Quantitative Analysis of Lung Shape in Idiopathic Pulmonary Fibrosis: Insights Into Disease- and Age-Associated Patterns

RATIONALE AND OBJECTIVES

Fibrotic scarring in idiopathic pulmonary fibrosis (IPF) typically develops first in the posterior-basal lung tissue before advancing to involve more of the lung. The complexity of lung shape in the costo-diaphragmatic region has been proposed as a potential factor in this regional development. Intrinsic and disease-related shape could therefore be important for understanding IPF risk and its staging. We hypothesized that lung and lobe shape in IPF would have important differences from controls.

MATERIALS AND METHODS

A principal component (PC) analysis was used to derive a statistical shape model (SSM) of the lung for a control cohort aged > 50 years (N = 39), using segmented lung and fissure surface data from CT imaging. Individual patient shape models derived for baseline (N = 18) and follow-up (N = 16) CT scans in patients with IPF were projected to the SSM to describe shape as the sum of the SSM average and weighted PC modes. Associations between the first four PC shape modes, lung function, percentage of fibrosis (fibrosis%) and pulmonary vessel-related structures (PVRS%), and other tissue metrics were assessed and compared between the two cohorts.

RESULTS

Shape was different between IPF and controls (P < 0.05 for all shape modes), with IPF shape forming a distinct shape cluster. Shape had a negative relationship with age in controls (P = 0.013), but a positive relationship with age in IPF (P = 0.026). Some features of shape changed on follow-up. Shape in IPF was associated with fibrosis% (P < 0.05) and PVRS% (P < 0.05).

CONCLUSION

Quantitative comparison of lung and lobe shape in IPF with controls of a similar age reveals shape differences that are strongly associated with age and percent fibrosis. The clustering of IPF cohort shape suggests that it could be an important feature to describe disease.

Evaluating Tissue Heterogeneity in the Radiologically Normal-Appearing Tissue in IPF Compared to Healthy Controls

RATIONALE AND OBJECTIVES

Idiopathic Pulmonary Fibrosis (IPF) is a progressive interstitial lung disease characterised by heterogeneously distributed fibrotic lesions. The inter- and intra-patient heterogeneity of the disease has meant that useful biomarkers of severity and progression have been elusive. Previous quantitative computed tomography (CT) based studies have focussed on characterising the pathological tissue. However, we hypothesised that the remaining lung tissue, which appears radiologically normal, may show important differences from controls in tissue characteristics.

MATERIALS AND METHODS

Quantitative metrics were derived from CT scans in IPF patients (N = 20) and healthy controls with a similar age (N = 59). An automated quantitative software (CALIPER, Computer-Aided Lung Informatics for Pathology Evaluation and Rating) was used to classify tissue as normal-appearing, fibrosis, or low attenuation area. Densitometry metrics were calculated for all lung tissue and for only the normal-appearing tissue. Heterogeneity of lung tissue density was quantified as coefficient of variation and by quadtree. Associations between measured lung function and quantitative metrics were assessed and compared between the two cohorts.

RESULTS

All metrics were significantly different between controls and IPF (p < 0.05), including when only the normal tissue was evaluated (p < 0.04). Density in the normal tissue was 14% higher in the IPF participants than controls (p < 0.001). The normal-appearing tissue in IPF had heterogeneity metrics that exhibited significant positive relationships with the percent predicted diffusion capacity for carbon monoxide.

CONCLUSION

We provide quantitative assessment of IPF lung tissue characteristics compared to a healthy control group of similar age. Tissue that appears visually normal in IPF exhibits subtle but quantifiable differences that are associated with lung function and gas exchange.

Inhaled pirfenidone solution (AP01) for IPF: a randomised, open-label, dose-response trial

INTRODUCTION

Oral pirfenidone reduces lung function decline and mortality in patients with idiopathic pulmonary fibrosis (IPF). Systemic exposure can have significant side effects, including nausea, rash, photosensitivity, weight loss and fatigue. Reduced doses may be suboptimal in slowing disease progression.

METHODS

This phase 1b, randomised, open-label, dose-response trial at 25 sites in six countries (Australian New Zealand Clinical Trials Registry (ANZCTR) registration number ACTRN12618001838202) assessed safety, tolerability and efficacy of inhaled pirfenidone (AP01) in IPF. Patients diagnosed within 5 years, with forced vital capacity (FVC) 40%-90% predicted, and intolerant, unwilling or ineligible for oral pirfenidone or nintedanib were randomly assigned 1:1 to nebulised AP01 50 mg once per day or 100 mg two times per day for up to 72 weeks.

RESULTS

We present results for week 24, the primary endpoint and week 48 for comparability with published trials of antifibrotics. Week 72 data will be reported as a separate analysis pooled with the ongoing open-label extension study. Ninety-one patients (50 mg once per day: n=46, 100 mg two times per day: n=45) were enrolled from May 2019 to April 2020. The most common treatment-related adverse events (frequency, % of patients) were all mild or moderate and included cough (14, 15.4%), rash (11, 12.1%), nausea (8, 8.8%), throat irritation (5, 5.5%), fatigue (4, 4.4%) and taste disorder, dizziness and dyspnoea (three each, 3.3%). Changes in FVC % predicted over 24 and 48 weeks, respectively, were -2.5 (95% CI -5.3 to 0.4, -88 mL) and -4.9 (-7.5 to -2.3,-188 mL) in the 50 mg once per day and 0.6 (-2.2 to 3.4, 10 mL) and -0.4 (-3.2 to 2.3, -34 mL) in the 100 mg two times per day group.

