The place of lung 99mTc DTPA aerosol transfer in the investigation of lung infections in HIV positive patients

Pneumocystis carinii pneumonia (PCP) is the most common cause of pneumonia in HIV antibody positive patients, but other pneumonias remain important, i.e. streptococcal and mycobacterial infections. A definitive diagnosis relies on obtaining samples from the lung either noninvasively (induced sputum), or invasively (bronchoalveolar lavage, transbronchial or open lung biopsy). We have used the noninvasive technique of nebulized 99mTc DTPA transfer, to assess patients with PCP (n = 30) and other lung infections (n = 20) to see whether this test will distinguish between the various infections. The presence of a biphasic, rapid transfer curve indicates severe extensive alveolar damage and is seen in PCP or legionella pneumonia. The mean transfer time (T50 +/- SEM) for patients with PCP (whether smokers or nonsmokers) was 2.1 +/- 0.2 min, and for two of the patients with legionella 3.2 min. In PCP effective treatment causes the transfer to slow (mean T50 22.7 +/- 3.3 min, n = 24) and become monoexponential. Other causes of these changes in transfer are discussed. The other pneumonias (streptococcal, mycobacterial, and staphylococcal) did not result in biphasic curves or very rapid times, their T50 values are indistinguishable from cigarette smokers. In this patient group the DTPA transfer is a useful noninvasive investigation with a very rapid, biphasic curve indicating a high probability of PCP.     

Increased lung permeability following long-term use of free-base cocaine (crack)

The clearance of inhaled 99mTc DTPA aerosol from the lungs is used as an index of lung epithelial permeability. Using the radioaerosol method, we investigated the effects of long-term "crack" (free-base cocaine) inhalation on lung permeability in 23 subjects. Eighteen control subjects (12 nonsmokers and 6 cigarette smokers) with no history of drug use were also studied. Subjects inhaled approximately 150 muCi (approximately 5.6 MBq) of 99mTc DTPA aerosol and quantitative gamma camera images of the lungs were acquired at 1-min increments for 25 minutes. Regions of interest (ROIs) were selected to include the following: (1) both lungs; (2) each individual lung; and (3) the upper, middle, and lower thirds of each lung. 99mTc DTPA lung clearance was determined from the slopes of the respective time-activity plots for the different RIOs. Radioaerosol clearance half-times (T1/2) for the seven nonsmoking crack users (61.5 +/- 18.3 minutes) were longer than for the seven cigarette-smoking crack users (27.9 +/- 16.9 minutes) and nine cigarette-smoking crack plus marijuana users (33.5 +/- 21.6 minutes). T1/2 for the nonsmoking crack users was significantly shorter (p less than 0.001) than for the nonsmoking control group (123.8 +/- 28.7 minutes). T1/2 for the cigarette-smoking drug users was similar to that of the cigarette-smoking control group (33.1 +/- 17.8 minutes), suggesting a similar mechanism of damage from the smoke of crack and tobacco. From these groups, one nonsmoker and 11 cigarette smokers displayed biexponential 99mTc DTPA clearances, indicative of greater lung injury than found in the usual cases of monoexponential clearance. The upper lungs of all crack users groups cleared faster than the lower lungs. The faster and biexponential clearance properties of inhaled 99mTc DTPA aerosol were the principal functional abnormalities found in all the drug users. In contrast, 19 of 23 crack users had normal spirometry and gas exchange. These results indicate that 99mTc DTPA may provide a sensitive and useful assay to evaluate the physiologic effects of cocaine inhalation in the lung.     

Granulomatous Pneumocystis carinii pneumonia in Wegener's granulomatosis.

This study reports on a first case of granulomatous Pneumocystis carinii pneumonia (PCP) in a human immunodeficiency virus-negative patient with antineutrophil cytoplasmic antibody-positive Wegener's granulomatosis whilst receiving immunosuppressive treatment. The patient presented with diffuse alveolar haemorrhage, pauci-immune rapid progressive glomerulonephritis and leukocytoclastic vasculitis of the skin. Granulomatous Pneumocystis carinii pneumonia developed under immunosuppressive treatment with cyclophosphamide and prednisone. At the time Pneumocystis carinii pneumonia developed, there was a marked lymphopenia with a very low CD8+ cell count in the blood. Grocott staining in bronchoalveolar lavage fluid revealed no Pneumocystis carinii. The diagnosis was made via a video-assisted thoracoscopic lung biopsy which showed granulomas containing high numbers of Pneumocystis carinii cysts.     

