Update on interstitial pneumonia

Retrospective study of pneumonia in non-racing horses in California

Pneumonia is a significant disease of horses. Although pneumonia has traditionally been studied in racehorses, little information is available for non-racing horses. Non-racing horses that died with pulmonary lesions (n = 156) were available from cases submitted for autopsy from January 2015 to June 2020. Bronchopneumonia (35%), interstitial pneumonia (29%), embolic pneumonia (21%), granulomatous pneumonia (13%), and pleuritis (2%) were observed in the examined horses. Seventy-four horses died or were euthanized because of pulmonary diseases, and 82 horses died or were euthanized because of non-pulmonary causes but had lung lesions. Of the horses that died from pulmonary causes, the most common finding was bronchopneumonia, with abscesses and/or necrosis in the cranioventral aspect of the lung. Bacteria isolated from cases of bronchopneumonia were Streptococcus equi subsp. zooepidemicus (48.5%), Klebsiella pneumoniae (12.1%), and Actinobacillus equuli subsp. haemolyticus (9.1%). The most common extrapulmonary lesions responsible for death in horses that also had lesions in the lung were mainly in the gastrointestinal system (30%), multiple systems (septicemia and/or toxemia; 27%), and musculoskeletal system (12%). The main postmortem findings in cases of bronchopneumonia of non-racing horses were similar to those reported previously in racehorses. However, some non-racing horses also had interstitial and granulomatous pneumonia, patterns not described previously in racehorses in California, likely as a result of the inclusion of extended age categories for non-racing horses. We also found that the equine lung was frequently affected in cases of sepsis and gastrointestinal problems of infectious origin.

Utility of lung ultrasound to identify interstitial lung disease: An observational study based on the STROBE guidelines

Lung ultrasound (LUS) has recently been used to identify interstitial lung disease (ILD). However, data on the role of LUS in the detection of ILD remain limited. The aim of this study was to investigate the diagnostic value of LUS compared with high-resolution computed tomography (HRCT) in patients with ILD.The retrospective study was carried out by reviewing the medical records of patients with respiratory signs and symptoms discharged from the respiratory ward. Only patients with suspected ILD who underwent HRCT and LUS within a week were selected. ILD was identified with a semi-quantitative score of B-lines >5 and a Warrick score >0 points. The endpoints of LUS in diagnosing ILD (i.e., sensitivity, specificity, positive likelihood ratio [PLR], negative likelihood ratio [NLR], positive predictive value [PPV], and negative predictive value [NPV], and receiver operating characteristic [ROC] curve) was compared with that of HRCT. The reference standard used for the diagnosis of ILD was based on history, clinical findings and examination, and laboratory and instrumental tests, including pulmonary function tests, lung histopathology, and HRCT (without LUS findings).The final clinical diagnosis of ILD was 55 in 66 patients with suspected ILD. HRCT was positive in 55 patients, whereas LUS detected ILD in 51 patients. Four patients with negative LUS findings were positive on HRCT. The results showed 93% sensitivity, 73% specificity, 3.40 PLR, 0.10 NLR, 94% PPV, and 67% NPV for LUS, whereas 100% sensitivity, 82% specificity, 5.49 PLR, 0.01 NLR, 97% PPV, and 100% NPV for HRCT. Comparison of the 2 ROC curves revealed significant difference in the diagnostic value of the 2 methods for the diagnosis of ILD (P = .048).Our results indicated that LUS is a useful technique to identify ILD. Considering its non-radiation, portable and non-invasive advantages, LUS should be recommended as a valuable screening tool in patients with suspected ILD.

Retrospective study of fatal pneumonia in racehorses

Respiratory diseases have a major impact on racehorses in training and are often cited as the second most common reason of horses failing to perform. Cases were submitted by the California Horse Racing Board to the California Animal Health and Food Safety laboratory for postmortem examination between January 1, 2005 and December 31, 2014. We determined the demographics of racehorses with fatal pneumonia, characterized the pathologic findings in animals with a postmortem diagnosis of respiratory infection, and determined the most significant pathogens associated with lower respiratory tract disease. We analyzed autopsy reports from 83 horses with a diagnosis of pneumonia, bronchopneumonia, and/or pleuropneumonia. The most common presentation was pleuropneumonia (71% of cases), with extensive areas of lytic necrosis and abscesses of the pulmonary parenchyma. Streptococcus equi ssp. zooepidemicus, a normal mucosal commensal of the upper respiratory tract of healthy horses, was the most commonly isolated organism (72% of cases), either in pure culture or accompanied by other aerobic or anaerobic bacteria. Its presence in the pulmonary parenchyma is associated with severe and extensive damage to the lung. Furthermore, this agent has zoonotic potential, which stresses the importance of early detection and proper management of cases of pneumonia in racehorses.

