Oliguria is when you pee less than usual. For adults, that means less than 400 milliliters of urine a day. The specific amounts for infants and children are based on their weight (less than 1 milliliter per kilogram per hour for infants, and less than 0.5 milliliters per kilogram per hour for children).
Lots of different things can cause oliguria. Many of them go away on their own, but some need medical treatment.
Burns and other serious injuries: Burns can dehydrate you and make you pee less. Other kinds of trauma that can cause oliguria include blood loss (hemorrhage), anaphylactic shock from a bad allergy, and septic shock after an infection or surgery.
Obstruction: To get from your kidneys to your urethra -- the tube that takes pee out of your body -- urine has to pass through a maze of “plumbing” called your urinary tract. A blockage anywhere in this area can cause oliguria or even anuria, which is when you don’t pee at all. Many different things can block your urinary tract, like scar tissue from surgery, kidney stones, or a tumor.
Medicines: Certain drugs can make you pee less, including:
- Nonsteroidal anti-inflammatories (NSAIDs), like aspirin and ibuprofen
- Certain antibiotics
- Some chemotherapy drugs
- ACE inhibitors to control blood pressure
- Medications used to treat overactive bladder
- Contrast liquids, sometimes used when doctors take an X-ray or another image of your body
Kidney disease: Oliguria can cause kidney failure, but more often it’s a symptom that your kidneys aren’t working the way they should.
Your doctor will start by asking questions about how long you’ve had the problem, how bad it is, and other things that might be going on with you. For example, she'll want to know if you've been vomiting, had diarrhea, or felt any pain in your belly. You also should tell her about any medications you take.
Your doctor probably will do a physical exam and may want a sample of your pee for testing. This looks for infections or other problems in your urine. In some cases, you may need an imaging test like an ultrasound so she can get a closer look at your kidneys or other organs.
The treatment for oliguria depends on the cause. If you're dehydrated, your doctor will recommend that you drink more fluids and electrolytes. In serious cases, you may need fluids through an IV (a tube that puts fluid directly into a vein in your hand or arm).
More fluids can also help you pass small kidney stones, as can drugs that relax the muscles in the tube that carries pee from your kidneys to your bladder (the ureter). If the stones are large, your doctor may recommend using sound waves to break them up or surgery to take them out. Surgery can also fix other types of obstructions.
If your doctor decides that your problem is caused by a certain medicine, she may suggest a lower dose or a different one. But never stop taking a medication without talking with your doctor first.
If oliguria is caused by kidney disease, you'll see a specialist (called a nephrologist) who will work with you to manage the condition or slow it down. In serious cases, you may need a transplant or dialysis, a process that takes out extra water and toxins from your blood since your kidneys can’t.