Idiopathic interstitial pneumonias (IIPs)

Question 1

Are IIPs a subset of DPLDs or vice versa?

Answer 1

IIPs are a SUBset of diffuse parenchymal lung diseases, 1 of 4 DPLD types DPLDs are diseases of interstitial space and parenchyma that are NOT caused by malignancy and infection

Question 2

What is the first question you should ask yourself when evaluating someone for suspected IIP?

Answer 2

Are you sure this is idiopathic? Take a DETAILED history and physical exam, especially of exposures over many years

Question 3

What is an average latency for silicosis, a type of occupational lung disease?

Answer 3

20-30 years i.e. your history better be from womb to tomb

Question 4

What should you include in your interview about exposure histories? (5)

Answer 4

jobs hobbies pets household mold/water damage medications + home remedies

Question 5

Other than exposures, what should you be aware of when you are trying to determine if your patient really has an IDIOPATHIC form of DPLD?

Answer 5

connective tissue disease

Question 6

What should rashes, joint pain, muscle aches, organ dysfunction, and stigmata (synovitis, etc) point you to when initially evaluating a suspected IIP?

Answer 6

Connective tissue disorder, i.e. this is NOT an IIP, but an ILD secondary to a known cause

Question 7

Once you have taken a detailed history which is negative, what should you ask yourself when evaluating someone for a suspected IIP?

Answer 7

Is this sarcoidosis?

Question 8

What is the most common radiographic finding in sarcoidosis?

Answer 8

bilateral hilar lymphadenopathy

Question 9

Where does sarcoidosis tend to predominate in the lung?

Answer 9

upper lobe parenchyma

Question 10

What is the classic radiographic pattern of lung damage in sarcoidosis?

Answer 10

reticular and reticulonodular pattern fibrosis at late stages

Question 11

Other than a consistent history and the absence of other causes of granulomatous disease, what do you need to diagnose sarcoidosis?

Answer 11

a tissue biopsy with non caseating granulomas

Question 12

How do you treat sarcoidosis? 1 standby + 2 options

Answer 12

immunosuppressive therapy prednisone +- steroid-sparing agents like methotrexate or azathioprine

Question 13

What are examples of steroid sparing agents? Where are they used?

Answer 13

methotrexate or azathioprine combined with corticosteroids in sarcoidosis tx

Question 14

If you have eliminated exposure history (except for smoking) and sarcoidosis, what should you ask yourself when evaluating a patient with suspected IIP?

Answer 14

are there a lot of eosinophils?

Question 15

How do you investigate for eosinophilia in working up suspected IIP? What’s a positive finding?

Answer 15

bronchoalveolar lavage (BAL) > 25 % eosinophils is highly suggestive of eosinophilic pneumonia

Question 16

What is a normal BAL eosinophil count?

Answer 16

near 0

Question 17

How do you treat eosinophilic pneumonias?

Answer 17

corticosteroids

Question 18

A patient presents with dramatic and acute hypoxemic respiratory failure. They are admitted to the ICU and a BAL finds a eosinophil count of 30%. What do they most likely have?

Answer 18

acute eosinophilic pneumonia

Question 19

A patient has a history of frequent fevers and dyspnea. They have been treated for bacterial pneumonia repeatedly, without improvement in symptoms. Upon BAL, they are found to have a eosinophil count of 45%. What should be added to the differential?

Answer 19

chronic eosinophilic pneumonia

Question 20

If a patient does not have a significant exposure history (except for smoking), does not have sarcoidosis and has a normal eosinophil count, what should you ask yourself next when working them up for suspected IIP?

Answer 20

Are they acutely ill without a prior history of lung disease? Acute illness in IIP is VERY rare and only has 2 causes: acute interstitial pneumonia (AIP) and cryptogenic organizing pneumonia (COP)

Question 21

What are the only 2 acute forms of IIP?

