Interstitial Lung Disease (ILD) is a term that can be used to describe any respiratory disorder that causes scarring of the tissues within the lungs.

This study guide provides an overview of this topic and has practice questions designed to help you learn this information.

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What is Interstitial Lung Disease?

Interstitial Lung Disease is a broad term used to describe a group of lung disorders that cause fibrosis (scarring) of lung tissue.

This results in stiffness, which decreases lung compliance and oxygenation, and makes it more difficult to breathe. Unfortunately, once this type of lung damage has occurred, it’s typically irreversible and progressively gets worse over time. 


Interstitial Lung Disease has several known and unknown causes. Some examples include:

  • Connective tissue diseases
  • Autoimmune diseases
  • Malignancy
  • Drug-induced
  • Infections
  • Inhaled substances

ILD can occur secondary to certain connective tissue and autoimmune diseases such as sarcoidosis, rheumatoid arthritis, lupus, systemic sclerosis, and polymyositis.

It is also caused by the inhalation of toxic substances, such as asbestosis, silicosis, hypersensitivity pneumonitis, and other occupational and environmental toxins.

There are also certain drugs and medications also known for causing ILD. Some examples include antibiotics, chemotherapy drugs, and certain anti-arrhythmic agents.

Lastly, ILD is caused by certain infections, such as atypical pneumonia, RSV, tuberculosis, and coronavirus.

Signs and Symptoms

Interstitial Lung Disease is known for causing a number of signs and symptoms. Some examples include:

  • Shortness of breath
  • Chest discomfort
  • Fatigue
  • Nonproductive cough
  • Weight loss
  • Hypertension

In general, these signs and symptoms typically develop slowly over several months.


The treatment for ILD varies depending on the patient’s symptoms. Some of the standard treatment methods include:

  • Oxygen therapy
  • Corticosteroid medications
  • Pulmonary rehabilitation
  • Lung transplantation

The treatment method may also vary depending on the specific cause. For example, if the cause is due to inhalation of a toxic substance, the best treatment would be to avoid the said substance.

If a specific medication is the known cause of ILD, the patient should stop taking said medication.

Interstitial Lung Disease Practice Questions:

1. What does ILD stand for?
ILD stands for Interstitial Lung Disease. It’s an abbreviation that we’ll use throughout the remainder of this study guide.

2. Interstitial lung diseases are a diverse group of illnesses that can be organized into groups based on what?
They are organized based on related causes.

3. Interstitial lung diseases generally cause what?
They cause chronic, progressive dyspnea on exertion and a nonproductive cough.

4. What breath sounds are common with ILD?
Fine, inspiratory crackles

5. What is the most common chest radiograph finding in ILD?
Diffuse reticular or reticulonodular infiltrates with reduced lung volumes

6. What are the PFTs like for a patient with ILD?
Pulmonary function testing usually reveals restrictive physiology and decreased diffusion capacity; however, other patterns may be seen.

7. What are the causes of ILD?
The causes most frequently occur from exposure (tobacco, hypersensitivity pneumonitis antigens, silica, asbestos), autoimmune dysfunction (sarcoidosis, connective tissue diseases), and abnormal injury healing (IPF).

8. What is the specific treatment for ILD depend upon?
It depends on the underlying disease and may consist of an immunosuppressive.

9. What is the most common treatment for interstitial lung disease?
A lung transplant

10. What is a common physical finding of ILD?
Bibasilar inspiratory dry crackles in the bases

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11. What is the classification of ILD based on?

12. What is the most effective way to diagnose ILD?
Open lung biopsy

13. How does ILD affect blood pressure?
Hypertension is a symptom of ILD

14. What form of ILD is typically seen in 50-70 year-old men with progressive dyspnea and bibasilar crackles?
Idiopathic Pulmonary Fibrosis

15. What form of ILD presents with intermittent episodes of dyspnea and is seen in people who live on farms?
Hypersensitivity pneumonitis

16. What is the most important thing to find when diagnosing hypersensitivity pneumonitis?
The patient’s history and work history

17. What does the diagnosis of drug-induced interstitial lung disease rely on?
The exclusion of all other processes

18. What type of ILD is commonly seen in coal miners, potters, and drill workers?

19. What is the primary goal of ILD treatment?
To prevent irreversible lung damage

20. The term Interstitial Lung Disease (ILD) refers to a broad group of inflammatory lung disorders that are characterized by what?
Acute, subacute, or chronic inflammatory infiltration of the alveolar walls by cells, fluid, and connective tissue

21. What are some other names for Interstitial Lung Diseases?
Diffuse interstitial lung disease, fibrotic interstitial lung disease, pulmonary fibrosis, or pneumoconiosis

22. If left untreated, an inflammatory process in the lungs can progress to what?
Irreversible pulmonary fibrosis

23. What are the major pathologic or structural changes of the lungs associated with interstitial lung disease?
Destruction of the alveoli and adjacent pulmonary capillaries; fibrotic thickening of the respiratory bronchioles, alveolar ducts, and alveoli; granulomas, honeycombing, and cavity formation; fibrocalcific pleural plaques (with asbestos); bronchospasm and excessive bronchial secretions

24. How is the acute stage of ILD characterized?
Edema and the infiltration of a variety of white blood cells in the alveolar walls and interstitial spaces

25. How is the chronic stage of ILD characterized?
In addition to the inflammation and infiltration of numerous white blood cells, some fibroblasts may be present in the alveolar walls and interstitial spaces.

