Serum procalcitonin is a valuable diagnostic marker in acute exacerbation of interstitial pneumonia

Acute exacerbation of interstitial lung disease in the intensive care unit: Principles of diagnostic evaluation and management

Interstitial lung disease (ILD) is typically managed on an outpatient basis. Critical care physicians manage patients with ILD in the setting of an acute exacerbation (ILD flare) causing severe hypoxia. The principles of management of acute exacerbation of ILD are different from those used to manage patients with acute respiratory distress syndrome from sepsis, etc. Selected patients may be candidates for aggressive measures like extracorporeal membrane oxygenation and lung transplantation, while almost all patients will benefit from early palliative care. This review focused on the types of ILD, diagnosis, and management pathways for this challenging condition.

Serum Procalcitonin in Patients With Combined Lung Cancer and Idiopathic Pulmonary Fibrosis (LC-IPF)

Background

Procalcitonin (PCT) is a potential biomarker for sepsis and acts as a guide to antibiotic administration. Previous studies showed that lung cancer (LC) may increase serum PCT levels. However, no studies addressed serum PCT in patients with combined LC and idiopathic pulmonary fibrosis (IPF): LC-IPF. We aimed to evaluate the significance of serum PCT in patients with LC-IPF.

Methods

A total of 137 patients with IPF who had complete follow-up data were reviewed. They were categorized into two groups: 30 patients with LC and IPF (LC-IPF) and 82 patients with IPF only (IPF). PCT assays in the two groups were done using the enzyme-linked immunosorbent assay (ELISA) technique.

Results

Median serum PCT (IQR) was significantly higher in patients with LC-IPF in comparison to those with IPF only (0.655± 3.60 vs 0.07 ± 0.11 ng/ml, p=0.016), respectively. LC-IPF patients with neuroendocrine (NE) component, stage IV disease, and with >2 metastatic sites had a significantly higher PCT in comparison to those with non-NE, stages I-III, and <2 metastatic sites, respectively. The presence of the NE component was the only independent risk factor predictive for PCT positivity in patients with LC-IPF; OR1.8 (95% confidence interval (CI) 0.042-2.145; p = 0.042).

Conclusion

Patients with LC-IPF have higher serum PCT levels than those with IPF alone. These levels are related to the presence of NE component, advanced cancer stage, and the presence of multiple metastases. The presence of the NE component is the only independent risk factor predictive for PCT positivity in patients with LC-IPF. Further studies are warranted.

Postoperative acute exacerbation of interstitial pneumonia in pulmonary and non-pulmonary surgery: a retrospective study

BACKGROUND

Acute exacerbation of interstitial pneumonia (AE-IP) is a serious complication of pulmonary surgery in patients with IP. However, little is known about AE-IP after non-pulmonary surgery. The aim of this study was to determine the frequency of AE-IP after non-pulmonary surgery and identify its risk factors.

METHODS

One hundred and fifty-one patients with IP who underwent pulmonary surgery and 291 who underwent non-pulmonary surgery were retrospectively investigated.

RESULTS

AE-IP developed in 5 (3.3%) of the 151 patients in the pulmonary surgery group and 4 (1.4%) of the 291 in the non-pulmonary surgery group; the difference was not statistically significant. A logistic regression model showed that serum C-reactive protein (CRP) was a predictor of AE-IP in the non-pulmonary surgery group (odds ratio 1.187, 95% confidence interval 1.073-1.344, P = 0.002).

CONCLUSIONS

This is the first study to compare the frequency of AE-IP after pulmonary surgery with that after non-pulmonary surgery performed under the same conditions. The results suggest that the frequency of AE-IP after non-pulmonary surgery is similar to that after pulmonary surgery. A high preoperative C-reactive protein level is a potential risk factor for AE-IP after non-pulmonary surgery.

Clinical significance of Charlson comorbidity index as a prognostic parameter for patients with acute or subacute idiopathic interstitial pneumonias and acute exacerbation of collagen vascular diseases-related interstitial pneumonia

Background

A prognostic factor for patients with acute or subacute idiopathic interstitial pneumonias (IIPs) or acute exacerbation (AE) of collagen vascular diseases-related interstitial pneumonia (CVD-IP) has not been established. We aimed to determine whether the Charlson comorbidity index (CCI) could serve as a prognostic factor for patients with these patients.

Methods

We assessed baseline prognostic factors among patients with acute or subacute IIPs and AE of CVD-IP who were admitted to hospital between January 2014 and December 2017. We classified them as survivors and non-survivors at 3 months and compared their age, sex, CCI, blood parameters [lactate dehydrogenase (LDH), surfactant protein (SP)-D, Krebs von den Lungen-6, and partial pressure of oxygen in arterial blood/fraction of the inspiratory oxygen], high resolution CT (HRCT) scores and treatment.

