NONRESOLVING AND SLOWLY RESOLVING PNEUMONIA

Paediatric pulmonary disease-are we diagnosing it right?

Background

It has been reported that differential diagnosis of bacterial or viral pneumonia and tuberculosis (TB) in infants and young children is complex. This could be due to the difficulty in microbiological confirmation in this age group. In this study, we aimed to assess the utility of a real-time multiplex PCR for diagnosis of respiratory pathogens in children with pulmonary TB.

Methods

A total of 185 respiratory samples [bronchoalveolar lavage (15), gastric aspirates (98), induced sputum (21), and sputum (51)] from children aged 3-12 years, attending tertiary care hospitals, Chennai, India, were included in the study. The samples were processed by N acetyl L cysteine (NALC) NAOH treatment and subjected to microbiological investigations for Mycobacterium tuberculosis (MTB) diagnosis that involved smear microscopy, Xpert® MTB/RIF testing, and liquid culture. In addition, DNA extraction from the processed sputum was carried out and was subjected to a multiplex real-time PCR comprising a panel of bacterial and fungal pathogens.

Results

Out of the 185 samples tested, a total of 20 samples were positive for MTB by either one or more identification methods (smear, culture, and GeneXpert). Out of these 20 MTB-positive samples, 15 were positive for one or more bacterial or fungal pathogens, with different cycle threshold values. Among patients with negative MTB test results (n = 165), 145 (87%) tested positive for one or more than one bacterial or fungal pathogens.

Conclusion

The results suggest that tuberculosis could coexist with other respiratory pathogens causing pneumonia. However, a large-scale prospective study from different geographical settings that uses such simultaneous detection methods for diagnosis of childhood tuberculosis and pneumonia will help in assessing the utility of these tests in rapid diagnosis of respiratory infections.

CT-guided biopsy of nonresolving focal air space consolidation

OBJECTIVES

To evaluate the diagnostic accuracy of percutaneous computed tomography (CT)-guided coaxial core needle biopsy in patients with nonresolving pulmonary focal air space consolidations and negative fiberoptic bronchoscopy results.

METHODS

From 1997 to 2005, 23 patients (11 woman, 12 men; age range, 45 to 81 y; mean age, 66 y) presenting with nonresolving pneumonia persisting more than 8 weeks (mean, 22 wk; range, 8 to 40 wk) with negative fiberscopic results, underwent coaxial percutaneous biopsy using an automated core needle (18-gauge) under CT guidance. Histologic and bacteriologic evaluations were obtained. The final diagnosis was confirmed by surgical pathology, culture results, or clinical follow-up.

RESULTS

Specimens adequate for histopathologic evaluations were obtained in 20 (87%) cases. Final diagnoses were lung cancer (n=15) and benign diseases (infectious pneumonia, 3; lipoid pneumonia, 1; Erdheim Chester disease: 1; and nonspecific chronic pneumonia, 3). Diagnostic yield of core needle biopsy was 78% (18 of 23). The sensitivity and specificity for malignancy were 87% and 100%, respectively. Immediate pneumothorax was present in 11 patients of cases, but only 2 patients required pleural drainage.

DISCUSSION

CT-guided lung biopsy using a core needle biopsy provides a high degree of diagnostic accuracy and allows specific characterization of nonresolving pulmonary focal air space consolidation.

Treatment failure in community-acquired pneumonia

Treatment failure (TF) is defined as a clinical condition with inadequate response to antimicrobial therapy. Clinical response should be evaluated within the first 72 h of treatment, whereas infiltrate images may take up to 6 weeks to resolve. Early failure is considered when ventilatory support and/or septic shock appear within the first 72 h. The incidence of treatment failure in community-acquired pneumonia is 10 to 15%, and the mortality is increased nearly fivefold. Resistant and unusual microorganisms and noninfectious causes are responsible for TF. Risk factors are related to the initial severity of the disease, the presence of comorbidity, the microorganism involved, and the antimicrobial treatment implemented. Characteristics of patients and factors related to inflammatory response have been associated with delayed resolution and poor prognosis. The diagnostic approach to TF depends on the degree of clinical impact, host factors, and the possible cause. Initial reevaluation should include a confirmation of the diagnosis of pneumonia, noninvasive microbiological samples, and new radiographic studies. A conservative approach of clinical monitoring and serial radiographs may be recommended in elderly patients with comorbid conditions that justify a delayed response. Invasive studies with bronchoscopy to obtain protected brush specimen and BAL are indicated in the presence of clinical deterioration or failure to stabilize. BAL processing should include the study of cell patterns to rule out other noninfectious diseases and complete microbiological studies. The diagnostic yield of imaging procedures with noninvasive and invasive samples is up to 70%. After obtaining microbiological samples, an empirical change in antibiotic therapy is required to cover a wider microbial spectrum.

