Fluid in the Lungs – Causes and Treatment

Fluid in the lungs is a broad term to describe two possible conditions that may give characteristic symptoms, like a bubbling sound in the lungs (rales) when breathing. The fluid accumulation may be inside the lung (pulmonary edema) or outside the lung (pleural effusion), in the space between the lung and chest wall. The term “fluid in the lungs” is also used to refer to mucus inside the lungs. Mucus or phlegm is a thick, sticky secretion while “lung water” is a thin fluid. Other fluid accumulation may be the result of  blood or pus.


The lungs are located in the thorax (chest) and lies on either side of the heart. Air travels through the air passages, which includes the nose, pharynx (throat), trachea (air pipe) and bronchi. The lung tissue is made of small air sacs, known as alveoli, which is thin and surrounded by blood capillaries. The structure of the respiratory system allows for an exchange of gases so that essential oxygen is taken into the body and waste products, along with gases, are excreted through the exhaled air. The lung is enclosed in an air tight pleural cavity, with a small pleural space separating the lung from the chest wall. This cavity is lined by the pleural lining, which also produces a little pleural fluid to reduce friction between the chest wall and lungs during breathing.

Fluid Inside the Lungs

The most common cause for fluid inside the lungs is mucus or phlegm, which is produced by the lining of the respiratory tract. The respiratory tract is lined with a mucus membrane, which is a specialized tissue that produce smucus. This mucus lubricates the lining, which may dry out due to the air moving in and out of the passages, as well as to trap any dust or microorganisms in the air. However in certain conditions, the mucus membranes of the air passages may produce excessive amounts of mucus and this may slowly ‘sink’ lower down the air passages until it settles in the lungs. The cough reflex or even spontaneous coughing will usually propel most mucus out through the mouth (sputum), however in cases of excessive mucus production, obstructive airway disease or diminished coughing, the mucus build up will quickly settle in the lungs.

“Lung water” or water in the lungs usually results from interstitial fluid or blood plasma and may be an indication of a more serious underlying disorder, usually cardiovascular conditions. This fluid inside the lung is known as pulmonary edema and may be accompanied by a shortness of breath or difficulty breathing (dyspnea), a feeling of suffocation, anxiety and restlessness. Abnormal breathing sounds are also present, particularly crackling. Pulmonary edema may be considered a medical emergency and immediate medical intervention is required.

Blood may also fill inside the lungs but this usually occurs as a result of severe trauma and the cause is clearly evident, like in a gunshot or stab wound. In most trauma cases where blood can fill into the lungs, the lungs collapse and the blood accumulates around the lungs in the pleural space (hemothorax). Infections like tuberculosis (TB) or lung cancer may also cause blood accumulation inside the lungs. Depending on the severity of the trauma, blood inside the lungs will cause drowning and requires immediate medical attention. Pus may also occur inside the lung due to a lung abscess and also requires immediate urgent medical attention.

Causes of Fluid Inside the Lungs

  • Bronchitis is the most common cause of mucus in the lungs and is often characterized by persistent coughing. This respiratory condition may develop after the common ‘cold’ or flu (seasonal influenza) , often a s a result of a secondary bacterial infection but may also be chronic and non-infectious as in the case of  smokers.
  • Infections may cause hypersecretion of mucus in the respiratory tract and/or pulmonary edema and this includes viral (example – H1N1 swine flu, SARS – Sudden Acute Respiratory Syndrome), bacteria (example  – tuberculosis, streptococcal or pneumococcal pneumonia), fungi (example – histoplasmosis, aspergillosis, candidiasis) and parasitic  (example – toxoplasmosis) infectious agents.
  • Pneumonia may also result in “lung water” or fluid with a thinner viscosity. This may arise only at the affected lobe of the lung due to inflammation of the lung tissue. Pneumonia is not only caused by infections but may be due to gastric contents that are aspirated from the stomach into the lungs.
  • Allergies often result in increased mucus production, however, in certain acute cases, there may be pulmonary edema. Post nasal drip may often lead to mucus collection within the lungs and allergies may cause inflammation of the bronchioles and mucus in the chest of asthmatics.
  • Near drowning results in fluid in the lungs and even if all the fluid is drained from the lungs, it is important to monitor the patient in hospital to prevent dry drowning.
  • Many cardiovascular conditions will possibly lead to pulmonary edema and this includes hypertension (high blood pressure), myocardial infarction (heart attack), heart valve disease or cardiomyopathy (damaged heart muscle).
  • Renal failure may cause pulmonary edema as the kidneys are unable to filter out toxins in the blood.
  • Smoke inhalation may cause severe inflammation of the lung tissue, which results in fluid accumulation in the lungs.
  • Lymphatic insufficiency result in inadequate drainage of lymph fluid.
  • Drug side effects may result in pulmonary edema and this includes OTC (over-the-counter) or prescription drugs, narcotics or anesthetics. This may also occur after usage of the drug, when the effects of the drug appear to have worn off.
  • Inhaled, ingested or injected toxins or poisons may increase the permeability of capillary walls, thereby leading to pulmonary edema. Some toxins may also increase mucus production in the lining of the lungs.
  • Autoimmune diseases like sarcoidosis may cause fluid in the lungs due to the inflammation of the lung tissue.
  • Shortage of oxygen due to high altitudes, COPD (chronic obstructive pulmonary disease) and suffocation may result in pulmonary edema.

