5. MTB Step 3 - Interstitial Lung Disease (ILD) & BOOP/COP

Question 1

DESCRIPTION

What is the Clinical Description/Definition of Interstitial Lung Disease (ILD)?

Answer 1

• ILD is a form of Pulmonary Fibrosis secondary to Occupational or Environmental exposures and Medications (e.g., TMP/SMX, Nitrofurantoin)
• If no cause is found, the Diagnosis = Idiopathic Pulmonary Fibrosis (ILD of unknown etiology) by exclusion.

Question 2

ETIOLOGY

What are the (6) Main Causes of Interstitial Lung Disease (ILD) and what are the Names of the Diseases each cause?

Answer 2

1. Asbestos ⇒ Asbestosis
2. Glassworkers, Miners, Sandblasters, Brickyards ⇒ Silicosis
3. Coal Worker ⇒ Coal Worker’s Pneumoconiosis
4. Cotton ⇒ Byssinosis
5. Electronics, Ceramics, Fluorescent light bulbs ⇒ Berylliosis
6. Mercury ⇒ Pulmonary Fibrosis

Question 3

PRESENTATION

What are (3) Presenting Signs/Symptoms in a patient with Interstitial Lung Disease (ILD)?

Answer 3

1. Shortness of Breath (SOB)
2. Dry, Nonproductive Cough
3. Chronic Hypoxia

Question 4

PRESENTATION

What are (3) Physical Exam Findings in a patient with Interstitial Lung Disease (ILD)?

Answer 4

1. Lungs = Dry, “Velcro” Rales
2. Cardiovascular = Loud P2 heart sound (sign of Pulmonary Hypertension)
3. Extremities = Clubbing

Question 5

DIAGNOSIS

What are (3) ECG Findings in a patient with Interstitial Lung Disease (ILD)?

Answer 5

1. Pulmonary Hypertension
2. Right Atrial Hypertrophy
3. Right Ventricular Hypertrophy

Question 6

DIAGNOSIS

What Kills Patients with Interstitial Lung Disease?

Answer 6

Pulmonary Hypertension:

• Pulmonary Hypoxia causes Vasoconstriction of the Lungs.
• Chronic Vasoconstriction causes Increased Pressure in the Pulmonary Artery.

Question 7

DIAGNOSIS

1. What is the Best INITIAL Test for Interstitial Lung Disease (ILD)?
2. What is a MORE Accurate Test for Interstitial Lung Disease (ILD)?
3. What is the Most ACCURATE Test for Interstitial Lung Disease (ILD)?

Answer 7

1. Chest X-Ray (CXR): Interstitial Fibrosis
2. High-Resolution CT Scan: more detailed Interstitial Fibrosis
3. Lung Biopsy

Question 8

DIAGNOSIS

What do the following Pulmonary Function Tests (PFTs) show in a patient with Interstitial Lung Disease (ILD)?

• FEV₁
• FVC
• FEV₁/FVC Ratio
• Total Lung Capacity (TLC)
• Residual Volume (RV)
• Diffusion Capacity Lung Carbon Monoxide (DLCO)

Answer 8

Pulmonary Function Tests in ILD:

• FEV₁ = Decreased
• FVC = Decreased
• FEV₁/FVC Ratio = Normal to INCREASED
• Total Lung Capacity (TLC) = Decreased
• Residual Volume (RV) = Decreased
• Diffusion Capacity Lung Carbon Monoxide (DLCO) = Decreased

Question 9

TREATMENT

1. What is the Best INITIAL Treatment for Interstitial Lung Disease (ILD)?
2. What is the Long-Term Treatment for Interstitial Lung Disease (ILD) in a patient that DOES respond to Initial Treatment?
3. What is the Long-Term Treatment for Interstitial Lung Disease (ILD) in a patient that does NOT respond to Initial Treatment?

Answer 9

There is NO specific therapy to reverse any of the forms of ILD:

1. Steroids
2. Azathioprine if the patient responds to steroids, switch to Azathioprine for Long-term treatment to get the patient off steroids
3. Cyclophosphamide if the patient does NOT respond to initial treatment with steroids OR if they do NOT respond to Long-term therapy with Azathioprine

Question 10

TREATMENT

What is the Most Common Adverse Effect of Cyclophosphamide?

Answer 10

Hemorrhagic Cystitis

Question 11

TREATMENT

What is the ONLY Form of Interstitial Lung Disease (ILD) that Definitely DOES respond to Steroids and why?

Answer 11

Berylliosis

Berylliosis definitely responds to Steroids because it is a Granulomatous Disease

Question 12

TREATMENT

What are (2) Medications used to Slow the Progression of Idiopathic Pulmonary Fibrosis (IPF) and what are their Mechanisms of Action (MOA)?

*REMEMBER: IPF is simply ILD of Unknown Etiology (no cause found)*

Answer 12

Pirfenidone and Nintedanib

Pirfenidone - an Antifibrotic agent that Inhibits Collagen Synthesis

Nintedanib - a Tyrosine Kinase Inhibitor that Blocks Fibrogenic Growth Factors and Inhibits Fibroblasts

Question 13

TREATMENT

What are (4) Causes of Interstitial Lung Disease (ILD) that Definitely have NO therapy?

Answer 13

1. Silicosis
2. Mercury Vapor-induced Fibrosis
3. Asbestosis
4. Byssinosis

Question 14

EXTRA

What is the Most Common Type of Cancer in Asbestosis?

Answer 14

LUNG Cancer

NOT Mesothelioma

Question 15

BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA

CRYPTOGENIC ORGANIZING PNEUMONIA

What is BOOP / COP?

Answer 15

BOOP/COP is a rare Bronchiolitis or Inflammation of Small Airways with a Chronic Alveolitis of unknown origin.

Question 16

BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA

CRYPTOGENIC ORGANIZING PNEUMONIA

What Disorder is Associated with a few cases of BOOP / COP?

Answer 16

Rheumatoid Arthritis

Question 17

BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA

CRYPTOGENIC ORGANIZING PNEUMONIA

What are (5) Characteristics of BOOP / COP that distinguish it from Interstitial Lung Disease (ILD)?

Answer 17

1. No Occupational Exposure
2. Acute Presentation - over weeks-to-months
3. Fever
4. Malaise
5. Myalgias

in addition to the shared Cough, Rales, and SOB (the systemic findings are absent from ILD.)

Question 18

BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA

CRYPTOGENIC ORGANIZING PNEUMONIA

1. What is the Best INITIAL Diagnostic Test for BOOP / COP?
2. What is MORE Accurate Diagnostic Test for BOOP / COP?
3. What is the Most ACCURATE Diagnostic Test for BOOP / COP?

Answer 18

1. CXR - shows Bilateral Patchy infiltrates
2. Chest CT - shows Interstitial Disease & Alveolitis
3. Open Lung Biopsy - the only Definitive way to make the diagnosis of BOOP/COP

Question 19

BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA

CRYPTOGENIC ORGANIZING PNEUMONIA

What is the Treatment for BOOP / COP?

Answer 19

Steroids

There is no response to antibiotics