Results

Sixty eight patients with (mean age, 75 years), were assessed. All patients received steroid pulse therapy. We found that 45 of acute or subacute IIPs and 16 of AE of CVD-IP were included. Stepwise multivariate analysis selected CCI (OR, 1.306; 95% CI, 1.090-1.573; P=0.004), serum LDH (OR, 1.003; 95% CI, 1.001-1.005; P=0.002), and sex (OR, 8.555; 95% CI, 1.729-154.978; P=0.038) as significant predictors of 3-month mortality among these patients. Three-month mortality was significantly worse among patients with high (≥4) than low (<4) CCI (mortality rates: 63.2% vs. 16.3%, P<0.001). Moreover, the composite scoring system including CCI, serum LDH, and sex was acceptable (Bootstrap AUC, 0.859; Bootstrap C-index, 0.747).

Conclusions

The composite scoring system including CCI, sex, and serum LDH could be a useful mortality prediction tool for patients with acute or subacute IIPs and AE of CVD-IP requiring steroid pulse therapy.

Baseline serum syndecan-4 predicts prognosis after the onset of acute exacerbation of idiopathic interstitial pneumonia

Background

Patients with idiopathic interstitial pneumonia can experience acute respiratory worsening, also known as acute exacerbation, with a large deterioration on prognosis. The precise mechanism remains unclear; however, syndecan-4 may be involved. Syndecan-4, a transmembrane heparan sulfate proteoglycan expressed in a variety of cells (e.g., epithelial cells, macrophages, fibroblasts, etc.), performs various biological roles by binding to several proteins through its heparan sulfate glycosaminoglycan side chains. The goal of this study was to clarify the role of syndecan-4 in acute exacerbation of idiopathic interstitial pneumonia.

Methods

Patients with idiopathic interstitial pneumonia who had been sequentially admitted to our hospital due to acute exacerbation were retrospectively analyzed. First, serum syndecan-4 levels in the acute exacerbation and clinically stable phases were compared. Second, the relationship between serum syndecan-4 levels and clinical parameters was analyzed. Third, the relationship between serum syndecan-4 levels and prognosis was evaluated.

Results

Serum syndecan-4 levels were significantly lower in patients with acute exacerbation of idiopathic interstitial pneumonia than in patients in the clinically stable phase. Serum syndecan-4 levels also showed a significant positive correlation with white blood cell count and a weak positive tendency with KL-6 and baseline %VC. Prognosis was significantly worse in patients with idiopathic interstitial pneumonia with high baseline serum syndecan-4 levels than with low baseline levels. Multiple logistic analysis indicated baseline serum syndecan-4 level as the only prognostic predictor following acute exacerbation.

Conclusions

Baseline serum syndecan-4 is a possible prognostic biomarker after the onset of acute exacerbation of idiopathic interstitial pneumonia.

Serum Procalcitonin for Differential Diagnosis of Acute Exacerbation and Bacterial Pneumonia in Patients With Interstitial Lung Disease

BACKGROUND

Acute exacerbation and bacterial pneumonia are major life-threatening conditions in patients with interstitial lung disease (ILD). The rapid recognition of these 2 different conditions is important for their proper treatment. An elevated procalcitonin (PCT) level is commonly detected in patients with bacterial infections. This study assessed the usefulness of the serum PCT level as a biomarker for the differential diagnosis of acute exacerbation and bacterial pneumonia in patients with ILD.

MATERIALS AND METHODS

In this prospective observational study, we enrolled patients with ILD who had experienced recently progressive dyspnea and exhibited new infiltrations on chest radiographs. We classified these patients into an acute exacerbation group and a bacterial pneumonia group and compared their baseline characteristics and laboratory parameters, including the PCT level.

RESULTS

Of 21 patients with ILD, 9 patients had bacterial pneumonia. Both the groups showed similar baseline characteristics. The bacterial pneumonia group demonstrated a high PCT level. The PCT level in the acute exacerbation group was significantly lower than that in the bacterial pneumonia group (0.05 versus 0.91ng/mL, respectively; P < 0.001). Other parameters, such as the C-reactive protein level, leukocyte count and body temperature, were also lower in the acute exacerbation group. At a cutoff value of 0.1ng/mL, the sensitivity, specificity and negative predictive values of the serum PCT level were 88.9%, 100.0% and 92.3%, respectively.

CONCLUSIONS

These findings suggest that the serum PCT level is useful in the differential diagnosis of acute exacerbation and bacterial pneumonia in patients with ILD.