and hematopoietic stem cells represents one of the landmark medical achievements of the twentieth century. Solid organ transplantation has emerged as the standard of care for select patients with severe vital organ dysfunction and hematopoietic stem cell transplantation has become an important treatment option for patients with a wide spectrum of nonmalignant and malignant hematologic disorders, genetic disorders, and solid tumors. Although advances in surgical techniques, immunosuppressive management, and prophylaxis and treatment of infectious diseases have made long-term survival an achievable goal, transplant recipients remain at high risk for developing a myriad of serious and often life-threatening complications. Paramount among these are pulmonary complications, which arise as a consequence of the immunosuppressed status of the recipient as well as from such factors as the initial surgical insult of organ transplantation, the chemotherapy and radiation conditioning regimens that precede hematopoietic stem cell transplantation, and alloimmune mechanisms mediating host-versus-graft and graft-versus-host responses. As the population of transplant recipients continues to grow and as their care progressively shifts from the university hospital to the community setting, knowledge of the pulmonary complications of transplantation is increasingly germane to the contemporary practice of pulmonary medicine.

Collectins

Collectins are a family of collagenous calcium-dependent defense lectins in animals. Their polypeptide chains consist of four regions: a cysteine-rich N-terminal domain, a collagen-like region, an alpha-helical coiled-coil neck domain and a C-terminal lectin or carbohydrate-recognition domain. These polypeptide chains form trimers that may assemble into larger oligomers. The best studied family members are the mannan-binding lectin, which is secreted into the blood by the liver, and the surfactant proteins A and D, which are secreted into the pulmonary alveolar and airway lining fluid. The collectins represent an important group of pattern recognition molecules, which bind to oligosaccharide structures and/or lipid moities on the surface of microorganisms. They bind preferentially to monosaccharide units of the mannose type, which present two vicinal hydroxyl groups in an equatorial position. High-affinity interactions between collectins and microorganisms depend, on the one hand, on the high density of the carbohydrate ligands on the microbial surface, and on the other, on the degree of oligomerization of the collectin. Apart from binding to microorganisms, the collectins can interact with receptors on host cells. Binding of collectins to microorganisms may facilitate microbial clearance through aggregation, complement activation, opsonization and activation of phagocytosis, and inhibition of microbial growth. In addition, the collectins can modulate inflammatory and allergic responses, affect apoptotic cell clearance and modulate the adaptive immune system.

Diagnostic Invasive Procedures in Diffuse Infiltrative Lung Diseases

The diagnosis of infiltrative diffuse lung disease may require invasive procedures after all noninvasive tools have failed. The clinical context in which these diseases develop and the radiological patterns are crucial for defining the timing and the methods to be used. Immunocompromised hosts are usually acutely ill with fever, cough, shortness of breath, and often with progressive hypoxemia. In this context a prompt diagnosis is necessary to decrease mortality. Bronchoalveolar lavage [especially in cases that show ground-glass attenuation or alveolar opacification in high-resolution CT scan (HRCT)] is the most important invasive procedure allowing the identification of infectious agents, neoplastic elements and characteristic cytological and phenotypical profiles (for drug injury) in the majority of cases. Less frequently transbronchial lung biopsy, transbronchial needle aspiration and biopsy or surgical lung biopsy are necessary. In immunocompetent patients the clinical spectrum of diffuse lung disease is quite broad. Furthermore, in the last two decades HRCT, used in conjunction with clinical and other noninvasive investigative modalities, has increased the accuracy of diagnosis for some diseases without the need of surgical biopsy. Also in these patients bronchoalveolar lavage, frequently in combination with transbronchial lung biopsy, is sufficient to achieve a definitive diagnosis in the majority of cases. Surgical lung biopsy is, however, still relevant in cases with idiopathic interstitial pneumonias. In this article invasive diagnostic procedures in patients with diffuse lung infiltrates are discussed from the perspective of their clinical context and their imaging characteristics.

The natural history of respiratory syncytial virus infection in cancer and transplant patients: implications for management

Respiratory syncytial virus (RSV) has been reported to cause severe morbidity and mortality among cancer patients receiving chemotherapy with or without autologous peripheral blood stem cell transplantation (APBSCT). However, little is known about the natural history of this infection in these patients, and current standard practice, aerosolized ribavirin plus intravenous immunoglobulin (IVIG), is extremely expensive, difficult to use, and not supported by controlled clinical trials. The purpose of this observational study was to determine the frequency, seasonality, morbidity, and mortality of RSV infection in a group of cancer patients receiving cytotoxic chemotherapy with neither ribavirin nor IVIG treatment. During the period of October 3, 1997, through October 14, 1998, 190 cancer patients (median age, 58 years; 71 women) underwent viral nasopharyngeal washing prior to chemotherapy. Multiple myeloma (MM) accounted for most patients (147, 77%). RSV was recovered from cultures taken from 71 patients (37%) throughout the year, although more frequently during fall and winter seasons (P < .001) than spring and summer. Serious respiratory complications developed in 19 (27%) of 71 RSV-positive patients versus 24 (20%) of 119 patients whose RSV cultures were negative (P = .384). The presence of renal failure or increased lactate dehydrogenase (LDH) prior to chemotherapy and the development of mucositis were the only predictive factors for severe respiratory complications. Recovery of RSV from nasopharyngeal washings among cancer patients is common, occurs throughout the year, and does not appear to increase serious morbidity or mortality. RSV infection may not necessarily be a contraindication for APBSCT or an indication for therapy with aerosolized ribavirin and IVIG.