DISCUSSION

Side effects commonly associated with oral pirfenidone in other clinical trials were less frequent with AP01. Mean FVC % predicted remained stable in the 100 mg two times per day group. Further study of AP01 is warranted.

TRIAL REGISTRATION NUMBER

ACTRN12618001838202 Australian New Zealand Clinical Trials Registry.

Pulmonary vessel volume in idiopathic pulmonary fibrosis compared with healthy controls aged > 50 years

Idiopathic pulmonary fibrosis (IPF) is characterised by progressive fibrosing interstitial pneumonia with an associated irreversible decline in lung function and quality of life. IPF prevalence increases with age, appearing most frequently in patients aged > 50 years. Pulmonary vessel-like volume (PVV) has been found to be an independent predictor of mortality in IPF and other interstitial lung diseases, however its estimation can be impacted by artefacts associated with image segmentation methods and can be confounded by adjacent fibrosis. This study compares PVV in IPF patients (N = 21) with PVV from a healthy cohort aged > 50 years (N = 59). The analysis includes a connected graph-based approach that aims to minimise artefacts contributing to calculation of PVV. We show that despite a relatively low extent of fibrosis in the IPF cohort (20% of the lung volume), PVV is 2-3 times higher than in controls. This suggests that a standardised method to calculate PVV that accounts for tree connectivity could provide a promising tool to provide early diagnostic or prognostic information in IPF patients and other interstitial lung disease.

Cardiorespiratory responses to muscle metaboreflex activation in fibrosing interstitial lung disease

New Findings

What is the central question of this study?

We determined whether sensory feedback from metabolically sensitive skeletal muscle afferents (metaboreflex) causes a greater ventilatory response and higher dyspnoea ratings in fibrosing interstitial lung disease (FILD).

What is the main finding and its importance?

Ventilatory responses and dyspnoea ratings during handgrip exercise and metaboreflex isolation were not different in FILD and control groups. Blood pressure and heart rate responses to handgrip were attenuated in FILD but not different to controls during metaboreflex isolation. These findings suggest that the muscle metaboreflex contribution to the respiratory response to exercise is not altered in FILD.

Abstract

Exercise limitation and dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD); however, the physiological mechanisms are poorly understood. In other respiratory diseases, there is evidence that an augmented muscle metaboreflex may be implicated. We hypothesized that metaboreflex activation in FILD would result in elevated ventilation and dyspnoea ratings compared to healthy controls, due to augmented muscle metaboreflex. Sixteen FILD patients (three women, 69±14 years; mean±SD) and 16 age‐matched controls (four women, 67±7 years) were recruited. In a randomized cross‐over design, participants completed two min of rhythmic handgrip followed by either (i) two min of post‐exercise circulatory occlusion (PECO trial) to isolate muscle metaboreflex activation, or (ii) rested for four min (Control trial). Minute ventilation (V˙E; pneumotachometer), dyspnoea ratings (0–10 Borg scale), mean arterial pressure (MAP; finger photoplethysmography) and heart rate (HR; electrocardiogram) were measured. V˙E was higher in the FILD group at baseline and exercise increased V˙E similarly in both groups. V˙E remained elevated during PECO, but there was no between‐group difference in the magnitude of this response (ΔV˙E FILD 4.2 ± 2.5 L·min^–1 vs. controls 3.6 ± 2.4 L·min^–1, P = 0.596). At the end of PECO, dyspnoea ratings in FILD were similar to controls (1.0 ± 1.3 units vs. 0.5 ± 1.1 units). Exercise increased MAP and HR (P < 0.05) in both groups; however, responses were lower in FILD. Collectively, these findings suggest that there is not an augmented effect of the muscle metaboreflex on breathing and dyspnoea in FILD, but haemodynamic responses to handgrip are reduced relative to controls.

A computational model of contributors to pulmonary hypertensive disease: impacts of whole lung and focal disease distributions

Pulmonary hypertension has multiple etiologies and so can be difficult to diagnose, prognose, and treat. Diagnosis is typically made via invasive hemodynamic measurements in the main pulmonary artery and is based on observed elevation of mean pulmonary artery pressure. This static mean pressure enables diagnosis, but does not easily allow assessment of the severity of pulmonary hypertension, nor the etiology of the disease, which may impact treatment. Assessment of the dynamic properties of pressure and flow data obtained from catheterization potentially allows more meaningful assessment of the strain on the right heart and may help to distinguish between disease phenotypes. However, mechanistic understanding of how the distribution of disease in the lung leading to pulmonary hypertension impacts the dynamics of blood flow in the main pulmonary artery and/or the pulmonary capillaries is lacking. We present a computational model of the pulmonary vasculature, parameterized to characteristic features of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension to help understand how the two conditions differ in terms of pulmonary vascular response to disease. Our model incorporates key features known to contribute to pulmonary vascular function in health and disease, including anatomical structure and multiple contributions from gravity. The model suggests that dynamic measurements obtained from catheterization potentially distinguish between distal and proximal vasculopathy typical of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. However, the model suggests a non-linear relationship between these data and vascular structural changes typical of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension which may impede analysis of these metrics to distinguish between cohorts.

Systemic Associations of Sarcoid Uveitis: Correlation With Uveitis Phenotype and Ethnicity

PURPOSE

To examine systemic associations of sarcoid uveitis and association with uveitis clinical phenotype and ethnicity.

DESIGN

Retrospective cross-sectional study.

