Clinical and bronchoscopic diagnosis of suspected pneumonia related to AIDS

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.

US hospital care for patients with HIV infection and pneumonia: the role of public, private, and Veterans Affairs hospitals in the early highly active antiretroviral therapy era

STUDY OBJECTIVES

We evaluated differences in processes and outcomes of HIV-related pneumonia care among patients in Veterans Affairs (VA), public, and for-profit and not-for-profit private hospitals in the United States. We compared the results of our current study (1995 to 1997) with those of our previous study that included a sample of patients receiving care during the years 1987 to 1990 to determine how HIV-related pneumonia care had evolved over the last decade.

SETTING/PATIENTS

The sample consisted of 1,231 patients with HIV infection who received care for Pneumocystis carinii pneumonia (PCP) and 750 patients with HIV infection who received care for community-acquired pneumonia (CAP) during the years 1995 to 1997.

MEASUREMENT

We conducted a retrospective medical record review and evaluated patient and hospital characteristics, HIV-related processes of care (timely use of anti-PCP medications, adjunctive corticosteroids), non-HIV-related processes of care (timely use of CAP treatment medications, diagnostic testing, ICU utilization, rates of endotracheal ventilation, placement on respiratory isolation), length of inpatient hospital stay, and inpatient mortality.

RESULTS

Rates of timely use of antibiotics and adjunctive corticosteroids for treating PCP were high and improved dramatically from the prior decade. However, compliance with consensus guidelines that recommend < 8 h as the optimal time window for initiation of antibiotics to treat CAP was lower. For both PCP and CAP, variations in processes of care and lengths of in-hospital stays, but not mortality rates, were noted at VA, public, private not-for-profit hospitals, and for-profit hospitals.

CONCLUSIONS

This study provides the first overview of HIV-related pneumonia care in the early highly active antiretroviral therapy era, and contrasts current findings with those of a similarly conducted study from a decade earlier. Quality of care for patients with PCP improved, but further efforts are needed to facilitate the appropriate management of CAP. In the third decade of the epidemic, it will be important to monitor whether variations in processes of care for various HIV-related clinical diagnoses among different types of hospitals persist.

Role of bronchoscopy in AIDS

The differential diagnosis of pulmonary disorders in the HIV-infected individual is broad. Clinical features and chest radiographs may point towards a diagnosis but cannot reliably establish one. It is important to know the conditions in which bronchoscopy, BAL, and TBB are likely to be diagnostic, just as it is to know when other invasive or noninvasive procedures may be more useful. Finally, the incidence of transmission of infections such as tuberculosis during bronchoscopy and cross-contamination of patients with an improperly sterilized bronchoscope, cannot be overemphasized.

Pneumocystis carinii pneumonia

Pneumocystis carinii pneumonia (PCP) remains an important complication of AIDS. Advances have been made in establishing the taxonomy of the organism but the life cycle of the organism and pathogenetic mechanisms of disease remain obscure. In HIV patients the incidence of PCP has decreased because of widespread use of prophylaxis and survival of those with PCP has improved with use of adjunctive corticosteroid therapy. Less toxic drug therapies are still needed as well as better noninvasive diagnostic techniques.

