Respirology - Interstitial Lung Disease

Question 1

Discuss the differential for interstitial lung disease

Answer 1

Upper Lung Disease (FASSTEN)
- Famer's lung (hypersensitivity pneumonitis)
- Anklyosing spondylotis
- Sarcoidosis
- Silicosis
- TB
- Eosinophilic Granuloma
- Neurofribromatosis
Lower Lung Disease (BADRASH)
- Bronchiolitis obliterans
- Abestosis
- Drugs
- Rheumatologic disease
- Aspiration
- Scleroderma
- Hamman Rich (acute interstitial pneumonia)

Question 2

Discuss the pathophysiology, presentation and management of idiopathic pulmonar fibrosis

Answer 2

- age over 50
Presentation
- dyspnea on exertion
- nonproductive cough
- fine crackles at bases is late finding
Investigations
- CXR: reticulonodular pattern, honeycombing
- CT: lower zone peripheral reticular markings, traction bronchiectasis, honeycombing
Treatment
- O2
- Pirdenidone
- Lung transplantation

Question 3

Discuss the pathophysiology, presentation and investigation of sarcoidosis

Answer 3

• idiopathic non-infectious granulomatous multi-system disease with lung involvement
• non-caseating granulomas
  Presentation
• fever, malaise, arthralgia
• Arrhythmia
• Anterior or posterior uveitis
• skin papules, erythema nodusum
• Hepatomegaly
  Investigation
• asymptomatic CXR with nodular opacities in upper lung zones with hilar adenopathy
• PFT: restrictive pattern with low DLCO
• transbronchial lung biopsy showing granulomas

Question 4

Discuss the staging and management of sarcoidosis

Answer 4

Staging
- 0: normal radiograph
- I: bilateral hilar adenopathy
- II: bilateral hilar adenopathy with pulmonary infiltration
- III: pulmonary infiltration alone
- IV: fibrosis (honeycombing)
Management
- Stage 1 resolve spontaneously
- Steroids for symptoms, declining lung function, hypercalcemia

Question 5

Discuss the pathophysiology, presentation and management of hypersensitivity pneumonitis

Answer 5

• Type IV sensitive reaction
  Types
• Farmers lung (thermophilic actinomycetes)
• Bird Breeders/Fanciers lung (immune response to bird IgA)
• Humidifier lung (aureobasidium pullulans)
• Sauna takers lung (aureobasidium spp)
  Presentation
• 4-6h after exposure: dyspnea, cough, fever, chills with CXR showing diffuse infiltrates
• Subacute: more insidious
• Chronic: dyspnea, cough, weight loss, CXR: reticulonodular
  Management
• remove exposure
• steroids

Question 6

Differentiate the three types of pneumoconioses

Answer 6

Etiology
- Abestosis from slowly progressive exposure from abestos fibers over 10-20yrs found in insulation, shipyard, pipe fitters
- Silicosis from gradual 20yr exposure in sandblasters, rock cutters
- Coal Workers: from coal and silica exposure
Presentation
- Abestosis: dyspnea, cough, clubbing
- Silicosis: dyspnea, cough, wheezing
- CW: asymptomatic
Investigation
- Abestosis: lower > upper lobe reticulonodular pattern, pleural plaques, ferruginous bodies
- Silicosis: upper > lower lobe of nodular disease, egg shell calcification of hilar lymph node
- CW: upper lobe multinodular opacities, coal macule
Complications
- Abestosis: bronchogenic Ca and mesothelioma
- Silicosis: TB
- CW: caplan’s syndrome

Question 7

List the factors that must be ruled out for idiopathic pulmonary hypertension

Answer 7

• Left sided cardiac valve disease
• Myocardial disease
• Congenital heart disease
• Parenchymal lung disease
• Systemic connective tissue disease
• Chronic thromboembolic disease

Question 8

Discuss the pathophysiology, presentation and management of idiopathic pulmonary arterial hypertension

Answer 8

Pathophysiology
- mean pulmonary arterial pressure >25mmHg at rest and >30mmHg with exercise
- Systolic pulmonary artery pressure >40mmHg at rest
Presentation
- Dyspnea, fatigue
- Syncope
- Loud palpable P2
- RV heave
- Right-sided S4
- Systolic murmur
- Reynauds
Investigation
- CXR: enlarged central pulmonary arteries and RV enlargement
- ECG: RV enlargement
- Cardiac catheterization to confirm diagnosis
- Echo for right ventricular systolic pressure
Management
- CCB
- PDE5 inhibitors
- Lung transplant

Question 9

Discuss the classification of causes for pulmonary hypertension

Answer 9

• Pulmonary arterial hypertension
• Pulmonary hypertension due to left heart disease
• Pulmonary hypertension due to lung disease and/or hypoxia
• Chronic thromboembolic pulmonary hypertension
• Pulmonary hypertension with unclear multifactorial mechanism

Question 10

Discuss the pathophysiology, presentation and management of acute respiratory distress syndrome

Answer 10

• within 7d of defined event with bilateral opacities and not due to cardiac failure or fluid overload
• ARDS is PaO2/FiO2 <=200
  Pathophysiology
• direct lung injury: gastric contents, drowing, pneumonia
• indirect: sepsis, shock, trauma
• disrupt alveolar capillary membranes leading to leaky capillaries and interstitial and alveolar pulmonary edema causing reduced compliance, V/Q mismatch, shunt, hypoxemia
  Presentation
• Exudative (less <7d): loss of normal tight alveolar barrier leading to dyspnea, tachypnea, increased work of breathing
• Fibroproliferative (>7d) improve and wean of ventilator
  Management
• mechanical ventilation with low tidal volume (<6mL/kg)
• Fluid and inotropes