Decreased Urine Output
Oliguria is the medical term for a decreased output of urine. This is clinically defined as an output of below 400 millilitres (~16 ounces) of ...

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What Is Decreased Urine Output?

Oliguria is the medical term for a decreased output of urine. This is clinically defined as an output of below 400 millilitres (~16 ounces) of urine over the course of 24 hours.

If you are still urinating in any amount, you are experiencing oliguria. On the other hand, the complete absence of urine is known as anuria and is defined as an output of less than 50 millilitres in a 24-hour period.

What Causes a Decreased Urine Output?

Many things can cause oliguria, or a decreased urine output. These range from temporary conditions to more serious illnesses.


Dehydration is the most common cause of decreased urine output. Typically, dehydration occurs when you are ill with diarrhea, fever, or another sickness and cannot replace the fluids that you are losing and your kidneys retain as much fluid as possible.


Infection is a less typical cause of oliguria. A severe infection can lead the body to go into shock, which reduces the blood flow to your organs. Shock is a medical emergency and requires immediate attention.

Urinary Tract Obstruction

A urinary tract obstruction, or blockage, occurs when urine cannot leave your kidneys. This can affect one or both kidneys and usually results in a decreased urine output. A blockage can also cause other symptoms, such as body pain, nausea, vomiting, swelling, and fever.


Some medications may cause you to release less urine. Medicines that are known to possibly cause this condition include nonsteroidal anti-inflammatory drugs (NSAIDs), high blood pressure medications (ACE inhibitors), and gentamicin (a type of antibiotic).

If your medication is causing you to release less urine, you should discuss your concerns with your doctor. He or she may change your medication or adjust your current dosage. Never change your dosage or stop taking a medication without first consulting your doctor.

When to Seek Medical Care

You should always alert your doctor to your condition if you experience decreased urine output.

You should seek emergency attention if you feel that your body may be going into shock. This could be due to a serious infection or trauma that needs quick medical treatment.

You should also seek immediate medical help if you think your urinary tract may be blocked by an enlarged prostate or other condition. This can quickly develop into anuria, which will require immediate treatment to prevent serious damage to the kidneys.

Call your doctor right away if you have a decreased urine output along with:

  • dizziness
  • rapid pulse
  • light-headedness

How Is a Decreased Urine Output Treated?

There are no self-treatment options for a decreased urine output. Medical attention is always required to identify the cause and provide the most appropriate treatment.

During your appointment, your doctor will ask you a number of questions before making a diagnosis. He or she will probably want to know when the decreased output began, whether it occurred suddenly, and if it has gotten any worse since it started.

It may help if you know approximately how much you drink each day, whether drinking more increases your urine output, and how much urine you produce each day.

The doctor may need you give a urine sample (or at least try). The sample will be analyzed for its color, protein, and uric acid levels and tested for infection.

Make sure to tell your doctor about any other symptoms that you have, any medications or herbal supplements that you take, and whether you have a history of problems with your kidneys or bladder.

Once your doctor has spoken to you, he or she may require additional tests. These could include:

  • blood tests
  • CT scans
  • abdominal ultrasounds
  • renal scans

Your treatment will depend on the cause of your oliguria. Your doctor may prescribe an IV drip that quickly rehydrates your body or dialysis to help remove toxins until your kidneys can work correctly again.

What Is the Outcome of Untreated Decreased Urine Output?

The outcome for oliguria depends on the cause. Most cases require medical treatment and will only worsen without it.

Left untreated, it is possible that decreased urine output can cause cardiovascular complications, such as hypertension or heart failure, anaemia, platelet dysfunction, and gastrointestinal problems.

How Can Decreased Urine Output Be Prevented?

In general, when decreased urine output is caused by a medical condition, it cannot be prevented. However, the most common cause of this symptom is dehydration, which can be avoided by ensuring that you remain hydrated at all times. Be sure to increase your fluid intake whenever you have a fever, diarrhea, or other sickness. You may also want to use special drink mixes to replace any electrolytes lost during this time and prevent oliguria.

Written by: Kati Blake
Edited by:
Medically Reviewed by: George Krucik, MD
Published: Sep 10, 2012
Published By: Healthline Networks, Inc.
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