Failure to eradicate AIDS-associated primary effusion lymphoma with high-dose chemotherapy and autologous stem cell reinfusion: case report and literature review

Primary effusion lymphoma (PEL), also known as body cavity-based lymphoma, is a newly recognized AIDS-related malignancy that is etiopathologically linked to Kaposi's sarcoma (KS)-associated human herpes virus type 8 (HHV-8). PEL is characterized by presentation in serous body cavities without identifiable tumor masses. Tumor cells have high-grade morphologic features, an indeterminate immunophenotype, B-lineage genotype, and contain HHV-8 and often Epstein-Barr virus. PEL rarely responds to systemic chemotherapy. Herein, we describe what we believe is the first patient with AIDS-associated PEL to be treated with high-dose chemotherapy and autologous stem cell reinfusion. Treatment was well tolerated but the patient succumbed to progressive cancer. Our experience with this patient serves to underscore the high mortality rate associated with this unique neoplasm.

Biatrial aspergillosis in a patient with immunocompetency

A 24-year-old man presented with a 24-hour history of pain and numbness in his left arm. The patient's clinical presentation of peripheral embolism was corroborated by angiography. Echocardiographic study showed masses in both right and left atria. Pathologic specimen from the embolus confirmed the diagnosis of aspergillosis.

Transfusion-related acute lung injury (TRALI) following allogeneic stem cell transplant for acute myeloid leukemia

Transfusion-related acute lung injury (TRALI) is a serious complication of transfusion characterized by dyspnea, hypoxemia, hypotension, fever, and bilateral pulmonary infiltrates. Although the frequency is estimated at 1/1,120 to 1/5,000 transfusions, few cases have been reported after hematopoietic stem cell transplant. We report a case occurring in an allogeneic transplant recipient who developed acute respiratory distress and bilateral pulmonary infiltrates 2 hr after a platelet transfusion due to the presence of anti granulocyte antibody HNA-3a in the product. As there is a wide differential diagnosis for pulmonary infiltrates developing post transplant, TRALI may be under-recognized and should be considered in this setting.

Capnography in Non-Tracheally Intubated Emergency Patients as an Additional Tool in Pulse Oximetry for Prehospital Monitoring of Respiration

Victims of minor trauma transported by paramedic-based rescue systems are usually monitored with pulse oximetry. Under the difficult surroundings of prehospital trauma care, pulse oximeters show considerable periods of malfunction. We tested the hypothesis that capnography is a good, easy to use tool for monitoring in nonintubated trauma victims. Seventy nonintubated trauma victims were included in this study. Vital variables and number and time of malfunctions were sampled for oximeter and capnometer recordings. Total number of alerts (63 versus 10), number of alerts per patient (3.3 [1.9] versus 0.3 [0.9]) (mean [SD]), total time of malfunction (191.5 [216.7] s versus 11.8 [40.2] s), time of malfunction per alarm (58.3 [71.4] s versus 5.5 [14.6] s), and the percentage of malfunction time during transport (13.2% [15.3%] versus 0.8% [2.8%]) differed significantly (P < 0.01) between oximetry and capnography. Although pulse oximetry is a standard method of monitoring in emergency care, we found capnography to be helpful as a monitoring device. We consequently recommend the use of capnography on transport as an additional monitoring tool to reduce periods lacking supervision of the vital variables.

IMPLICATIONS

Capnography is a useful tool to improve respiratory monitoring in nonintubated trauma victims on emergency transport and an easy to use supplement to pulse oximetry.

Dimensions of Neutropenia in Adult Cancer Patients

Neutropenia is a common and dangerous toxicity of cancer therapy that profoundly affects patients' lives. Neutropenia is typically defined by the numerical value of the absolute neutrophil count. However, considering neutropenia exclusively as the numerical value of the absolute neutrophil count limits its conceptualizations to physiologically related aspects, minimizes its complexities, and neglects dimensions of human response and the patient experience. This article offers a dimensional analysis of neutropenia derived from 42 research and clinical articles. Schatzman's dimensional analysis methods were applied to the literature to identify aspects of this phenomenon lying beyond its numerical boundaries. Dimensions of neutropenia that emerged were sorted into categories of perspective, context, conditions, processes, and consequences. The presence of the same dimension in more than 1 category and the circuitous relationships among categories begin to explicate the complexity and gravity of neutropenia. Articulation of these dimensions is necessary to assemble the beginnings of a theoretical understanding of neutropenia, which is crucial for the development and application of knowledge to research and practice. Limitations evident in the literature illuminate the urgent need for research into the psychosocial as well as physiologic dimensions of neutropenia.