Approach to the patient with pulmonary disease

The approach to the HIV-infected patient with pulmonary disease is summarized by the algorithms in Figures 3 and 4. These are not intended to be followed in a rigid step-wise fashion. Rather, the practitioner's knowledge of the patient with his or her accompanying medical risks influences the path taken, including the depth and the speed of the evaluation. For example, the patient with cough who is afebrile and breathing at 18 breaths a minute, with a normal chest radiograph and a CD4 count of 350 cells/mm3, is reasonably treated with a macrolide or cephalosporin for bacterial bronchitis and clinical follow-up while awaiting cultures (see Fig. 4). A febrile patient with a cough productive of thin mucus, but known to have a CD4 count of 60 cells/mm3 should be started on anti-PCP therapy while being evaluated for PCP with an induced sputum and if nondiagnostic, a bronchoscope despite a normal chest radiograph. Screening can be as simple as placing an oximeter on the patient's finger in the clinic. If the oxygen saturation of a patient with a normal chest radiograph is low, then the patient should be hospitalized and begun on treatment for PCP while diagnostic evaluation is initiated. If the oxygen saturation is normal, the patient can be exercised to elicit desaturation. If there is no desaturation, PCP is unlikely. If the results are equivocal (i.e., a decrease in saturation, but less than 3%), rest and exercise arterial blood gases can be performed, along with a Dlco-Gallium scanning can be done in patients known to have abnormal Dlco or those who cannot exercise. Patients with focal infiltrates who have acute onset of symptoms (see Fig. 4) commonly have bacterial infections, but the possibility of PCP or TB should not be dismissed. Induced sputum should be examined if TB or PCP is suspected. Patients who are severely ill might go quickly to bronchoscopy without awaiting improvement on empiric therapy. The patient with diffuse infiltrates (see Fig. 4) needs no screening because the presence of disease is apparent from the radiograph. The diagnostic part quickly leads to bronchoscopy for these patients and the initiation of therapy for PCP when suspected. In patients with known pulmonary KS, gallium scanning can be helpful to rule out acute infection, but bronchoscopy is warranted if the patient is severely ill, or at high risk for PCP. This approach should avoid unnecessary procedures in patients with simple bacterial infections, without missing opportunistic infections and tumors.

Pneumocystis carinii

Improved understanding of Pneumocystis carinii, in particular the widespread use of chemoprophylaxis, has resulted in a declining incidence of infection in patients infected with HIV since the late 1980s. Despite these advances, P. carinii pneumonia continues to represent an important cause of pulmonary disease in HIV-seropositive individuals who do not receive chemoprophylaxis or when breakthrough episodes occur. This article reviews the history, biology, clinical manifestations, prognostic markers, therapy, and chemoprophylaxis of P. carinii pneumonia in HIV-seropositive patients.

The role of bronchoscopy in the diagnosis and treatment of pulmonary disease in HIV-infected patients

BACKGROUND

Pulmonary disease is the most common reason for presentation and the major cause of death in HIV-infected patients. There has been an evolution in the optimal approach to the investigation of a pulmonary infiltrate in HIV-infected patients since the introduction of induced sputum for the diagnosis of Pneumocystis carinii pneumonia (PCP).

AIMS

To evaluate the usefulness of flexible fibreoptic bronchoscopy (FFB), bronchoalveolar lavage (BAL), transbronchial biopsy (TBB) and bronchial brushings (BB) in the diagnosis of pulmonary disease in HIV-infected patients and to examine the effect of FFB on changes in therapy and survival.

METHODS

The histories of all HIV-infected patients referred to Fairfield Hospital for FFB between January 1990 and June 1993 were examined retrospectively.

RESULTS

Forty-two FFB were performed on 41 patients (40 male and one female). Definitive diagnoses made at FFB included Kaposi's sarcoma (KS) (n = 9), invasive aspergillosis (n = 5), PCP (n = 4), Mycobacterium avium complex (MAC) pneumonia (n = 2), cytomegalovirus (CMV) pneumonia (n = 1), Cryptococcus neoformans pneumonia (n = 1), microsporidium (n = 1) and Pseudomonas aeruginosa pneumonia (n = 1). TBB and BB did not provide a diagnosis for diseases not seen macroscopically at FFB or diagnosed by BAL. FFB findings altered diagnosis in 21/42 (50%) presentations and changed therapy in 26/42 (62%) cases.

CONCLUSIONS

FFB together with BAL altered the working diagnosis and changed therapy in a significant number of patients. TBB and BB should not be routinely performed in all patients as these procedures are of limited value in this setting.

Bronchoscopy versus empirical therapy in HIV-infected patients with presumptive Pneumocystis carinii pneumonia. A decision analysis

The outcomes of alternative strategies for the management of pulmonary complications in patients infected with the human immunodeficiency virus (HIV) and with suspected Pneumocystis carinii pneumonia were compared using a decision analysis model. A decision tree was constructed using baseline probabilities derived from published data and expert opinion. The case scenario analyzed was that of a patient not currently receiving anti-Pneumocystis prophylaxis who presents with moderate pulmonary symptoms and fulfills the Centers for Disease Control (CDC) criteria for presumptive P. carinii pneumonia. Two strategies were compared: (1) early bronchoscopy with appropriate therapy based on the results, and (2) empiric treatment for P. carinii (trimethoprim/sulfamethoxazole or pentamidine, and steroids) with delayed bronchoscopy in those not responding to 5 days of empiric therapy. The expected 1-month survival rate (with and without quality of life adjustment) was found to be essentially the same for the two strategies using the baseline probabilities, and the decision remained a toss-up within the clinically relevant range of published probabilities for P. carinii pneumonia in patients fulfilling the CDC criteria. Because early bronchoscopy does not offer any additional survival benefits and is associated with greater costs and disutility, empiric therapy would appear to be the superior management strategy in this scenario.

