Interstitial lung diseases (ILDs) encompass many unrelated conditions with both known and unknown etiologies, which often present diagnostic and therapeutic difficulties for treating physicians. Moreover, many believe that early specific diagnosis and immediate management are of no value, as the prognosis and treatment response are universally poor. As a result, many patients experience diagnostic delays and are not referred to specialists for better management. Consequently,both physicians and patients are frustrated due to the lack of a clear etiology and an ideal treatment for ILDs. In this article, we analyze the obstacles and consequences of the late diagnosis of ILDs.
By América Torres
What Is Interstitial Lung Disease? Definition, Scope, and Clinical Impact
Interstitial lung disease (ILD) is a general term that encompasses more than 200 respiratory diseases affecting normal lung parenchyma. These conditions, in turn, are associated with significant morbidity and mortality. Confirming a diagnosis requires a combination of criteria: clinical, radiological, and, in some cases, pathological.
The most common types of ILD that physicians may encounter are:
- Sarcoidosis
- Hypersensitivity pneumonitis
- Idiopathic pulmonary fibrosis
- ILDs secondary to connective tissue diseases
- Drug-induced ILDs
- Pneumoconiosis
Why Interstitial Lung Disease Diagnosis Is So Challenging
Key Steps in the Interstitial Lung Disease Diagnostic Process
When discussing a positive diagnosis of diffuse interstitial lung disease, there are several steps that both the patient and the physician must follow to ensure greater diagnostic accuracy.
First, the evaluation of a patient with this condition begins with a high degree of clinical suspicion based on a detailed history and a thorough clinical examination. There are two main steps in establishing a positive diagnosis. First, physicians confirm the presence of ILD and differentiate it from other respiratory or non-respiratory diseases. Second, they determine the specific etiology of the ILD.
Essential Tests for Accurate Interstitial Lung Disease Diagnosis
Subsequently, the second step requires a series of extensive investigations, such as:
- Laboratory analyses
- Immune markers
- Lung function tests
- Chest HRCT exam
- Bronchoscopy
- Bronchoalveolar lavage
- And, in certain situations, a lung biopsy
Among all these investigations, imaging (chest HRCT) is the key component for diagnosis, as it often provides essential information for diagnosis.
Multidisciplinary Team Approach: The Gold Standard for ILD Diagnosis
Once the physician has gathered all the necessary information, the ideal course of action is for the final diagnostic decision to be made by a multidisciplinary team.The gold standard in ILD diagnosis is considered to be a team composed of the following specialists:
- A respiratory physician
- A radiologist
- A pathologist
- A thoracic surgeon or a rheumatologist
The role of the rheumatologist within the multidisciplinary team has gained significance, especially in cases where a systemic autoimmune rheumatological disease is suspected. The input of this physician and the range of investigations they can suggest can make the difference between a correct and an incorrect diagnosis.
Common Causes of Delayed or Missed Interstitial Lung Disease Diagnosis
Unfortunately, vague respiratory symptoms, the relatively rare nature of the condition, insufficient information about ILDs, and limited access to key investigations often delay the correct diagnosis. These delays can have significant consequences for patients. Therefore, establishing a diagnosis with greater accuracy within an acceptable timeframe to initiate effective treatment represents a challenge for physicians. Despite this, an early diagnosis, in most cases, represents better treatment efficacy for the patient. It can sometimes reduce unnecessary investigations and can also mean a better prognosis for the patient.
Given the significant impact that ILDs with a progressive fibrosing phenotype have on mortality and morbidity, we list some of the most common diagnostic difficulties and errors below.
Key Diagnostic Errors in Interstitial Lung Disease
Patient-Related Factors Leading to Delayed ILD Diagnosis
The first diagnostic error can be the patient’s. Constitutional differences between individuals, their perception of the severity of symptoms, and individual fragility can lead them to attribute nonspecific symptoms to age or another condition. Added to this are the lack of access to specialized medical care and ignorance of symptoms. Therefore, the time window from symptom onset to final diagnosis can vary. A study by van der Sar et al.,shows that only 30% of patients with pulmonary fibrosis received a final diagnosis within 3 months; however, 40.2% of patients received a final diagnosis in a year or more.
The Role of Primary Care in Early Interstitial Lung Disease Detection
In most cases, the patient with ILD first visits the primary care physician. This visit plays a crucial role in reaching the diagnosis. Clinical suspicion of the disease by this physician can shorten the time to diagnosis. The study by Purokivi et al. found that the majority of referral letters (59%) came from primary care, with a mean time from symptom onset to referral of 1.5 years. The main reason for the referrals was suspicion of ILD.
Limited Access to Diagnostic Investigations in ILD
Another challenging issue in the diagnostic process for these patients is the need for extensive investigations to establish an accurate diagnosis. In this regard, there are several real and significant problems to consider when discussing errors and delays in ILD diagnosis, such as the increase in the number of investigations and their complexity, the shortage of well-trained medical staff to correctly interpret the results, a long period between conducting an investigation and receiving the results, and the need to repeat some tests in certain cases or diagnoses.
Comorbidities and Risk Factors That Delay ILD Diagnosis
Patients with associated coronary disease, diabetes, or gastroesophageal reflux disease undergo a longer diagnostic process compared to those without these comorbidities. The study by Farkas et al., based on the EMPIRE registry, showed that more than half of the patients (51.6%) had comorbidities associated with idiopathic fibrosis, with the most frequent being cardiovascular diseases and arterial hypertension. Another set of risk factors for delaying the correct diagnosis, according to other studies, may be male sex and advanced age.