Non-invasive management of fever and breathlessness in HIV positive patients

In a prospective study of 72 human immunodeficiency virus (HIV) positive patients presenting with fever and breathlessness, a non-invasive management protocol, incorporating a scanning technique using radioactively labelled diethylenetriamine penta acetate (DTPA) and sputum induction, was found to be highly sensitive and specific in the early detection of Pneumocystis carinii pneumonia (PCP). At presentation, the DTPA scan was abnormal in 34 of 36 cases of PCP, irrespective of smoking history, whilst the chest radiograph was diffusely abnormal in 21 cases. Sputum induction identified 7 of 14 patients with PCP in the first six months of its use and 7 of 10 patients over the last six months. The DTPA lung scan and induced sputum examination are non-invasive techniques which can be used to investigate out-patients. In combination they detected all cases of PCP at presentation, reduced the need for bronchoscopy, resulted in a low case fatality (5.4%) and reduced the need for admission.     

Pneumocystis pneumonia increases the clearance rate of inhaled 99mTc DTPA from lung to blood

Despite no radiographic change, a patient with Pneumocystis pneumonia showed increased clearance of inhaled 99mTc DTPA from lung to blood. Gas transfer for carbon monoxide was also reduced, but improved with treatment. This was paralleled by serial increase in the t1/2 LB.     

Occurrence of Pneumocystis carinii in HIV-positive patients with suspected pulmonary tuberculosis in Ethiopia

OBJECTIVE: To investigate the prevalence of Pneumocystis carinii in consecutive HIV-positive patients with suspected pulmonary tuberculosis (PTB) attending a university hospital in Ethiopia. METHODS: A PCR for P. carinii and an indirect immunoflorescence (IF) assay were performed on expectorated sputum samples from: 119 HIV-1-positive patients with negative smears and sputum cultures for Mycobacterium tuberculosis; 96 HIV-1-positive patients with culture-verified PTB; and 97 HIV-negative patients with negative mycobacterial cultures and 72 HIV-negative patients with culture-verified PTB, serving as controls. Outcome of PCR and IF were compared with the chest radiographic (CXR) and initial clinical diagnosis. RESULTS: In the HIV+PTB- group, P. carinii was found in 10.9% by IF, 8.4% by single PCR (sPCR) and 30.3% by nested PCR (nPCR). In the HIV+PTB+ group, 3.1% were P. carinii positive by IF and sPCR and 13.5% by nPCR. All IF- and sPCR-positive samples were nPCR positive. In the HIV-PTB+ and HIV-PTB- groups, 4.2% and 3.1% were nPCR positive, respectively. Six out of eight HIV+PTB- patients with CXR suggesting P. carinii pneumonia (PCP) were IF and/or nPCR positive for P. carinii. In the IF-positive and nested PCR-positive HIV+PTB- patients more than one-third were interpreted as PTB by CXR whereas only one patient was diagnosed with clinical PCP. CONCLUSIONS: P. carinii is prevalent in HIV-positive PTB suspects, suggesting that PCP may be an important, but not well recognized, differential diagnosis. Our findings have implications for treatment and primary prophylaxis for PCP in Ethiopia.     

Thoracic magnetic resonance imaging in the evaluation of HIV-1/AIDS pneumonitis.

Magnetic resonance imaging of the thorax was performed on ten occasions in eight HIV-positive patients with a clinical picture suggestive of Pneumocystis carinii pneumonia. The diagnosis of PCP was subsequently confirmed on six occasions. Patients without PCP had low MRI profusion scores, while four of six patients with PCP had MRI profusion scores greater than 6/21. Neither the chest roentgenogram appearance nor computer-generated T1 and T2 relaxation times could reliably distinguish between these two groups. Magnetic resonance imaging may be useful in the early and noninvasive diagnosis of PCP in HIV-positive patients.     

Procoagulant and fibrinolytic activities in bronchoalveolar fluid of HIV-positive and HIV-negative patients.