Integrative Cardiopulmonary Ultrasound for Interstitial Lung Disease Assessment: Correlation between Lung Ultrasound Performance and Cardiac Involvement

The aims of this study were to apply integrative cardiopulmonary ultrasound (thoracic ultrasound) to the evaluation of patients with interstitial lung disease (ILD) and to determine the relationship between lung ultrasound signs and echocardiographic parameters such as systolic pulmonary artery pressure (SPAP) and various right ventricular parameters. ILD patients and healthy controls underwent lung ultrasound (LUS) and echocardiographic tests. In addition to traditional echocardiographic parameters, right ventricular free wall longitudinal strain (RVLS_FW) was measured using 2-D speckle-tracking echocardiography. The degree of pulmonary fibrosis or the disease severity of each ILD patient was scored with a semiquantitative scoring method, taking into account multiple LUS signs. Statistical analyses were performed to compare various parameters between ILD patients with and those without pulmonary hypertension. Correlations between the different parameters were then evaluated, and the LUS scores were used to predict pulmonary hypertension using a receiver operating characteristic curve analysis. Among the 90 patients who qualified for entry into this study, 30% (n = 27) had pulmonary hypertension. The patients with pulmonary hypertension had larger right ventricular dimensions, lower RVLS_FW and higher LUS scores. An effective correlation was found between ILD LUS scores and echocardiographic parameters, especially SPAP (r = 0.735, p < 0.001). The groups were comparable with respect to most echocardiographic parameters, with mild, moderate and severe pulmonary fibrosis, whereas SPAP was significantly higher in the moderate and severe groups. RVLS_FW was obviously reduced in the group with severe pulmonary fibrosis. Although RVLS_FW in the mild pulmonary fibrosis group was in the normal range, it was slightly reduced compared with that of the controls. A cutoff of more than 16 LUS points had 85.2% sensitivity and 80.3% specificity in predicting elevated SPAP (>36 mm Hg). Thoracic ultrasound is useful in the assessment of ILD. As ILD progresses, the structure or function of the right ventricle gradually deteriorates. LUS not only detects lung conditions in ILD, but also indirectly reflects SPAP and right ventricular function. Integrated use of LUS and echocardiography will provide an invaluable point-of-care imaging modality to facilitate the diagnosis, management and treatment of patients with ILD.

Procalcitonin as a biomarker in equine chronic pneumopathies

BACKGROUND

Procalcitonin (PCT), a precursor protein of the hormone calcitonin, is a sensitive inflammatory marker in human medicine, which is primarily used for diagnosis of bacterial sepsis, but is also useful in diagnosis of exacerbation of asthma and COPD. In this study, PCT was evaluated as a potential biomarker for different chronic pneumopathies in the horse using an equine specific ELISA in comparison to established clinical markers and different interleukins. Sixty-four horses were classified as free of respiratory disease, recurrent airway obstruction (RAO), inflammatory airway disease (IAD) or chronic interstitial pneumopathy (CIP) using a scoring system. PCT concentrations were measured in plasma (n = 17) and in the cell-free supernatant of bronchoalveolar lavage (n = 64). PCT concentrations were correlated to interleukins IL-1ß and IL-6 in BALF, clinical findings and BALF cytology.

RESULTS

The median PCT concentrations in plasma were increased in respiratory disease (174.46 ng/ml, n = 7) compared to controls (13.94 ng/ml, n = 10, P = 0.05) and correlated to PCT in BALF supernatant (rs = 0.48). Compared to controls (5.49 ng/ml, n = 15), median PCT concentrations in BALF supernatant correlated to the overall clinical score (rs = 0.32, P = 0.007) and were significantly increased in RAO (13.40 ng/ml, n = 21) and IAD (16.89 ng/ml, n = 16), while no differences were found for CIP (12.02 ng/ml, n = 12). No significant increases were found for IL-1 and IL-6 between controls and respiratory disease in general as well as different disease groups.

CONCLUSIONS

Although some correlations were found between PCT in plasma, BALF supernatant and clinical scores, PCT in BALF does not seem to be a superior marker compared to established clinical markers. PCT in plasma seems to be more promising and a greater number of samples should be evaluated in further studies.