Imaging Features ofPneumocystis cariniiPneumonia

Pneumocystis jirovecii pneumonia presenting as a large pulmonary mass in a patient with AIDS

Pneumocystis jirovecii pneumonia typically presents with diffuse bilateral infiltrates or ground-glass opacities. However, the radiographic pattern may be atypical. We report a case of a woman in her 40s who presented with multiple pulmonary masses and prolonged symptoms of non-productive cough, generalised weakness and fatigue. Serial chest CT performed prior to her presentation showed a large right lower lobe lung mass with multiple additional bilateral pulmonary nodules. Her workup revealed a new diagnosis of AIDS. Pathology of several CT-guided needle biopsies was consistent with Pneumocystis which was confirmed by microbial DNA sequencing. No additional pathogens were identified. Her clinical symptoms and radiographs improved significantly with trimethoprim-sulfamethoxazole and treatment of her HIV infection. Clinicians should evaluate for underlying immunodeficiency and seek infectious disease and pulmonary consultation early for consideration of alternative diagnoses when patients present with cough, dyspnoea and atypical chest radiographs, and initial pathological examination is unrevealing.

Development and Validation of a Diagnostic Nomogram for Pneumocystis jirovecii Pneumonia in Non-HIV-Infected Pneumonia Patients Undergoing Oral Glucocorticoid Treatment

Purpose

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic but potentially fatal infection with increasing prevalence in HIV-free patients. Glucocorticoid therapy is one of the most important risk factors for PJP. The delay in diagnosis contributes to poor outcomes. Hence, the aim of this study was to develop and validate a nomogram for the diagnosis of PJP in patients with non-HIV-infected pneumonia who are undergoing oral glucocorticoid treatment.

Patients and Methods

This study was a retrospective, cross-sectional research. The development group included 434 patients who were admitted with pneumonia from 6 hospitals. Demographics, symptomatic features, laboratory and computed tomography data were analyzed using the least absolute shrinkage and selection operator (LASSO) to select potential diagnostic indicators. Binary logistic regression was used to develop a diagnostic nomogram. Another 119 patients with pneumonia admitted at Sichuan Provincial People's Hospital was used as the validation group. The diagnostic performance of the nomogram was measured by area under the receiver-operating-characteristics curve (AUC), calibration curves, and the net benefit by decision curve.

Results

PJP prevalence was 25.3% in the development group. LASSO regression revealed that age, lymphocyte count, fever, dry cough, respiratory failure, ground-glass opacity in lungs, glucocorticoid therapy duration, and immunosuppressive therapy were indicators of PJP. The nomogram showed robust discrimination, with an AUC of 0.82 (95% CI 0.77-0.86) in the development group and an AUC of 0.87 (95% CI 0.80-0.94) in the validation group, both showing acceptable calibration. In the decision curve analysis, our model consistently achieved a greater net benefit across almost all ranges of clinical thresholds.

Conclusion

We developed a nomogram with good diagnostic power for PJP diagnosis in pneumonia patients receiving oral glucocorticoids. This nomogram may help promote timely treatment of PJP and thus reduce the mortality rate in these patients.

Double Infection in a Patient with Chronic GVHD Post Allogeneic Transplant: “Hickam's Dictum” Trumps “Occam's Razor”!—A Case Report with Review of Literature

Double pneumonia with Pneumocystis jirovecii (PCP) and Mycobacterium tuberculosis (MTB) has been reported in patients with acquired immune deficiency syndrome. A similar immune-suppressed state exists in allogeneic transplant survivors treated for graft-versus-host disease (GVHD). The clinical features and imaging findings could be quite similar in both the etiologies. Reaching a timely diagnosis and initiation of appropriate therapy is essential to prevent complications. We report a patient who had concurrent PCP and MTB pneumonia while on treatment for chronic GVHD. We describe the diagnostic challenge, the treatment, and outcome of this patient. We intend to sensitize physicians to consider more than one etiology in this subset of patients.

