> Table of Contents > Pulmonary Fibrosis
Pulmonary Fibrosis
Anna Rudnicki, MD
image BASICS
DESCRIPTION
  • Characterized by fibrosis of the lung parenchyma
  • Chest CT shows reticular pattern and honeycombing, with subpleural and lower lobe predominance.
  • Lung biopsy shows “usual interstitial pneumonia” pattern.
  • Classified based on etiology
    • Idiopathic
    • Nonidiopathic
EPIDEMIOLOGY
Incidence
  • Incidence of IPF is 7 to 16/100,000 person-years
  • Idiopathic pulmonary fibrosis (IPF) is more common in men.
  • Most patients with IPF are >60 years.
  • Incidence of nonidiopathic pulmonary fibrosis is unknown.
Prevalence
  • Prevalence of IPF is 2 to 39 cases/100,000 people.
  • Prevalence of nonidiopathic pulmonary fibrosis is unknown.
ETIOLOGY AND PATHOPHYSIOLOGY
  • Postulated that microinjury to alveolar epithelial cells causes release of cytokines that activates fibroblasts, which in turn leads to excess production of extracellular matrix.
  • Causes of the nonidiopathic form include:
    • Occupational exposure
    • Environmental exposure
    • Drugs
    • Systemic connective tissue diseases
    • Granulomatous diseases
Genetics
  • <5% of IPF is familial and may involve mutations in surfactant protein A2 and C and/or abnormal telomere shortening.
  • Most likely mode of transmission is autosomal dominant with variable penetrance.
RISK FACTORS
  • Family history of pulmonary fibrosis
  • Gastroesophageal reflux disease (GERD)
  • Smoking
  • Exposure to birds, livestock, dust from metals or wood, solvents
GENERAL PREVENTION
Avoid the risk factors mentioned earlier, such as smoking, certain occupational exposures, or drugs that induce pulmonary fibrosis.
COMMONLY ASSOCIATED CONDITIONS
  • Pulmonary hypertension: occurs in 30-80% of patients with IPF, likely as a result of hypoxemic vasoconstriction
  • GERD
  • Nonidiopathic pulmonary fibrosis may be associated with connective tissue diseases (e.g., rheumatoid arthritis and scleroderma).
image DIAGNOSIS
PHYSICAL EXAM
  • Tachypnea
  • Fine inspiratory crackles
  • Possible clubbing
DIFFERENTIAL DIAGNOSIS
  • Asbestosis
  • Berylliosis
  • Coal worker's pneumoconiosis
  • Chronic hypersensitivity pneumonitis
  • Sarcoidosis
  • Silicosis
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • High-resolution chest computed tomography (HRCT) is required to make diagnosis. Characteristic findings include a reticular pattern, traction bronchiectasis, and honeycombing. There is a subpleural and lower lobe predominance. There is minimal to no evidence of active inflammation (1,2).
  • If the patient has characteristic findings of pulmonary fibrosis on chest CT, then lung biopsy may not necessarily be required (1).
  • HRCT is needed as part of initial workup (as above).
Follow-Up Tests & Special Considerations
  • Surgical lung biopsy should be considered if clinical presentation and HRCT are not entirely characteristic of pulmonary fibrosis (1).
  • Blood work to rule out associated collagen vascular disease (1)
  • Bronchoscopy with bronchoalveolar lavage may help rule out other types of interstitial lung disease and concurrent infection (1).
Diagnostic Procedures/Other
  • Pulmonary function testing (PFT): initially, may see only decrease in diffusing capacity; later in disease, may develop decrease in lung volumes as well
  • Echocardiogram to evaluate for concomitant pulmonary hypertension
  • Resting and exercise pulse oximetry to determine need for supplemental oxygen
Test Interpretation
Usual interstitial pneumonitis: shows interstitial scarring, honeycombing, and fibroblastic foci. There is temporal heterogeneity, meaning, there may be areas of normal lung adjacent to fibrosed or inflamed lung.
image TREATMENT
GENERAL MEASURES
  • Pulmonary rehabilitation (1)[C]
  • Consider treating for GERD, even if asymptomatic (1)[B].
  • Consider lung transplant evaluation.
MEDICATION
First Line
Supplemental oxygen, if needed (1)[C]
ISSUES FOR REFERRAL
  • Patients should be evaluated and cared for longitudinally by a pulmonologist.
  • If any uncertainty in diagnosis, then consider referral to thoracic surgery for lung biopsy (3,4).
  • Depending on patient age, comorbidities, and preference, may consider referral for lung transplant.
ADDITIONAL THERAPIES
  • A recent study showed an increase in mortality in patients treated with a combination of prednisone, azathioprine, and N-acetylcysteine when compared with those receiving placebo or N-acetylcysteine alone (3).
  • P.887

  • Recent studies have shown a benefit with the antifibrotic agent pirfenidone and the tyrosine kinase inhibitor nintedanib for slowing the progression of IPF (4,5). These drugs were approved by the FDA in 2014.