Optimal management strategies for HIV-infected patients who present with cough or dyspnea: a cost-effective analysis

OBJECTIVE

To determine the effectiveness and costs of alternative management strategies for patients infected with the human immunodeficiency virus (HIV) who present with pulmonary symptoms.

DESIGN

Decision analysis comparing initial testing (arterial blood gas analysis, induced sputum analysis, or bronchoscopy with bronchoalveolar lavage) with empiric antibiotics (trimethoprim-sulfamethoxazole or erythromycin). Subsequent steps in management are detailed based on the results of initial management. Patients were stratified by initial CD4 lymphocyte count (less than 200/mm3, 200-500/mm3, or greater than 500/mm3) and results of chest radiography.

SETTING

Hypothetical.

MEASUREMENTS AND MAIN RESULTS

The estimated levels of effectiveness among strategies were relatively similar, but costs varied markedly. If potentially reasonable strategies are defined as those that have incremental cost-effectiveness ratios below $50,000 per quality-adjusted life year (QALY), the recommended strategies would be: for patients at highest risk for Pneumocystis carinii pneumonia (PCP), with a probability of PCP above 30% (CD4 less than 200/mm3 and abnormal chest radiograph or prior history of PCP), begin with induced sputum analysis ($34,174/QALY); for intermediate-risk patients, with a probability of PCP between 6% and 30% (CD4 less than 200/mm3, regardless of chest radiograph; or CD4 200-500/mm3, regardless of chest radiograph findings), begin with arterial blood gas analysis ($4,593 to $8,310/QALY); for low-risk patients, with a probability of PCP below 6% (CD4 greater than 500/mm3, regardless of chest radiograph findings), begin with one week of erythromycin, followed by induced sputum examination if symptoms persist ($675 to $3,306/QALY). For highest-risk patients, if empiric trimethoprim-sulfamethoxazole was considered entirely to be outpatient therapy, it was preferred management if the probability of PCP was above 38%.

CONCLUSIONS

The authors conclude that preferred management strategies are determined more by differences in costs than by differences in levels of effectiveness, and that they vary depending on the probability of PCP in definable patient subgroups.

Fiberoptic bronchoscopy and sputum examination for diagnosis of pulmonary disease in AIDS patients in Stockholm

For diagnosing pulmonary disease on 82 occasions in 68 patients (64 males) aged 39 (23-73) years infected with HIV-1 we used flexible fiberoptic bronchoscopy (FFB) with bronchoalveolar lavage (BAL) or washing with or without transbronchial lung biopsy (TBB) and brushing. A clinical diagnosis of lower respiratory tract disease was obtained in 68/82 episodes (83%). An etiological diagnosis was reached by FFB in 59/82 episodes (72%). Pneumocystis carinii (PC), the dominating pathogen causing pneumonia in 54/82 episodes (66%), was detected by FFB in 51/54 (94%). In spite of being isolated in bronchoscopy material in 36/82 episodes (44%) cytomegalovirus (CMV) seemed to be the cause of pneumonia only in 2/36 (5%) episodes. Except PC and CMV, only bacteria (including mycobacteria) were found as infectious etiological agents. Kaposi's sarcoma and pulmonary edema were diagnosed in one patient each. For detection of PC in 37 episodes we compared staining of BAL fluid with indirect immunofluorescence (IF) using monoclonal antibodies (MoAB) with staining of BAL material by silver methenamine (Grocott). Staining with IF MoAB alone of BAL fluid only seemed to be even more sensitive than silver methenamine staining of BAL, TBB and brushing material. When using IF MoAB staining of BAL fluid, TBB and brushing added nothing to the result, except in the patient with Kaposi's sarcoma, diagnosed by TBB. Sputum investigation using IF MoAB for detection was increasingly adopted during the study time. It was very useful (sensitivity approximately 74%) and reduced the number of required FFBs.