Comparative study of the serum hepcidin level of patients with pneumonia in COVID-19 and Pneumocystis pneumonia

In the context of a pandemic caused by the SARS-CoV-2 virus, for a patient with respiratory symptoms and bilateral lung damage, COVID-19 becomes the first disease in the differential diagnostic search. Pneumonia in COVID-19 shares many characteristics with Pneumocystis pneumonia. One of the possible markers of the severe course of COVID-19 is hepcidin, a peptide hormone that negatively regulates iron metabolism. There are no data on the value of hepcidin in Pneumocystis pneumonia in the published scientific literature. The purpose of this study is to conduct a comparative analysis of hepcidin in the blood serum of patients with pneumonia in COVID-19 and Pneumocystis pneumonia to clarify their pathogenetic features. A case-control observational study was conducted, including 68 patients with pneumonia in COVID-19 and 44 patients with HIV infection and Pneumocystis pneumonia (PCP/HIV). Determination of hepcidin was carried out by ELISA using the ELISA Kit for Hepcidin. Statistical data processing was carried out using the MedCalc 19.2.6 software. Results. Comparative analysis of serum hepcidin levels in the study groups showed that hepcidin is statistically significantly higher in PCP/HIV than in COVID-19 - the median value is 22 times higher (p <0.0001). When examining the ROC curve for hepcidin, it was found that this biomarker has a high diagnostic potential and indicates a higher probability of COVID-19 than PCP/HIV at values ≤768.044 pg / ml. In the context of the COVID-19 pandemic, it is necessary to remember about other diseases that manifest themselves with a similar clinical and radiological picture. COVID-19 and PCP/HIV share many similarities; the peptide hormone hepcidin has shown itself as a potential differential diagnostic marker between them, and therefore the need for further studies of hepcidin is justified, taking into account the severity of the course of COVID-19, the presence of comorbidities and in a comparative aspect with pathologies that «mimic» under COVID-19.

Initial diagnosis of HIV/AIDS in patients presenting to the emergency department: Imaging and clinical findings at a single institution

PURPOSE

To evaluate the clinical, laboratory, and imaging findings along with treatment and outcomes associated with patients presenting to the emergency department (ED) who were subsequently diagnosed with HIV/AIDS.

METHODS

591 patients with HIV and available imaging studies presenting to our hospital's ED between 2004 and 2019 were identified in the medical record. Following initial review, we identified 19 patients who were diagnosed with HIV within one week after an initial ED visit and also had received CT imaging during the ED visit. Demographic, clinical, treatment, imaging, and outcome data were reviewed and recorded for each patient.

RESULTS

Among this 19-patient cohort, the most common indication for HIV testing was oral/esophageal candidiasis (n = 8, 42%). 12 patients presented with an AIDS-defining illness upon initial diagnosis; the most common were esophageal candidiasis (4) and Pneumocystis jiroveci pneumonia (PJP) (3). 10 patients (59%) presented with CD4+ counts <200 cells/L. The most common imaging findings were liver abnormalities (n = 9, 47%). Five of the 19 patients were confirmed deceased at the time of this study, with the median time from diagnosis to death of 5.6 months (range 8 days-14 months).

CONCLUSION

Our series demonstrates the breadth of potential imaging findings and clinical presentations of late-stage HIV in the emergency setting, including common AIDS-defining illnesses such as PJP and PML. Although the incidence of these conditions is decreasing, maintaining awareness of their clinical and imaging findings, as well as the potential for multi-organ involvement, is essential due to the possibility of rapid decline in these patients.

Cavitary lung lesions caused by Pneumocystis jirovecii in setting of common variable immune deficiency

Pneumocystis pneumonia affects immunocompromised hosts. The typical imaging finding is bilateral diffuse ground glass opacities. Here we presented a case of Pneumocystis causing biopsy-confirmed cavitary lung lesions in a patient with a predominant B cell defect with common variable immune deficiency.

Clinical Performance of (1,3) Beta-D Glucan for the Diagnosis of Pneumocystis Pneumonia (PCP) in Cancer Patients Tested With PCP Polymerase Chain Reaction

BACKGROUND

Serum (1,3)-beta-D glucan (BDG) is increasingly used to guide the management of suspected Pneumocystis pneumonia (PCP). BDG lacks specificity for PCP, and its clinical performance in high-risk cancer patients has not been fully assessed. Polymerase chain reaction (PCR) for PCP detection is highly sensitive, but cannot differentiate between colonization and infection. We evaluated the diagnostic performance of serum BDG in conjunction with PCP PCR on respiratory samples in patients with cancer and unexplained lung infiltrates.

METHODS

We performed a retrospective analysis of adult patients evaluated for PCP at our institution from 2012 to 2015, using serum BDG and PCP PCR. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the serum BDG at different thresholds were evaluated using PCP PCR alone or in conjunction with clinical presentation in PCP PCR-positive patients.