Answer 21

acute interstitial pneumonia and cryptogenic organizing pneumonia

Question 22

A patient develops acute hypoxemic respiratory failure and bilateral alveolar filling. They are previously healthy, without surgeries, sepsis, aspiration, pneumonia, trauma or pancreatitis, but require mechanical ventilation in the ICU. Chest imaging shows bilateral consolidation and ground glass opacities. On histology, they have diffuse alveolar damage. Swan Ganz catheterization shows normal left atrial pressures. Do they have ARDS?

Answer 22

No, they have acute interstitial pneumonia

Question 23

Between acute interstitial pneumonia and cryptogenic organizing pneumonia, which one makes people more sick?

Answer 23

AIP. Mortality is over 50%

Question 24

A patient presents with weeks of fever, cough, malaise, and dyspnea. BAL finds normal eosinophil counts, and chest imaging shows patchy areas of consolidation favoring the pleural periphery. The patient is treated for recurrent bacterial pneumonia but does not improve. Upon repeat imaging, the abnormalities have migrated. Histology is negative for granulomas, but there is accumulation of plugs of connective tissue in the bronchioles, alveolar ducts, and alveolar spaces. There are some signs of inflammation and type II pneumocyte hyperplasia. No identifiable cause of lung injury was identified on biopsy or in the patient history. What does this suggest?

Answer 24

cryptogenic organizing pneumonia plugs are organizing pneumonia (OPs) and are histopathologic hallmarks

Question 25

How do you treat COP?

Answer 25

prolonged corticosteroids

Question 26

If you have eliminated occupational exposures (except for active smoking), sarcoidosis, and eosinophilia in a chronically ill patient with no signs of acute distress, what should you ask yourself next when working them up for IIP?

Answer 26

Is your patient an active smoker with predominantly ground glass opacities or nodules in their chest CT?

Question 27

What are the 2 possible diseases in a patient that is an active smoker, without other exposures, sarcoidosis, eosinophilia, or acute illness?

Answer 27

respiratory bronchiolitis associated ILD (RB-ILD) and desquamative interstitial pneumonia (DIP)

Question 28

An active smoker in his 40s presents with chronic cough and dyspnea. Ct shows bronchial wall thickening, ground glass opacities, and centrilobular nodules. Darkly pigmented cells, identified as macrophages, fill the alveolar space, ducts and bronchioles. What do they have? how do you treat it?

Answer 28

Either RB-ILD or DIP Complete and immediate smoking cessation.

Question 29

If you've eliminated all other possibilities and you are fairly certain your patient has an IIP, what should you ask yourself?

Answer 29

is this, specifically, idiopathic pulmonary fibrosis (IPF)? Outcomes and treatments are VERY different for IPF v. other IIPs

Question 30

Progressive remodeling of the lung parenchyma and collagen deposition in the extracellular matrix is classic for what type of IIP?

Answer 30

IPF

Question 31

What is the most important part of diagnosing IPF?

Answer 31

HRCT with a UIP pattern

Question 32

A patient presents with slowly progressive dyspnea, cough, crackles, and restrictive physiology PFTs. They are 70 years old, and have a prior history of cigarette use. they have no evidence of connective tissue disorders, exposures other than cigarette smoke, are not acutely ill, and have normal eosinophil counts on BAL. What is your next step?

Answer 32

HRCT to evaluate for IPF

Question 33

Bilateral, basilar predominant, sub pleural and recitulative fibrosis is what pattern of radiologic findings? What can it progress to?

Answer 33

UIP pattern IPF diagnostic can progress to honeycomb lung

Question 34

If a patient has a consistent history and a UIP radiologic pattern, do you need to biopsy them to confirm IPF?

Answer 34

no

Question 35

What is the HISTOPATHOLOGIC UIP pattern?

Answer 35

temporal and spatial heterogeneity, sub pleural involvement, fibroblastic foci, microscopic honeycombing

Question 36

What did the PANTHER trial determine about IPF treatment?

Answer 36

immunosuppressive medications increase risk of death in IPF

Question 37

What is the mainstay of IPF treatment?