Fluid Outside the Lungs

Pleural effusion is when fluid accumulates around the lung, in the pleural space. Blood (hemothorax), fatty lymphatic fluid (chylothorax) or pus (empyema) may also fill the pleural space although this occurs less frequently. Any fluid accumulation around the lungs should be taken seriously and requires immediate medical attention. The fluid accumulation around the lungs compress the lung and this prevents normal respiration, which results in inadequate gas exchange. The types and causes of pleural effusions are discussed in detail under fluid around the lungs.

Some Causes of Fluid Around the Lungs

  • Congestive cardiac failure is one of the most common causes of a pleural effusion. This fluid is more thicker (transudative) due to protein that is ‘forced’ out of the blood vessels and into the pleural space.
  • An exudative effusion is a watery fluid accumulation due to inflammation, caused by lung cancer like pleural mesothelioma, infections like TB or pneumonia, lung disease like asbestosis or drug reactions.
  • A hemothorax may be a result of a trauma or rupture of large blood vessels in the case of an aortic aneurysm although the latter causing a pleural effusion is uncommon.
  • An empyema is the accumulation of pus within the pleural space often due to a lung abscess.
  • A chylothorax is the accumulation of lymphatic fluid, which has a high concentration of fat, and may occur in certain cancers like lymphoma.
  • Some of the causes of fluid accumulation inside the lungs may also cause a pleural effusion, including kidney failure and liver disease.

Diagnosis of Fluid in the Lungs

Upon physical examination, your doctor will be able to identify abnormal sounds like bubbling or crackling (rales) with a stethoscope upon respiration. A wheezing sound (stridor) may be clearly audible as well when exhaling. Percussion is a tapping motion conducted against the chest wall and will assist your doctor with identifying areas of the lung that may be affected. Typically fluid accumulation causes a dull sound compared to the normal hollow sound of the air filled lung. Based on clinical findings and other signs and symptoms, your doctor may request further diagnostic investigations, which may include the following procedures.

  • A chest x-ray is one of the main diagnostic investigations conducted to identify the severity and area that is affected. For further imaging, a thoracic CT scan or chest ultrasound may be conducted.
  • Due to the incidence of cardiovascular disorders related to fluid in the lungs, your doctor may conduct an ECG (electrocardiography), ultrasound of the heart (echocardiography) and other cardiac investigations.
  • Fluid may be aspirated from the pleural space, which is known as thoracentesis, but this has to be carefully done to prevent a pneumothorax (accumulation of air in the pleural space). A pleural fluid analysis is then conducted to identify the type of exudate or any microorganisms.
  • A sputum culture may be necessary to identify the cause of infection.
  • A range of blood tests may be requested by your doctor to verify kidney and liver function, proper gas exchange and heart disorders.

Treatment of Fluid in the Lungs

Treatment is dependent on the cause of the fluid in the lungs. Some of the treatment options may include :

  • Antibiotics, antivirals or antifungals may be necessary in the case of an infection.
  • Diuretics assist with passing out additional fluid but should be used cautiously in the case of cardiac diseases.
  • Antihistamines may be necessary in allergic reactions and this may need to be continued on a chronic basis to prevent exacerbations.
  • Corticosteroids may be useful for controlling inflammation and mucus production, as in asthma, and this may be used long term to prevent acute attacks.
  • Chest drainage with a tube may be necessary for an empyema or a therapeutic thoracentesis may be required for a pleural effusion.
  • Anti-hypertensive drugs may be administered in cases of high blood pressure.
  • Oxygen is administered in severe cases of fluid in the lungs where proper gas exchange is impaired. While this does not immediately treat the cause of fluid in the lungs, except in a shortage of oxygen, it assists with adequate gas exchange.
  • Physiotherapy may be necessary to assist with mucus drainage.


