Interstitial Lung Disease & Pulmonary Fibrosis
ILD High-yield Verified · Sep 2026"Interstitial lung diseases (ILDs) are a group of several disorders that can cause scarring in your lungs. The scar tissue in your lungs affects your lungs’ ability to carry oxygen and can make it harder for you to breathe normally" (NHLBI). IPF "is a progressive lung disorder characterized by scarring of the lungs from an unknown cause" (StatPearls).
Interstitial lung diseases can be caused by jobs, home exposures, medicines such as amiodarone, methotrexate and nitrofurantoin, or autoimmune disease. Idiopathic pulmonary fibrosis has no known cause. For the nurse, the essentials are: recognize a sudden worsening over days as a possibly fatal acute exacerbation; give oxygen when saturation falls below 88% at rest or with activity; and teach the two antifibrotics — nintedanib, with its diarrhea and liver risks, and pirfenidone, with its sun sensitivity. Pulmonary rehabilitation, vaccines and quitting smoking complete the care. Steroids are not a maintenance treatment for IPF.
What’s going wrong in the body
The normal physiology, where it fails, and why the body’s compensation backfires.
01 A thick, stiff interstitium blocks gas exchange
NHLBI: "If you have an ILD, your lung interstitium becomes thick and stiff. This makes it harder for oxygen to move out of the lungs and into the bloodstream and for carbon dioxide to move out of the bloodstream and into the lungs."
IPF. "Idiopathic pulmonary fibrosis (IPF) is a serious chronic (long term) disease that affects the tissue surrounding the air sacs, or alveoli, in the lungs. This condition develops when that lung tissue becomes thick and stiff for unknown reasons. Over time, these changes can cause permanent scarring in the lungs, called fibrosis, that makes it progressively more difficult to breathe" (NHLBI). StatPearls: "The current theory on the etiology of IPF suggests that recurrent injury to the alveolar epithelium triggers a cascade of signaling by the immune system, leading to fibroblast formation." "Usual interstitial pneumonia (UIP) is the histological pattern of IPF."
Low oxygen. "Resting hypoxia (oxygen saturation, SpO2 < 88%) develops as fibrosis replaces functional parenchyma, leading to ventilation-perfusion mismatch and impaired gas transfer (DLCO decline)" (StatPearls).
Scar is permanent. "Once fibrosis has initiated, no treatment has been shown to reverse it, but nintedanib can slow disease progression." "A lung transplant is the only treatment modality that can restore physiological function in patients" (StatPearls).
02 Many causes under one umbrella
"Interstitial lung disease encompasses a heterogeneous group of more than 200 parenchymal lung disorders that carry significant morbidity and mortality, particularly in progressive fibrotic subtypes such as idiopathic pulmonary fibrosis" (StatPearls). NHLBI: "Some types of ILDs have no known cause, including the most common type, idiopathic pulmonary fibrosis (IPF)."
Exposures matter. "clinicians must conduct a comprehensive review of a patient's complete employment history and home environment to identify any potential agent-disease relationships" (StatPearls). "In hypersensitivity pneumonitis, identifying and avoiding the causative antigen is the cornerstone of management."
Drug-induced ILD (StatPearls). Amiodarone: "Prevalence of pulmonary toxicity 5% to 10% with long-term use; insidious onset; bilateral opacities on CT; foamy macrophages on bronchoalveolar lavage; may progress despite discontinuation" — its "very long half-life (40 to 55 days) means pulmonary toxicity may persist or progress even after drug discontinuation." Methotrexate: "Hypersensitivity pneumonitis pattern; occurs at any dose; rechallenge generally contraindicated." Nitrofurantoin: "Acute (within weeks) or chronic (>6 months) patterns." Bleomycin: "Cumulative dose-dependent," with higher risk from "supplemental oxygen use and renal impairment." "Immune checkpoint inhibitor-related pneumonitis" occurs "in 3% to 5% of patients receiving anti-PD-1 therapy."
Progressive pulmonary fibrosis (2022 guideline). In a non-IPF fibrotic ILD, PPF is "at least two of the following three criteria occurring within the past year with no alternative explanation": worsening respiratory symptoms, an absolute FVC decline of 5% predicted or more, and radiological progression. "PPF is not a diagnosis, and the definition of PPF is agnostic to the underlying condition."