Increased Exhaled Nitric Oxide Following Autologous Peripheral Hematopoietic Stem-Cell Transplantation

BACKGROUND

Increased production of nitric oxide (NO) and oxidative stress following bone marrow transplantation may play a role in the pathogenesis of idiopathic pneumonia syndrome (IPS). We hypothesize that patients who received high-dose chemotherapy followed by autologous peripheral hematopoietic stem-cell transplantation (APHSCT) have increased exhaled NO.

METHOD

We measured exhaled lower respiratory tract NO concentration with a chemiluminescent NO analyzer during a slow vital capacity maneuver against a positive pressure of 16 cm H(2)O at an expiratory flow rate of 50 mL/s in 20 female patients who received high-dose chemotherapy (cyclophosphamide, carmustine, and cisplatin) followed by APHSCT for the treatment of stage III or IV breast carcinoma. Pulmonary function tests were performed, and exhaled NO measurements and clinical and laboratory data were obtained before transplantation and at every 6-week visit after transplantation for 24 weeks.

RESULTS

All study patients had evidence of IPS with dyspnea and reduction in diffusion capacity of the lung for carbon monoxide (DLCO). Lower respiratory tract exhaled NO was significantly higher after APHSCT and during the 6 months of follow-up. Mean (+/- SD) exhaled NO increased from (mean +/- SD) 12.54 +/- 1.32 parts per billion (ppb) before APHSCT to 21.26 +/- 1.94 ppb at 6 weeks (p = 0.099), 21.26 +/- 1.94 ppb (p = 0.006) at 12 weeks, 24.62 +/- 2.55 ppb (p = 0.012) at 18 weeks, and 25.28 +/- 3.31 ppb (p = 0.013) at 24 weeks (all p values were compared to baseline). There was a strong negative correlation between DLCO and exhaled NO (regression coefficient - 0.60, p = 0.01).

CONCLUSION

Lower respiratory tract concentration of exhaled NO is significantly increased following APHSCT and correlates with reduction in DLCO. Increase in lower respiratory tract concentration of NO is a potential marker of IPS.

Pulmonary function after autologous bone marrow transplantation in children: a long-term prospective study

We performed serial pulmonary function tests (PFTs) consisting of spirometry and diffusing capacity in 26 children after BMT. The median follow-up was 10 years. The influence of total body irradiation (TBI) on long-term pulmonary function was of particular interest. In the 20 children who had received TBI, after an initial decrease the PFTs showed recovery, but the mean lung volumes were still significantly decreased 5 years after BMT at 10% below baseline. The proportions of children with restrictive impairment 5 and 10 years after BMT were 20 and 21%, respectively. Only one child was diagnosed with obstructive impairment. The proportions of children with isolated diffusing impairment at 5 and 10 years were 7/20 (35%) and 7/13 (54%), respectively. Six children had received chemotherapy only and showed isolated diffusing impairment as the only long-term sequela in 4/5 and 1/3 at 5 and 10 years. Our main finding was that there was little change in PFTs 1-10 years after BMT. TBI was associated with persistently decreased lung volumes in a proportion of patients, whereas chemotherapy also might have been of importance for the development of impaired gas exchange.

Late-onset noninfectious pulmonary complications after allogeneic stem cell transplantation are significantly associated with chronic graft-versus-host disease and with the graft-versus-leukemia effect

Late-onset noninfectious pulmonary complications (LONIPCs) occurring beyond 3 months after allogeneic stem cell transplantation (allo-SCT) have become recognized as life-threatening complications, and they reduce the recipient's quality of life. However, the pathogenesis and optimal treatment for LONIPCs are still unclear. In this study, we retrospectively analyzed the incidence and outcome of LONIPCs among allo-SCT recipients. Between October 1993 and September 2001, 96 patients underwent allo-SCT and 76 patients who survived and were free of disease for more than 3 months after SCT were enrolled. Among the 76 patients, 18 patients (23.7%) developed LONIPCs at a median interval of 227 days after allo-SCT (range, 91-1105 days). The patients with LONIPCs were subclassified into those with bronchiolitis obliterans (BO) (6 patients), with interstitial pneumonia (IP) (11 patients), or with both BO and IP (1 patient). The presence of extensive chronic graft-versus-host disease (GVHD) was significantly associated with the development of LONIPCs (P =.0008). Liver or skin involvement in chronic GVHD was not associated, but sicca syndrome was significantly associated with the development of LONIPCs (P <.0001). Most of the IP patients (58.3%) responded well to immunosuppressive treatment, while BO patients did not respond to the therapy. Eight of the 18 patients with LONIPCs died. The major cause of death was respiratory failure (62.5%). The relapse rate of primary malignant disease in the LONIPC patients was significantly lower than that of non-LONIPC patients (1 of 17 [5.9%] versus 16 of 52 [30.8%]; P =.0387). These results indicate that the development of LONIPCs was strongly associated with chronic GVHD and especially with sicca syndrome and the graft-versus-leukemia (GVL) effect.