  1. Pulmonary Edema. Merck
  2. Pleural Effusion. Pulmonology Channel
  3. Chylothorax. Medscape

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  • sainikhil

    My grand father aged 79 is suffering from unknown problem. Doctors are saying that phleam is creating inside lungs it is very difficult to remove and also from last one month he has kept in ventilation also now they arranged pipe for separete breathing and food pipe in nose. They are not responding about any situation.

  • sandeep ghosh

    Doctor told that it’s due to mucus which cause congestion..and says as i’m not lose any weight it is nothing related to heart.

  • Hi Sandeep. It’s good that your doctor has put your concerns at ease. You have posted many questions on different articles around the same issue. Please refrain from posting pictures of your medical reports. It is against our comments policy and contains all your personal details which can be viewed by the public.

  • Hi Sainikhil. It is difficult to say for sure what is going on as there has been no diagnosis provided. Considering he is in respiratory distress, currently on a ventilator and his age, the prognosis is not very promising. Hopefully he will recover fully but you need to speak to his doctor about the case for a more definitive answer.

  • Lin

    my 83yr old dad has a chronic cough for month..on xray showed fluid in lungs…he lived in a town where asbestos was there. he had a quad bypass surgery 4yrs ago.. He is strong…still exercises and shovels snow….what do you think it is…

  • Hi Lin. Can’t say for sure. The doctor who requested the x-ray should have explained it further to you. Asbestosis is a possibility but there should be more symptoms at this point. Heart failure is another possibility, especially given his age and prior surgery. However, it could be a lung condition itself like pneumonia.The doctor overseeing his case should advise you further.

  • Dana D

    I have fluid in my lungs that the clinic doc just diagnosed. He put me on antibiotics. What can I do to help with sleep. The crackling sound is horrible and I can’t really bring up anything.

  • Hi Guest. Speak to your doctor about whether you can sleep slightly upright. This may help to some degree. However, these symptoms like the crackling sound will resolve as you continue with your antibiotics. Make sure you follow up with your doctor after completing the course of antibiotics even if you are symptom-free.

  • bmw_babe

    My brother just had 3 1/2 liters of dark fluid with a foamy top drained from his lungs. His doctor said it could be caused by cancer or infection. It will be several weeks before it is analyzed and the results are available. Do you have any idea what this might be? He’s 82 and in good health otherwise.

  • Asad Kamran

    My elder brother had pneumonia from 3 weeks, a weak before doctor drain the fluid from his right Lung with the help of a syringe and ultrasound. He has shortening of breath if talk consecutively for 5 min or more. He is on antibiotics, and loss his appetite, only takes some fluids.Doctor propose to drain the fluid with the help of a tube but last day Doctor told that now Fluid is solidify in right lung, and only antibiotic course can remove it. I am worried by this last news. Please help regarding this solidification of fluid in lungs, is it dangerous, And also suggest to improve Appetite.

  • Hi Bmw_babe. It is difficult to say for sure what the cause of this fluid is. The cause can vary depending on whether the fluid was drained from around the lungs (pleural effusion) or from within the lung (pulmonary edema). Yes, an infection and even cancer can cause this. Heart problems could also be a cause but the fluid should not be dark (which is most likely due to degraded blood). The results from the tests are necessary to draw any conclusions from this. Hopefully the results have come in by now.

  • Hi Asad. Yes it could be very dangerous if he doesn’t take his antibiotics or other medication exactly as prescribed. It is also more of a risk if he has a weakened immune system like in the case of HIV infection or other severe chronic diseases. He must follow the doctor’s advise closely and if there are no complications he should recover in due course. Whether the damage to the lungs will clear up is not something that we can answer through an online platform. It is best to discuss it with his doctor.

