The Interstitial Lung Diseases (ILDs) are a diverse group of disorders characterized by a varying combination of inflammation and fibrosis of the pulmonary parenchyma [1].

People with interstitial lung disease usually go to the doctor because of shortness of breath or a cough. Doctor will probably use imaging tests of your lungs to find out the problem. Chest X-ray. A simple chest X-ray is the first test for most people with a breathing problem. Chest X-rays in people with interstitial lung disease may show fine lines in the lungs [2].

The ILDs are classified together due to their similar clinical, radiologic manifestations and currently an etiology-based classification system based on multidisciplinary diagnosis is the cornerstone of ILD management. Main categories include ILD related to environmental exposures, Connective Tissue Disease (CTD)-related ILD, sarcoidosis and the Idiopathic Interstitial Pneumonias (IIPs) e.g., Idiopathic Pulmonary Fibrosis (IPF), characterized by the morphologic pattern of Usual Interstitial Pneumonia (UIP) and Nonspecific Interstitial Pneumonia (NSIP) [1].

Among the imaging techniques, Chest X-Ray (CXR) still plays an important role in the diagnostic workup of ILD, especially in the initial evaluation of lung abnormalities, during follow-up and in the detection of comorbidities. CXR is inexpensive and easily available and uses lower doses of ionizing radiations than High-Resolution CT (HRCT) [3].

An accurate ILD diagnosis additionally requires supplementing the medical history with results of the physical, clinical, Biochemical, blood gas and X-Ray examination if appropriate [4]. The final diagnosis of ILD entities requires dynamic interaction between clinicians and radiologists to reach a clinico-radiologic diagnosis [1].

There is paucity of studies on the Biochemical and Radiographic findings of patients diagnosed with interstitial Lung Diseases (ILD), in this hilly area of northern India. The present study was done to evaluate the Clinical characteristics of Interstitial Lung Diseases (ILDs) patients.

Aims and Objectives

To study the Biochemical and Radiographic findings of Interstitial Lung Diseases (ILDs) patients.

The present study was conducted at Indira Gandhi Medical College, Shimla which is a tertiary care center of Himachal Pradesh, located in North India in Asian Continent and covers the majority of the population of this state. All consecutive patients of Interstitial Lung Diseases (ILDs), attending the outpatient services of the Department of Pulmonary Medicine, IGMC Shimla from July 2018 to June 2019 were screened for enrolment in the study. All types of ILDs were enrolled in the study.

Inclusion Criteria

• Stable ILD patients: diagnosis of ILD according to ATS/ERS guidelines based on an overall assessment of high-Resolution Computed Tomography (HRCT) scan, lung function tests, (bronchoscopy and biopsy, if available)

• Age >18 years, written consent

Exclusion Criteria

• Subjects with evidence of left heart disease, Chronic kidney disease, Liver disease

• Chronic lung diseases other than ILDs

• Patients with HIV

• Pregnant

Patients presenting with respiratory symptoms such as cough, shortness of breath and diagnosed cases of ILD were evaluated. 

All consecutive ILD patients were subjected to focused history and physical examination as structured questionnaire record information related to; Demographics, Duration of ILD, Biochemical and Radiographic findings etc.

The data was collected, entered in the MS Excel sheet and analyzed using Epi info V7 software. Continuous variables were reported as mean±SD or median and interquartile range depending on the distribution of the variables. Categorical variables were recorded as counts and percentages. Differences between means of continuous variables were compared using the unpaired student’s’ test. A p-value of <0.05 was considered as statistically significant.

Among the study population, 50 patients 27 (54%) were female and 23 (46%) were male. The mean age of the study population was 57.821+5.03 years. The mean age of males and females was 62.561+3.84 years and 53.771+5.07 years respectively. The mean duration of symptoms of ILD was 3.034+2.62 years. There was no significant difference between males and females regarding the duration of illness (2.76+2.46 years versus 3.39+2.77 years, p = 0.40). (Table 1).

Table 1: Age and Gender Distribution of the Study Population (N = 50)

For 50 patients, laboratory investigations like Hemoglobin (HB), ABG was done in the central laboratory of IGMC Shimla. The mean value of (HB) among study population was 15.24+2.19g%. The mean (HB) level of 15.78+1.50 and 14.77+2.57 were reported in male and female respectively, with a p-value of 0.10.

