Diagnostic Invasive Procedures in Diffuse Infiltrative Lung Diseases

Functional predictors of exertional dyspnea, 6-min walking distance and HRCT fibrosis score in idiopathic pulmonary fibrosis

BACKGROUND

Exertional dyspnea and exercise incapacity are the most prominent and disabling symptoms and the main contributors to health-related quality of life in patients with idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

There are no comprehensive studies on pulmonary function tests (PFTs), dyspnea, exercise capacity and radiographic scores in IPF. We therefore sought to investigate the functional variables that can predict dyspnea, exercise capacity and disease extent in IPF.

METHODS

Thirty-four patients with IPF according to the ATS/ERS criteria underwent PFTs, Medical Research Council (MRC) dyspnea scoring, 6-min walking distance (6-MWD) and radiographic evaluation of fibrosis (HRCT score).

RESULTS

The 6-MWD (% pred.) was more impaired than PFTs. Residual volume (RV) showed the best correlation with the extent of fibrosis (r = -0.67, p = 0.0001) and, together with the alveolar-arterial gradient for O(2) [DeltaP(A - a)O(2)], was an independent predictor of disease extent (R(2) = 0.44). PFTs showed significant though weak correlations with MRC score and 6-MWD. According to the regression analysis, DL(CO) and the HRCT fibrosis score were independent predictors of dyspnea, though they explained only 28% of the overall variance. FEV(1) and DeltaP(A - a)O(2) were independent predictors of 6-MWD (R(2) = 0.31).

CONCLUSIONS

PFTs and lung volumes in particular are closely related to the HRCT score, a measure of the extent of IPF. The correlation of dyspnea score and 6-MWD to PFTs is limited, due to the complexity of mechanisms leading to exercise limitation in IPF. Therefore dyspnea and exercise performance are largely independent indices and should be followed together with PFTs and HRCT score in order to better assess the status and progress of IPF patients.

[Usefulness of transbronchial and surgical biopsies for the management of interstitial lung disease]

Interpretation of lung material can be very difficult in patients with interstitial lung disease. The pathologist must be particularly familiar with this type of situation since, unlike tumor diseases, the diagnosis is not purely histological and must always be established in correlation with the clinical and radiological presentation. In patients with suspected interstitial lung disease, the first diagnostic step is to perform a transbronchial biopsy or bronchoalveolar lavage. In many cases the two minimally invasive techniques can be combined to guide the diagnosis or establish confirmation. The indications for surgical biopsy can thus be limited to very exceptional situations. We recall here the requirement for rigorous handling of the endoscopic or surgical specimens and discuss the specific difficulties in interpreting the pathological material, focusing on the contribution of the pathological study to clinical surveillance of the disease course and its complications, particularly in treated patients. A close collaboration between clinicians and pathologists is essential for optimal diagnosis and management of interstitial lung disease.

[Contribution of bronchoalveolar lavage to the management of interstitial lung disease]

Bronchoalveolar lavage (BAL) is a minimally invasive method for exploring the distal lung. It enables collection of free cellular and acellular material present in the alveoli. Over the last two decades BAL has become a fundamental tool for positive diagnosis of interstitial lung disease and even more for differential diagnosis. It has contributed greatly to the diagnosis of lung infections, particularly in immunosuppressed patients. In the context of non-infectious infiltrative disease, the diagnostic contribution of BAL is limited due to the lack of a specific cell profile. It remains a fundamental tool for the differential diagnosis of idiopathic interstitial pneumonia. With BAL, a number of infectious or tumoral diseases can be ruled out with precision. It is also an important element for the evaluation of possible iatrogenic disease. BAL has transformed the diagnosis of interstitial lung disease and considerably reduced the indications for surgical biopsy.

Induced sputum versus bronchoalveolar lavage fluid in the evaluation of patients with idiopathic pulmonary fibrosis

BACKGROUND

Induced sputum (IS) has been proposed as a useful noninvasive method for the assessment of airway diseases. Bronchoalveolar lavage fluid (BALF), an important tool for evaluating interstitial lung diseases, has limited utility due to its invasiveness and the difficulties of performing it in severely ill patients, while it is impractical for follow-up evaluation.

OBJECTIVES

The aim of this study was to investigate the differences and the possible correlation of cell differential and lymphocyte subpopulations between BALF and IS samples in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

We studied prospectively 20 patients (18 male, 2 female) of median age 67 years (range 40-75) with IPF and 10 normal subjects (5 female, 5 male) of median age 59 years (range 36-70). IS was performed with hypertonic saline solution using an ultrasonic nebulizer (Ultraneb 2000). BALF was performed by a conventional procedure using fiberoptic bronchoscopy within 3 days from IS. May-Grunewald-Giemsa-stained preps were differentially counted and T-lymphocyte subsets were analyzed by a flow-activated cell sorter.