Clinical Consequences of Incorrect or Delayed Interstitial Lung Disease Diagnosis
The first consequence of an incorrect diagnosis for the patient is the delay in receiving the correct diagnosis and starting the appropriate treatment. The study by Marlies Wijsenbeek et al. shows a delay of more than 12 months before a positive diagnosis is made, and also that up to 55% of ILD patients are misdiagnosed.
On the other hand, the consequences of these incorrect diagnoses are reflected in the prescription of ineffective and possibly harmful treatments for the patient. According to some studies, patients who were diagnosed with other conditions received treatment with systemic corticosteroids, antibiotics, combinations of bronchodilators and inhaled corticosteroids, proton pump inhibitors, or antacid therapy. Interestingly, specific inhaled therapy was administered even to patients who did not meet the criteria for asthma or COPD.
The delay in obtaining an accurate diagnosis has several repercussions for the patient with ILD:
- For example, patients with idiopathic pulmonary fibrosis who are diagnosed later have a worse prognosis and an increased risk of death.
- At the same time, the longer the delay, the lower the chances of a lung transplant, to the point where this possibility may be eliminated.
- Additionally, another study shows that the longer the delay, the greater the extent of lung fibrosis identified in these patients, which also means a worse prognosis.
How to Reduce Diagnostic Delays in Interstitial Lung Disease
Improving the process and shortening the time needed to establish an accurate diagnosis can be achieved by making changes at the patient level, medical staff level, facility level, and improving public access to these facilities, as well as by deepening clinical studies.
Regarding patients, medical education can achieve these goals. It encourages them to see a doctor when symptoms first appear without ignoring them or attributing them to other causes.
For healthcare professionals, the primary care physician plays an important role. They are often the first contact the patient has with the healthcare system. Therefore, it is essential that they carefully assess the symptoms and perform a clinical examination that includes pulmonary auscultation. Additionally, improving access to specialized ILD diagnostic centers enhances patient care and supports timely intervention. Also, streamlining bureaucratic processes further reduces delays in referrals to specialists, ensuring patients receive the care they need faster.
A Practical Diagnostic Tool for Primary Care in Suspected ILD
Since primary care physicians are often the first point of contact for patients with suspected interstitial lung disease, having the right diagnostic tools at hand is essential. Early assessment of lung function enables timely referral to specialists—often at the first indication that something may be wrong. This helps reduce diagnostic delays and improve patient outcomes.
SCHILLER- GANSHORN’s SpiroScout ultrasonic spirometer supports early detection of interstitial lung disease (ILD) directly at the point of care. Its simplicity and ease of use allow primary care physicians to assess lung function accurately—without needing to be pulmonary specialists. The calibration-free design and intuitive operation make spirometry straightforward while maintaining clinical precision. This empowers physicians to refer patients to respiratory specialists promptly at the first sign of a potential problem, helping improve outcomes and speed up diagnosis.
SpiroScout uses LFX, an advanced software that actively guides patients with real-time visual feedback to ensure valid maneuvers. It delivers clear, easy-to-interpret reports using color-coded charts. This helps clinicians make informed decisions and refer patients promptly.
Watch the video to learn how SpiroScout integrates seamlessly into daily practice. It also shows how the device helps clinicians assess lung function with confidence across diverse clinical settings.
REFERENCE
Raluca Ioana Arcana. Speaking of the “Devil”: Diagnostic Errors in Interstitial Lung Diseases. J Pers Med. 2023 Nov; 13(11): 1589. Published online 2023 Nov 10. DOI: 10.3390/jpm13111589
Frequently Asked Questions About Interstitial Lung Disease Diagnosis
What Are Interstitial Lung Diseases (ILDs)?
Interstitial lung diseases (ILDs) are a group of over 200 disorders that affect the lung parenchyma. They can be caused by autoimmune diseases, environmental exposures, medications, or unknown factors. ILDs are challenging to diagnose because symptoms like shortness of breath and cough are nonspecific, and diagnosis requires integration of clinical history, imaging, lung function tests, and sometimes pathology.
Why Is Early Diagnosis of ILD Important?
Early interstitial lung disease diagnosis allows timely treatment, reduces unnecessary investigations, and improves patient outcomes. Delays in diagnosis can worsen prognosis, increase the risk of lung fibrosis progression, and limit options such as lung transplantation.
How Do Physicians Diagnose Interstitial Lung Disease?
Diagnosis involves two main steps: confirming ILD and determining its cause. Physicians use clinical evaluation, imaging (especially HRCT), laboratory tests, pulmonary function tests, and sometimes lung biopsy. Multidisciplinary teams, including respiratory physicians, radiologists, pathologists, and rheumatologists, improve diagnostic accuracy.
What Are the Common Challenges in Diagnosing ILD?
Diagnostic delays occur due to vague symptoms, patient perception, limited access to specialists, and complex investigations. Comorbidities such as cardiovascular disease, diabetes, along with older age and male sex, can also complicate diagnosis.
How Can Lung Function Assessment Help in Early ILD Detection?
Lung function testing, including spirometry, helps detect reduced lung capacity and early changes associated with ILD. Tools like SCHILLER-GANSHORN’s SpiroScout ultrasonic spirometer provide accurate, user-friendly assessments at the point of care, supporting timely referrals and informed clinical decisions.