Interstitial Lung Disease (Raf)

Question 1

what is a hydrocarbon?

Answer 1

What are hydrocarbons?

* Petroleum solvents
* Household cleaning products
* Kerosene 
* Liquid polishes and waxes 
* Furniture polish  * Typical age group for accidental ingestion: 
* Toddlers 
* Age <5 years  * Often these products are stored in containers that look like beverage containers

Question 2

How do hydrocarbons cause lung damage?

Answer 2

• Lung injury is through DIRECT aspiration
• Hypoxia is the MAIN issue, as opposed to hypercapnia. This is due to:
  
  • Surfactant inactivation—>atelectasis and V/Q mismatch
  • Bronchospasm
  • Hydrocarbon vapours will displace alveolar gas

Question 3

What type of lung damage do hydrocarbons cause?

Answer 3

• Autopsy samples in humans have shown:
• Necrosis of bronchi, bronchioles and alveolar tissue
• Hemorrhagic pulmonary edema
• Interstitial inflammation
• Thromboses

Question 4

What is a non-infectious cause of pneumatoceles?

Answer 4

Hydrocarbon aspiration

Question 5

Long term complication of hydrocarbon aspiration?

Answer 5

Peripheral small airway disease–>obstruction with low FEV1, air trapping so high RV/TLC
No increased bronchial reactivity

Question 6

What features of hydrocarbons enable them to cause lung damage?

Answer 6

Hydrocarbons are vicious b/c:

• Low surface tension—>spread through tracheobronchial tree
• Low viscosity—>can go deep into lung
• High volatility—>high level of blood stream absorption, which causes CNS effects

Question 7

Which surfactant disorders can have a delayed presentation?

Answer 7

• ABCA3

- Surfactant protein C

Question 8

Lamellar body in SP-B?

Answer 8

Disorganized with large whirls and vaculoar inclusions.

Looks like a hole with inclusions, as opposed to a tree trunk

Question 9

Lamellar body in ABCA3?

Answer 9

Fried egg (yolk and surrounding white of the egg)

Question 10

Treatment for ABCA3 and SP-C?

Answer 10

Streoids, hydroxychloroquine, azithromycin

Question 11

Which diseases cause non-caseating granulomas?

Answer 11

• Hypersensitivity pneumonitis

- Sarcoid

Question 12

Which disease cause caseating granulomas?

Answer 12

• TB
• Granuomatosis with polyangitis
• IBD (necrobiotic nodules)

Question 13

Pathology findings in HP?

Answer 13

• Alveolitis
• Giant cells
• Foamy alveolar macrophages
• Non-caseating granulomas

Question 14

4 airway manifestations of SLE

Answer 14

• pleuritis with pleural effusion
• pulmonary embolus
• infection such as pseudomonas, PJP, CMV–>very important to rule out infection for pulmonary presentations of lupus
• shrinking lung syndrome
• chronic ILD
• pulmonary hemorrhage

Question 15

Is routine CT for asymptomatic patients with lupus recommended?

Answer 15

No

Question 16

Risk factors for acute chest syndrome

Answer 16

• Age, in particular 2-4 years of age, though pediatrics>adults
• Pulmonary infection, such as atypicals like mycoplasma
• lower HbF
• HbSS has more ACS than HbSC
• Asian haplotype
• Fat embolism
• Post op atelectasis
• Bronchospasm
• Higher WBC count

Question 17

What is the biggest risk factor for sickle cell chronic lung disease?

Answer 17

• ACS

Question 18

What is the relationship between asthma and sickle cell disease complications?

Answer 18

• Asthma and wheezing are independently associated with SCD complications
• ONLY wheezing is associated with ACS

Question 19

What is ACS?

Answer 19

It's not a disease, but it's a syndrome of respiratory symptoms (fever, cough, dyspnea, hemoptysis) + new radiographic infiltrate in a patient with sickle cell. 
Variety of causes:
- infectious - eg. mycoplasma
- atelectasis - eg. post op 
- fat embolism

Question 20

What type of lung disease is sickle cell chronic lung disease?