RESULTS

With PCP PCR alone as the reference method, BDG (≥80 pg/mL) had a sensitivity of 69.8%, specificity of 81.2%, PPV of 34.6%, and NPV of 95.2% for PCP. At ≥200 pg/mL in patients with a positive PCR and a compatible PCP clinical syndrome, BDG had a sensitivity of 70%, specificity of 100%, PPV of 100%, and NPV of 52.0% for PCP.

CONCLUSIONS

Patients negative by both BDG and PCR were unlikely to have PCP. In patients with a compatible clinical syndrome for PCP, higher BDG values (>200 pg/mL) were consistently associated with clinically-significant PCP infections among PCP PCR-positive oncology patients.

Anidulafungin as an alternative treatment for Pneumocystis jirovecii pneumonia in patients who cannot tolerate trimethoprim/sulfamethoxazole

Evidence supporting the use of an echinocandin alone as an alternative agent for the treatment of Pneumocystis jirovecii pneumonia (PCP) is limited and controversial. This retrospective cohort study was conducted at National Taiwan University Hospital from 1 July 2015 to 31 December 2017. Using multivariable Cox regression analyses, the outcomes of patients receiving trimethoprim/sulfamethoxazole (TMP-SMZ) or anidulafungin single therapy as an alternative treatment for PCP were investigated. A total of 207 patients with PCP were screened and 170 patients were included in the final analysis, among whom 134 (78.8%) received TMP-SMZ and 36 (21.2%) received anidulafungin as alternative anti-PCP treatment. Overall 60-day mortality was 34.1% (58/170), and 60-day mortality did not differ significantly between the anidulafungin group (38.9%; 14/36) and the TMP-SMZ group (32.8%; 44/134) (P = 0.554). Age ≥60 years [hazard ratio (HR) = 1.840, 95% confidence interval (CI) 1.039-3.259; P = 0.036] and HIV infection (HR = 0.102, 95% CI 0.013-0.771; P = 0.027) independently predicted 60-day mortality. Patients with lower SpO₂/FiO₂ ratio (HR = 0.994, 95% CI 0.990-0.998; P = 0.005) showed a higher 60-day mortality. In the Kaplan-Meier survival analysis, anidulafungin as alternative anti-PCP treatment was not correlated with higher mortality (P = 0.605). Using TMP-SMZ or anidulafungin as alternative anti-PCP treatment had similar 60-day mortality. These findings suggest that anidulafungin therapy may be an effective and alternative treatment for PCP in patients who cannot tolerate TMP-SMZ.

Pneumocystis jiroveci pneumonia (PJP) in non-HIV immunocompromised individuals

OBJECTIVES

PJP is a major cause of morbidity and mortality in immunocompromised individuals. Diagnosing PJP is often difficult because respiratory signs might be minimal or absent and the sensitivity of a chest X-ray (CXR) is low. We studied the clinical risk factors in order to increase awareness and facilitate the diagnosis.

METHODS

We studied a prospective case series over a one year period (from 1 January 2015 to 1 January 2016) and did a retrospective analysis (from 2013 to 2016) of all PJP positive bronchoalveolar lavage (BAL) analysis.

RESULTS

Seven patients with metastatic solid tumors were diagnosed with symptomatic PJP (based on positive polymerase chain reaction) over a one year period. The median age was 61 years. Three patients had brain metastasis. Four of them were on steroids, the median dose was 16 mg methylprednisolone with three of them at a tapered dose. Respiratory failure developed in four cases and prompted intensive care monitoring. Two patients needed non-invasive ventilation and the third patient was intubated and mechanically ventilated. No patient died of PJP. A retrospective analysis on microbiological results obtained from BAL in our hospital from 2013 to 2016 shows a striking high percentage PJP positivity in cancer patients (including hematologic cancers) of nearly 22% (15/69) as opposed to the overall number of PJP-positives 7.3% (59/803).

DISCUSSION

The incidence of clinical PJP in patients treated for metastatic cancer is substantial. A high index of suspicion, especially in cases with unexplained respiratory symptoms, concurrent or recent use of steroids, a normal CXR and otherwise unexplained increased lactate dehydrogenase levels, is critical. The threshold for performing a CT-scan must be low and the diagnosis needs to be confirmed microbiologically.

