Interstitial lung diseases (ILDs) encompass many unrelated conditions with both known and unknown etiologies, which often present diagnostic and therapeutic difficulties for treating physicians. Many believe that early specific diagnosis and immediate management are of no value, as the prognosis and treatment response are universally poor. Due to this belief, many patients experience diagnostic delays and are not referred to specialists for better management. 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.
A complex condition
Interstitial lung disease (ILD) is a general term that encompasses more than 200 respiratory diseases affecting normal lung parenchyma and 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, and pneumoconiosis.
Complicated diagnoses
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.
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. It can be stated that there are two main steps in establishing a positive diagnosis: the first step is to establish the diagnosis of ILD and differentiate it from other respiratory or non-respiratory diseases, and the second step is the etiological diagnosis of ILD.
This 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. Of all these investigations, imaging (chest HRCT) is the key component for diagnosis, as it often provides essential information for 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.
Unintentional errors
Unfortunately, vague respiratory symptoms, the relatively rare nature of the condition, insufficient information about ILDs, and lack of access to certain key investigations can lead to delays in establishing the correct diagnosis, which 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.
Difficulties in Diagnosing Interstitial Lung Disease
Perception Error by the Patient. 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 the Primary Care Physician. 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.
Lack of Investigations. 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.
Factors Complicating 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.
Consequences of Incorrect or Delayed ILD Diagnoses
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.
A shared responsability
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, these goals can be achieved through medical education, encouraging 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 as 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, it is necessary to facilitate patient access to specialized diagnostic centers for ILD and improve the bureaucratic processes that delay referrals to specialists.
The Ideal Tool for the Primary Care Physician
Since the primary care physician is the first professional that patients with interstitial lung disease typically visit, it is advisable for them to have tools that allow them to assess the patient’s lung condition. This way, they can refer patients to specialists at the first suspicion that something may be wrong.
SCHILLER´s ultrasonic spirometer, SpiroScout, can be a valuable tool to achieve this goal. It is calibration-free and very user-friendly, requiring no extensive training to perform accurate and reliable spirometry. Additionally, its LFX software guides patients with graphics indicating if their attempts are valid and provides doctors with an easy-to-understand report using color-coded charts. Click the button to request a free demonstration. We have representatives in Latin America, so the demonstration can be conducted virtually or in person in your country.
Discover the SpiroScout ultrasonic spirometer, the easy-to-use tool that helps assess pulmonary function accurately.
SOURCE
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
