In their study on the diagnosis and management of idiopathic pulmonary fibrosis (IPF), Munchel and Shea wrote that IPF “is the most common of the idiopathic interstitial pneumonias.” However, they noted, “its signs and symptoms are relatively non-specific, and patients often present with chronic cough, progressive dyspnea, resting or exertional hypoxemia, and inspiratory crackles on lung auscultation.” 

Here Munchel and Shea have captured the seemingly contradictory nature between the epidemiology of IPF and its diagnosis: IPF is the most common type of idiopathic interstitial pneumonia, yet by virtue of it still being idiopathic, its signs and symptoms are naturally vague, making diagnosing the disease a challenge. 

Read more about IPF diagnosis 

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IPF is a diagnosis of exclusion, so other causes of interstitial lung disease, such as connective tissue disease, drug toxicity, and environmental influences, should be ruled out. The best way to do so? “Multidisciplinary discussion involving pulmonologists, radiologists, and pathologists with expertise in the diagnosis of IPF and other forms of interstitial lung disease is recommended and often required,” Munchel and Shea wrote. 

Once a patient has been diagnosed with IPF, the next step would be to manage it to the best of our ability. IPF is a progressively worsening disease, but the rate of disease progression varies from individual to individual. Munchel and Shea wrote that IPF “is a clinically heterogeneous disease process with considerable variability in the pace of disease progression between both different individuals with the disease and within any given individual over time.” 

However, a feature of IPF in most patients, sooner or later, is the occurrence of acute exacerbations that require hospitalization. There is no standard definition to what constitutes an “acute exacerbation” of IPF, but, it generally involves the acute worsening of symptoms, a sharp decline in lung function, and medical imaging showing bilateral ground-glass opacification or consolidation that is superimposed on a background consistent with usual interstitial pneumonia (UIP). 

The Power of Algorithms 

In a letter to the editor of the Journal of Internal Medicine, Francisco León-Román et al from the Respiratory Department of Ramón y Cajal Hospital in Madrid, Spain proposed a medical algorithm that can be used to diagnose acute exacerbations of IPF. 

“Currently, there are no specific international guidelines or recommendations based on clinical trials for the diagnosis and management of acute exacerbations of IPF,” the authors wrote. “Therefore, we propose a diagnostic–therapeutic algorithm for acute exacerbations of IPF in patients with hospital admission criteria based on the best available evidence and research center experience.”

Medical algorithms are part and parcel of medicine today, and many diseases have diagnostic and management algorithms that are used by physicians. Medical algorithms resemble decision-making flowcharts; for example, a “yes” might result in the divergence of clinical decision-making from a “no.” 

When I was studying medicine in the UK, I quickly learned that medical algorithms are powerful tools to bring all the physicians in one country on the same page on an issue (in addition to being useful for passing exams). For example, if a patient presents with symptoms in a general practice that qualifies for a specialist referral according to the medical algorithm, then a referral is made and accepted, no further questions are asked. 

In the UK, medical algorithms are set by the National Institute for Health and Care Excellence (NICE) and updated when new evidence becomes available. British physicians have a deep respect for institutional accountability, and medical algorithms mean that physicians at any seniority level can make clinical decisions without having to consult any one medical consultant, who may have his or her own preferences on how things should be done. 

My personal opinion is that this is one of the greatest advantages of having medical algorithms: it removes personal biases and smoothens the clinical decision-making process for everyone involved. 

The medical algorithm proposed by León-Román et al to diagnose acute exacerbations of IPF starts with clinical suspicion of one. Does the patient have an established diagnosis of IPF? Is progressive dyspnea one of the patient’s symptoms? What findings does a physical chest exam yield?

The next step is to carry out complementary tests, such as ECGs, chest x-rays, blood tests, arterial blood gas tests, and blood cultures, to better help physicians come up with a list of differential diagnoses. If common lung pathologies, such as pneumonia, pneumothorax, and pulmonary embolism, can be ruled out, a chest CT should be ordered. If new bilateral ground-glass opacification and/or consolidation superimposed on a background pattern consistent with UIP is observed, then a diagnosis of an acute exacerbation of IPF can be made, and treatment begun. 

Better Patient Care 

If a physician was to follow the medical algorithm created by León-Román et al for diagnosing an acute exacerbation of IPF, the process from patient presentation to clinical management can happen a lot quicker, which would translate to better patient care. 

Read more about IPF treatment 

“Currently there are no known risk factors for the development of acute exacerbations, other than lower functional vital capacity (FVC) and diffusing capacity of lung for carbon monoxide (DLCO) at baseline, and these events can occur at any point in the disease course regardless of underlying disease severity,” Munchel and Shea wrote. Hence, medical algorithms such as the one proposed by León-Román and colleagues can take a lot of the guesswork out of diagnosing conditions such as acute exacerbations of IPF. 


León-Román F, Pintado-Cort B, Máiz-Carro L, et al. Acute exacerbation of idiopathic pulmonary fibrosis: an algorithmic approach to diagnosis and managementJ Intern Med. 2021;289(6):930-932. doi:10.1111/joim.13225

Munchel JK, Shea BS. Diagnosis and management of idiopathic pulmonary fibrosisR I Med J. Published online September 1, 2021.