SUBJECTS

A total of 362 subjects with definite or presumed sarcoid uveitis from Moorfields Eye Hospital, Royal Victorian Eye and Ear, and Auckland District Health Board.

METHODS

Data were collected from the review of clinical notes, imaging, and investigations. Sarcoidosis was diagnosed in accordance with the International Workshop on Ocular Sarcoidosis guidelines.

MAIN OUTCOME MEASURE

Diagnosis of associated systemic disease secondary to sarcoidosis.

RESULTS

A total of 362 subjects with sarcoid uveitis were identified. Median age was 46 years, and 226 (62.4%) were female. Granulomatous anterior uveitis (47.8%), intermediate uveitis with snowballs (46.4%), and multifocal choroiditis (43.1%) were the most frequent clinical presentations, and disease was bilateral in 313 (86.5%). Periphlebitis was observed in 21.0%, and solitary optic nerve or choroidal granuloma in 11.3%. Lung parenchymal disease was diagnosed in 200 subjects (55.2%), cutaneous sarcoid in 98 (27.1%), sarcoid arthritis in 57 (15.7%), liver involvement in 21 (5.8%), neurosarcoid in 49 (13.5%), and cardiac sarcoid in 16 subjects (4.4%). Subjects with cardiac sarcoid were less likely to have granulomatous anterior uveitis (P = .017). Caucasian subjects were older at presentation (48 vs 41 years; P = .009), had less granulomatous anterior uveitis (26.4% vs 51.7%; P < .001), and were less likely to present with cutaneous involvement (23.1% vs 35.4%; P = .040).

CONCLUSIONS

Ophthalmologists need to be aware of the systemic associations of sarcoid uveitis, in particular potentially life-threatening complications such as cardiac sarcoidosis. Differences observed in uveitis phenotype and between ethnicities require further investigation.

Diagnosis and management of connective tissue disease-associated interstitial lung disease in Australia and New Zealand: A position statement from the Thoracic Society of Australia and New Zealand

Pulmonary complications in CTD are common and can involve the interstitium, airways, pleura and pulmonary vasculature. ILD can occur in all CTD (CTD-ILD), and may vary from limited, non-progressive lung involvement, to fulminant, life-threatening disease. Given the potential for major adverse outcomes in CTD-ILD, accurate diagnosis, assessment and careful consideration of therapeutic intervention are a priority. Limited data are available to guide management decisions in CTD-ILD. Autoimmune-mediated pulmonary inflammation is considered a key pathobiological pathway in these disorders, and immunosuppressive therapy is generally regarded the cornerstone of treatment for severe and/or progressive CTD-ILD. However, the natural history of CTD-ILD in individual patients can be difficult to predict, and deciding who to treat, when and with what agent can be challenging. Establishing realistic therapeutic goals from both the patient and clinician perspective requires considerable expertise. The document aims to provide a framework for clinicians to aid in the assessment and management of ILD in the major CTD. A suggested approach to diagnosis and monitoring of CTD-ILD and, where available, evidence-based, disease-specific approaches to treatment have been provided.

Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: an international case-cohort study

We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts.A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κ_w). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index.A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κ_w=0.65, IQR 0.53-0.72, p<0.0001) than academic physicians (κ_w=0.56, IQR 0.45-0.65, p<0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κ_w=0.54, IQR 0.45-0.64, p<0.0001). The prognostic accuracy of academic physicians with >20 years of experience (C-index=0.72, IQR 0.0-0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70-0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72-0.75).Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts.

Bone density is normal and does not change over 2 years in sarcoidosis

SUMMARY

Small studies have previously suggested that sarcoidosis may be associated with low bone mineral density. In this observational study of 64 patients with sarcoidosis, bone mineral density was within the normal range at baseline, and there was no evidence of accelerated bone loss over 1-2 years.

INTRODUCTION

Several small studies have suggested that sarcoidosis may be associated with low bone mineral density (BMD).

METHODS

We undertook a cross-sectional study of BMD in 64 patients with sarcoidosis. Of these, 27 with 25-hydroxyvitamin D<50 nmol/L entered a 1-year intervention study of vitamin D supplements, and 37 entered a 2-year longitudinal study of BMD, with the primary endpoint of the change in lumbar spine BMD.

RESULTS

The mean age of participants was 58 years, 68% were female, and 8% were currently using oral glucocorticoids. At baseline, BMD for the entire cohort was greater than the expected values for the population at the lumbar spine (mean Z-score 0.7, P<0.001) and total body (0.5, P<0.001) and similar to expected values at the femoral neck (0.2, P=0.14) and total hip (0.2, P=0.14). BMD did not change at any of these four sites (P>0.19) over 2 years in the longitudinal study. In the intervention study, vitamin D supplements had no effect on BMD, and therefore we pooled the data from all participants. BMD did not change over 1 year at the spine, total hip, or femoral neck (P>0.3), but decreased by 0.7% (95% confidence interval 0.3-1.1) at the total body (P=0.019).

CONCLUSIONS

BMD was normal at baseline, and there was no consistent evidence of accelerated bone loss over 1-2 years, regardless of baseline vitamin D status. Patients with sarcoidosis not using oral glucocorticoids do not need routine monitoring of BMD.