[Guidelines for the management of community pneumonia in adult who needs hospitalization]

Community acquired pneumonia is still an important health problem. In Spain the year incidence is 162 cases per 100,000 inhabitants with 53,000 hospital admission costing 115 millions of euros per year. In the last years there have been significant advances in the knowledge of: aetiology, diagnostic tools, treatment alternatives and antibiotic resistance. The Spanish Societies of Intensive and Critical Care (SEMICYUC), Infectious Diseases and Clinical Microbiology (SEIMC) and Pulmonology and Thoracic Surgery (SEPAR) have produced these evidence-based Guidelines for the management of community acquired pneumonia in Adults. The main objective is to help physicians to make decisions about this disease. The different points that have been developed are: aetiology, diagnosis, treatment and prevention.

Non-infectious and unusual infectious mimics of community-acquired pneumonia

Noninfectious or unusual infectious diseases may present with clinical, radiological and laboratorial characteristics of community-acquired pneumonia (CAP). Usually their presence is only suspected after treatment failure, leading to inappropriate interventions, unnecessary costs and risks related to the untreated potentially life-threatening disease. The present study aimed to assess the noninfectious or unusual infectious diseases that may be misdiagnosed as CAP that progresses with treatment failure. Sixteen hospitalized patients with presumptive diagnosis of CAP and treatment failure were described. The most prevalent symptoms were fever and cough. Radiological pattern of air-space disease was observed in 10 (62%) patients. The diagnosis was established by autopsy (12%) or invasive procedures (88%), as follows: open lung biopsy (nine), flexible fiberoptic bronchoscopy (two), transthoracic fine needle aspiration (two) and bone marrow aspiration (one). Eight patients had noninfectious diseases: pulmonary embolism, cryptogenic organizing pneumonia, Wegener's granulomatosis, hypersensitivity pneumonitis, bronchocentric granulomatosis, neoplastic disease and acute leukemia. The unusual infectious diseases were: tuberculosis, cryptococcosis, actinomycosis, histoplasmosis and paracoccidioidomycosis. Patients with noninfectious or unusual infectious diseases may present with symptoms and radiological findings that mimic CAP. These diseases should always be suspected in patients who do not respond to initial empirical antimicrobial treatment, especially young patients or those without comorbidity.

Treatment failures in patients with ventilator-associated pneumonia

Treatment failures in patients with VAP are a complex issue and form a major challenge for clinicians. The following key elements inherent to a rational approach to treatment failures have been elucidated: (1) the presence of treatment failure must be thoroughly defined and assessed; (2) the many causes behind treatment failures must be realized, particularly the possibility of pneumonia-related and extrapulmonary reasons; (3) the recognition of different patterns of treatment failures as a useful framework for decisions about modalities and intensity of diagnostic reassessment; and (4) the establishment of a protocol for the search of pulmonary and extrapulmonary sites of infection and noninfectious causes of nonresponse. Only such a rational approach precludes the adverse effects of blind empiricism, which always implies a dangerous and costly overtreatment. Many issues related to treatment failures remain unsettled, and efforts will have to be made in the future to improve current clinical attitudes to treatment failures in VAP.

Radiographic Resolution of Community-Acquired Bacterial Pneumonia in the Elderly

OBJECTIVES

To investigate the radiographic clearance of proven community-acquired nontuberculous bacterial pneumonia in nonimmunocompromised older patients to provide working estimates of the rate of radiographic resolution as a function of the patient cumulative comorbidities, extent of initial radiographic involvement, functional status, and causative pathogens.