Pneumocystis jirovecii detection in asymptomatic patients: what does its natural history tell us?

Pneumocystis jirovecii is an unusual ascomycetous fungus that can be detected in the lungs of healthy individuals. Transmission from human to human is one of its main characteristics in comparison with other fungi responsible for invasive infections. P. jirovecii is transmitted through the air between healthy individuals, who are considered to be the natural reservoir, at least transiently. In immunocompromised patients, P. jirovecii multiplies, leading to subacute infections and acute life-threatening pneumonia, called Pneumocystis pneumonia [PCP]. PCP is caused by genotypically distinct mixtures of organisms in more than 90% of cases, reinforcing the hypothesis that there is constant inhalation of P. jirovecii from different contacts over time, although reactivation of latent organisms from previous exposures may be possible. Detection of P. jirovecii DNA without any symptoms or related radiological signs has been called “colonization”. This situation could be considered as the result of recent exposure to P. jirovecii that could evolve towards PCP, raising the issue of cotrimoxazole prophylaxis for at-risk quantitative polymerase chain reaction (qPCR)-positive immunocompromised patients. The more accurate way to diagnose PCP is the use of real-time quantitative PCR, which prevents amplicon contamination and allows determination of the fungal load that is mandatory to interpret the qPCR results and manage the patient appropriately. The detection of P. jirovecii in respiratory samples of immunocompromised patients should be considered for potential risk of developing PCP. Many challenges still need to be addressed, including a better description of transmission, characterization of organisms present at low level, and prevention of environmental exposure during immunodepression.

Acute exacerbation of interstitial pneumonia associated with rheumatoid arthritis during the course of treatment for Pneumocystis jirovecii pneumonia: a case report

Background

Pneumocystis jirovecii pneumonia (PCP) is potentially fatal infectious complication in patients with rheumatoid arthritis (RA) during immunosuppressive therapy. Hospital survival due to human immunodeficiency virus—unrelated PCP reaches to 60 %. The high mortality rate results from difficulties in establishing an early diagnosis, concurrent use of prophylactic drugs, possible bacterial coinfection. We herein report a case of PCP in RA patients who developed the architectural distortions of lung in spite of combined modality therapy.

Case presentation

A 73-year-old Japanese woman with RA was admitted with shortness of breath. Five weeks previously, she had been started on etanercept in addition to methotrexate (MTX). Chest computed tomography (CT) demonstrated diffuse ground glass opacities distributed throughout the bilateral middle to lower lung fields, and serum β-d-glucan was elevated. Bronchoalveolar lavage fluid revealed no P. jirovecii, but the organism was detected by polymerase chain reaction method. Trimethoprim/sulfamethoxazole was administered with methylprednisolone pulse therapy. However, the follow-up chest X-ray and chest CT demonstrated aggravation of the pneumonia with architectural distortions. Additional direct hemoperfusion with polymyxin B-immobilized fibers and intravenous cyclophosphamide therapy were insufficiently effective, and the patient died on day 25.

Conclusion

The architectural distortions of lung should be considered as a cause of death of PCP. For this reason, a high suspicion of this infectious complication must be kept in mind in order to establish an early diagnosis and treatment in patients with RA managed with MTX and biologics.

Thin-Section CT Characteristics and Longitudinal CT Follow-up of Chemotherapy Induced Interstitial Pneumonitis: A Retrospective Cohort Study

To describe the computed tomography (CT) features of chemotherapy-induced interstitial pneumonitis (CIIP) with longitudinal follow-up.The study was approved by the local ethics committee. One hundred consecutive patients with CIIP between May 2005 and March 2015 were retrospectively enrolled. The initial CT was reviewed by 2 independent chest radiologists and categorized into 1 of 4 CT patterns in accordance with the 2013 guidelines for idiopathic interstitial pneumonia: nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), hypersensitivity pneumonitis (HP) mimicking desquamative interstitial pneumonitis, and diffuse alveolar damage (DAD). We assessed semiquantitative analysis on a 5% scale to assess the extent of parenchymal abnormalities (emphysema, reticulation, ground-glass opacity, consolidation, honeycombing cyst) and their distribution on initial (n = 100), subsequent (n = 87), and second follow-up CT (n = 48). Interval changes in extent on follow-up CT were compared using paired t test. The clinic-radiologic factors were compared between Group 1 (NSIP and OP patterns) and Group 2 (HP and DAD patterns) using χ and independent t tests.The most common pattern of CIIP on the initial CT was HP (51%), followed by NSIP (23%), OP (20%), and DAD (6%). Diffuse ground-glass opacity was the most common pulmonary abnormality. The predominant distribution was bilateral (99%) and symmetric (82%), with no craniocaudal (60%) or axial (79%) dominance. Subsequent and second follow-up CTs showed decreased extent of total pulmonary abnormalities (P < 0.001, respectively). In comparison with Group 1 CIIP, Group 2 CIIP was more likely to be caused by molecularly targeted drugs (P = 0.030), appeared earlier (P = 0.034), and underwent more complete resolution (P < 0.001). Use of a CT pattern-recognition approach to CIIP is appropriate and practical in interpreting radiological findings.