Answer 20

• fibrotic (interstitial fibrosis), difuse

- restrictive lung disease

Question 21

Why are sickle cell disease at risk for OSA?

Answer 21

• functional asplenia—>compensatory T+A hypertrophy and extra medullary hematopoiesis

Question 22

Sickle cell disease patient with obstruction, but no BD response. Etiology?

Answer 22

Consider causes for fixed airway obstruction, but can also have obstruction in sickle cell due to increased pulmonary capillary blood volume.

Question 23

In sickle cell patients with suspected hypoxemia, how should this be confirmed?

Answer 23

Poor correlation between SpO2 and arterial blood gas, so should get PaO2 (blood gas)

Question 24

What are signs of severe acute chest syndrome?

Answer 24

• Multilobar disease
• increased hypoxia
• increased RR
• low platelets

Question 25

Which drug is strongly not recommended for PH management in sickle cell disease patient?

Answer 25

- phosphodiesterase inhibitors

Question 26

Sickle cell patient with wheezing. Approach to investigation?

Answer 26

- PFT with pre/post bronchodilator testing - Airway hyper-reactivity challenge tests, such as with exercise or cold air - Methacholine challenge is NOT advised since this can cause ACS - Key point: wheezing in SCD patient should NOT be labelled as asthma right away since there "other causes" (Kendig's doesn't go into details, but presumably the SCD itself with changes in pulmonary blood volume). That being said, may have lower threshold for treating for possible asthma since wheezing is a risk factor for ACS and both wheezing and asthma are independently risk factors for VOC

Question 27

Sickle cell patient with dyspnea during exercise. DDx?

Answer 27

- Pulmonary hypertension - Sickle cell chronic lung disease - (Sleep disordered breathing is a co-morbidity that may be a role, but wouldn't be top on the differential) - Obstructive disease--asthma or wheezing (which seems to be intrinsically related to SCD)

Question 28

Why is oximetry not reliable for SCD?

Answer 28

* increased carboxyhemoglobin in patients with sickle cell disease since faster Hb turnover. Most older oximeters in the hospital can’t differentiate between carboxy and oxygenated hemoglobin * HbS absorbs light at a different frequency than HbA

Question 29

Appearance of lamellar body in SP-B and ABCA3?

Answer 29

SP-B: abnormally formed lamellar body with large whorls and vacuolar inclusions ABCA3: small and dense lamellar body, with eccentrically placed inclusions-->appearance of fried egg

Question 30

BAL findings in HP?

Answer 30

Lymphocytosis Decreased CD4/CD8 ratio (since there is predominance of CD8 cells) increased NK cells

Question 31

Immune pathogenesis of HP?

Answer 31

Sensitization to inhaled antigen-->alveolitis, with accumulation of neutrophils in the alveoli in first 48 hours-->then, increased lymphocytes and macrophages with prodominance of CD8 cells - Both type 3 and type 4 cell mediated immune responses are involved, but there is no immune complex deposition in the lung

Question 32

Patient with lupus presents with pleural effusion. Differential?

Answer 32

Infection is high on the differential! Patients with lupus are at high risk for pulmonary infection, even in the absence of drug side effects - Inflammatory: pleuritis/Serositis - Transudative due to renal failure or cardiac involvement (renal involvement would be more common)

Question 33

Lupus patient who presents with fever, cough, chest pain, new infiltrate on CXR. DDx?

Answer 33

- Infection!!- they are at risk for opportunisitc infections like aspergillus, PJP, pseudomonas , CMV - In general for acute pulmonary symptoms in lupus patient, think about PE, though that wouldn't fit with fever Other less common: - DAH, which is more likely if associated nephritis, drop in Hb or hemoptysis - Acute pneumonitis (but this would pretty much be a diagnosis of exclusion)

Question 34

Lupus patient with chronic dyspnea with exercise, chronic cough. DDx?

Answer 34

- chronic ILD | - pulmonary hypertension

Question 35

Lupus patient with PFT showing restriction, DDx?

Answer 35

- chronic ILD - Shrinking lung syndrome - I think normal DLCO corrected for VA, since there's no parenchymal disease - Pleural effusion - ?DAH, but may expect increased DLCO if acute hemorrhage