RESULTS

The percentage of macrophages was significantly lower in IS than in BALF (p < 0.0001), while the neutrophils were lower in BALF (p < 0.0001). A significant correlation was found between BALF and IS eosinophil counts (r = 0.54, p = 0.01) and CD4+/CD8+ ratio (r = 0.74, p < 0.0001).

CONCLUSION

Our data suggest that different information is obtained by IS and BALF and thus, the two methods are complementary in IPF.

Increased levels of interleukin-18 in bronchoalveolar lavage fluid of patients with idiopathic nonspecific interstitial pneumonia

BACKGROUND

Interleukin-18 (IL-18) is a proinflammatory cytokine that can induce interferon-gamma (IFN-gamma), and it plays an important role in T-helper 1 responses. Among idiopathic interstitial pneumonia (IIP), nonspecific interstitial pneumonia (NSIP) has an increased number of lymphocytes in bronchoalveolar lavage (BAL) fluid compared with usual interstitial pneumonia (UIP). However, the difference in their pathogenesis is unclear.

OBJECTIVE

The present study aims to investigate the roles of IL-18 in patients with idiopathic UIP and idiopathic NSIP.

METHODS

We measured the serum and BAL fluid (BALF) levels of IL-18 and IFN-gamma in 22 patients with IIP (12 with UIP, 10 with NSIP) and 9 healthy volunteers.

RESULTS

Lymphocyte proportions in BALF were significantly higher in NSIP than in UIP and healthy subjects. No significant differences were observed in the serum IL-18 levels of all subjects, while the BALF levels of IL-18 in patients with NSIP were significantly higher than in patients with UIP (p < 0.005) and in healthy subjects (p < 0.005). Among all subjects, the levels of IL-18 in BALF correlated significantly with those in serum and the lymphocyte proportions in BALF. The serum IFN-gamma levels of all subjects were below sensitivity, but there was significant reverse correlation between the levels of IFN-gamma and the lymphocyte proportions in BALF.

CONCLUSION

The lymphocytosis in BALF of patients with idiopathic NSIP and a part of idiopathic UIP might be associated with the high levels of IL-18.

Do High-Resolution CT Findings of Usual Interstitial Pneumonitis Obviate Lung Biopsy?

BACKGROUND

High-resolution CT (HRCT) of the lungs has become an essential component to evaluate patients with diffuse lung disease. Little is known, however, about the current practices of pulmonologists caring for patients with these complex conditions, and, in particular, whether HRCT can obviate the need for surgical lung biopsy.

OBJECTIVES

To investigate the practices of pulmonologists concerning the acceptability of a HRCT diagnosis in lieu of lung biopsy in diffuse lung disease.

METHODS

We asked practicing pulmonologists among membership of the American College of Chest Physicians whether HRCT results could replace lung biopsy in 16 diffuse lung diseases. Responses were examined in light of published evidence, practice guidelines, and certain practice parameters.

RESULTS

Two hundred and thirty (52.6%) of 437 eligible physicians responded. Sixty-seven percent (67%) of respondents accepted HRCT diagnosis for idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) despite their awareness of guidelines recommending histological diagnosis. Most would not accept a radiologic diagnosis for lymphangioleiomyomatosis (LAM; 37%) or eosinophilic granuloma (Langerhans' cell histiocytosis, LCH; 19%), even though CT findings are frequently characteristic. Responses were similar by type of clinical practice and recency of fellowship training. Chest physicians who referred patients for HRCT more frequently were more likely to accept HRCT diagnosis (p=0.008) and those who had higher self-ratings of proficiency in reading HRCT (p = 0.004) were more likely to believe HRCT often suggests specific diagnosis.

CONCLUSIONS

Most US pulmonologists will accept an HRCT diagnosis of IPF/UIP without lung biopsy, but are reluctant to do so for most other diffuse lung conditions including LAM and LCH.

Unusual Presentation of Sarcoidosis

The extrapulmonary presentation of sarcoidosis is a frequent occurrence - over 30% of cases when the observation is prospective - but early diagnosis may still be a challenge. A comparison between two different Italian series - (1) patients visiting the Milan Sarcoidosis Clinic of an Internal Medicine Department and (2) an Italian Register from many pneumology centers (RIPID) - has shown a different approach to the diagnosis because pneumologists are more likely to use transbronchial biopsy, while internists are more likely to use extrapulmonary biopsies. Such a different clinical approach may be due in part to a different case mix of the two series.