[Pneumocystis: epidemiology and molecular approaches]

Pneumocystosis is a common opportunistic infection in immunocompromised patients, especially in AIDS patients. The diagnosis of this pneumonia has presented several difficulties due to the low sensitivity of conventional staining methods and the absence of culture system for Pneumocystis. The molecular biology techniques, especially the PCR, have improved the detection of DNA of this fungus in invasive and noninvasive samples, and in the environment which highlighted human transmission and the existence of environmental source of Pneumocystis. In addition, various molecular biology techniques were used for typing of Pneumocystis strains, especially P. jirovecii, which is characterized by a significant genetic biodiversity. Finally, the widespread use of cotrimoxazole for the treatment and prophylaxis of pneumocystosis has raised questions about possible resistance to sulfa drugs in P. jirovecii.

Radiological spectrum of pulmonary infections in patients post solid organ transplantation

Pneumonia remains an important source of morbidity and mortality in transplant recipients. Since clinical findings are nonspecific and cultures may be time-consuming, imaging plays an important role in establishing the probable etiology of pneumonia. Plain films are used as an initial study. However, they have a limited capacity in differentiating the causative factors. HRCT is used as a problem-solving tool in patients with unclear plain film findings and/or no response to treatment. The main advantage of HRCT is a very detailed depiction of the lung parenchyma. Even though HRCT findings are not always specific, there are several sings that are more common in certain types of pneumonia. The aim of the article is to present radiological findings suggestive of a particular causative microorganism and show how they can narrow the differential diagnosis when coupled with clinical data.

Chest radiographic presenting features and radiographic progression of pneumocystis pneumonia in South African children

PURPOSE

To describe the radiographic features of PCP in South African children, including the progression of changes and the impact of HIV-infection and respiratory co-infections.

METHODS

A paediatric radiologist blinded to clinical details retrospectively reported the chest radiographs of children diagnosed with PCP at a South Africa paediatric hospital between January 2003 and June 2006 inclusive. Radiographic features were correlated with clinical findings and compared using Fisher's exact test and Wilcoxon's ranks-sum test. Institutional ethics approval was obtained.

RESULTS

Of 113 cases of PCP, 110 (97.3%) had presenting and 96 (84.9%) follow-up radiographs; 88 (82%) were HIV-infected; 65 (59%) had respiratory co-infection; 48 (43%) died in hospital. The commonest presenting radiographic findings were increased lung volumes (n = 86; 78%) and diffuse parenchymal opacification (n = 70; 64%); 89 (92.7%) ultimately progressed to diffuse alveolar opacification. Median time to maximum pulmonary opacification was 72 hours (inter-quartile range (IQR): 24-144 hrs). Pulmonary interstitial emphysema (PIE) developed in 33 patients (30%). There was no significant difference in the radiographic features of PCP when comparison was made between i) HIV-infected and -uninfected children, ii) those with and without respiratory co-infection and iii) fatal cases and survivors (P > 0.05 in all cases).

CONCLUSION

Increased lung volumes and PIE should be recognised as features of PCP in South African children. HIV-infection and respiratory co-infections do not influence the radiographic features of PCP in our setting.

Cost-effectiveness analysis of diagnostic options for pneumocystis pneumonia (PCP)

Background

Diagnosis of Pneumocystis jirovecii pneumonia (PCP) is challenging, particularly in developing countries. Highly sensitive diagnostic methods are costly, while less expensive methods often lack sensitivity or specificity. Cost-effectiveness comparisons of the various diagnostic options have not been presented.