  • Many other clinical trials are currently under way. Some of the targets being studied include TGF-&bgr;, connective tissue growth factor; IL-13; CCL2; CXCR4; and CXCL12, ACE, and angiotensin II (6).
SURGERY/OTHER PROCEDURES
Lung transplant carries a 5-year survival of 50-56%.
COMPLEMENTARY & ALTERNATIVE MEDICINE
None
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
Worsening shortness of breath and/or increased oxygen requirements:
  • Provide adequate supplemental oxygen.
  • Workup for other possible causes of respiratory decompensation
  • If no other cause for respiratory decompensation is found, then consider administration of high-dose steroids.
Nursing
Supplemental oxygen to keep saturations >90%
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient should follow-up with a pulmonologist
Patient Monitoring
Disease progression can be monitored by periodic PFTs and HRCT.
DIET
No specific dietary requirements
PATIENT EDUCATION
  • Patients should be counseled extensively regarding the prognosis of this diagnosis and given as much support as possible. Information about support groups in the local community and online may be helpful.
  • American Lung Association: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/pulmonary-fibrosis/
  • Pulmonary Fibrosis Foundation: http://www.pulmonaryfibrosis.org/ which includes information about active pulmonary fibrosis clinical trials
PROGNOSIS
  • Median survival time was thought to be 2 to 3 years from time of diagnosis. However, recent data from clinical trials suggest that this may be an underestimate.
  • Some patients may deteriorate quickly, whereas others can remain stable for an extended period of time. Acute exacerbations carry a high mortality, and ICU treatment (mechanical ventilation) is mostly unsuccessful.
  • A higher extent of fibrosis increases the risk of death, whereas a higher percentage-predicted diffusing capacity of lung for carbon monoxide reduced the risk of death.
REFERENCES
1. Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011;183(6):788-824.
2. Lynch DA, Godwin JD, Safrin S, et al. High-resolution computed tomography in idiopathic pulmonary fibrosis: diagnosis and prognosis. Am J Respir Crit Care Med. 2005;172(4):488-493.
3. Raghu G, Anstrom KJ, King TE Jr, et al. Prednisone, azathioprine, and N-acetylcysteine for pulmonary fibrosis. N Engl J Med. 2012;366(21):1968-1977.
4. King TE Jr, Bradford WZ, Castro-Bernardini S, et al. A phase 3 trial of pirfenidone in patients with idiopathic pulmonary fibrosis. N Engl J Med. 2014;370(22):2083-2092.
5. Richeldi L, du Bois RM, Raghu G, et al. Efficacy and safety of nintedanib in idiopathic pulmonary fibrosis. N Engl J Med. 2014;370(22):2071-2082.
6. Rafii R, Juarez MM, Albertson TE, et al. A review of current and novel therapies for idiopathic pulmonary fibrosis. J Thorac Dis. 2013;5(1):48-73.
Additional Reading
&NA;
  • Castriotta RJ, Eldadah BA, Foster WM, et al. Workshop on idiopathic pulmonary fibrosis in older adults. Chest. 2010;138(3):693-703.
  • Covvey JR, Mancl EE. Recent evidence for pharmacological treatment of idiopathic pulmonary fibrosis. Ann Pharmacother. 2014;48(12):1611-1619.
  • Coward WR, Saini G, Jenkins G. The pathogenesis of idiopathic pulmonary fibrosis. Ther Adv Respir Dis. 2010;4(6):367-388.
  • Hoo ZH, Whyte MK. Idiopathic pulmonary fibrosis. Thorax. 2012;67(8):742-746.
  • Lee JS, McLaughlin S, Collard HR. Comprehensive care of the patient with idiopathic pulmonary fibrosis. Curr Opin Pulm Med. 2011;17(5):348-354.
  • O'Connell OJ, Kennedy MP, Henry MT. Idiopathic pulmonary fibrosis: treatment update. Adv Ther. 2011;28(11):986-999.
  • Rafii R, Juarez MM, Albertson TE, et al. A review of current and novel therapies for idiopathic pulmonary fibrosis. J Thorac Dis. 2013;5(1):48-73.
  • Ryu JH, Moua T, Daniels CE, et al. Idiopathic pulmonary fibrosis: evolving concepts. Mayo Clin Proc. 2014;89(8):1130-1142.
  • Spagnolo P, Del Giovane C, Luppi F, et al. Nonsteroid agents for idiopathic pulmonary fibrosis. Cochrane Database Syst Rev. 2010;(9):CD003134.
Codes
&NA;
ICD10
  • J84.10 Pulmonary fibrosis, unspecified
  • J84.112 Idiopathic pulmonary fibrosis
Clinical Pearls
&NA;
  • Pulmonary fibrosis can usually be diagnosed based on characteristic chest CT findings, which include a reticular pattern, traction bronchiectasis, and honeycombing with a peripheral and basilar predominance.
  • There are idiopathic and nonidiopathic forms of pulmonary fibrosis.
  • Treatment options for pulmonary fibrosis are very limited and, at best, serve to slow the progression of disease.