AIDS and UK respiratory physicians: attitudes to confidentiality, infection control, and management

Respiratory physicians are concerned in the management of most patients with AIDS. Attitudes and practices of 463 respiratory physicians in the United Kingdom in relation to confidentiality, infection control, and treatment were sought by questionnaire from December 1987 to March 1988; 266 replies were received. Thirty eight per cent of respondents had not seen an HIV positive patient at the time of the survey. Respiratory physicians followed General Medical Council guidelines in relation to consent and confidentiality, except that if the patient's consent was withheld three quarters of the physicians would still inform an at risk hospital health care worker; only a quarter, however, would inform an at risk spouse. Routine infection control was frequently inadequate and "disease specific"--that is, substantially increased for known HIV positive patients. Given an HIV positive patient with respiratory symptoms and an abnormal chest radiograph, two thirds of respiratory physicians said that they would treat empirically for Pneumocystis carinii pneumonia as opposed to immediate bronchoscopy for accurate diagnosis. If a patient with AIDS who had pneumocystis pneumonia developed respiratory failure, half the physicians said at that time that they would elect not to ventilate the patient.

Empirical treatment without bronchoscopy for Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome

An empirical approach to treating Pneumocystis carinii pneumonia was adopted in a prospective study of 73 men with antibodies to human immunodeficiency virus 1 (HIV-1) presenting with respiratory problems. At presentation 49 patients (group 1) were thought to have a history, findings at clinical examination, chest radiograph, and arterial blood gas tensions typical of pneumocystis pneumonia, and empirical treatment was begun immediately. Twenty four patients (group 2) were thought to have features not typical of pneumocystis pneumonia. All patients were subsequently referred for bronchoscopy to determine the diagnosis. In group 1 four patients were excluded from the analysis because bronchoscopy was not possible. Of the remaining 45, 42 had pneumocystis pneumonia, which was diagnosed at bronchoscopy in 40, and on the basis of the clinical response to co-trimoxazole in two who had negative results from investigations. Of the three patients without pneumocystis pneumonia, one patient with lymphoid interstitial pneumonitis and Branhamella catarrhalis infection would have failed to respond to empirical treatment. The other two had multiple bacterial pathogens at bronchoscopy; one already had Kaposi's sarcoma and the other would have been misdiagnosed as having AIDS. In group 2 a specific diagnosis was made at bronchoscopy in 21 cases, including pneumocystis pneumonia in seven (all had atypical chest radiographs). In three cases no diagnosis was made and spontaneous recovery occurred. Adopting an empirical approach to treatment for typical pneumocystis pneumonia (group 1) led to the correct treatment in 43 of 45 cases (95%) and would have saved 44 of the 45 of bronchoscopies in this group. Adopting an empirical approach would have caused one patient to be misdiagnosed as having AIDS. Overall, 44 out of 69 bronchoscopies (64%) would have been saved; the specificity for the diagnosis of pneumocystis pneumonia was 85% and the sensitivity was 85%. Adopting an "empirical" treatment policy for typical pneumocystis pneumonia will cause a large reduction in the number of "high risk" bronchoscopies performed.

Diagnosis, treatment and outcome of pneumonia in the acquired immune deficiency syndrome

Fibreoptic bronchoscopy was performed in 43 of 52 consecutive patients with opportunistic pneumonia in the acquired immune deficiency syndrome (AIDS). The 15 patients in whom a likely pathogen was not found by bronchoscopy (including the nine not having the procedure) were treated for Pneumocystis carinii pneumonia (PCP) alone and all responded. In 11 of these a diagnosis of AIDS was confirmed because of an alternative opportunistic infection within 6 months. PCP was confirmed in 38 of the 52 patients and cytomegalovirus (CMV) was isolated from 15 patients. The lower the partial pressure of arterial oxygen (PaO2) on admission the more likely was a pathogen to be found by bronchoscopy. The admission PaO2 while the patient was breathing room air was the single most reliable prognostic indicator. The mean PaO2 for survivors was 9.6 kPa and 6.7 kPa for non-survivors (P less than 0.01 Student's t-test), with 50% mortality for patients with a PaO2 of less than 8 kPa on admission. Temperature and pulse rate were sensitive indicators of response to treatment, obviating the need for frequent arterial gas measurements and chest radiography. Our findings suggest that although fibreoptic bronchoscopy contributed little to the treatment and final outcome of the infection, it identified the causative pathogen in most patients.