Methods and Findings

We compared cost-effectiveness, as measured by cost per life-years gained and proportion of patients successfully diagnosed and treated, of 33 PCP diagnostic options, involving combinations of specimen collection methods [oral washes, induced and expectorated sputum, and bronchoalveolar lavage (BAL)] and laboratory diagnostic procedures [various staining procedures or polymerase chain reactions (PCR)], or clinical diagnosis with chest x-ray alone. Our analyses were conducted from the perspective of the government payer among ambulatory, HIV-infected patients with symptoms of pneumonia presenting to HIV clinics and hospitals in South Africa. Costing data were obtained from the National Institutes of Communicable Diseases in South Africa. At 50% disease prevalence, diagnostic procedures involving expectorated sputum with any PCR method, or induced sputum with nested or real-time PCR, were all highly cost-effective, successfully treating 77–90% of patients at $26–51 per life-year gained. Procedures using BAL specimens were significantly more expensive without added benefit, successfully treating 68–90% of patients at costs of $189–232 per life-year gained. A relatively cost-effective diagnostic procedure that did not require PCR was Toluidine Blue O staining of induced sputum ($25 per life-year gained, successfully treating 68% of patients). Diagnosis using chest x-rays alone resulted in successful treatment of 77% of patients, though cost-effectiveness was reduced ($109 per life-year gained) compared with several molecular diagnostic options.

Conclusions

For diagnosis of PCP, use of PCR technologies, when combined with less-invasive patient specimens such as expectorated or induced sputum, represent more cost-effective options than any diagnostic procedure using BAL, or chest x-ray alone.

HRCT-features of Pneumocystis jiroveci pneumonia and their evolution before and after treatment in non-HIV immunocompromised patients

OBJECTIVE

This study retrospectively analyzes the characteristics and kinetics of pulmonary changes in Pneumocystis jiroveci pneumonia (PJP) before and after treatment as depicted by thin-section-CT in HIV-negative patients.

MATERIALS AND METHODS

Serial CT scans of 84 consecutive HIV-negative PJP patients were reviewed retrospectively encompassing a median follow-up of 76 (range, 37-506) days. Along with underlying disease and time span between the onset of symptoms and specific antimicrobial therapy, early and late pulmonary CT-findings were evaluated.

RESULTS

Imaging findings at initial diagnosis differed from those in the posttherapeutic setting. In the acute (initial) PJP-phase, most frequent finding was symmetric, apically distributed ground glass opacities (GGO) with peripheral sparing 43% (n = 36). These initial changes resolved up to 1st follow-up-examination in 57% (n = 48), and finally in all except for two patients after a median period of 13 (mean 26, range 1-58) days following application of specific therapy. In 42% (n = 35) architectural distortions occurred, but they resolved after a median period of 27 (mean 60, range 11-302) days. Only in 9 patients, complete resolution could not be documented. Significant correlations of the underlying disease or the time span between the onset of symptoms and specific antibiotic therapy and morphologic kinetic could not be found.

CONCLUSION

Thin-section CT-findings of PJP usually resolve soon after onset of specific therapy. Postinfectious fibrosis rarely occurs following PJP in HIV-negative patients.

Update on the diagnosis and treatment of Pneumocystis pneumonia

Pneumocystis is an opportunistic fungal pathogen that causes an often-lethal pneumonia in immunocompromised hosts. Although the organism was discovered in the early 1900s, the first cases of Pneumocystis pneumonia in humans were initially recognized in Central Europe after the Second World War in premature and malnourished infants. This unusual lung infection was known as plasma cellular interstitial pneumonitis of the newborn, and was characterized by severe respiratory distress and cyanosis with little or no fever and no pathognomic physical signs. At that time, only anecdotal cases were reported in adults and usually these patients had a baseline malignancy that led to a malnourished state. In the 1960-1970s additional cases were described in adults and children with hematological malignancies, but Pneumocystis pneumonia was still considered a rare disease. However, in the 1980s, with the onset of the HIV epidemic, Pneumocystis prevalence increased dramatically and became widely recognized as an opportunistic infection that caused potentially life-treating pneumonia in patients with impaired immunity. During this time period, prophylaxis against this organism was more generally instituted in high-risk patients. In the 1990s, with widespread use of prophylaxis and the initiation of highly active antiretroviral therapy (HAART) in the treatment of HIV-infected patients, the number of cases in this specific population decreased. However, Pneumocystis pneumonia still remains an important cause of severe pneumonia in patients with HIV infection and is still considered a principal AIDS-defining illness. Despite the decreased number of cases among HIV-infected patients over the past decade, Pneumocystis pneumonia continues to be a serious problem in immunodeficient patients with other immunosuppressive conditions. This is mostly due to increased use of immunosuppressive medications to treat patients with autoimmune diseases, following bone marrow and solid organ transplantation, and in patients with hematological and solid malignancies. Patients with hematologic disorders and solid organ and hematopoietic stem cell transplantation are currently the most vulnerable groups at risk for developing this infection. However, any patient with an impaired immunity, such as those receiving moderate doses of oral steroids for greater than 4 weeks or those receiving other immunosuppressive medications are at also at significant risk.