Hypoxic pulmonary vasoconstriction as a contributor to response in acute pulmonary embolism

Hypoxic pulmonary vasoconstriction (HPV) is an adaptive response unique to the lung whereby blood flow is diverted away from areas of low alveolar oxygen to improve ventilation-perfusion matching and resultant gas exchange. Some previous experimental studies have suggested that the HPV response to hypoxia is blunted in acute pulmonary embolism (APE), while others have concluded that HPV contributes to elevated pulmonary blood pressures in APE. To understand these contradictory observations, we have used a structure-based computational model of integrated lung function in 10 subjects to study the impact of HPV on pulmonary hemodynamics and gas exchange in the presence of regional arterial occlusion. The integrated model includes an experimentally-derived model for HPV. Its function is validated against measurements of pulmonary vascular resistance in normal subjects at four levels of inspired oxygen. Our results show that the apparently disparate observations of previous studies can be explained within a single model: the model predicts that HPV increases mean pulmonary artery pressure in APE (by 8.2 ± 7.0% in these subjects), and concurrently shows a reduction in response to hypoxia in the subjects who have high levels of occlusion and therefore maximal HPV in normoxia.

Randomised controlled trial of vitamin D supplementation in sarcoidosis

OBJECTIVES

The role vitamin D intake/production plays in sarcoidosis-associated hypercalcaemia is uncertain. However, authoritative reviews have recommended avoiding sunlight exposure and vitamin D supplements, which might lead to adverse skeletal outcomes from vitamin D insufficiency. We investigated the effects of vitamin D supplementation on surrogate measures of skeletal health in patients with sarcoidosis and vitamin D insufficiency.

DESIGN

Randomised, placebo-controlled trial.

SETTING

Clinical research centre.

PARTICIPANTS

27 normocalcaemic patients with sarcoidosis and 25-hydroxyvitamin D (25OHD) <50 nmol/L.

INTERVENTION

50 000 IU weekly cholecalciferol for 4 weeks, then 50 000 IU monthly for 11 months or placebo.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary endpoint was the change in serum calcium over 12 months, and secondary endpoints included measurements of calcitropic hormones, bone turnover markers and bone mineral density (BMD).

RESULTS

The mean age of participants was 57 years and 70% were women. The mean (SD) screening 25OHD was 35 (12) and 38 (9) nmol/L in the treatment and control groups, respectively. Vitamin D supplementation increased 25OHD to 94 nmol/L after 4 weeks, 84 nmol/L at 6 months and 78 nmol/L at 12 months, while levels remained stable in the control group. 1,25-Dihydroxy vitamin D levels were significantly different between the groups at 4 weeks, but not at 6 or 12 months. There were no between-groups differences in albumin-adjusted serum calcium, 24 h urine calcium, markers of bone turnover, parathyroid hormone or BMD over the trial. One participant developed significant hypercalcaemia after 6 weeks (total cholecalciferol dose 250 000 IU).

CONCLUSIONS

In patients with sarcoidosis and 25OHD <50 nmol/L, vitamin D supplements did not alter average serum calcium or urine calcium, but had no benefit on surrogate markers of skeletal health and caused one case of significant hypercalcaemia.

TRIAL REGISTRATION

This trial is registered at the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au). The registration number is ACTRN12607000364471, date of registration 5/7/2007.

Ventilatory and cardiac responses to pulmonary embolism: consequences for gas exchange and blood pressure

Acute thromboembolic pulmonary embolism (PE) is a life threatening condition that can lead to pulmonary hypertension and right ventricular dysfunction or failure. There is typically an increase in ventilation rate and cardiac output as a response to PE prior to cardiac failure, which is at least in part due to systemic hypoxemia. Here we assess the response of the lungs to changes in these parameters using anatomically-based computational models of pulmonary perfusion, ventilation and gas exchange. We show that increases in ventilation and cardiac output improve overall gas exchange in PE. However, this comes at the cost of an increased pulmonary blood pressure, which may contribute to pulmonary hypertension as a result of PE.

The prevalence and predictors of airway hyperresponsiveness in sarcoidosis

BACKGROUND AND OBJECTIVE

Obstructive airflow limitation is the most common physiological impairment in sarcoidosis. This study determined the prevalence of airway hyperresponsiveness (AHR) in sarcoidosis, the correlation between responses to direct (using histamine) and indirect (using hypertonic saline) bronchial challenge, and the clinical, physiological and radiological predictors of AHR.

METHODS

Subjects with sarcoidosis and a baseline forced expiratory volume in 1 s (FEV(1)) >35% predicted underwent hypertonic and histamine challenge, lung function testing and high resolution computed tomography (HRCT) of the chest. AHR was defined as a 15% fall in FEV(1) to hypertonic saline and a 20% fall in FEV(1) to histamine.

RESULTS

The 52 subjects had well-preserved lung function (FEV(1) = 2.8 ± 0.7 L, 87% predicted). AHR was detected in 5/47 (11%) to hypertonic saline and 19/43 (44%) to histamine challenge. On univariate analysis, response to histamine challenge was predicted by conglomerate fibrosis (P = 0.02) and reticular pattern (P = 0.03) on HRCT. The baseline % predicted forced expiratory volume in 1 s was significantly inversely associated with AHR on univariate (P = 0.004) and multivariate analysis (P = 0.01) when adjusted by HRCT patterns.

CONCLUSIONS

The higher prevalence of AHR using histamine challenge than hypertonic saline challenge and the association with baseline % predicted FEV(1) suggest that the AHR in sarcoidosis may reflect the consequences of airway remodelling following inflammation.