Coronavirus 229E-related pneumonia in immunocompromised patients

Coronaviruses strains 229E and OC43 have been associated with various respiratory illnesses ranging from the self-resolving common cold to severe pneumonia. Although chronic underlying conditions are major determinants of severe respiratory virus infections, few data about coronavirus-related pneumonia in immunocompromised patients are available. Here we report 2 well-documented cases of pneumonia related to coronavirus 229E, each with a different clinical presentation. Diagnosis was made on the basis of viral culture and electron microscopy findings that exhibited typical crown-like particles and through amplification of the viral genome by reverse transcriptase-polymerase chain reaction. On the basis of this report, coronaviruses should be considered as potential causative microorganisms of pneumonia in immunocompromised patients.

Small-volume frequency-domain oximetry: phantom experiments and first in vivo results

We describe a new method to determine the oxygen saturation and the total hemoglobin content of tissue in vivo absolutely at small source-detector separations (<10 mm). Phase and mean intensity of modulated laser light of various wavelengths was measured at several predetermined source-detector separations in the frequency domain. From these measured quantities, the absorption coefficient was derived using the modified time-integrated microscopic Beer-Lambert law (MBL). In addition, the interaction volume of the photons was determined using a multi-layer Monte-Carlo model of human skin. To evaluate the method, we employed homogenous solid phantoms (consisting of TiO2 particles embedded in resin) with mean scattering and absorbing properties comparable to those of human skin. Furthermore, in vivo measurements were performed in a healthy volunteer to demonstrate that the technique is applicable for the determination of the oxygen saturation and the total hemoglobin content in the skin in vivo. The proposed technique is especially suited for the on-line determination of the oxygen saturation and total hemoglobin content in applications where small applicators are required (e.g., fetal oxygen monitoring sub partu).

Diffuse alveolar hemorrhage following allogeneic bone marrow transplantation in children

BACKGROUND

Diffuse alveolar hemorrhage (DAH) is a frequent life-threatening complication of bone marrow transplantation (BMT) in adults. This noninfectious pulmonary disorder is rarely reported following BMT in neonates and children.

STUDY OBJECTIVES

To review the clinical features and course of children who underwent allogeneic BMT and developed DAH in the posttransplant period.

DESIGN

A retrospective 6-year chart review.

SETTING

Pediatric ICU in a university hospital.

PATIENTS AND INTERVENTIONS

At total of 138 children who had undergone allogeneic BMT for nonmalignant (n = 66) or malignant (n = 72) diseases.

MEASUREMENTS AND RESULTS

Six of 138 children (4.3%) aged 2 months to 10 years (male/female ratio, 1:1) developed DAH. Each had a fulminant course with rapidly developing severe respiratory failure, mandating mechanical ventilation within 24 h following symptom onset. They were all treated with methylprednisolone, 6 mg/kg/d for 3 days. Only one child survived, and there have been no sequelae at 2 years post-BMT. Four children died of respiratory causes, and one died of multiorgan failure.

CONCLUSIONS

DAH is a potentially fatal respiratory complication that should be included early in the differential diagnosis of acute respiratory failure in children following allogenic BMT for both malignant and nonmalignant diseases. Therapy with high doses of steroids apparently do not affect the course of the disease.

Life-threatening pulmonary hemorrhages post bone marrow transplantation in Hurler syndrome. Report of three cases and review of the literature

Hurler syndrome (MPS-IH) is an autosomal recessive mucopolysaccharide storage disorder caused by deficiency of lysosomal alpha-L-iduronidase (IDU) enzyme activity. This results in accumulation of heparan sulfate and dermatan sulfate substances. Untreated children develop progressive developmental deterioration and multisystem morbidity with a median survival of 5 years. Allogeneic bone marrow transplantation (BMT) is the only long-lasting treatment that ameliorates or halts the aggressive course of the disease. Pulmonary hemorrhage (PH) is an unusual complication of BMT and has not been previously reported in MPS-IH post-BMT. We report three children with MPS-IH with life-threatening PH around the time of engraftment. All needed intensive-care support and one child developed recurrent PH that required prolonged ventilation.

Infectious pulmonary nodules in immunocompromised patients: usefulness of computed tomography in predicting their etiology

PURPOSE

To review the high-resolution computed tomography (CT) findings in immunocompromised patients who had nodular opacities and a proven diagnosis to determine whether the various infectious pulmonary nodules have distinguishing features on CT.

MATERIALS AND METHODS

The high-resolution CT scans obtained in 78 immunocompromised patients with solitary or multiple nodular opacities of proven infectious etiology were reviewed retrospectively by 2 independent thoracic radiologists. Patients whose predominant abnormality consisted of branching linear or nodular opacities (tree-in-bud pattern) characteristic of infectious bronchiolitis and endobronchial spread of tuberculosis were excluded. The CT scans were assessed for the presence, appearance, size, and distribution of parenchymal nodules. Relations between findings at CT and the different infectious etiologies of nodules were assessed with regression analysis. Agreement between the 2 observers was assessed using the kappa statistic.

