Interstitial lung disease

Background

• General group of diseases that involve the lung parenchyma
• Grouped together because of similar clinical, physiologic, radiographic, or pathologic findings
• Specific diseases separated into ones with known causes and idiopathic
• Treatment and prognosis differs between specific diseases
• Examples of specific diseases: interstitial pneumonia, hypersensitivity pneumonitis, cryptogenic organizing pneumonia, acute interstitial pneumonitis, sarcoidosis, idiopathic pulmonary fibrosis

Clinical Features

• Symptoms: progressive exertional dyspnea, persistent nonproductive cough, hemoptysis, pleuritic chest pain
• History of occupational exposure: asbestosis, silicosis
• Abnormal chest imaging or pulmonary function tests
• Take detailed history making sure to focus on past medical history (connective tissue disease, inflammatory bowel disease, malignancy), smoking history, family history, medications, occupational and environmental exposures
• Physical exam is generally nonspecific

Differential Diagnosis

• Pneumonia
• Asbestosis
• Berylliosis
• Pulmonary edema
• Coal worker's pneumoconiosis
• Cryptogenic organizing pneumonia
• Drug induced pulmonary toxicity
• Farmer's lung
• Hypersensitivity pneumonitis
• Interstitial pulmonary fibrosis
• Collagen-vascular disease
• Lung malignancy
• Restrictive lung disease
• Sarcoidosis
• Silicosis

Acute dyspnea

Emergent

• Pulmonary
  • Airway obstruction
  • Anaphylaxis
  • Angioedema
  • Aspiration
  • Acute respiratory distress syndrome (ARDS)
  • Asthma
  • Cor pulmonale
  • Epiglottitis
  • Inhalation exposure
  • Noncardiogenic pulmonary edema
  • Pneumonia
  • Pneumocystis Pneumonia (PCP)
  • Pulmonary embolism
  • Pulmonary hypertension
  • Tension pneumothorax
  • Idiopathic pulmonary fibrosis acute exacerbation
  • Cystic fibrosis exacerbation
• Cardiac
  • Aortic dissection
  • Cardiac tamponade
  • Cardiogenic pulmonary edema (CHF)
  • Myocardial Infarction
  • Pericarditis
  • Myocarditis
• Other Associated with Normal/↑ Respiratory Effort
  • Abdominal distension
  • Anemia
  • CO Poisoning
  • Salicylate toxicity
  • Diabetic ketoacidosis (DKA)
  • Diaphragm injury
  • Electrolyte abnormalities
  • Flail chest
  • Hypotension
  • Metabolic acidosis
  • Pneumothorax/hemothorax
  • Renal Failure
  • Sepsis
  • Superior vena cava syndrome
  • Toxic ingestion
• Other Associated with ↓ Respiratory Effort
  • Guillain-Barre syndrome
  • Lambert-Eaton Syndrome
  • Multiple sclerosis
  • Myasthenia Gravis
  • Organophosphate toxicity
  • Stroke (Main)
  • Tick paralysis

Non-Emergent

• ALS
• Ascites
• Uncorrected ASD
• Congenital heart disease
• COPD exacerbation
• Deconditioning
• Fever
• Hyperventilation
• Interstitial lung disease
• Neoplasm
• Obesity
• Obstructive sleep apnea
• Panic attack
• Pleural effusion
• Polymyositis
• Porphyria
• Pregnancy
• Rib fracture
• Spontaneous pneumothorax
• Thyroid Disease
• URI
• Vocal cord dysfunction

Evaluation

Work up and test results differ between types of interstitial lung diseases. Below are common studies obtained to determine disease. See page for specific disease for specific labs/imaging and findings.

• CBC/CMP
• Serologic studies: ANA, Rheumatoid factor
• Imaging: Chest x-ray, chest CT
• Pulmonary function tests
• Cardiac ECHO
• Bronchoalveolar lavage
• Lung biopsy

Management

• Management differs between specific types of interstitial lung diseases. This is why it is important to determine specific cause of disease. See specific disease page for management.

Disposition

• Depending on how stable the patient is, patient can be admitted for work up or discharged for outpatient work up.
• Important to determine acute vs chronic symptoms.

See Also

• Sarcoidosis
• Idiopathic pulmonary fibrosis