Pulmonary embolism: predicting disease severity

Pulmonary embolism (PE) is the most common cause of acute pulmonary hypertension, yet it is commonly undiagnosed, with risk of death if not recognized promptly and managed accordingly. Patients typically present with hypoxemia and hypomania, although the presentation varies greatly, being confounded by co-morbidities such as pre-existing cardio-respiratory disease. Previous studies have demonstrated variable patient outcomes in spite of similar extent and distribution of pulmonary vascular occlusion, but the path physiological determinants of outcome remain unclear. Computational models enable exact control over many of the compounding factors leading to functional outcomes and therefore provide a useful tool to understand and assess these mechanisms. We review the current state of pulmonary blood flow models. We present a pilot study within 10 patients presenting with acute PE, where patient-derived vascular occlusions are imposed onto an existing model of the pulmonary circulation enabling predictions of resultant haemodynamic after embolus occlusion. Results show that mechanical obstruction alone is not sufficient to cause pulmonary arterial hypertension, even when up to 65 per cent of lung tissue is occluded. Blood flow is found to preferentially redistribute to the gravitationally non-dependent regions. The presence of an additional downstream occlusion is found to significantly increase pressures.

Lower occurrence of idiopathic pulmonary fibrosis in Maori and Pacific Islanders

OBJECTIVE

Idiopathic pulmonary fibrosis (IPF), a chronic fibro-proliferative interstitial pneumonia, has not been reported to occur more frequently in any particular race. We have observed that our patients with IPF comprise a proportionately lower number of Maori and Pacific Islanders and set out to evaluate this further.

METHODS

Retrospective analysis of an IPF database from a single tertiary respiratory institution was undertaken. Demographic and survival data were collected. Ethnicity was compared with 2001 New Zealand census data from the same catchment area.

RESULTS

Eighty-seven cases of IPF were identified. Overall median survival was 46 months. Ethnicity data were available for 84 of the 87 cases. 76/84 (90%) were European, 6/84 (7%) were Asian or Indian, 2/84 (2%) were Maori, and 0/84 (0%) were Pacific Islanders. For Maori and Pacific Islanders, this represented a significant trend in difference when compared with ethnicity data from the hospital catchment population (P < 0.001).

CONCLUSIONS

Our department is the tertiary referral centre for pulmonary disease in the upper North Island of New Zealand, and therefore referral centre bias is likely to be low. The preliminary observation that the occurrence of IPF is lower in those of Maori or Polynesian ethnicity warrants further study. This may, in part, help in our understanding of the pathogenic mechanisms in IPF.

Interstitial Lung Disease: Effects of Thin-Section CT on Clinical Decision Making

PURPOSE

To retrospectively quantify the change in the diagnosis and management of suspected interstitial lung disease when thin-section computed tomography (CT) is added to pretest probabilities.

MATERIALS AND METHODS

The institutional review board does not require approval or patient informed consent for retrospective study of case records and CT studies. Six pulmonologists reviewed data sheets containing clinical information and results of pulmonary function tests and chest radiographs of 168 consecutive patients (86 women and 82 men; mean age, 59.8 years; age range, 22-86 years) suspected of having interstitial lung disease. Differential diagnoses and responses to specific questions regarding patient care were recorded before and after assimilation of thin-section CT findings. Both unweighted and weighted kappa analyses were used to determine agreement between pulmonologists before and after CT.

RESULTS

First-choice diagnosis changed in 520 (51%) of 1008 cases, and agreement on first-choice diagnosis increased from 0.47 to 0.72 after thin-section CT. In addition, confidence in the first-choice diagnosis increased, and there was a reduction in the number of differential diagnoses offered by all pulmonologists (P < .005 and P < .001, respectively). Agreement on diagnostic probabilities for individual disorders increased substantially, particularly for diagnoses of idiopathic pulmonary fibrosis (weighted kappa = 0.58-0.89). With CT findings, pulmonologists changed their pre-CT responses regarding the use of bronchoalveolar lavage, transbronchial biopsy, and thoracoscopic biopsy in 242 (24.0%), 282 (28.0%), and 292 (29.0%) of 1008 cases, respectively. However, agreement for the use of these investigations was low both before and after CT. The request rate for thoracoscopic biopsy in patients in whom idiopathic fibrosis was diagnosed decreased from 48 of 179 (26.8%) to 26 of 233 (11.2%) after CT.

CONCLUSION

Thin-section CT resulted in a change in first-choice diagnosis in half the cases. Diagnostic confidence improved, and CT findings increased agreement between pulmonologists on diagnostic probabilities across a range of interstitial lung diseases.

Exhaled nitric oxide in sarcoidosis

BACKGROUND

Increased production of nitric oxide (NO) by the lower respiratory tract is viewed as a marker of airway inflammation in asthma and bronchiectasis. NO is a potentially important immune modulator, inhibiting the release of several key pro-inflammatory cytokines. As sarcoidosis is characterised by granulomatous airway inflammation, we hypothesised that exhaled NO levels might be raised in sarcoidosis and correlate with the morphological extent and functional severity of disease.

METHODS

Fifty two patients with sarcoidosis (29 men) of mean age 42 years underwent thin section computed tomography (CT), pulmonary function tests, and measurement of exhaled NO.

RESULTS

Exhaled NO levels (median 6.8 ppb, range 2.4-21.8) did not differ significantly from values in 44 control subjects, and were not related to the extent of individual CT abnormalities or the level of pulmonary function impairment.

CONCLUSION

Exhaled NO levels are not increased in pulmonary sarcoidosis.

Asthma phenotypes in Niue Islanders

OBJECTIVE

The aim of this study was to identify asthma phenotypes in patients of Niue Island ancestry that might be suitable for susceptibility gene mapping studies.

