[Pnemocystis jiroveci pneumonia: Comparison between conventional PCR and staining techniques]

Chest X-ray Features of HIV-Associated Pneumocystis Pneumonia (PCP) in Adults: A Systematic Review and Meta-analysis

Background

The performance of chest x-ray (CXR) features for Pneumocystis pneumonia (PCP) diagnosis has been evaluated in small studies. We conducted a systematic review and meta-analysis to describe CXR changes in adults with HIV-associated laboratory-confirmed PCP, comparing these with non-PCP respiratory disease.

Methods

We searched databases for studies reporting CXR changes in people >15 years old with HIV and laboratory-confirmed PCP and those with non-PCP respiratory disease. CXR features were grouped using consensus terms. Proportions were pooled and odds ratios (ORs) generated using random-effects meta-analysis, with subgroup analyses by CD4 count, study period, radiology review method, and study region.

Results

Fifty-one studies (with 1821 PCP and 1052 non-PCP cases) were included. Interstitial infiltrate (59%; 95% CI, 52%-66%; 36 studies, n = 1380; I2 = 85%) and ground-glass opacification (48%; 95% CI, 15%-83%; 4 studies, n = 57; I2 = 86%) were common in PCP. Cystic lesions, central lymphadenopathy, and pneumothorax were infrequent. Pleural effusion was rare in PCP (0%; 95% CI, 0%-2%). Interstitial infiltrate (OR, 2.3; 95% CI, 1.4-3.9; I2 = 60%), interstitial-alveolar infiltrate (OR, 10.2; 95% CI, 3.2-32.4; I2 = 0%), and diffuse CXR changes (OR, 7.3; 95% CI, 2.7-20.2; I2 = 87%) were associated with PCP diagnosis. There was loss of association with alveolar infiltrate in African studies.

Conclusions

Diffuse CXR changes and interstitial-alveolar infiltrates indicate a higher likelihood of PCP. Pleural effusion, lymphadenopathy, and focal alveolar infiltrates suggest alternative causes. These findings could be incorporated into clinical algorithms to improve diagnosis of HIV-associated PCP.

Massive Cavitation by Pneumocystis jirovecii in an Immunocompromised Patient

Since the development of antiretroviral therapy (ART) and antibiotic prophylaxis, the incidence of opportunistic infections in human immunodeficiency virus-acquired immunodeficiency syndrome (HIV-AIDS) has been drastically reduced. However, third-world countries remain a fertile ground for medication nonadherence and inappropriate patient follow-up. Here, we present the case of a 42-year-old male with a history of HIV who presented with worsening shortness of breath and atypical chest pain. A chest X-ray and chest computed tomography scan revealed a left parahilar cavitation measuring 86 mm in diameter. A percutaneous lung biopsy revealed Pneumocystis jirovecii. Appropriate antibiotics were started, and the patient’s clinical status significantly improved. This case illustrates the devastating consequences of uncontrolled HIV-AIDS. ART and prophylactic antibiotics remain the cornerstone of treatment to ameliorate progressive lung damage in patients.

Is real time PCR preferable to the direct immunofluorescence in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected patients?

Objectives

In this study, we compared IFA and real-time PCR in bronchoalveolar lavage specimens of HIV infected patients. A total of 66 BALs from 62 HIV patients were included in the study. 30 IFA positive and 36 IFA negative specimens were tested with real-time PCR, targeting the major surface glycoprotein. We performed a retrospective analysis of the patient’s medical records, compared the results of the IFA and PCR tests and analyzed costs, expenditure of time and personal expenses.

Results

All of the 30 IFA positive samples were PCR positive. 35 of 36 IFA negative probes were also negative in the PCR assay. Considering the PCR results as a binary outcome (positive/negative) sensitivity was 100%, specificity 97.2%. The patient with negative IFA and positive PCR had a clear clinical picture of PCP and responded to PCP treatment. PCR was more than twice as expensive and time-consuming as IFA. Diagnostic accuracy for PCP of PCR and IFA was comparable in HIV-infected patients, but IFA was significantly less expensive and less time-consuming. Therefore, IFA testing can continue to be used as gold standard in the diagnosis of PCP in HIV patients. However, in special cases, IFA may lack sensitivity and PCR should be added to the diagnostic armamentarium.