Radiographic features of paediatric pneumocystis pneumonia -- a historical perspective

AIM

To determine differences between the plain radiographic features of paediatric pneumocystis pneumonia (PCP) recorded before the emergence of human immunodeficiency virus (HIV) in 1982 and those documented in the HIV era. To establish differences in the radiographic features of PCP documented in HIV-infected children in developed and developing countries.

METHOD

A Medline search of articles was conducted from 1950 to 2006, using the terms "pneumocystis pneumonia in children" and "chest radiographic features" or "bilateral opacification" or "lobar consolidation" or "asymmetrical opacification" or "pneumatocoeles" or "cavities" or "pneumothorax" or "pneumomediastinum" or "pleural effusion" or "mediastinal adenopathy" or "nodules" or "normal chest radiography". Appropriate articles were retrieved, radiological data extracted, reference lists examined and hand searches of referenced articles conducted.

RESULTS

Diffuse bilateral "ground-glass" or alveolar pulmonary opacification, which may show some asymmetry, has been consistently documented as the commonest radiographic finding in childhood PCP throughout the period under review. The less common radiological features of PCP in children are similar to those in adults. In developed countries, PCP-related pulmonary air cysts have been reported at an earlier age in HIV-infected children, compared with uninfected children. PCP-related air cysts, pneumothorax, and pneumomediastinum have been reported in children in developed but not in developing countries.

CONCLUSION

The radiological features of paediatric PCP documented before the HIV epidemic are similar to those recorded in the HIV era. Further study of the determinants of the uncommon radiographic features in children is warranted.

Pneumocystis pneumonia in patients with HIV infection: clinical manifestations, laboratory findings, and radiological features

Pneumocystis pneumonia (PCP) remains the most common opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). Familiarity with the clinical features of PCP is crucial for prompt diagnosis, even if the patient is unaware of their HIV serostatus. We describe herein the clinical features of 34 episodes in 32 patients with AIDS-associated PCP and review the existing literature. As for symptoms, the frequency of fever, cough, and dyspnea was 74%, 74%, and 65%, respectively, and the complete triad was present in only 14 of the 34 episodes on first examination. Median duration from onset of symptoms until diagnosis was 3 weeks, and AIDS-associated PCP tended to take an insidious clinical course. Although laboratory findings were generally nonspecific, measurement of beta-D-glucan levels in the serum or plasma was highly useful in the diagnosis of PCP. All but 1 of the patients showed beta-D-glucan levels higher than the cutoff value (median, 147 pg/ml; range, 5-6920 pg/ml). Typical radiographic features of PCP are bilateral, symmetrical ground-glass opacities, but a wide variety of radiographic findings were observed. In our patients, high-resolution computed tomography (HRCT) of the lung showed ground-glass opacities sparing the lung periphery (41% of episodes) or displaying a mosaic pattern (29%), or being nearly homogeneous (24%), ground-glass opacities associated with air-space consolidation (21%), associated with cystic formation (21%), associated with linear-reticular opacities (18%), patchily and irregularly distributed (15%), associated with solitary or multiple nodules (9%), and associated with parenchymal cavity lesions (6%).