03 Acute exacerbation — the most feared event
"Acute exacerbation (AE)-ILD is defined as a new bilateral ground-glass opacity superimposed on a preexisting fibrotic pattern with no identifiable cause (excluding infection, cardiac failure, or volume overload) and is the most feared complication of IPF and other fibrotic ILDs. AE-IPF carries an in-hospital mortality exceeding 50%, with a median survival of less than 3 months from the event" (StatPearls).
The new change "should prompt urgent workup to exclude infection and cardiac cause before diagnosing acute exacerbation of IPF." Exacerbations are treated with high-dose corticosteroids, "but immunosuppression in the context of pneumonia can be fatal" — and bacterial pneumonia "may precipitate AE-ILD and carries high mortality" (StatPearls).
NHLBI: "Exacerbations from IPF can be life threatening and are more common in advanced stages of IPF." Nintedanib or pirfenidone "may also help to prevent an acute exacerbation, which is an unexpected and sudden worsening of symptoms over a period of days or weeks."
Causes & risk factors
Modifiable factors are teaching targets — the patient can act on them.
Signs & symptoms
Each finding tied to the mechanism that produces it — and the triage it calls for.
Diagnostics
Complications
Medications for this condition
Why each class is prescribed here — every card links to its full pharmacology page.
Not a maintenance treatment for IPF. "Previously, corticosteroids, immunosuppressants such as azathioprine, and N -acetyl cysteine were utilized, but the current recommendation advises against their use in IPF due to findings from the PANTHER-IPF trial" (StatPearls). Acute exacerbation: high-dose corticosteroids after infection is excluded — "immunosuppression in the context of pneumonia can be fatal."
Azathioprine (with steroids and N-acetylcysteine) is advised against in IPF after PANTHER-IPF (StatPearls). Methotrexate can itself cause ILD — "occurs at any dose; rechallenge generally contraindicated." Antifibrotics (no class page): nintedanib and pirfenidone "can help your lungs work better," "may also help to prevent an acute exacerbation," "and may prolong survival" (NHLBI); StatPearls: antifibrotic therapy "slows FVC decline but does not alter the underlying progressive natural history for most patients." The 2022 guideline suggests nintedanib for progressive pulmonary fibrosis after standard management fails. No doses here.
Beyond medications
- Supplemental oxygen "when SpO2 decreases below 88% at rest or with exertion, improving exercise tolerance, dyspnea, and quality of life, though the effect on survival in ILD has not been definitively established" (StatPearls). "Some people who have IPF carry portable oxygen when they go out" (NHLBI).
- Pulmonary rehabilitation "is a core component of ILD treatment and should be offered to all symptomatic patients (Medical Research Council dyspnea scale score >2), regardless of disease subtype" (StatPearls).
- Quit smoking — "the single most important modifiable risk factor in ILD" — and avoid dust, chemicals and secondhand smoke (StatPearls, NHLBI).
- Vaccines — "Annual influenza and pneumococcal vaccination are recommended for all patients with ILD" (StatPearls).
- Address the cause — identifying and avoiding the antigen is "the cornerstone of management" in hypersensitivity pneumonitis; in drug-induced ILD, amiodarone toxicity "may persist or progress even after drug discontinuation," and methotrexate "rechallenge generally contraindicated" (StatPearls).
- Reflux — NHLBI (2022 page) says antacids may help keep acid out of the lungs, but the 2022 ATS/ERS/JRS/ALAT guideline suggests "not treating patients with IPF with antacid medication for the purpose of improving respiratory outcomes" and not referring for antireflux surgery for that purpose. Reflux symptoms are treated on their own merits, not as IPF therapy.
- Lung transplant — "the only treatment modality that can restore physiological function"; afterward, rejection and infection are the major complications and anti-rejection medicines are lifelong (NHLBI).
- Screen for sleep apnea "in all patients with ILD," and include psychological assessment and palliative care in routine follow-up (StatPearls, NHLBI).
Nursing considerations
The RN-specific layer — each action paired with the reason it matters.
How a real nurse thinks
The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.
- 1 Recognize cues
Exertional desaturation to 85% with a resting SpO2 of 93%, and persistent diarrhea on nintedanib despite loperamide, with thirst and fatigue. Breathing is stable over months, so this is not a sudden exacerbation.
- 2 Analyze cues
StatPearls: "Supplemental oxygen is recommended when SpO2 decreases below 88% at rest or with exertion." OFEV label: treat diarrhea "at first signs with adequate hydration and antidiarrheal medicine," and "Discontinue OFEV if severe diarrhea, nausea, or vomiting persists despite symptomatic treatment." His thirst and fatigue suggest fluid loss.