METHODOLOGY

Two hundred and sixteen Niue Islanders with physician-diagnosed asthma that was not secondary to other medical conditions were recruited through community organisations. Fifty-one of the subjects with asthma were resident on Niue Island and 165 in New Zealand. Each subject was interviewed and tested for atopy, serum [IgE] (5% quantile, median, 95% quantile) and lung function.

RESULTS

There were two groups of subjects defined by an age of onset of asthma less than 12 years of age (childhood-onset, boys:girls 64:65) and greater than 12 years of age (adult-onset, men:women 11:76). A positive response (wheal > 3 mm) to at least one aeroallergen was seen in 181 patients, with 168/181 (92.8%) responding to house dust mite. Twenty-eight subjects with asthma were non-atopic (no detectable wheal) and the atopy status of seven subjects with asthma could not be determined (wheal < 3 mm). In childhood-onset asthma, serum IgE levels were higher (P < 0.0001) in subjects with atopic than in subjects with non-atopic asthma. In adult-onset asthma, serum IgE levels were higher (P < 0.0001) in subjects with atopic asthma than in either subjects with non-atopic asthma or matched non-atopic subjects without asthma. The asthma phenotypes in Niue Island and New Zealand residents were similar.

CONCLUSIONS

Both atopic and non-atopic asthma phenotypes exist in Niue Islanders resident in Niue and New Zealand. The potential for mapping asthma susceptibility genes in this isolated population is discussed.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Human in vitro immune responses to Mycobacterium tuberculosis

SETTING

T helper cells can be divided into 2 subsets on the basis of their cytokine generation. T helper 1 cells secreting gamma interferon and interleukin 2 appear to be more prominent in patients with limited tuberculous disease.

OBJECTIVE

The purpose of this study was to evaluate human T helper cell immune responses to mycobacterial antigens in vitro and correlate these with the clinical features of patients with tuberculous infection or disease.

DESIGN

We studied 51 subjects and 11 controls who were grouped according to disease involvement as follows: 1) Mantoux negative, BCG negative, no disease; 2) Mantoux positive, no disease; 3) localized extrapulmonary; 4) healed pulmonary; 5) active pulmonary; and 6) miliary/disseminated. Peripheral blood mononuclear cells were cultured with PHA, PPD or Tetanus Toxoid, proliferation assessed and the supernatant analysed using an ELISA for IFN gamma. ELISA was also used to measure M. tuberculosis specific antibodies in the serum.

RESULTS

Mantoux size correlated with PPD proliferation r = 0.5, P = 0.005 and gamma IFN production r = 0.36, P < 0.01. All groups produced abundant gamma IFN although there was a trend toward higher production in groups 3 and 4. M. tuberculosis specific IgA (P = 0.003) and IgG1 (P = 0.002) was higher in groups 5 and 6. Those patients with limited disease (groups 2-4) had significantly lower levels of IgG4 than patients with severe disease (groups 5 & 6) (P < 0.02).

CONCLUSION

In conclusion patients with healed or extrapulmonary disease have immune responses in vitro suggestive of a TH1 (cell mediated immune) response, whereas patients with miliary/disseminated disease have antibody production suggestive of a TH2 response, together with high gamma IFN production. Both TH1 and TH2 responses may be necessary for host protection if there is a high bacillary load.

Bronchiolitis obliterans organising pneumonia associated with the use of nitrofurantoin

The spectrum of nitrofurantoin lung injury continues to widen. The case histories are presented of two patients who developed lung disease associated with the use of nitrofurantoin with histological features of bronchiolitis obliterans organising pneumonia (BOOP), a rare but recognised form of drug induced injury. The two middle aged women presented with respiratory symptoms after prolonged treatment with nitrofurantoin. Both had impaired lung function and abnormal computed tomographic scans, and their condition improved when nitrofurantoin was withdrawn and corticosteroid treatment commenced. The favourable outcome in these two patients contrasts with the fatal outcome of the two other reported cases of nitrofurantoin induced BOOP. We suggest that the previous classification of nitrofurantoin induced lung injury into "acute" and "chronic" injury is an oversimplification in view of the wide variety of pathological entities that have subsequently emerged.

Cystic fibrosis diagnosed in adult patients

AIM

To review the presentation, diagnosis and long-term, clinical follow-up of cystic fibrosis in adult patients diagnosed in adulthood at Green Lane Hospital.

METHODS

A retrospective review of the case notes of patients with cystic fibrosis diagnosed in adulthood at Green Lane Hospital or referred there for management. Information was collected on diagnostic tests, including sweat tests and genotyping. Relevant family history was documented as were spirometry results and microbial colonisation.

RESULTS

Six patients conclusively fulfilled the diagnostic criteria for cystic fibrosis. There was a wide range of ages at diagnosis (18-68) and half of the patients had a positive family history. A single mutation was identified in all, but in only one of the cases was the second mutation identified. All patients had evidence of bronchopulmonary suppuration and all had retained pancreatic function. Colonisation with P aeruginosa was associated with marked impairment in lung function.

CONCLUSION

The patients at Green Lane Hospital represent part of the broad-spectrum disease in adult patients diagnosed with cystic fibrosis and highlight the differences between this group and those patients diagnosed in childhood with the more classical phenotype. Patients generally have less severe lung disease and retain pancreatic function. Sweat testing is useful diagnostically but gene testing is of limited value in making the diagnosis.

Pulmonary sarcoidosis: morphologic associations of airflow obstruction at thin-section CT

PURPOSE

To identify relationships between the obstructive defects of pulmonary sarcoidosis and the computed tomographic (CT) patterns of disease.