RESULTS

The infectious causes included mycobacteria (n = 24), fungi (n = 22), bacteria (n = 20), and viruses (n = 12). Multivariate analysis demonstrated that a diameter <10 mm was the only independent predictor of etiology (P < 0.0001) and that patients whose nodules all measured less than 10 mm in diameter were most likely to have a viral infection. Nodules limited in size to less than 10 mm in diameter were seen in 83% of viral infections compared with 5% of bacterial infections (odds ratio [OR] = 95.0; 95% confidence interval (CI): 6.08-4,321.5, P < 0.0001), 0% of mycobacterial infections (OR = 91.7; 95% CI: 7.21-4,090.22, P < 0.0001), and 14% of fungal infections (OR = 31.67; 95% CI: 3.56-375.09, P = 0.0003).

CONCLUSION

Although some overlap exists, nodule size is helpful in the differential diagnosis of infectious causes of nodules in immunocompromised patients. Patients whose nodules are all less than 10 mm in diameter are most likely to have a viral infection.

Pulmonary complications following bone marrow transplantation

Pulmonary complications account for significant morbidity and mortality in patients following bone marrow transplants (BMT). They are distinct from other immunosuppressed patients in that there is a predictable course of immunosuppresion and therefore of likely pulmonary complications. This is important when interpreting abnormal radiology as the predictable time course will enable narrowing the differential diagnoses to certain pulmonary complications that characteristically occur at a particular time following BMT. Early recognition and correct treatment of the pulmonary complications should minimize the significant mortality and morbidity. This review aims to discuss the role of radiology in the diagnosis and management of pulmonary complications following BMT.

Granulomatous Pneumocystis carinii pneumonia complicating hematopoietic cell transplantation

Pneumocystis carinii pneunonia (PCP) is associated with a wide spectrum of clinical and histopathological presentations. While granulomatous PCP uncommonly occurs in AIDS patients, it is extremely rare in other non-AIDS immunocompromised patients. We identified three patients who developed granulomatous PCP after bone marrow or blood stem cell transplantation. In all cases, fiberoptic bronchoscopy with bronchoalveolar lavage was non-diagnostic, and an open lung biopsy was required for diagnosis. All patients were successfully treated with trimethoprim-sulfamethoxazole. The histological appearance varied from an ill-defined granulomatous pneumonia to well-formed necrotizing granulomas. The typical intraalveolar eosinophilic frothy exudate was absent. Often sparsely distributed, the organisms were detected by GMS and immunohistochemical stains for P. carinii. No other pathogens were identified by additional histochemical stains or by microbiological cultures. Awareness of this unusual granulomatous tissue response to P. carinii and initiation of specific treatment can lead to successful resolution of this potentially lethal infection.

Fungal pneumonias in transplant recipients

Fungi are ubiquitous in the environment. Opportunistic fungal pneumonias in the immunocompromised host continue to increase most commonly due to Aspergillus sp. Affected patients are usually hematopoietic stem cell and lung transplant recipients. Clinical presentation is protean, and the diagnosis is challenging. Culture of respiratory specimens has limited utility. The detection of circulating fungal antigens and DNA seems promising, but more studies are needed. Value of prophylactic strategies or preemptive therapy remains contentious. New antifungal drugs for managing invasive pulmonary aspergillosis continue to emerge, with better safety, efficacy, and pharmacologic profiles.

Infection of mesothelial cells with human herpes virus 8 in human immunodeficiency virus-infected patients with Kaposi's sarcoma, Castleman's disease, and recurrent pleural effusions

Recurrent pleural effusions are common complications of hospitalized patients with human immunodeficiency virus (HIV) infection and may pose difficult diagnostic dilemmas. A common cause of recurrent pleural effusions in up to 30% of HIV-seropositive patients is pulmonary involvement by Kaposi's sarcoma, a human herpesvirus 8 (HHV 8)-related neoplasm. The pathogenesis of these effusions is unclear. These recurrent effusions, although benign, have shown significant mesothelial atypia/reactive changes of uncertain etiology. We attempted to evaluate these effusions morphologically and molecularly for the presence of HHV 8, with particular attention to mesothelial cells. All recurrent pleural effusions, as defined by any effusion tapped for cytological examination on more than two occasions, in HIV-positive patients at the National Institutes of Health were examined from 1998 to the present. Cases were stratified according to patients with and without histologically confirmed HHV 8 disease manifestations. Five patients with HHV 8 diseases (four with disseminated Kaposi's sarcoma and one with Castleman's disease) were identified. As a control group, five effusions from HIV-seropositive patients without known HHV 8-related diseases were identified. Cytological examination of effusions in patients with HHV 8-related diseases demonstrated atypical/markedly reactive mesothelial cells accompanied by a polymorphous background of lymphocytes. Molecular studies for B- and T-cell clonality in microdissected whole samples showed no definitive clones in these cases. Conversely, polymerase chain reaction (PCR) studies for the HHV 8 virus was positive in these samples. PCR studies on pure populations of microdissected mesothelial cells from the HHV 8-related effusions were positive for HHV 8 sequences, whereas those from HIV patients with non-HHV 8 related diseases were negative. Immunohistochemistry for HHV 8 (monoclonal antibody to latent nuclear antigen (LNA-1; ORF-73) on cellblock material demonstrated scattered positive mesothelial cells in three of the five cases of HHV 8-associated effusions. HHV 8 has been recently implicated in the pathogenesis of Kaposi's sarcoma and primary effusion lymphoma. Mesothelial cells in recurrent pleural effusions from patients with Kaposi's sarcoma and Castleman's disease appear to be infected with HHV 8. Additional studies need to be done to define the role of mesothelial cell infection in the pathogenesis of these HHV 8-associated effusions and define the prognostic significance.

