Idiopathic pulmonary fibrosis (IPF) is a devastating progressive fibrosing interstitial lung disease associated with a high burden of morbidity and death. 1 A clinical diagnosis of IPF is made only after careful interpretation of integrated clinical, radiologic, and often histopathologic data.
Interstitial lung disease encompasses a broad spectrum of parenchymal lung diseases, and a classification of IPF is restricted to a lung injury pattern of usual interstitial pneumonia (UIP) based on high-resolution computed tomography or surgical lung biopsy, after all known causes of UIP have been excluded. 1
However, a lung injury pattern of UIP is not synonymous with IPF, as UIP can be seen with connective tissue disease, chronic hypersensitivity pneumonitis, drug toxicity, and sarcoidosis. 1 As such, rendering a diagnosis of IPF requires a thorough evaluation to exclude such diverse potential etiologies.
In this issue of the Cleveland Clinic Journal of Medicine , Tolle and colleagues 2 provide an up-to-date, broad overview of IPF focused on what the primary care provider needs to know about the disease. Their review is timely and serves as a useful primer for the practicing clinician.
The field of IPF is actively evolving, as this era has been witness to a recent paradigm shift in pharmacologic management. Immunosuppression is no longer recommended 3 and may even be harmful. 4 And the US Food and Drug Administration has approved 2 antifibrotic drugs—pirfenidone and nintedanib—that have been shown to delay progression of IPF. 5,6
Primary care providers have a unique opportunity to play an integral role in the evaluation and care of patients with IPF, in particular with earlier disease recognition, initial disease assessment, and timely specialty consultative referral—as well as implementing a comprehensive longitudinal care plan.
EARLIER DISEASE RECOGNITION
IPF is a rare disease primarily affecting men over the age of 65. 1 It is reasonable to presume that many or most of these individuals ultimately diagnosed with IPF are already seeking routine care for existing common medical conditions such as hypertension or dyslipidemia—or at least having periodic routine health maintenance assessments. Such evaluations may offer an opportunity for earlier recognition of an underlying fibrotic lung disease that may be subclinical in nature.
IPF has a lower-lung zone predominance. The importance of chest auscultation, particularly listening carefully to the lung bases, is poignantly highlighted in a recent editorial: “It is time that the stethoscope draped around the neck of physicians, which tends to be used for identification purposes rather than for medical diagnosis, be also the (presently only) genuine tool for an earlier diagnosis of IPF.” 7
Advances in imaging also provide an opportunity for earlier diagnosis. Many patients undergo screening computed tomography for coronary calcium scoring or lung cancer surveillance, and these studies may incidentally identify subtle interstitial lung abnormalities. These incidental findings should lead to further investigation, as they have been shown to be functionally important and carry risk of progression to clinical interstitial lung disease. 8
INITIAL ASSESSMENT, TIMELY REFERRAL
But whether evidence of interstitial lung disease is detected incidentally or during testing for respiratory symptoms, further evaluation is necessary. Primary care providers are uniquely positioned to initiate the assessment and to expedite and guide further evaluation and specialty referral consultation to ensure an accurate diagnosis. They can also help grade the severity of the disease with pulmonary function testing, oxygen assessments at rest and with ambulation, and ordering thoracic high-resolution computed tomography to provide valuable information about disease extent and interstitial lung disease pattern.