Oliguria, also referred to as hypouresis, is a medical condition characterized by low excretion of urine. According to official classification, oliguria is diagnosed when the output does not exceed 400 ml a day. In fact, it is a common sign of acute kidney injury (AKI), a condition, which can have serious consequences. Speaking of mortality, at least 30% of all AKI incidents are fatal among children and infants. In addition, there are several complications of untreated oliguria, which may include anorexia, hypertension or various infections due to fluid and chemical elements retention, which is further weakening the entire human organism.
This type of ailment may be confused with anuria, a completely different condition, during which urine is excreted in volume less than 50 ml a day, or not excreted at all.
Classification and possible causes
There are three major types of oliguria, that are based on the source of the symptom:
- Pre-renal ? the most common form of oliguria, which accounts for up to 60% of all incidents. Popular causes include dehydration, diarrhoea, significant loss of blood, cardiogenic shock myocardial infarction and low cardiac output. In some cases, pre-renal oliguria has many sources occurring simultaneously, which are rapidly decreasing excreted urine volume when combined together.
- Renal ? related with structural damage to the kidneys. Acute tubular necrosis, use of certain medications or drugs and vascular disorders are the most common causes of such form.
- Post-renal ? refers to all malfunctions, either functional or mechanical, associated with blockage of the urinary tract. The most common causes of post-renal oliguria include benign prostatic hyperplasia and bladder or sphincter dysfunctions.
Early identification of the form and source of oliguria is crucial for further treatment. Fast response will not only reverse the underlying disorder, but will increase the chance of avoiding dangerous complications. Possible diagnostic methods include medical history investigation, physical examination, urinalysis, C-reactive protein test and ultrasonography. In some cases, a healthcare provider may be forced to perform kidney biopsy, if both, pre-renal and post-renal, causes have been excluded.
Treatment and it?s outcome depend on the type, as well as advancement, of an underlying disorder. At first, it is required to handle the source of oliguria. Apart from drugs administration and dialysis, there is also a possibility of a surgery, especially when decreased excretion of urine is caused by an obstruction of the urinary tract. Afterwards, it is recommended to restore fluid and electrolytes balance in order to maintain proper functioning of the organism and quicken the recovery. Excluding complications resulting from an underlying disorder, oliguria itself may also lead to dangerous complications. Without treatment, this type of ailment can lead to anaemia, vomiting, anorexia, nausea, seizures and increased tendency to infection development.
When to see a doctor
Oliguria alone is a very dangerous ailment, regardless of the source. That is why it is highly recommended to visit a specialist as soon as possible, especially when the victim experience heart palpitations, lightheadedness and dizziness.