Calibration of three capnographs for use with helium and oxygen gas mixtures

Capnography is considered essential in the management of mechanically-ventilated patients. Helium, as an adjunct to mechanical ventilation, is the subject of renewed interest and used increasingly. However, helium affects the performance of infrared capnometry. We constructed a simple device to generate variable mixtures of helium, oxygen and carbon dioxide within the normal physiological range, and tested the performance of two side-stream and one in-line capnographs. We found that addition of helium to the gas mixture caused all three capnographs to underestimate the concentration of carbon dioxide. The underestimation increased as the proportion of helium increased. The maximum underestimation (30%) occurred in a 79:21 helium/oxygen mixture.

Comparison of end-tidal CO2 and Paco2 in children receiving mechanical ventilation

OBJECTIVE: To determine whether end-tidal CO(2) (Petco(2)) measurement provides a reliable estimate of ventilation in critically ill children who are mechanically ventilated. DESIGN: Prospective, nonrandomized, consecutive enrollment study. SETTING: A university-affiliated children's hospital pediatric intensive care unit. PATIENTS: All intubated, mechanically ventilated pediatric patients. INTERVENTIONS: All Petco(2)-Paco(2) pairs were from patients ventilated with a Servo 300 Ventilator (Siemens-Elema AB, Stockholm, Sweden). When a blood gas sample was obtained, Petco(2) as measured by a continuous mainstream Petco(2) capnograph was recorded. Measurements: The results of blood gas measurements and corresponding Petco(2) measurements were recorded. Demographic data and primary diagnosis were noted. Petco(2)-Paco(2) pairs obtained from patients with intracardiac shunts or obtained during high-frequency oscillation or extracorporeal membrane oxygenation at the time of measurement were excluded from analysis. Linear regression was used to analyze Petco(2)-Paco(2) pairs. Repeated measure analysis of variance with the mixed-model algorithm in SAS software (SAS Institute, Carey, NC) was used to analyze the trend in the Petco(2) and Paco(2) relationship. Chi-square was used to analyze categorical data. Statistical significance was considered p <.05. RESULTS: A total of 129 children were enrolled, and 1708 paired Paco(2) and Petco(2) measurements were recorded. The mean age +/- sd was 4.1 +/- 5.6 yrs. Paco(2) positively correlated with Petco(2). The linear equation for the regression analysis was y = 0.71x (95% confidence interval, 0.69-0.73) + 8.93 (95% confidence interval, 7.89-9.97), with r (2) =.716 and p <.001. The Petco(2)-Paco(2) difference was </=5 mm Hg (0.67 kPa) in 54% and </=10 mm Hg (1.33 kPa) in 80% of paired data. Increased lung disease had a negative effect on Petco(2) correlation with Paco(2). A total of 223 of 640 (35%) blood gases (defined by Pao(2)/Fio(2) ratio of <200) had >10 mm Hg (1.33 kPa) difference between the Petco(2) and Paco(2). However, only 111 of 1068 (10%) Petco(2)-Paco(2) pairs had a difference of >10 mm Hg (1.33 kPa) in patients with a Pao(2)/Fio(2) ratio >200. Trend analysis showed the Petco(2)-Paco(2) difference increased with increasing duration of mechanical ventilation. CONCLUSION: In most intubated, mechanically ventilated infants and children, Petco(2) reliably estimates ventilation.

Open lung biopsy in bone marrow transplant recipients has a poor diagnostic yield for a specific diagnosis

The diagnostic yield of open lung biopsy (OLB) in bone marrow transplantation (BMT) recipients having pulmonary infiltrates has not been evaluated recently. Therefore, we reviewed our 2-year experience (1998-99) with such patients at The University of Texas M. D. Anderson Cancer Center. We found 12 BMT recipients who underwent OLB analysis for the evaluation of pulmonary infiltrates. A treatable infectious etiology leading to the initiation or modification of antimicrobial agent administration was found in only two patients having bilateral nodular disease and one having bilateral parenchymal infiltrates. We conclude that OLB in BMT patients having diffuse pulmonary infiltrates has a low diagnostic yield for treatable infectious etiologies.