Imbalance between intra-alveolar procoagulant activity (PCA) and fibrinolytic activity may lead to fibrin deposition, as described in several pneumopathies, and may eventually contribute to fibrotic changes as observed in Pneumocystis carinii pneumonia (PCP). The aim of our study was to compare these activities in bronchoalveolar lavages of human immunodeficiency virus (HIV)-positive and HIV-negative patients. The material comprised: a) controls (n = 7); b) HIV-positive patients subdivided into PCP (n = 11), bacterial pneumonia (n = 8) and other pneumopathies (n = 22); and c) HIV-negative patients with bacterial pneumonia (n = 8). PCA was significantly increased (p less than 0.05) in all patient groups compared to controls. The urokinase-type plasminogen activator (u-PA) antigen levels were highest during bacterial pneumonia. Regardless of the HIV status, in bacterial pneumonia there was a marked elevation of plasminogen activator inhibitor antigens with little residual fibrinolytic activity. In contrast, the fibrinolytic activity was not decreased in PCP. D-dimer were elevated during PCP compared to controls; the highest levels were found in HIV-negative bacterial pneumonia. These data indicate that transient fibrotic changes seen in PCP may be favoured by increased PCA, but not by a depressed fibrinolytic activity. In bacterial pneumonia PCA is increased and fibrinolysis decreased independently of the HIV status.     

Postoperative respiratory failure secondary to Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia (PCP) occurs frequently in individuals infected with the HIV virus. Malignancy, immunosuppressive drugs, and congenital immune deficiency may be associated with PCP. We describe a patient with stage 1 testicular carcinoma who developed hypoxemic respiratory failure two days after retroperitoneal lymph node dissection. Pneumocystis carinii organisms were demonstrated by catheter lavage samples and confirmed on bronchoalveolar lavage. Testing for HIV antibody by ELISA and the Western blot test were negative; HIV viral culture and polymerase chain reaction were also negative. Pneumocystis carinii pneumonia is unusual in localized surgically cured malignancies without obvious immunodeficiency and, to our knowledge, has not been described as a cause of postoperative respiratory failure.     

Help yourself defeat the lung infection called PCP. National Institutes of Health

Many HIV patients develop Pneumocystis carinii pneumonia (PCP), a lung infection characterized by fever, fatigue, weight loss, dry cough, and shortness of breath. Medicines can help fight PCP by keeping the immune system stronger, preventing the onset of the disease, and preventing recurrent infections. Patients are encouraged to maintain regular health care check-ups, develop a healthy style of living, and follow any PCP treatment or prophylaxis as prescribed to prevent this potentially severe infection.     

Detection of HIV-1 in human lung macrophages using the polymerase chain reaction

We have used the polymerase chain reaction to investigate HIV-1 infection of lung macrophages from 44 AIDS patients with pneumonia. Proviral HIV-1 DNA was detected in the lung macrophages of 47% (21 of 44) of patients tested; 32% (seven of 21) of the patients had Pneumocystis carinii pneumonia (PCP), and 56% (11 of 21) had pneumonia caused by other aetiological agents. Matched peripheral blood specimens were obtained from 22 patients in this study, and HIV-1-specific DNA was detected in 100% (22 out of 22) of non-adherent white cell preparations tested. HIV was detected in blood monocytes of 11 out of 22 patients (50%), and a virus signal was also found in the lung macrophages of eight of these patients. Our results indicate that PCP does not predispose lung macrophages to HIV-1, nor does HIV-1 infection of lung macrophages increase the probability of contracting PCP.     

Presentation of Pneumocystis carinii pneumonia as unilateral hyperlucent lung

Pneumocystis carinii pneumonia (PCP) presented as unilateral hyperlucent lung in a 27-month-old patient with a brain tumor who was receiving chemotherapy. Although unilateral pneumonia is an uncommon presentation of PCP in non-AIDS patients, PCP must be suspected in any pediatric cancer patient not receiving trimethoprim-sulfamethoxazole prophylaxis and receiving intensive chemotherapy.     

S-adenosylmethionine levels in the diagnosis of Pneumocystis carinii pneumonia in patients with HIV infection.