Rapid diagnostic test for respiratory infections

Acute respiratory infections are the second cause of morbidity and mortality in children and adults worldwide, being viruses, bacteria and fungi involved in their aetiology. The rapid diagnosis allows for a better clinical management of the patient, for adopting public health measures and for controlling possible outbreaks. The main etiologic agents can be diagnosed within the first hours after the onset of symptoms with antigen detection techniques, primarily immunochromatography. Results are obtained in 15–30 min, with 70–90% sensitivity and >95% specificity for the diagnosis of Streptococcus pneumoniae and Legionella pneumophila serogroup O1 infections from urine, Streptococcus pyogenes from throat swabs and respiratory syncytial virus from nasopharyngeal aspirates. Worse results are obtained for influenza viruses and Pneumocystis jirovecii with these techniques; however, other easy-to-perform molecular techniques are available for the rapid diagnosis of these microorganisms. In general, these techniques should not be used for monitoring the outcome or response to treatment.

[Rapid diagnostic test for respiratory infections]

Acute respiratory infections are the second cause of morbidity and mortality in children and adults worldwide, being viruses, bacteria and fungi involved in their etiology. The rapid diagnosis allows for a better clinical management of the patient, for adopting public health measures and for controlling possible outbreaks. The main etiologic agents can be diagnosed within the first hours after the onset of symptoms with antigen detection techniques, primarily immunochromatography. Results are obtained in 15-30minutes, with 70-90% sensitivity and >95% specificity for the diagnosis of Streptococcus pneumoniae and Legionella pneumophila serogroup O1 infections from urine, Streptococcus pyogenes from throat swabs and respiratory syncytial virus from nasopharyngeal aspirates. Worse results are obtained for influenza viruses and Pneumocystis jirovecii with these techniques; however, other easy-to-perform molecular techniques are available for the rapid diagnosis of these microorganisms. In general, these techniques should not be used for monitoring the outcome or response to treatment.

[Pneumocystosis during HIV infection]

Pneumocystosis is an opportunistic disease caused by invasion of unicellular fungus Pneumocystic jirovecii which is responsible for febrile pneumonia among patients with cellular immunodeficiency especially those HIV infected. Despite the decreasing of its incidence due to the introduction of antiretroviral therapy, as well as anti-Pneumocystis prophylaxis among these patients, Pneumocystis pneumonia remains the first AIDS-defining event and a leading cause of mortality among HIV-infected patients. The usual radiological presentation is that of diffuse interstitial pneumonia. The diagnosis is confirmed by the detection of trophozoides and/or cysts P. jirovecii in bronchoalveolar lavage (BAL) samples using several staining techniques. The use of polymerase chain reaction in the BAL samples in conjunction with standard immunofluorescent or colorimetric tests have allowed for more has allowed for more rapid and accurate diagnosis. The standard regimen of treatment is the association of trimethoprim-sulfamethoxazole which has been utilized as an effective treatment with a favourable recovery. Early HIV diagnosis and antiretroviral therapy should reduce the incidence of this dreaded disease.

[Pneumocystis pneumonia biological diagnosis at Fann Teaching Hospital in Dakar, Senegal]

BACKGROUND

Data relative to Pneumocystis pneumonia in sub-Saharan Africa are not well known. Weakness of the technical material and use of little sensitive biological tools of diagnosis are among the evoked reasons. The objective of this study is to update the data of the disease at the Fann Teaching Hospital in Dakar and to estimate biological methods used in diagnosis.

MATERIALS AND METHODS

A descriptive longitudinal study was carried out from January 5th, 2009 to October 31st, 2011 in the parasitology and mycology laboratory of the Fann Teaching Hospital in Dakar. The bronchoalveolar lavages received in the laboratory were examined microscopically for Pneumocystis jirovecii by indirect fluorescent assay or after Giemsa or toluidine blue O staining.

RESULTS

One hundred and eighty-three bronchoalveolar lavages withdrawn from 183 patients were received in the laboratory. Sixteen were positive for P. jirovecii at 9% frequency. Four among these patients were HIV positive. Indirect fluorescent assay allowed finding of P. jirovecii among 16 patients while Giemsa staining discovered P. jirovecii only in a single patient. No case was diagnosed by toluidine blue O staining.

CONCLUSION

Pneumocystis pneumonia in Parasitology and Mycology Laboratory of Fann Teaching Hospital at Dakar was mainly diagnosed among HIV patients.