Oliguria is an abnormal decrease in urine production. It is diagnosed when urine output is below 400 mL per day or less than 20 mL per hour.
Oliguria can be caused by dehydration, chronic kidney disease, certain medications, or heart failure. It can also occur when a blockage prevents urine from flowing normally.
Treatment depends on the underlying cause of the reduced urine output. A urologist or nephrologist may recommend increased fluid intake, intravenous fluids, medications, surgery, or hemodialysis.
Signs and symptoms
The main signs and symptoms of oliguria include:
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Swelling in the legs and feet
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Increased heart rate
It is important to seek urgent medical attention if these symptoms occur along with decreased urine output. A healthcare provider can identify the underlying cause, begin appropriate treatment, and refer the person to a nephrologist or urologist if needed.
Anuria vs oliguria
Anuria is an absence or near absence of urine production. It is defined as urine output below 100 mL per day.
Oliguria occurs when urine production is significantly reduced. It is defined as urine output below 400 mL per day or less than 20 mL per hour.
Possible causes
Oliguria may be caused by conditions such as:
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Dehydration caused by bleeding, low fluid intake, burns, vomiting, or diarrhea
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Vascular problems, such as a heart attack, congestive heart failure, thrombosis, or cardiac tamponade
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Kidney problems, such as chronic kidney disease, vasculitis, kidney failure, glomerulonephritis, scleroderma, or interstitial nephritis
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Certain medications and medical substances, such as anesthetics, contrast agents, some blood pressure medications, diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), and antibiotics
Oliguria may also occur when the urinary tract becomes blocked, preventing urine from flowing from the kidneys to the bladder and leaving the body. Possible causes of urinary tract obstruction include kidney stones and tumors.
Confirming a diagnosis
Oliguria may be evaluated by a primary care provider, nephrologist, or urologist based on the person’s urine output, medical history, and physical examination.
To determine the underlying cause, the doctor may order urine and blood tests to measure creatinine, blood urea nitrogen (BUN), and electrolyte levels. Imaging tests, such as a kidney ultrasound or CT scan, may also be ordered, particularly if a urinary tract blockage is suspected.
Treatment options
Treatment for oliguria depends on the amount of urine being produced and its underlying cause. It may include medication, hydration, surgery, or hemodialysis.
1. Medications
Antibiotics or antifungal medications may be prescribed when a bacterial or fungal infection is contributing to severe diarrhea or vomiting.
In some cases, a healthcare provider may prescribe a low dose of a diuretic to increase urine output. According to the American Urological Association, an alpha blocker such as tamsulosin may be prescribed off-label as medical expulsive therapy to help certain distal ureteral stones pass more easily.
2. Hydration
If oliguria is caused by vomiting or diarrhea, a healthcare provider may recommend drinking more fluids and using an oral rehydration solution.
Severe dehydration may require intravenous fluids, which are given in a hospital or another supervised medical setting.
Also recommended: Signs of Dehydration: 9 Symptoms & How to Treat tuasaude.com/en/signs-of-dehydration3. Surgery
When oliguria is caused by kidney stones, a doctor may recommend a procedure such as extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, or ureteroscopy. These procedures can break up or remove the stone and restore urine flow.
4. Hemodialysis
If the kidneys are not working properly, the doctor may recommend hemodialysis. According to the National Institute of Diabetes and Digestive and Kidney Diseases, this treatment filters waste and excess water from the blood and helps maintain the balance of important minerals.