BACKGROUND: S-adenosylmethionine (AdoMet) is a key molecule involved in methylation reactions and polyamine synthesis. Pneumocystis carinii are unable to synthesize this molecule and have been shown to scavenge this metabolic intermediate from the plasma of rats during active infection. A prior study involving humans strongly suggested that low levels of plasma AdoMet are sensitive and specific indicators of acute infection. METHODS: From March 2004 through January 2006, we collected plasma AdoMet levels from patients with human immunodeficiency virus (HIV) infection and either confirmed Pneumocystis carinii pneumonia (PCP), confirmed pulmonary tuberculosis, or confirmed bacterial pneumonia. We compared levels in patients with PCP with those in patients with other diseases and also monitored changes in levels during treatment of PCP. RESULTS: Initial AdoMet levels were significantly lower in patients with PCP, and there was no overlap between the groups. Among patients with PCP, levels of AdoMet increased with successful treatment. CONCLUSIONS: Measurement of plasma AdoMet levels in patients with HIV infection who have pulmonary infections can identify those with PCP.     

The spectrum of chest infections in HIV positive patients in Edinburgh.

In a retrospective analysis of all known HIV-positive patients admitted to the City Hospital before November 1989, 208 patients accounted for 612 admissions, 72% being injection drug users (IDUs). One hundred and eighty admissions (29%) were for chest-related disorders, and this was the commonest reason for admission. Unlike other U.K. centres where more than 50% chest problems are due to Pneumocystis carinii pneumonia (PCP), only 27% of our chest admissions were for PCP. Fifty-four percent of chest admissions were for bacterial chest infections (BCIs), the commonest organism isolated being Haemophilus influenzae. Despite the fact that most (50/97) of these admissions were in patients with 'asymptomatic' HIV disease (CDC classification 2 and 3), 50% had radiological pneumonia, 43% were hypoxic, 28% were hypercapnic and the average duration of hospitalisation was 10 days. BCIs were more common in HIV-positive IDUs when compared with HIV-negative IDUs, other HIV-positive patients and the general age-matched population. Medical provision for IDU-related HIV disease should take into account the high rate of BCIs and of hospital admissions in patients who do not yet have CDC stage 4 disease.     

Role of multiple induced sputum examination in the diagnosis of Pneumocystis carinii pneumonia

We evaluated the usefulness of repeated nebulized saline induced sputum examinations among 60 HIV infected patients clinically suspected to have Pneumocystis carinii pneumonia (PCP). We found that the first sample was positive for 15 episodes (21.4%); the second sample was positive in 33 episodes (47.1%); the third sample was positive in 22 episodes (31.4%). Repeated nebulized saline induced sputum examination imporved the yield of Pneumocystis carinii and enhanced the sensitivity of a positive result. This technique is simple, cost-effective, non-invasive, and reliable. We recommend the examination of multiple induced samples of nebulized saline induced sputum in all HIV infected patients with suspected PCP. This recommendation may decrease the need for invasive procedures.     

Pneumocystis carinii pneumonia in AIDS patients: clinical course in relation to the parasite number found in routine specimens obtained by fiberoptic bronchoscopy.

The aim of this study was to evaluate whether the amount of Pneumocystis carinii organisms found at fiberoptic bronchoscopy (FB) performed on HIV-positive patients correlated to the character of the P. carinii pneumonia (PCP). A consecutive series of 105 patients presented with 131 episodes of pulmonary symptoms requiring FB, and in 75 of these episodes a diagnosis of PCP was made. Specimens were stained with Giemsa and methenamine silver nitrate and the number of parasites found was given as: numerous, many, few or none. The following signs and symptoms were registered: cough, dyspnoea, fever, loss of weight, chest radiograph, haemoglobin, WBC, CD4 cell count, PO2 and HIV p24 antigen. The PCP was characterized by the clinical course: mild, moderate, severe, and by the outcome: pulmonary healthy, pulmonary insufficiency and death. No correlations between the number of P. carinii organisms and the clinical course or outcome of the PCP, the symptoms before the FB or the paraclinical examinations were found. In conclusion, the routinely obtained quantitative results of the microbiological examinations of material from the lungs were not correlated to the severity of the PCP.     

