Fluid overload means that there is too much fluid in the body. The increased level of fluid results in an excessive volume of fluid flowing around the circulatory system. This can overwork the heart and lead to heart failure.
The excess fluid circulating around the body can cause waterlogging of the lungs, leading to breathlessness. The medical term for this is acute pulmonary oedema. 'Acute' means 'of quick onset'.
If fluid overload goes on for a long term it eventually leads to heart failure. This causes tiredness, breathlessness and swelling of the legs and feet. The type of swelling that occurs is called pitting oedema. This means that when the swelling is pressed with a finger, it leaves an indentation, or 'pit'.
The heart and kidneys interact to control fluid volume and the sodium content in the body. This system is quite complex. More information about it can be found in the separate article written for doctors, called Fluid Overload.
- Treatment with fluid can be a cause. It is sometimes difficult to calculate how much fluid the body needs. This can happen when nutritional fluid or blood is given through a drip. The risk of overload may be increased if you are elderly, you have had a major injury or operation, or your kidneys or heart do not work as well as they should,
- Sometimes the problem is not so much fluid as too much sodium. Sodium is a chemical that occurs naturally in the body and needs to be at a certain level in the blood and other body fluids. If too much sodium is given, the body will retain water to try to correct this.
- People with heart failure may have fluid overload,
- People whose kidneys suddenly stop working properly (acute kidney injury) can be similarly affected.
How is fluid overload diagnosed?
A number of conditions produce signs and symptoms that resemble fluid overload, and these need to be excluded. These conditions include:
- Lung problems, such as blood clots, infections, asthma.
- Heart problems, such as inflammation of the covering of the heart (pericarditis).
- Problems with the venous circulation or lymphatic circulation.
- Disorders causing a low protein level in the blood (hypoproteinaemia).
- Liver disease.
- Thyroid disease.
Will I need any tests?
It's not surprising that with all these conditions to rule out you will need several tests. These may include:
- Heart tests: heart tracing (electrocardiogram, or ECG) and ultrasound scanning of the heart (echocardiogram, or echo).
- Chest X-ray.
- Blood tests to check your kidney function, blood count, liver function, blood gases.
- A special test for heart failure, called B-type natriuretic peptide (BNP).
- Charts to check how much you drink and pee and any weight changes in response to treatment.
What are the treatment options for fluid overload?
The treatment depends on your symptoms and the underlying cause. The possible treatments include:
- 'Water tablets' (diuretics): see the leaflets on Loop Diuretics and Thiazide Diuretics for more information.
- Mineralocorticoid/aldosterone receptor antagonists (MRAs), eg spironolactone and eplerenone, like diuretics, also prevent the build-up of fluid.
- Other treatments such as dialysis may also be needed for severe fluid overload.
What is the outlook for fluid overload?
This depends on the underlying cause and how well you were before the fluid overload occurred. For example, if the fluid overload was due to a problem with your heart, the outlook (prognosis) depends on how treatable your heart condition is. If the fluid overload resulted from being given too much fluid during intravenous treatment, the outlook will depend on the reason why you needed intravenous fluid in the first place. If you were given it because you had just had a simple operation but were well beforehand, the outlook should be good once the overload is corrected. However, if intravenous treatment was given because you had a serious problem such as extensive burns, correcting the overload may be more complicated.
Further reading and references
Kim IY, Kim JH, Lee DW, et al; Fluid overload and survival in critically ill patients with acute kidney injury receiving continuous renal replacement therapy. PLoS One. 2017 Feb 1412(2):e0172137. doi: 10.1371/journal.pone.0172137. eCollection 2017.
Byrne L, Van Haren F; Fluid resuscitation in human sepsis: Time to rewrite history? Ann Intensive Care. 2017 Dec7(1):4. doi: 10.1186/s13613-016-0231-8. Epub 2017 Jan 3.
Glatz T, Kulemann B, Marjanovic G, et al; Postoperative fluid overload is a risk factor for adverse surgical outcome in patients undergoing esophagectomy for esophageal cancer: a retrospective study in 335 patients. BMC Surg. 2017 Jan 1317(1):6. doi: 10.1186/s12893-016-0203-9.