MATERIAL AND METHODS

CT scans obtained in 45 patients were scored semiquantitatively for extent of five CT patterns, and the functional importance of each pattern was evaluated.

RESULTS

The most prevalent CT patterns were decreased attenuation (n = 40), a reticular pattern (n = 37), and a nodular pattern (n = 36). At univariate and multivariate analyses, a reticular pattern was the main determinant of functional impairment, particularly airflow obstruction. The extent of a reticular pattern was independently associated with airflow obstruction, as shown by the inverse relationships with the forced expiratory volume in 1 second (FEV1) (P < .001), FEV1-forced vital capacity ratio (P < .01), maximum expiratory flow at 25% above residual volume (P < .001), and maximum expiratory flow at 50% above residual volume (P < .001) and the positive relationship with the residual volume-total lung capacity ratio (P < .001).

CONCLUSION

In sarcoidosis, CT features compatible with small airways disease are common but contribute little to airflow obstruction, particularly in more advanced disease, which is characterized by an extensive reticular pattern. A reticular pattern at CT is the major morphologic association of airflow obstruction.

Seasonal clustering of sarcoidosis presenting with erythema nodosum

Seasonal clustering of sarcoidosis presenting with erythema nodosum (EN) has previously been reported only in the northern hemisphere. Of 59 patients presenting to a single centre in New Zealand with a new diagnosis of sarcoidosis, 21 had EN and three more had acute arthralgia without EN. These patients were compared with the rest of the cohort. The patients with EN or arthralgia alone presented exclusively between April and December, with peak clustering in the spring months of August, September and October (p<0.001, Fisher's exact test). This cohort was more likely to have a stage I chest radiograph and to be female (p<0.05), but there were no other differences between the groups. This is the first report of seasonal clustering in the southern hemisphere suggesting a common environmental trigger in the aetiology of sarcoidosis.

Mycobacterium tuberculosis DNA in tissues affected by sarcoidosis

BACKGROUND

Although some studies have reported the presence of Mycobacterium tuberculosis (MTb) DNA in tissues affected by sarcoidosis, the data are conflicting. The aim of this study was to collect prospectively tissue from patients with sarcoidosis in whom tuberculosis had been excluded, and to use polymerase chain reaction (PCR) to search for DNA sequences specific for MTb.

METHODS

Fresh tissue samples (node or lung biopsy) taken from 23 patients with newly diagnosed sarcoidosis, 10 with other respiratory disease, and four patients with culture positive tuberculosis were analysed using PCR to amplify a 123 bp fragment of IS6110, the insertion element present in MTb, and nested PCR to further amplify an 85 bp sequence within the 123 bp product. DNA was also extracted from formalin fixed tissue from eight additional patients with sarcoidosis.

RESULTS

MTb DNA was not detected in any of the tissue samples from patients with sarcoidosis or other respiratory disease but was found in all four patients with tuberculosis.

CONCLUSIONS

This study has shown the absence of MTb DNA in lymph node and lung biopsy samples from patients with sarcoidosis. MTb is therefore unlikely to be a factor in the pathogenesis of this disease.

Medical thoracoscopy in the diagnosis of unexplained pleural effusion

Approximately 20% of pleural effusions remain without an established aetiology after evaluation. Thoracoscopy has a very high sensitivity for the diagnosis of both benign and malignant diseases and greatly increases the diagnostic yield for pleural effusion. We sought to evaluate the diagnostic yield and safety of medical thoracoscopy at this institution. The records of all patients undergoing medical thoracoscopy for the evaluation of undiagnosed pleural effusion between 1990 and 1996 were reviewed. The procedure was performed under local anaesthesia with sedation using a Stortz rigid thoracoscope. Fifty-eight patients had thoracoscopy, most having had two (range: 1-6) non-diagnostic pleural aspirations and biopsies of the pleura. Nineteen patients were found to have mesothelioma and nine metastatic malignancy. Three patients were considered likely to have tuberculous pleural disease, six had asbestos related benign pleural fibrosis and three post-cardiotomy syndrome. There was one chylous effusion of uncertain aetiology, one posttraumatic and two other benign effusions, both of which resolved without clear aetiology. On seven occasions the pleural space could not be adequately accessed, but none of these patients had prior computerized tomography (CT) or ultrasound of the pleural space. There were five false negative diagnoses of malignancy, but no false positives. The diagnostic sensitivity for pleural malignancy was 85% and specificity 100%. There were no major complications, but four patients had late tumour seeding at the thoracoscopy site. Medical thoracoscopy is a safe procedure with a high diagnostic yield. Pre-operative evaluation of the pleural collection using ultrasound or CT increases the likelihood of successful access to the pleural space and may increase diagnostic yield.

Nosocomial acquisition of Burkholderia gladioli in patients with cystic fibrosis

Burkholderia gladioli has been reported as colonizing the airways of patients with cystic fibrosis (CF) but has not previously been associated with adverse outcome. We describe six patients with CF in whom the same strain of B. gladioli, on the basis of ribotyping and biochemical characteristics, was grown in their sputum. Acquisition of this organism was followed by a fatal outcome in all six patients; one had a rapid decline in respiratory status and another developed fulminant B. gladioli bacteremia. Evidence suggests that patient-to-patient transmission of the organism occurred, and supports nosocomial infection in the ward and/or outpatient clinic despite general and stringent infection-control measures. This is the first report of adverse clinical outcome following sputum colonization with B. gladioli, and the first to demonstrate person-to-person transmission.

