Drug induced pulmonary disease is an umbrella term that refers to a number of clinical problems associated with the lungs. It is not a single disorder or disease, rather a range of problems occurring to a person, who has never had any other pulmonary diseases.
Drug Induced Pulmonary Disease: An Overview
When certain lung diseases occur as a side effect of certain medicines, it is referred to as drug induced pulmonary disease. These diseases can be mild as well as severe. It is usually a reversible condition, but there can be severe conditions in which, the problems are irreversible.
When drug induced pulmonary disease is diagnosed, all other possibilities and diseases processes must be ruled out. This kind of pulmonary disease would have no association with recreational, occupational and environmental exposure to irritants or pollutants as well as respiratory infection. In case of these diseases, the causes are entirely associated with certain drugs or medicines. However, in most cases, the pathological changes of the drug induced pulmonary disease are non-specific. Hence, identifying this condition and the particular or root cause associated with it is unsure.
The lungs are the organs that receive the entire circulation in a body. It is because of this metabolic and physiologic capacity of these organs that the pulmonary diseases induced by the drugs and medicines are possible. However, despite of this capacity of the lungs, these diseases are not too common.
Signs and Symptoms of Drug Induced Pulmonary Disease
There are quite a number of signs and symptoms of drug induced pulmonary disease; however, they are non-specific for the different kinds of diseases. The common ones are –
- Irritating cough
- Chest pain
- Bloody sputum
- Excessive fluid in lungs or oedema
- Shortness of breath or asthma
Causes of Drug Induced Pulmonary Disease
Lung diseases or pulmonary diseases can be of different kinds. Different kinds of medicines or drugs too can cause these diseases. What kind of drug will lead to which kind of diseases and who will be affected from these drugs, is not possible to predict. However, the drugs can broadly be categorised and also the types of pulmonary diseases can be categorized broadly in the following ways:
Types of Medicines Leading to Pulmonary Diseases:
- Chemotherapy Drugs: Cyclophosphamide, bleomycin, methotrexate etc. are some of the common chemotherapy drugs that are commonly found to have led to pulmonary diseases.
- Antibiotic drugs: Sulfa drugs, nitrofurantoin etc.
- Illegal Drugs
- Cardiovascular Medicines: Amiodarone.
Those, who take these medicines, are at a higher risk of developing these diseases.
- Types of Pulmonary Diseases Caused by Medicines and Drugs:
- Inflammation of Lungs:
- Allergic Reaction:
- Damage and Bleeding of Lungs:
- Interstitial fibrosis or damage of tissue of lungs
- Alveolar haemorrhage or bleeding of alveoli or lung air sacks
- Fluid build-up:
- Pleural effusion or fluid build-up between lung tissue layers and chest cavity tissue layers
- Pulmonary oedema or abnormal fluid build-up in lungs.
Lupus erythematosus is yet another disease that is caused by the side effects of certain drugs or medicines. It affects various internal organs, including the lungs.
Risk Factors for Drug Induced Pulmonary Disease
- Age as a Risk Factor for Drug induced Pulmonary Disease: Children and elderly people are more likely to develop these conditions. As excretory functions of the kidney are lower in aged people, they develop these conditions more than others.
- Sex: Certain drug induced pulmonary diseases are more common in females.
- Race or Ethnicity Might Increase the Risk for Drug Induced Pulmonary Disease: Some drug induced pulmonary diseases are more common in certain races, such as Bortezomib can cause severe pneumonitis in African American race. Sarcoidosis treating drugs can cause certain pulmonary diseases more in the African Americans races.
Epidemiology for Drug Induced Pulmonary Disease
Because of the lack of recognition and difficulty in diagnosis, the exact frequency of drug induced pulmonary diseases is not clear. However, in USA, there are about 2 million cases registered of drug induced pulmonary disease. About 10,000 deaths occur annually due to this. About 0.3% deaths in the hospitals of USA occur due to drug induced diseases or drug side effects. About 10% pulmonary cases are caused by chemotherapy drugs.
Prognosis for Drug Induced Pulmonary Disease
Usually, acute episodes subside within 48 to 72 hours, after the medicine is stopped being taken. In case of chronic symptoms, it takes longer time to deal with the condition. Some conditions just never subside. Some of the most difficult drug induced pulmonary diseases include –
- Respiratory failure requiring mechanical ventilation
- Pulmonary fibrosis
- Pulmonary embolism
- Increased incidence of pneumonia
- Pulmonary hypertension.
If the condition is not properly diagnosed and if the drug that is responsible in causing this condition is not diagnosed, it can lead to mortality. Some of the statistical data attributed to the mortality rates associated with drug induced pulmonary disease are –
- 10% cases of Amiodarone induced pneumonitis
- 50% cases of Cyclophosphamide-induced pulmonary fibrosis
- 10% cases of Bleomycin induced pulmonary toxicity
- 2-50% cases of NCPE caused by Cytosine arabinoside
- 7% cases of MTX-induced hypersensitivity fibrosis
- 8% cases of progressive respiratory failure.
Diagnosis of Drug Induced Pulmonary Disease
This is very important to determine the exact drug or medicine that has caused the drug induced pulmonary disease. If the diagnosis is not proper, it is very difficult to prevent the condition from worsening. Since the basic treatment method is to stop taking the drug, the responsible drug must be diagnosed. For that the doctor will take a complete medical history and the medicines that the patient has been taking. If it includes some of the medicines that are more likely to cause the conditions, they are stopped. If medical history cannot help, chest X-ray and other tests are important to diagnose the problem.
Treatment for Drug Induced Pulmonary Disease
The doctor will stop the medicine that is causing the disease in the patient. During the recovery period, the patient stays on oxygen support. In case of inflammatory diseases, steroid and other drugs are given to heal the inflammation.
Prevention of Drug Induced Pulmonary Disease
The only way to prevent the drug induced pulmonary diseases is by staying away from any drug that has led to a pulmonary disease in the past. You need to note down, if you ever had a reaction from any of the drugs that you have taken. In that case, staying away from the illegal drugs is always a must and beneficial.
Drug induced pulmonary diseases are almost always irreversible and they go away fast. However, careful evaluation of the condition and the diagnosis is a must. It is highly curable; however, if neglected the chances of mortality is also high.