Answer 37

nintedanib (TK inhibitor) and pirfenidone (TGF beta inhibitor)

Question 38

How do nintedanib and pirfenidone affect IPF?

Answer 38

they slow the rate of forced vital capacity decline no effect on mortality is known of

Question 39

How do you treat acute exacerbations of IPF?

Answer 39

corticosteroids

Question 40

A patient with a prior diagnosis of IPF presents with acute hypoxemic respiratory failure. What should you look for on their CT?

Answer 40

ground glass opacities

Question 41

If you suspect IPF but the HRCT findings do not suggest a definite UIP pattern, what is the other possible diagnosis? What should you do to establish it?

Answer 41

non specific interstitial pneumonia (NSIP) histopathology through lung biopsy

Question 42

A patients HRCT shows basilar predominant, sub pleural, ground glass opacities without honeycombing. What might they have? how do you confirm?

Answer 42

NSIP REQUIRES biopsy radiographic findings only correlate with biopsies 50% of the time in NSIP

Question 43

If you find NSIP histology patterns in a work up for IPF after you've already answered the rest of Mac's questions about this patient should make you think what?

Answer 43

That you were wrong, because NSIP patterns on pathology frequently correlate with CTD and drug induced pneumonitis. Go ask your patient some more questions you dummy.

Question 44

How do you treat idiopathic NSIP?

Answer 44

corticosteroids + steroid sparing drug

Question 45

A 60-year-old man with history of smoking presents with three months of progressive cough and difficulty breathing. No other significant medical history is noted. There are no signs or symptoms to suggest connective tissue disease. He has held an office job all his life and has no history of exposures, recreational drug use, or radiation exposure. Physical examination shows clubbing of the fingers and bibasilar crackles. High resolution CT of chest (HRCT, **Figure 1**) shows interstitial reticular opacities with sub-pleural, basal predominance and honeycombing with or without traction bronchiectasis. Pulmonary function tests show a moderately severe restrictive abnormality with decreased diffusion capacity. Serologic testing fails to show any evidence of autoantibodies. Which of the following statements is correct with regards to this patient: 1. This patient likely does not have idiopathic pulmonary fibrosis 2. This patient could have idiopathic pulmonary fibrosis, but a transbronchial bronchoscopic biopsy is needed to make the diagnosis 3. This patient could have idiopathic pulmonary fibrosis, but a surgical lung biopsy is needed to make the diagnosis 4. This patient has idiopathic pulmonary fibrosis and no further workup is needed to make the diagnosis

Answer 45

D: This patient has no clear trigger for his lung disease and has HRCT findings consistent with a definite UIP pattern (bilateral, basilar-predominant, sub-pleural fibrosis characterized by reticulation and honeycombing). Given the consistent clinical and radiographic findings, a diagnosis of IPF can be made without a surgical lung biopsy.

Question 46

A 65-year-old woman is diagnosed with idiopathic pulmonary fibrosis (IPF) after a detailed history, physical examination, CT chest, pulmonary function testing, and a surgical lung biopsy. She has no other comorbidities, is limited only by her pulmonary disease, and shows progressive decline in her functional status and effort tolerance. The most reasonable therapeutic approach for this patient would be which of the following: 1. High dose corticosteroids 2. A combination of azathioprine, corticosteroids and N-Acetylcysteine 3. Monthly intravenous cyclophosphamide 4. Treatment with pirfenidone or nintedanib and referral for lung transplant evaluation

Answer 46

**D**: The available evidence-based therapies for IPF are anti-fibrotic medications (pirfenidone or nintedanib) and referral for lung transplantation.

Question 47

Describe the typical presentation (clinical and radiographic findings) for a patient with cryptogenic organizing pneumonia.

Answer 47

COP presents very similar to recurrent infectious pneumonia with subacute fevers, malaise, cough, and dyspnea. Chest imaging typically shows migratory multifocal peripheral opacities.