  • tabitha

    Hello everyone, i got out the hospital 3 weeks ago . I had to have surgery done on my left lung because of pus being on there. They drained over a liter of pus from my lung during surgery and had chest tubes on my side a few days following the procedure. I still feel alot of discomfort and.pain where it all took place . Why is this ?

  • namrata

    i am 17 years old and have chest pain since 2 months . it is sharp and comes for 5-6 sec 10 times a day . i hear bubbling sounds when i suddenly move or something . my ecg and ekg are very normal. i went to a physician and he said i am absolutley fine . he said sometimes due to some stimulators getting activated it pains and it will dissapear on its own and there is no cure for it and if i want i can spray volini on it . he said to ignore it . when he checked my heartbeat n all there was no bubbling sound or anythig. whats wrong with me ?cani ignore it really ?

  • Hi Tabitha. It is not uncommon for discomfort and pain to persist for quite a while. The exact reason for this pus must be also treated which your doctor would have done.Hopefully you used medication exactly as prescribed. Pain could be from the site where the drainage was done, but it could also be related to the underlying condition which may not have resolved despite the treatment. It would be advisable that you follow up with your doctor.

  • Lorraine butler

    hi I’ve been told there are shadows on my lung and fluid what could cause this? I’ve had a ct scan and due a camera down to look but I’m very worried I had a bad flu bug and had severe pain in upper back a friend said I had pleurisy as she had it before would this possible cos obviulsy I’m worried about cancer any help or advice would be much appreciated

  • Hi Namrata. From what you say it seems to be more of a musculoskeletal condition. Given your age and lack of other symptoms, heart and lung conditions are unlikely but it is good that you underwent all these tests. You may want to read up on Tietze syndrome and costochondritis. The former is quite common in your age group. It is usually not serious although it can be quite painful. You may also want to follow up again with your doctor and possibly a physical therapist. We cannot say for sure that this is your problem but it is something to consider.

  • shannon

    Hello! About a week ago I had trauma to my back upper and lower. As of yesterday I’ve been feeling like an ice cold fluid feeling in my lower throat/ chest. My chiropractor said it’s allergies and not related. It’s a terrible feeling. I feel like I’m drowning or choking on liquid. had anyone experienced this? I’m going to call My primary tomorrow. I’ve had terrible anxiety over this.

  • shannon

    Hello! About a week ago I had trauma to my back upper and lower. As of yesterday I’ve been feeling like an ice cold fluid feeling in my lower throat/ chest. My chiropractor said it’s allergies and not related. It’s a terrible feeling. I feel like I’m drowning or choking on liquid. had anyone experienced this? I’m going to call My primary tomorrow. I’ve had terrible anxiety over this.

  • Megan Gardner

    After giving birth by way of c- section two weeks later I was in the. Hospital because of fluid in and around my lungs. They did x-rays and a ct scan. They also did an ultrasound on my heart. And ekg. My heart came back fine. They told me they don’t know why I have fluid in and around my lungs. They prescribed me lasix for two weeks. It went away. Now I’m out of lasix and now when im laying down. I can feel the rumble in my lung again. Also its only been my right lung. What can I do. I’m scared.

  • nichaa lini

    Sometimes when i get into the swimming pool, i feel like my lungs are full altho i can breathe. N i cant last long in water as i usually can a few years back. When im out of the water i still feel like my lungs are full, it just gets worse when im in water. Does this have anything to do with this disease ?

  • Denise

    My husband has got fluid on the lungs after a recent surgery for perforated stomach ulcers . He is hardly able to get out of bed and his breathing is very difficult . He has a tube in his nose draining a green / black fluid and is having antibiotics and chest physio . I’m really worried for him . Nobody has really said if he is going to recover or how long recovery is likely to take ?? And advice ??

  • susheel dutt

    hi, my dad is on dialysis, his kidney is not functioning, but he seems to have a lot of fluid in his lungs.
    what will be the best treatment , he is 83.

  • Hi Susheel. The fluid in the lungs is not uncommon with kidne failure. Hopefully your Dad is having the required dialysis treatment at regular intervals as advised by his doctor. Also if there was dietary recommendations for his condition, ensure that he makes those changes in what he is eating. It can play a major role in his condition. You will need to discuss the treatment options for the fluid in his lungs with his doctor. It may have to be drained and medication may also be prescribed. His doctor will be able to advise you further.

  • Mohaze Abdi

    This week I started to produce foamy/frothy like sputum. What does this mean? Please help.