Gamma/delta cells in tissue from patients with sarcoidosis

BACKGROUND

Because gamma/delta T lymphocytes (gamma delta cells) respond to myco-bacterial antigens in vitro and accumulate in the skin lesions of patients with certain granulomatous infections (leprosy, leishmaniasis), it was hypothesised that these cells might have a role in the pathogenesis of sarcoidosis, a disease also characterised by granuloma formation. Having failed to demonstrate an increase in gamma delta cells in the blood of patients with sarcoidosis, the aim of this study was to examine samples of bronchoalveolar lavage (BAL) fluid and biopsy tissue.

METHODS

Samples from 23 patients (13 women) with newly diagnosed sarcoidosis, of mean age 31 years and median percentage of lymphocytes in the BAL fluid of 31%, were studied. Controls included normal subjects and patients with other interstitial lung diseases (ILD). Cytopreparations of BAL fluid (n = 13) and cryostat sections (five mediastinal nodes, 14 transbronchial biopsies) were stained with alkaline phosphatase-antialkaline phosphatase and monoclonal antibodies to CD3, CD4, CD8, CD25, and gamma delta T cell receptor (TCR).

RESULTS

All patients had typical chest radiographs (16 stage I, four stage II, three stage III). All were Mantoux negative with negative tuberculosis cultures. Compared with normal controls and patients with other interstitial lung diseases there was no increase in gamma delta cells in the BAL fluid (sarcoidosis, 1% (range 0-4%) total cells; ILD, 1% (0-2%); controls, 0.5% (0-2%); p > 0.05, Kruskal-Wallis). Likewise, there was no increase in gamma delta cells in the transbronchial biopsy specimens (sarcoidosis, 1/high power field (hpf) (range 0-2); ILD, < 1/hpf (0-4); controls < 1/hpf (0-2); p > 0.05). gamma delta cells were rarely seen in the lymph nodes in spite of the presence of numerous granulomas.

CONCLUSION

These results provide further evidence that gamma delta cells are not increased in most patients with sarcoidosis.

Transtracheal aspiration using rigid bronchoscopy and a rigid needle for investigating mediastinal masses

BACKGROUND

Use of the flexible needle via the fibreoptic bronchoscope to aspirate mediastinal nodes or masses has largely superseded the use of the rigid needle via the rigid bronchoscope. However, the yield at fibreoptic bronchoscopy is relatively low, although this improves with the use of a wider gauge needle. In this study the sensitivity and the safety of rigid needle sampling of the mediastinum in the diagnosis of lung cancer is evaluated.

METHODS

Transtracheal needle aspiration (TTNA) was performed with the rigid bronchoscope and a rigid aspiration needle under general anaesthesia using a previous computed tomographic (CT) scan as a guide to the sample site. A cytopathologist immediately examined the specimens for adequacy and preliminary diagnosis, thus determining the number of aspirations.

RESULTS

Twenty four patients were evaluated. The diagnostic sensitivity of TTNA was 88%. This led to a management decision in 21 patients. There were no false positives and no complications.

CONCLUSIONS

TTNA using the rigid bronchoscope with CT scanning and a cytopathologist present is a sensitive and safe way of diagnosing lung cancer in patients with a mediastinal mass or enlarged mediastinal nodes.

Gamma/delta T lymphocytes in the blood of patients with sarcoidosis

BACKGROUND

Gamma/delta T lymphocytes are thought to have a role in granulomatous immune responses at peripheral sites of antigen contact such as the gut, skin and lung. The aim of this study was to determine if gamma/delta T lymphocytes are increased in the peripheral blood of patients with active sarcoidosis.

METHODS

Peripheral blood from 21 untreated patients with a new presentation of sarcoidosis (12M, 9F), 20 normal volunteers (12M, 8F), and 12 patients with cavitary pulmonary tuberculosis were subjected to Ficoll Hypaque separation and flow cytometry analysis using monoclonal antibodies to CD3, 4, 8, 25, HLA-DR and gamma/delta T cell receptor.

RESULTS

All patients with sarcoidosis had compatible chest radiographs and all were Mantoux negative in spite of previous BCG vaccination. In all but one patient histological examination showed non-caseating granuloma. There was no difference in the mean percentage or absolute numbers of gamma/delta positive peripheral blood lymphocytes between the three populations. Thirteen patients with sarcoidosis had an absolute lymphopenia and the mean percentage of CD3 positive peripheral blood lymphocytes in the group with sarcoidosis was lower than the other two groups. The percentage of CD25 and HLA-DR positive cells was higher in the group with sarcoidosis, supporting the fact that these patients had active disease.

CONCLUSION

Gamma/delta T lymphocytes are not increased in the peripheral blood of patients with sarcoidosis and are unlikely to have a role in the pathogenesis of this disease.

Transtracheal needle aspiration

A series of 27 transtracheal needle aspiration biopsies performed on 25 patients were reviewed. A rigid bronchoscope and rigid needle were used. The biopsies were performed as staging procedures in patients with bronchogenic carcinoma, or to obtain diagnoses in patients with mediastinal adenopathy. A cytopathologist attended 11 biopsies and microscopically examined a direct smear to determine adequacy. Repeat biopsies were taken at the time if necessary. A diagnosis was obtained in 9/11 (81%) of these cases. Only 3/16 biopsies (18.8%) performed in the absence of a pathologist were diagnostic. All negative cases were subsequently found to have disease (2 sarcoidosis, 13 cancer) by other methods including mediastinoscopy in 5 cases. In the patient group sampled, the technique of rigid needle and rigid bronchoscope with a cytopathologist in attendance resulted in a much higher sensitivity for the test than has been previously reported.