Differences and similarities of cytomegalovirus and pneumocystis pneumonia in HIV-negative immunocompromised patients thin section CT morphology in the early phase of the disease

The purpose of this study was to assess CT morphology of pneumocystis pneumonia (PcP) and cytomegalovirus (CMV) pneumonia for specific characteristic features, similarities as well as differences, which might contribute to an early diagnosis and, therefore, influence patient management 58 patients were included, 31 with CMV pneumonia and 27 with PcP. All patients with CMV pneumonia had underlying haematological malignancies (n = 31) mainly treated by haematopoietic cell transplantation (HCT) (n = 26). Patients with PcP had haematological malignancies (n = 17) treated by HCT in 6, solid tumours (n = 5) and corticosteroid therapy (n = 5). Thin section CTs were analysed retrospectively by two radiologists. 18 CT morphological criteria were evaluated for presence or absence. Significance was calculated by chi2 test. Interobserver correlation was tested by kappa-statistic (K) Only 5 of the 18 features were found to have significantly different frequencies in the two entities. Apical distribution (p<0.01), mosaic pattern (p<0.01) and homogeneous structure of ground-glass opacities (GGO) (p<0.05) were found more frequently in PcP (each K: 0.7-0.9), whereas small nodules or unsharp demarcation of GGO and consolidation were typical of CMV pneumonia (p<0.05). Peripheral sparing, consolidation and septal thickening inter alia were found equally in both groups In conclusion analysis of craniocaudal distribution, demarcation and structure of infiltrates may be helpful in prioritizing differential diagnosis of CMV pneumonia or PcP. However, some features thought typical for one or the other entities appear with similar frequency in both groups in HIV-negative patients.

Pulmonary fungal infection with yeasts and pneumocystis in patients with hematological malignancy

Invasive fungal infections are an important cause of morbidity and mortality in patients with hematological malignancies, and in particular fungal pneumonia is the main clinical manifestation in this category of patients. The fungal agents responsible for this complication are various, but Aspergillus spp. and other molds such as Zygomycetes or Fusarium spp. represent the most frequently isolated micro-organisms. Less commonly, pneumonia could be due to other 'no-molds' fungal agents such as Candida spp, Cryptococcus spp, or Pneumocystis jirovecii . This review mainly focuses on practical aspects relevant to epidemiology, diagnosis and therapeutic management of the rare cases of pneumonia due to no-molds agents in patients affected by hematological malignancies.

Granulomatous Pneumocystis carinii Pneumonia in a Non-AIDS Patient

We present the computed tomographic findings of pulmonary involvement by granulomatous Pneumocystis carinii pneumonia in a 73-year-old woman recently tapered from a high-dose long-term systemic corticosteroid therapy for Factor VII deficiency.

Cystic and cavitary lung diseases: focal and diffuse

Cysts and cavities are commonly encountered abnormalities on chest radiography and chest computed tomography. Occasionally, the underlying nature of the lesions can be readily apparent as in bullae associated with emphysema. Other times, cystic and cavitary lung lesions can be a diagnostic challenge. In such circumstances, distinguishing cysts (wall thickness < or = 4 mm) from cavities (wall thickness > 4 mm or a surrounding infiltrate or mass) and focal or multifocal disease from diffuse involvement facilitates the diagnostic process. Other radiological characteristics, including size, inner wall contour, nature of contents, and location, when correlated with the clinical context and tempo of the disease process provide the most helpful diagnostic clues. Focal or multifocal cystic lesions include blebs, bullae, pneumatoceles, congenital cystic lesions, traumatic lesions, and several infectious processes, including coccidioidomycosis, Pneumocystis carinii pneumonia, and hydatid disease. Malignant lesions including metastatic lesions may rarely present as cystic lesions. Focal or multifocal cavitary lesions include neoplasms such as bronchogenic carcinomas and lymphomas, many types of infections or abscesses, immunologic disorders such as Wegener granulomatosis and rheumatoid nodule, pulmonary infarct, septic embolism, progressive massive fibrosis with pneumoconiosis, lymphocytic interstitial pneumonia, localized bronchiectasis, and some congenital lesions. Diffuse involvement with cystic or cavitary lesions may be seen in pulmonary lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, honeycomb lung associated with advanced fibrosis, diffuse bronchiectasis, and, rarely, metastatic disease. High-resolution computed tomography of the chest frequently helps define morphologic features that may serve as important clues regarding the nature of cystic and cavitary lesions in the lung.

Update on lung disease in AIDS

Pulmonary disorders remain an important complication of HIV infection, even in the current era of potent antiretroviral therapy. Using an integrated approach that combines radiographic pattern recognition with knowledge of a patient's clinical symptoms, laboratory data, immune status level, demographic information, and drug therapy can enhance the interpretation of imaging studies in HIV-infected patients. Although chest radiography remains the mainstay of imaging the HIV-positive patient with respiratory symptoms, CT plays an increasingly important secondary role in selected cases.