LO1
List etiologies of interstitial lung disease on the board, then relate each etiology to its respective risk factors.
BOTH teams, GO!
Idiopathic Pulmonary fibrosis (most common is idiopathic interstitial pneumonia)
- smoking, metal/dust fumes, farming/hairdressing/stone-polishing, genetic factors (germline loss-of-function mutations in the TERT and TERC genes, which encode components of telomerase.), and age over 50.
Cryptogenic organizing pneumonia
- NA
Pnuemoconioses
- disease caused by organic (HS pneumonitis) and inorganic fumes, moldy hay/grain exposure (farmers lung), and dust. There are many of these compounds and being exposed to them on a regular basis is the main risk factor.
- Inorganic: asbestosis (lower lobes, pleural plaques, asbestos bodies), silicosis (upper lobes, egg shell calcifications), coal miners lung (upper lobes), and chronic beryllium disease
*** What is the most common cancer caused by asbestosis?
- Organic (HS pneumonitis): bird species/feces, animal pelts, rats/gerbils, dust
Medical conditions
- RA, scleroderma, SLE, pulmonary sarcoidosis, pulmonary Langerhans cell histiocytosis
Drug induced
- cephalosporins, quinine, NSAIDs, ACIs, statins, Amiodarone, cyclophosphamide, rituximab, methotrexate, Busofan, Bleomycin, etanercept, infliximab... and many more
Infection
- viral, bacterial, parasitic, fungal
*** BC
Each team outline restrictive or obstructive lung diseases in simple terms and then relate each to lung volumes (FVC, TV, FEV, RV)
Team 1: Obstructive
Team 2: Restrictive
Image
Team 1: What form(s) of interstitial have a poor prognosis?
Team 2: Which have a good prognosis?
Bad: Asbestosis, IPF, silicosis,
Good: HS pneumonitis (with treatment and removal from exposure), cryptogenic organizing pneumonia, sarcoidosis (mostly good), coal workers pneumoconiosis (usually)
- What is the common thread between the three bolded diseases?
Hemoglobin! Taut and relaxed, do we understand this?
What factors contribute to formation of the R and T forms?
Taut form = low affinity for oxygen = favored form in tissues
Relaxed form = high affinity for oxygen = favored form in lungs
In lungs -> High pH, low H+, low CO2
In tissues -> Low pH, high H, high CO2
A 55-year-old male with chronic dyspnea is intubated and started on mechanical ventilation for respiratory failure. Pressure-volume scalars on the ventilator show decreased change in volume for each unit change in pressure as compared to normal values. Of the following options, which is the most likely cause of his respiratory failure?
A. Amyotrophic lateral sclerosis
B. Asthma
C. Centriacinar emphysema
D. Pulmonary fibrosis
E. Alpha-1-antitrypsin deficiency
D.
A decreased change in volume for each unit change in pressure (decreased compliance, or decreased dV/dP) is the hallmark of pulmonary fibrosis.
Idiopathic pulmonary fibrosis is diagnosed if there is a pattern of usual interstitial pneumonia (honeycombing) on high-resolution CT. Biopsy results may confirm diagnosis if CT is not definitive. Connective tissue diseases, drug toxicity, exposure to asbestos and causes of hypersensitivity pneumonitis must be ruled out through history and laboratory testing. Pulmonary function testing reveals restricted volume, normal flow (or above normal), with evidence of decreased gas exchange.
Team 1: Outline on board simple schematic for pathogenesis of idiopathic pulmonary fibrosis.
Team 2: Outline on board pathogenesis for silicosis.
Team 1: image
Team 2: Image
What type of HS is HS pneumonitis? (its a combo)
Each team add to the flow-volume curve.
Team 1: Restrictive
Team 2: Obstructive
Image.
Relate these images to both pathophysiology and clinical presentation. (we can focus on restrictive)
Discuss as a group the moa of corticosteroids and identify a form of interstitial lung disease that would NOT be treated by corticosteroids.
image.
Interstitial lung diseases that primarily involve fibrosis (such as IPF) are generally not treated with steroids. Is there an exception? Why?