26. What can occur after the chronic stage of ILD?
Further interstitial thickening, fibrosis, granulomas, and in some cases, honeycombing and cavity formation

27. The exposure to what organic materials can cause ILD?
Moldy hay, silage, moldy sugar cane, mushroom compost, barley, cheese, wood pulp, bark, dust, cork dust, bird droppings, and paint

28. The exposure to what medications can cause ILD?
Antibiotics, anti-inflammatory agents, cardiovascular agents, chemotherapy agents, and illicit drugs

29. What connective tissue diseases can lead to ILD?
Scleroderma, rheumatoid arthritis, Sjogren’s syndrome, systemic lupus erythematosus, and sarcoidosis

30. The exposure to what irritant gases can cause ILD?
Chlorine, ammonia, and nitrogen dioxide

31. What is idiopathic pulmonary fibrosis (IPF)?
A progressive inflammatory disease of an unknown cause that leads to varying degrees of fibrosis and honeycombing in severe cases

32. What are the two most rare diseases that lead to ILD?
(1) Lymphangioleiomyomatosis (LAM), and (2) Pulmonary Langerhans cell histiocytosis (PLCH)

33. Which two miscellaneous diffuse interstitial lung diseases involve recurrent pulmonary hemorrhage?
(1) Goodpasture’s syndrome, and (2) Idiopathic pulmonary hemosiderosis

34. How is DLCO affected by interstitial lung disease?
IDL can result in an increase in DLCO.

35. What is expected during the physical examination of a patient with ILD?
An increased heart rate, blood pressure, and respiratory rate; cyanosis, digital clubbing, peripheral edema, venous distention, and a nonproductive cough

36. What chest assessment findings can be expected with ILD?
Increased tactile and vocal fremitus, dull percussion note, bronchial breath sounds, crackles, pleural friction rub, and whispered pectoriloquy

37. What could be found on a chest radiograph associated with ILD?
Bilateral reticulonodular pattern, irregularly shaped opacities, granulomas, cavity formation, honeycombing, and pleural effusion

38. Why is the management of ILD so difficult?
Because there is often no specific cause

39. What are the respiratory care treatment protocols for ILD?
Oxygen therapy, bronchopulmonary hygiene therapy, mechanical ventilation, pulmonary rehabilitation, research trials, lung transplantation, and palliative care

40. What is Idiopathic Pulmonary Fibrosis?
The formation of scar tissue in the connective tissue of the lungs without a known cause, resulting in severe chronic restrictive lung disease

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41. What is the definition of Interstitial Lung Disease?
A group of respiratory disorders characterized by a dry, unproductive cough and dyspnea on exertion. The chest radiograph usually shows fibrotic infiltrates in the lower lobe

42. What is occupational ILD?
Interstitial lung disease resulting from occupational exposure (e.g., asbestosis)

43. What is required to make a diagnosis of interstitial lung disease?
A lung biopsy is typically required to make a definitive diagnosis of interstitial lung disease

44. What are the key diagnostic features of interstitial lung disease (ILD)?
The key diagnostic features of interstitial lung disease (ILD) include dyspnea at rest or with exertion; bilateral diffuse interstitial infiltrates on a chest radiograph, physiologic abnormalities of a restrictive lung defect, and histopathologic features of inflammation or fibrosis of the pulmonary parenchyma.

45. Which interstitial lung disease has an unknown cause?

46. What is used to identify the type and etiology of interstitial lung disease?
Physicians perform many different tests to determine if a patient has interstitial lung disease (ILD). However, the patient’s medical history is most valuable in determining the specific type and etiology.

47. A physician is examining a patient whom she suspects has a form of interstitial lung disease (ILD). The patient is a smoker and presents with dyspnea, cough, fever, chills, and night sweats. The physical exam reveals digital clubbing. What disease might the patient have?
Patients with interstitial lung disease present with many different symptoms, however, the most likely diagnosis is idiopathic pulmonary fibrosis (IPF).

48. A physician is examining the chest radiograph of a patient she suspects has a form of interstitial lung disease (ILD). The radiograph shows eggshell calcification. What disease might the patient have?
The appearance of eggshell calcification on a chest radiograph is almost always unique to silicosis.

49. What are the indications for surgical lung biopsy in patients whom physicians suspect interstitial lung disease (ILD)?
Indications for surgical lung biopsy include a patient younger than 65 years; a history of fevers, weight loss, and sweats; a history of hemoptysis; symptoms and signs of peripheral vasculitis; a history of pneumothorax; a normal chest radiograph; and rapidly progressing disease.

50. What test can help physicians determine the needed biopsy sites for patients with suspected interstitial lung disease (ILD)?
Physicians use high-resolution computed tomography (HCRT) to help determine the best sites to biopsy in patients suspected with interstitial lung disease (ILD).

51. What is the primary objective of therapy in patients with interstitial lung disease (ILD)?
The most important tenet of therapy for patients with interstitial lung disease (ILD) is to remove the agent of injury, if possible. If the agent cannot be found and removed, suppressing inflammatory and cellular immune responses is the next priority.

52. What is the treatment for ILD dependent on?
The treatment method is dependent on the specific cause and symptoms.

53. Is coronavirus a potential cause of ILD?
Yes, ILD can occur secondary to coronavirus.

54. What is the most common drug administered for ILD?

55. Is lung scarring from ILD reversible?
No; once the damage has occurred, it is generally irreversible.

Medical Disclaimer: This content is for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you read in this article. We strive for 100% accuracy, but errors may occur, and medications, protocols, and treatment methods may change over time.


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