DESIGN

A prospective study.

PARTICIPANTS

Seventy-four patients aged 70 and older, consecutively admitted to a hospital for community-acquired bacterial pneumonia.

SETTING

A university-affiliated teaching hospital.

MEASUREMENTS

Chest radiographs were performed every 3 weeks from the date of admission for a total period of 12 weeks or until all radiographic abnormalities had resolved or returned to baseline.

RESULTS

Sixty-four patients (86%) completed the study. The rate of radiographic clearance was estimated at 35.1% within 3 weeks, 60.2% within 6 weeks, and 84.2% within 12 weeks. Radiographic resolution was significantly slower for those with high comorbidity index, bacteremia, multilobar involvement, and enteric gram-negative bacilli pneumonias. Multivariate regression analysis demonstrated that the comorbidity index (relative risk for clearance=0.67 per class index, P<.001) and multilobar disease (relative risk for clearance=0.24 for more than one lobe, P<.001) had independent predictive value (Cox proportional hazards regression model) on the rate of resolution.

CONCLUSION

The radiographic resolution of nontuberculous bacterial pneumonia in the elderly should take into account the extent of lobar disease and the burden of underlying illnesses. A waiting period of 12 to 14 weeks is recommended for slowly resolving pneumonia to be considered nonresolving.

Nonresolving or slowly resolving pneumonia

Given the variability in rate of radiographic resolution, it remains controversial to decide when to initiate an invasive diagnostic work-up for nonresolving or slowly resolving pulmonary infiltrates. In immunocompetent patients who present with classical features of CAP (i.e., fever, chills, productive cough, new pulmonary infiltrate), clinical response to therapy is the most important determinant for further diagnostic studies. Within the first few days, persistence or even progression of infiltrates on chest radiographs is not unusual. Defervescence, diminished symptoms, and resolution of leukocytosis strongly support a response to antibiotic therapy, even when chest radiographic abnormalities persist. In this context, observation alone is reasonable, and invasive procedures can be deferred. Serial radiographs and clinical examinations dictate subsequent evaluation. In contrast, when clinical improvement has not occurred and chest radiographs are unchanged or worse, a more aggressive approach is warranted. In this setting, we advise fiberoptic bronchoscopy with BAL and appropriate cultures for bacteria, legionella, fungi, and mycobacteria. When endobronchial anatomy is normal and there is no purulence to suggest infection, TBBs should be done to exclude noninfectious causes (discussed earlier) or infections attributable to mycobacteria or fungi. An aggressive approach is also warranted in patients who are clinically stable or improving when the rate of radiographic resolution is delayed. As discussed earlier, what constitutes excessive delay is controversial, and depends upon the acuity of illness, specific pathogen, extent of involvement (i.e., lobar versus multilobar), comorbidities, and diverse host factors. Stable infiltrates even 2 to 4 weeks after institution of antibiotic therapy does not mandate intervention provided patients are improving clinically. Invasive techniques can also be deferred when unequivocal, albeit incomplete, radiographic resolution can be demonstrated. Lack of at least partial radiographic resolution by 6 weeks, even in asymptomatic patients, however, deserves consideration of alternative causes (e.g., endobronchial obstructing lesions, or noninfectious causes). Fiberoptic bronchoscopy with BAL and TBBs has minimal morbidity and is the preferred initial invasive procedure for detecting endobronchial lesions or substantiating noninfectious causes. The yield of bronchoscopy depends on demographics, radiographic features, and pre-test likelihood. In the absence of specific risk factors, the incidence of obstructing lesions (e.g., bronchogenic carcinomas, bronchial adenomas, obstructive foreign body) is low. Bronchogenic carcinoma is rare in nonsmoking, young (< 50 years) patients but is a legitimate consideration in older patients with a history of tobacco abuse. Non-neoplastic causes (e.g., pulmonary vasculitis, hypersensitivity pneumonia, etc.) should be considered when specific features are present (e.g., hematuria, appropriate epidemiologic exposures). Ancillary serologic tests or biopsies of extrapulmonary sites are invaluable in some cases. In rare instances, surgical (open or VATS) biopsy is necessary to diagnose refractory or non-resolving "pneumonias."