52 y/o female presents with periodic episodes of rapid HR, anxiety, lightheadedness for the past two days. PMHx is positive for HTN and DM II. She is currently having an episode and ECG is taken. What condition is she in and what would you use to treat her?
ECG: A fib
Treat: beta blocker or diltiazem for a fib and depending on her CHA2DS2-VASc score, she may require a stronger anti thrombolytic. (LMWH/warfarin/Dabigatran)
Is there anything else we can do if her A fib is not resolved?
A 57-year-old man presents to his primary care physician with shortness of breath. The patient has had worsening shortness of breath for the past year. He has a past medical history of asthma and constipation. His current medications include albuterol and sodium docusate. The patient was an officer in the navy and currently lives at home with his wife. He has a 52 pack-year smoking history. Pulmonary function testing is performed at this visit as revealed in Figure A. The results of this test at this visit are revealed by the blue loop, as compared to his results 12 years ago as seen in the green dotted loop of Figure A. Which of the following is a possible diagnosis for this patient's presentation?
A. Chronic obstructive pulmonary disease
B. Unstable angina
C. Interstitial lung disease
D. Poorly treated asthma
E. Small cell carcinoma of the lung
C.
This patient is presenting with shortness of breath and a flow-volume loop demonstrating restrictive lung disease. Interstitial lung disease can cause this restrictive pattern of lung disease.
Interstitial lung disease presents with shortness of breath, crackles on physical exam, and a diffuse pattern of infiltration on chest radiography. A flow-volume loop will demonstrate decreased lung volumes and a sharper slope upward on inspiration. Though the FEV1/FVC ratio in these patients is normal/elevated, the absolute values of the FEV1 and FVC are decreased. Some common causes of interstitial lung disease include idiopathic pulmonary fibrosis, sarcoidosis, asbestosis, silicosis, and coal pneumoconiosis.
I DID NOT enjoy researching pathogenesis as it seemed that each type of interstitial lung disease involved its own pathogenesis. However dynamed had a general pathogenesis that applied to most. Please discuss as a group your thoughts on this and any interesting facts that you may have found regarding pathogenesis, risk factors, or etiologies.
Pathogenesis
Discuss as a group the differences seen in FEV1/FVC ratio and DLCO between obstructive vs restrictive diseases. Add curves to volume/time graph and please explain the differences seen.
Can a patient with restrictive lung disease have a normal DLCO? Why or why not?
Why is CO used in the DLCO test?
Any questions/comments on treatment?
Management overview
Dynamed and up to date have etiology specific treatments if you want to look them up.
15 y/o male patient is currently in the ICU. He collapsed during a basketball game at school, was pulseless and unresponsive, and EMS found him to be in A fib. ACLS was successful and current ECG is shown below. Physical exam shows a harsh crescendo-decrescendo systolic murmur slightly after S1 and bilateral rales. What does he most likely have? Please identify the type of heart failure he is in and explain.
HCM
HFpEF
SV = EDV - ESV
EF = SV/EDV X 100%
A 38-year-old African American female presents to her primary care physician with uveitis, cough, and arthralgias in her ankles and legs. Bloodwork reveals elevated angiotensin converting enzyme levels, and skin PPD testing shows no observable induration after 48 hours. The patient demonstrates reduced FEV1 and FVC upon spirometry. FEV1/FVC is 85%. Which of the following would you expect to see upon chest X-ray:
A. Enlarged hilar lymph nodes
B. Kerley B Lines
C. Bilateral diaphragmatic elevation.
D. Pleural effusion
E. Fluid in alveolar walls
A.
The clinical presentation is consistent with sarcoidosis. Enlarged hilar lymph nodes are commonly seen on chest radiographs of patients with sarcoidosis.
Sarcoidosis is a syndrome involving granuloma formation in multiple organs, namely the lungs, liver, spleen, and bones. It is most commonly found in African American females and results in symptoms such as uveitis, cough, and arthralgias. Spirometry findings in these patients are consistent with restriction, though total lung capacity would need to be reduced to confirm restriction. Spirometry in sarcoidosis can also show obstruction or a mixed pattern.