Reviews

Idiopathic pulmonary fibrosis: What primary care physicians need to know

Author and Disclosure Information

Release date: May 1, 2018
Expiration date: April 30, 2019
Estimated time of completion: 1 hour

Click here to start this CME activity.

Click here to complete post-test and CME certificate.

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a specific type of fibrosing interstitial pneumonia of unknown cause. It is usually chronic and progressive, tends to affect mainly adults over age 60, has a predilection for men, and is often fatal. The condition is still underappreciated by pulmonologists and primary care physicians. This article attempts to close that information gap by reviewing the natural course of IPF and presenting an algorithmic approach to diagnosis and treatment based on evidence-based international guidelines. New treatment options are briefly discussed, to raise awareness of new medications that target pulmonary fibrosis.

KEY POINTS

  • IPF is characterized by a pattern of usual interstitial pneumonia on imaging and histopathology without another known etiology.
  • We recommend early referral to a center specializing in interstitial lung disease to confirm the diagnosis and to initiate appropriate therapy.
  • Specialized centers offer advice on prognosis, enrollment in disease registries and clinical trials, and candidacy for lung transplant.


 

References

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal lung disease that generally affects older adults. It is characterized by a radiographic and histopathologic pattern of usual interstitial pneumonia (UIP) that has no other known etiology.

See related editorial

Accurate diagnosis of IPF is crucial. We recommend early referral to a center specializing in interstitial lung disease to confirm the diagnosis, start appropriate therapy, advise the patient on prognosis and enrollment in disease registries and clinical trials, and determine candidacy for lung transplant.

Primary care physicians are uniquely positioned to encounter patients with IPF, whether because of a patient complaint or as an incidental finding on computed tomography. The goal of this article is to delineate the features of IPF so that it may be recognized early and thus expedite referral to a center with expertise in interstitial lung disease for a thorough evaluation and appropriate management.

WHAT IS IDIOPATHIC PULMONARY FIBROSIS?

Overview of interstitial lung diseases
IPF is 1 of more than 150 interstitial lung diseases, conditions that share nonspecific symptoms such as dysp­nea and a dry cough with insidious onset, certain radiologic findings, and a restrictive ventilatory defect.1 More specifically, IPF is categorized with the idiopathic interstitial pneumonias, which include idiopathic nonspecific interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, diffuse alveolar hemorrhage, cryptogenic organizing pneumonia, and acute interstitial pneumonia (Table 1).2 Identification of the pattern of UIP, the hallmark of IPF, is integral to establishing the diagnosis, as is exclusion of other causes of interstitial lung disease—eg, connective tissue disease, medication reaction, inhalational exposure, pneumoconioses, and granulomatous diseases (both infectious and noninfectious).

MORE COMMON THAN ONCE THOUGHT

The true incidence and prevalence of IPF are difficult to assess. IPF is generally considered a rare disease, but it is more common than once thought. In 2011, Raghu et al3 estimated the prevalence in Medicare beneficiaries to be 495 cases per 100,000. Based on this estimate and the current US population, up to 160,000 Americans could have IPF.4 Raghu et al also showed that IPF more often affects adults over age 65, which suggests that as the US population ages, the incidence of IPF may rise. Studies have also reported an increased incidence of IPF worldwide.5

Further, with the rising use of low-dose computed tomography to screen for lung cancer, more incidental cases of IPF will likely be found.6–8

Older data showed a lag from symptom onset to accurate diagnosis of 1 to 2 years.9 A more recent study found a lag in referral of patients with IPF to tertiary care centers, and this delay was associated with a higher rate of death independent of disease severity.10

TYPICALLY PROGRESSIVE, OFTEN FATAL

IPF is typically progressive and limited to the lungs, and it portends a poor prognosis. The median survival is commonly cited as 2 to 5 years from diagnosis, although this is based on older observations that may not reflect current best practice and newer therapies. More recent studies suggest higher survival rates if patients have preserved lung function.11

As the name indicates, the etiology of IPF is unknown, but studies have indicated genetic underpinnings in a notable proportion of cases.12 Regardless of the cause, the pathogenesis and progression of IPF are thought to be the result of an abnormal and persistent wound-repair response. The progressive deposition of scar tissue disrupts normal lung architecture and function, eventually causing clinical disease.13

Pages

Next Article:

It takes a village to care for the patient with idiopathic pulmonary fibrosis

Related Articles