AIDS-related Pneumocystis carinii pneumonia with disappearance of cystic lesions after treatment

A 21-year-old hemophiliac with human immunodeficiency virus (HIV) infection was admitted to our hospital because of bilateral pneumothoraces associated with Pneumocysis carinii pneumonia (PCP). He underwent chest tube drainages and intravenous pentamidine therapy, resulting in clinical improvement. Two months after treatment for PCP, cystic lesions that had existed before treatment disappeared on chest computed tomography. We concluded that Pneumocystis carinii infection might be associated with lung destruction and cyst formation, and that inflammatory exudates in the small bronchioles might act as a ball-valve with subsequent spontaneous pneumothoraces.     

Discontinuation of chemoprophylaxis against Pneumocystis carinii pneumonia in patients with HIV infection. HIV Outpatient Study (HOPS) Investigators

BACKGROUND: HIV-infected patients with sustained immunologic improvement from antiretroviral therapy may be able to discontinue chemoprophylaxis against Pneumocystis carinii pneumonia (PCP). OBJECTIVE: To compare PCP incidence in HIV-infected patients who had sustained CD4+ lymphocyte counts greater than 200 cells/mm3 and who either discontinued or continued PCP prophylaxis. DESIGN: Nonrandomized prospective cohort study. SETTING: 10 HIV clinics in eight U.S. cities. PATIENTS: 146 patients had follow-up visits for a mean of 18.2 months after discontinuation of PCP prophylaxis, and 345 patients who continued PCP prophylaxis had follow-up visits for a mean of 14.0 months. MEASUREMENTS: Incidence of PCP. RESULTS: Patients who discontinued PCP prophylaxis had higher maximum and minimum CD4+ cell counts and lower vira loads than patients who continued PCP prophylaxis. Pneumocystis carinii pneumonia did not develop in either group (upper 95% exact binomial confidence limit of incidence for those who discontinued PCP prophylaxis, 2.3/100 person-years). CONCLUSIONS: Discontinuation of PCP chemoprophylaxis may be appropriate for some HIV-infected ambulatory patients.     

Bilateral upper-lobe cavitary Pneumocystis carinii pneumonia in a patient on dapsone prophylaxis

Pneumocystis carinii pneumonia (PCP) presenting as bilateral upper-lobe cavitary disease is rare. Isolated upper-lobe involvement has traditionally been associated with aerosolized pentamidine prophylaxis. Dapsone is a cheap and effective prophylactic agent against P carinii in patients who cannot tolerate trimethoprim-sulfamethoxazole. This is a case of a man who presented with bilateral upper-lobe cavitary P carinii pneumonia despite being on dapsone prophylaxis. Bronchoalveolar lavage was negative for P carinii. Transbronchial biopsy was positive for P carinii. The patient improved significantly with radiological resolution on specific treatment for P carinii. PCP should be included in the differential diagnosis of upper-lobe cavitary lung disease, and a transbronchial biopsy should be performed when the diagnosis is suspected.     

Surfactant analysis during Pneumocystis carinii pneumonia in HIV-infected patients.

Pulmonary surfactant is altered in experimental Pneumocystis carinii pneumonia. Although P carinii is a major causative agent of pneumonia in immunocompromised patients, the pathophysiology of lung injury caused by this organism is poorly understood. Therefore, we studied bronchoalveolar lavage specimens obtained from 19 HIV-infected subjects with PCP compared with specimens from ten healthy control subjects. As iterative BAL was performed, 37 BAL specimens were analyzed for protein and phospholipid. The BAL samples were divided into two groups as follows: 22 BAL samples with the presence of P carinii and 15 BAL samples without P carinii. Compared to control subjects, HIV+ BAL presented a significant increase of PR and a decrease of total PL in both P carinii+ and P carinii- BAL, but in P carinii+ BAL, the fall of PL/PR ratio was significantly more pronounced compared to P carinii- (0.09 +/- 0.02 vs 0.19 +/- 0.04, p less than 0.02). The BAL performed during the recovery of PCP showed an improvement of initial biochemical abnormalities. Surfactant composition was also altered, with a phosphatidylcholine and phosphatidylglycerol drop and a sphingomyelin and lysophosphatidylcholine increase. The presence, even in P carinii- BAL, of less polar compounds of undetermined nature, was revealed. We concluded that in HIV+ patients, abnormalities of pulmonary surfactant were present before PCP, and that the development of PCP enhances these abnormalities. These surfactant alterations may contribute to the saprophyte-pathogen transformation of P carinii, but this hypothesis requires further investigation that is presently in progress.