Diagnostic problems in AIDS and the lung

Since the first case of AIDS in the United Kingdom was described in 1981 (1), there have been up to October 1988, 1794 AIDS cases reported, of whom 965 are dead and 8794 individuals known to be Human Immunodeficiency Virus (HIV) seropositive (2). In fact the actual number of seropositive individuals is likely to be far greater than this figure. A recent study of an HIV seropositive cohort suggests that the majority of individuals infected with HIV will eventually develop AIDS (3). Most of the cases in the U.K. have occurred in homo- or bisexual men, and the pattern of disease in the U.K. closely follows that of the epidemic in the United States. The association between AIDS and infection with HIV was demonstrated in 1983-4 (4,5) and HIV induced damage to the immune system with profound depression of cell mediated immunity is responsible for many of the manifestations of this extraordinary new disease (6). As the lung is the most frequently affected organ in AIDS (7), and as case numbers are likely to increase in the U.K., if the epidemic trend continues, Respiratory Physicians in the U.K. will be increasingly involved in the management of these patients. The purpose of this review is to highlight some of the diagnostic problems encountered in AIDS patients with lung disease.

Bronchoesophageal manifestations of acquired immunodeficiency syndrome

Among the more common manifestations of acquired immunodeficiency syndrome (AIDS) are tumors and infections that occur in regions treated by the bronchoesophagologist. In reviewing our institutional experience in the diagnosis and treatment of 396 patients with AIDS in 1987, we have noted that 226 (57%) had some form of pneumonia and 133 (34%) had candidiasis. In this communication we discuss the various types of bronchopulmonary, oropharyngeal, and esophageal infections that have been reported among AIDS patients. We also review the universal precautions and specific guidelines recommended for safeguarding the bronchoesophagologist and other health care workers who treat these patients.

Yield of diagnostic tests for opportunistic infections in AIDS: a survey of 33 patients

To examine the therapeutic consequences of diagnostic tests for AIDS-related infections, case records from 33 deceased AIDS patients were reviewed; 23 were autopsied. Determination of serum antibody titres was not important. In particular, there was no relation between titres and isolation of cytomegalovirus (CMV); isolation attempts or possibly antigen determination would be better. Samples for CMV isolation were obtained from 31 patients; only 7 were negative. Blood, faeces, and particularly sputum cultures gave a low yield; the number of such examinations could be reduced considerably. However, 4/7 disseminated infections with atypical mycobacteria were only revealed at autopsy, despite numerous cultures in vivo. Liver biopsies were not helpful. Diagnostic procedures for Pneumocystis carinii pneumonia by lung biopsy caused pneumothorax in 3/15 patients; bronchoalveolar lavage or treatment/prophylaxis without diagnosis could be considered. In 8 autopsies, microscopy was suggestive of cerebral toxoplasmosis, but only 1 patient had presented important clinical symptoms. We suggest a schedule with regular microbiologic and parasitic examinations and few antibody tests, but with more antigen tests.

Diagnosis of lung disease in acquired immune deficiency syndrome: biopsy or cytology and implications for management

One hundred and twenty consecutive bronchoscopic examinations were carried out on 80 patients with acquired immune deficiency syndrome (AIDS) between January 1982 and December 1986. Ninety one paired biopsy and cytology specimens from 72 of these patients were analysed. There was no significant difference between biopsy and cytology in diagnosing Pneumocystis carinii pneumonia (0.95 greater than p greater than 0.1). In 10 cases P carinii pneumonia was diagnosed by biopsy but not cytology and in seven cases by cytology but not biopsy. Nineteen patients had multiple infections or Kaposi's sarcoma. Biopsy was more useful than cytology in the diagnosis of other infections (n = 20) and Kaposi's sarcoma (n = 2) with positive cytological correlation in only three of the infections. Biopsy and cytology together have a diagnostic yield of 78.3%. We conclude that all patients presenting with respiratory disease who have, or are in a high risk group for, AIDS should be examined by bronchoscopy at an early stage with both cytology and biopsy.