- 3 Prioritize
Two problems to report today: oxygen need with exertion, and persistent diarrhea with possible dehydration while on nintedanib. Neither is a sudden-worsening emergency.
- 4 Generate solutions
Report both to the provider for an exertional-oxygen prescription and a decision about nintedanib. Encourage fluids, and check whether liver tests are due. Reinforce the emergency sign: sudden worsening of breathing over days or weeks.
- 5 Take action
SBAR to the provider: IPF on nintedanib 6 weeks; walking SpO2 85% (93% at rest); diarrhea 5 per day for 4 days despite loperamide, thirsty and tired. Requesting evaluation for ambulatory oxygen and nintedanib management. Teaches the couple the warning signs and to take nintedanib with food.
- 6 Evaluate
At the next visit: walking SpO2 on the prescribed oxygen, stool frequency, hydration, weight, and liver tests.
Scenario — you’re the nurse
Work each question before revealing the answer. Rationales explain the wrong options too.
A 71-year-old man with idiopathic pulmonary fibrosis (former smoker, 50 pack-years) started nintedanib 6 weeks ago. He comes for follow-up with his wife.
Q1 Select all that apply Which findings fit idiopathic pulmonary fibrosis? Select all that apply. - A. A dry, nonproductive cough
- B. Restrictive pattern on pulmonary function tests with a low DLCO
- C. Clubbing of the fingers
- D. Oxygen saturation that falls with exertion
- E. An obstructive pattern with a low FEV1/FVC ratio
- F. Lasting improvement with long-term corticosteroids
Reveal answer & rationale
Q2 Multiple choice A patient with IPF has an SpO2 of 94% at rest that falls to 86% while walking. What does the nurse anticipate? - A. No oxygen, because the resting saturation is normal
- B. Supplemental oxygen for exertion
- C. A long course of high-dose corticosteroids
- D. Stopping all physical activity
Reveal answer & rationale
Q3 Multiple choice A patient starting pirfenidone asks what to do differently. Which instruction is most important? - A. Take it on an empty stomach for better absorption
- B. Avoid sunlight and sunlamps, and wear sunscreen and protective clothing daily
- C. Double the dose if a meal is skipped
- D. Stop smoking only if the cough worsens
Reveal answer & rationale
Q4 Multiple choice A patient with IPF has had rapidly worsening breathlessness over 5 days with a rising oxygen need, and CT shows new bilateral ground-glass opacities. What is the priority? - A. Reassure him that IPF always progresses slowly
- B. Treat it as a possible acute exacerbation — escalate urgently; infection and heart causes must be excluded
- C. Hold oxygen to avoid suppressing his breathing drive
- D. Start pirfenidone to reverse the new changes
Reveal answer & rationale
Q5 Multiple choice Why are corticosteroids not used as long-term treatment for idiopathic pulmonary fibrosis? - A. They cure IPF too quickly
- B. The current recommendation advises against them after the PANTHER-IPF trial
- C. They are used only for obstructive lung disease
- D. IPF responds best to steroids taken for years
Reveal answer & rationale
Common questions
What causes interstitial lung disease & pulmonary fibrosis?
Is pulmonary fibrosis the same as COPD?
Do antifibrotics cure IPF?
Can a medicine cause pulmonary fibrosis?
Should people with IPF take antacids?
What is the outlook?
Sources
- What Is Idiopathic Pulmonary Fibrosis? — National Heart, Lung, and Blood Institute (NIH)
- Idiopathic Pulmonary Fibrosis — Diagnosis — National Heart, Lung, and Blood Institute (NIH)
- Idiopathic Pulmonary Fibrosis — Treatment — National Heart, Lung, and Blood Institute (NIH)
- Idiopathic Pulmonary Fibrosis — Living With — National Heart, Lung, and Blood Institute (NIH)
- What Are Interstitial Lung Diseases? — National Heart, Lung, and Blood Institute (NIH)
- Interstitial Lung Disease — StatPearls — StatPearls (NCBI Bookshelf)
- Idiopathic Pulmonary Fibrosis — StatPearls — StatPearls (NCBI Bookshelf)
- Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults (ATS/ERS/JRS/ALAT 2022) — open-access PMC copy — PubMed Central (CC BY-NC-ND 4.0)
- OFEV (nintedanib) — FDA label (DailyMed) — U.S. Food and Drug Administration / DailyMed
- ESBRIET (pirfenidone) — FDA label (DailyMed) — U.S. Food and Drug Administration / DailyMed
Reviewed by Hae Suk Lee, RN
Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.