Out of 50 patients, the mean ABG (sO2) and ABG (paO2) were 82.50+10.76 mmHg and 55.77+10.30mmHg respectively. Eighteen (36%) patients (sO2) >88% and thirty-two (64%) had (sO2) <88%. No male and female disparity of ABG sO2. (p-value of 0.86). Among 50 patients 23 (46%) had (paO2) >55mmHg and 27 (64%) had (paO2) <55mmHg. The prevalence of hypoxemia was not significantly different among men and women p-value of 0.36 (Table 2).

Table 2: Biochemical Findings of ILD Patients

Chest x-rays of all the study population were done at the department of radiology IGMC Shimla. Out of 50 patients, 32 (62%) had Reticular shadow as radiological finding. 

Male had predominantly this radiological finding of 18 (78.26%) with statically significant of a p-value of 0.04. Out of 50 patients 27 (54%) had Reduced lung volume as radiological finding, no male and female disparity (56. 52% versus 51.85% with a p-value of 0.48). Out of 50 patients 14 (28%) had Right pulmonary artery prominence (dilatation) as radiological finding with no male and female difference (26% in versus 29.63%), with a p-value of 0.5 (Table 3).

Table 3: Radiographic Findings of ILD Patients

ILD is characterized by continued deterioration with progressive respiratory insufficiency leading to end-stage fibrosis [5].

The mean age of the study population was 57.821+5.03 with male and female mean age 62.561+3.84 and 53.77+15.07 respectively. Females were more than male and younger with a mean duration of ILD of 3.034±2.62 years. A similar finding was also reported in the study conducted by Agarwal et al. [6]. In the ILD registry of Indian data, it was reported that ILDs occur at a younger age compared to the western countries and females are affected more [7].

In the radiological analysis, we found reticular shadow (64%), reduced lung volume (54%) and right pulmonary artery prominence (26%), these radiological signs are present in ILD patients and those with ILD and PH. Agarwal. et al. [6], reported the similar results in their study. 

In our study ABG was analyzed with gender, the mean ABG (sO2) was in total and males and females had 82.60+10.42 and 82.40+11.24 respectively. The mean ABG (paO2) was 55.77+10.30 with male and female had 54.79+9.55 and 56.61+11.01 respectively with no statistical significance, the similar comparable finding was observed in the study done by Agarwal et al. [6].

Most of ILD patients had non anemic, sO2 <88% & paO2 <55mmHg. They had Reticular shadow, reduced lung volume and Right pulmonary artery prominence (dilatation) in X-Ray Chest.

Limitations of the Study

The small number of the population were included in this study represents a methodological limitation and study over a larger population is recommended.

1. Buzan, M.T. and C.M. Pop. “State of the art in the diagnosis and management of interstitial lung disease.” Medicine and Pharmacy Reports, vol. 88, no. 2, April 2015, pp. 116–123.

2. WebMD. “Interstitial lung disease.” WebMD, July 2021, www.webmd.com/lung/interstitial-lung-disease.

3. Vizioli, L. et al. “Integrated use of lung ultrasound and chest x-ray in the detection of interstitial lung disease.” Respiration, vol. 93, no. 1, 2017, pp. 15–22.

4. Kalchiem-Dekel, O. et al. “Interstitial lung disease and pulmonary fibrosis: A practical approach for general medicine physicians with focus on the medical history.” Journal of Clinical Medicine, vol. 7, no. 12, December 2018, article 476.

5. Shorr, A.F. et al. “Pulmonary hypertension in patients with pulmonary fibrosis awaiting lung transplant.” European Respiratory Journal, vol. 30, no. 4, October 2007, pp. 715–721.

6. Agarwal, R. et al. “Noninvasive estimation of clinically asymptomatic pulmonary hypertension in idiopathic pulmonary fibrosis.” The Indian Journal of Chest Diseases & Allied Sciences, vol. 47, no. 4, October 2005, pp. 267–271.

7. Indian ILD Registry. “Indian interstitial lung disease registry.” Lung India, vol. 31, no. 4, October–December 2014, pp. 320–322.