Interstitial lung disease

Interstitial lung disease
Classification and external resources
End-stage pulmonary fibrosis of unknown origin, taken from an autopsy in the 1980s.
ICD-10	J84.9
ICD-9	506.4, 508.1, 515, 516.3, 714.81, 770.7
DiseasesDB	31509
eMedicine	ped/1950
MeSH	D017563

Interstitial lung disease (ILD), also known as diffuse parenchymal lung disease (DPLD),^[1] refers to a group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs). ^[2] It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, perivascular and perilymphatic tissues.

The term ILD is used to distinguish these diseases from obstructive airways diseases.

Most types of ILD involve fibrosis, but this is not essential. The term "pulmonary fibrosis" is no longer considered a synonym. Idiopathic pulmonary fibrosis is one form of "interstitial lung disease".

Causes

The alveoli

Micrograph of usual interstitial pneumonia (UIP). UIP is the most common pattern of idiopathic interstitial pneumonia (a type of interstitial lung disease) and usually represents idiopathic pulmonary fibrosis. H&E stain. Autopsy specimen.

ILD may be classified according to the cause.^[3] One method of classification is as follows:

1. Inhaled substances
   • Inorganic
     • Silicosis
     • Asbestosis
     • Berylliosis
   • Organic
     • Hypersensitivity pneumonitis
2. Drug induced
   • Antibiotics
   • Chemotherapeutic drugs
   • Antiarrhythmic agents
3. Connective tissue disease
   • Systemic sclerosis
   • Polymyositis
   • Dermatomyositis
   • Systemic lupus erythematosus
   • Rheumatoid arthritis
4. Infection
   • Atypical pneumonia
   • Pneumocystis pneumonia (PCP)
   • Tuberculosis
   • Chlamydia Trachomatis
   • Respiratory Syncytial Virus
5. Idiopathic
   • Sarcoidosis
   • Idiopathic pulmonary fibrosis
   • Hamman-Rich syndrome
6. Malignancy
   • Lymphangitic carcinomatosis

Investigation

Patients with pneumocystis pneumonia can present with interstitial lung disease, as seen in the reticular markings on this AP chest x-ray

Investigation is tailored towards the symptoms and signs. Most patients have blood testing, chest x-ray, pulmonary function testing, and high resolution CT thorax.

A lung biopsy is required if the clinical history and imaging is not clearly suggestive of a specific diagnosis or malignancy cannot otherwise be ruled-out.

TLCO will be decreased in these patients.

Prevention

There are currently no 100% ways of preventing Pulmonary Fibrosis, but many people believe the avoidance of smoking or smoke filled environments, as well as not going into heavily polluted areas. Also easily inhaled chemicals should be avoided as they can effect and inflame the alveoli and broncus.

Treatment

ILD is not a single disease, but encompasses many different pathological processes. Hence treatment is different for each disease.

If a specific occupational exposure cause is found, the person should avoid that environment. If a drug cause is suspected, that drug should be discontinued.

Many idiopathic and connective tissue-based causes of ILD are treated with corticosteroids,^[4] such as prednisolone. Some patients respond to immunosuppressant treatment. Patients with hypoxemia may be given supplemental oxygen.

External links

• AIMIP Onlus - Italian Interstitial Lung Diseases No-Profit Organization
• 00736 at CHORUS
• 1476788304 at GPnotebook
• MeSH Pulmonary+Fibrosis
• MedlinePlus Overview pulmonaryfibrosis
• coalitionforpf.org - Coalition for Pulmonary Fibrosis: Pulmonary Fibrosis Patient Services, Education; Funding Research to Find a Cure for PF* Dorothy P. and Richard P. Simmons Center for Interstitial Lung Diseases at University of Pittsburgh Medical Center
• UCSF Interstitial Lung Disease Program at University of California San Francisco
• Interstitial Lung Disease Program at University of Chicago Medical Center
• Interstitial Lung Disease Center at University of Cincinnati
• PA-IPF - The Pennsylvania Idiopathic Pulmonary Fibrosis State Registry at University of Pittsburgh

References