The clinical spectrum of pulmonary aspergillosis

Aspergillus is a ubiquitous fungus that causes a variety of clinical syndromes in the lung, ranging from aspergilloma in patients with lung cavities, to chronic necrotizing aspergillosis in those who are mildly immunocompromised or have chronic lung disease. Invasive pulmonary aspergillosis (IPA) is a severe and commonly fatal disease that is seen in immunocompromised patients, while allergic bronchopulmonary aspergillosis is a hypersensitivity reaction to Aspergillus antigens that mainly affects patients with asthma. In light of the increasing risk factors leading to IPA, such as organ transplantation and immunosuppressive therapy, and recent advances in the diagnosis and treatment of Aspergillus-related lung diseases, it is essential for clinicians to be familiar with the clinical presentation, diagnostic methods, and approach to management of the spectrum of pulmonary aspergillosis.

Diffuse alveolar hemorrhage in pediatric hematopoietic cell transplant patients

OBJECTIVE

Diffuse alveolar hemorrhage (DAH) is defined as a syndrome of hypoxia, dyspnea, infiltrates on chest radiograph, and bloody fluid on successive bronchoalveolar lavages without apparent infection. Minimal experience has been reported with DAH after hematopoietic cell transplant (HCT) in children. We reviewed the incidence, management and outcome of DAH in a pediatric HCT population.

METHODS

Retrospective review of 138 patients undergoing allogeneic (n = 89) or autologous (n = 49) HCT at a referral children's medical center between January 1996 and April 2000.

RESULTS

Seven (5.1%) of 138 patients met criteria for DAH; all were allogeneic recipients. Mean age of DAH patients was 11 years (range: 1.4-15.2). Median onset of DAH following HCT was day 24 (range: 10-50), median day of engraftment day 20 and white blood cell count 0.54 x 10(9)/L (range: < 0.1-7.03), with no difference between survivors and nonsurvivors. All patients developed clinical respiratory failure and 6 required intubation, with PaO(2)/fraction of inspired oxygen <200. Patients were intubated a median of 12 days (range: 1-75). All patients experienced >1 episode of bleeding and 3 patients required reintubation after successful extubation resulting from recurrent DAH. Bronchoalveolar lavage fluid cultures were negative for viruses, bacteria and fungi. All DAH patients received steroids. Three patients died with progressive pulmonary failure and other organ system involvement. Four of 7 DAH patients (57%) survived to discharge, but 3 died from disease relapse at days 116, 138, and 273 post-HCT.

CONCLUSION

DAH occurred more frequently in allogeneic HCT recipients compared with autologous recipients. Onset of DAH coincided closely with white blood cell engraftment. Although associated with significant respiratory failure and need for mechanical ventilation, HCT patients can survive DAH.

Mycobacterium haemophilum infections in heart transplant recipients: case report and review of the literature

Non-tuberculous mycobacteria are becoming increasingly important pathogens among transplant recipients. We report a case of disseminated Mycobacterium haemophilum infection in a heart transplant recipient, manifesting as cellulitis, subcutaneous nodules, septic arthritis, and pneumonitis. Our case illustrates diverse challenges in the identification and treatment of this pathogen, such as its unique culture requirements and variable antimicrobial susceptibilities. Heightened clinical suspicion is necessary to establish a timely diagnosis so that optimal treatment can be administered.

Invasive airway aspergillosis with new airflow obstruction mimicking post-BMT bronchiolitis obliterans

A 52-year-old male with severe gastrointestinal graft-versus-host disease (GVHD), developed dyspnea and irreversible airflow obstruction, 11 weeks post-allogeneic bone marrow stem cell transplantation. Based on the clinical picture and presence of 'mosaic attenuation' pattern on chest high-resolution computerized tomography (HRCT), he was presumed to have bone marrow transplantation-related bronchiolitis obliterans. Post-mortem examination revealed invasive airway aspergillosis with no evidence of bronchiolitis obliterans.

Pulmonary complications in bone marrow transplantation

This article reviews the most common pulmonary complications after bone marrow transplantation (BMT) and their radiologic presentations. An approach emphasizing the common complications that occur in relation to the immunosuppression recovery timeline is presented. An update on newer techniques of marrow transplantation and preparatory regimen drugs will be discussed. These newer techniques may have an effect on the radiologic appearance of some BMT complications. The diagnostic approach, management, and some evolving therapies of BMT patients with pulmonary complications will also be discussed.

Treatment of right heart thromboemboli

BACKGROUND

The presence of right heart thromboemboli complicating pulmonary thromboemboli carries with it an increased mortality rate compared to pulmonary thromboemboli alone, but little is known about the optimal management of this difficult clinical situation. This fact is highlighted in the case study of a patient with a 19-cm right atrial thrombus complicating bilateral pulmonary thromboemboli.

STUDY OBJECTIVES

We sought to determine the effects of anticoagulation therapy, thrombolysis, and surgical embolectomy on mortality rate in patients with right heart thromboemboli.

DESIGN

Retrospective analysis of all reported cases in the English language literature (1966 to 2000) of right heart thromboembolism in which age, sex, therapy, and outcome were reported.

MEASUREMENTS AND RESULTS

We analyzed 177 cases of right heart thromboembolism. Pulmonary thromboembolism was present in 98% of the cases. The patients were evenly divided by gender with an average age of 59.8 years (SD, 16.6 years) years. Dyspnea (54.2%), chest pain (22.6%), and syncope (17.5%) were the most common presenting symptoms. The treatments administered were none (9%), anticoagulation therapy (35.0%), surgical procedure (35.6%), or thrombolytic therapy (19.8%). The overall mortality rate was 27.1%. The mortality rate associated with no therapy, anticoagulation therapy, surgical embolectomy, and thrombolysis was 100.0%, 28.6%, 23.8%, and 11.3%, respectively. Using multivariate modeling with survival as the primary outcome, age and gender were not associated with mortality rate, but thrombolytic therapy was associated with an improved survival rate (p < 0.05) when compared either to anticoagulation therapy or surgery.

CONCLUSION

The presence of right heart thromboemboli may have diagnostic and therapeutic implications in pulmonary thromboembolism patients. A well-designed prospective, randomized trial is needed to determine the optimal treatment of right heart thromboemboli.

Early onset of acute immune-mediated lung injury in a child undergoing allogeneic peripheral blood transplantation

Animal models have recently clarified the lung injury after allogeneic hematopoietic transplantation. These works have confirmed the role of donor T lymphocytes in immune-mediated inflammatory reactions in the lung. We report here a fatal case of a 3-year-old child who developed acute respiratory failure coinciding with the onset of hyper-acute graft versus host disease (aGVHD) after allogeneic peripheral stem cell transplantation. aGVHD was refractory to treatment and the patient died on day +28. Lung necropsy showed interstitial pneumonia and peribronchial and perivascular infiltration by mononuclear cells, with no viral inclusions. These findings are not specific but have been found by some authors in animal models with acute immune-mediated lung injury related with donor T lymphocytes. Immune-mediated lung injury, as defined by animal models, should be considered in patients with severe signs of systemic aGVHD while excluding other known etiologies of pulmonary disease.

Transplant-related toxicity and mortality: an AIEOP prospective study in 636 pediatric patients transplanted for acute leukemia

Hematopoietic stem cell transplantation can cure high-risk acute leukemia (AL), but the occurrence of non-leukemic death is still high. The AIEOP conducted a prospective study in order to assess incidence and relationships of early toxicity and transplant-related mortality (TRM) in a pediatric population. Between 1990 and 1997 toxicities reported in eight organs (central nervous system, heart, lungs, liver, gut, kidneys, bladder, mucosa) were classified into three grades (mild, moderate, severe) and prospectively registered for 636 consecutive children who underwent autologous (216) or allogeneic (420) transplantation, either from an HLA compatible related (294), or alternative (126) donor in 13 AIEOP transplant centers. Overall, 47% of the patients are alive in CR (3-year EFS: 45.2%, s.e.: 2.1), 19% died in CR at a median of 60 days (90-day TRM: 14.3%, s.e.: 1.4), 34% relapsed. Toxicity of any organ, but mucosa and gut, was positively correlated with early death; moderate and severe toxicity to heart, lungs, liver and kidneys significantly increased early TRM, with estimated relative risks of 9.1, 5.5, 2.7 and 2.8, respectively, as compared to absent or mild toxicity. Patients with grade III-IV aGVHD experienced more than double (56% vs. 19%) TRM than patients with grade 0-II aGVHD. A higher cumulative toxicity score, estimating the impact of toxicity on TRM, was significantly associated with transplantation from an alternative donor. Quantitative assessment allowed us to describe the extent to which 'grade' of toxicity and 'type' of involved organs were related to mortality and pre-transplant characteristics and yielded a prognostic score potentially useful to compare different conditioning regimens and predict probability of early death.

Diffuse lung disease in the immunocompromised non-HIV patient

Physicians are encountering an increasing number of patients with various levels of immunosuppression, such as patients with AIDS, transplant recipients, patients on immunosuppressive therapy, and those with congenital immune defects and malignancy. This results in a greater diagnostic dilemma for the medical community because of the significant increased risk of opportunistic infections and noninfectious complications, as well as a more aggressive clinical course with typical pathogens. [figure: see text] Furthermore, it is not just the pathogens that are changing but also their clinical and radiographic presentations. The radiologist has a large role in not only detecting the presence of disease but also in narrowing the differential possibilities. This can be an overwhelming task given the wide variety of presentations of diseases on radiographs. However, by understanding the level and degree of the patient's immunosuppression, the radiologist may anticipate the most likely pulmonary complications. By using the radiographic morphology, distribution, and temporal evolution of the abnormalities, a manageable differential diagnosis can be created for referring clinicians.