Specialty Nephrology ICD-9-CM 788.5 MedlinePlus 003147 | ICD-10 R34 DiseasesDB 23641 Patient UK Oliguria | |
Oliguria or hypouresis (both names from roots meaning "not enough urine") is the low output of urine. In humans, it is clinically classified as an output more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration, kidney failure, hypovolemic shock, HHNS hyperosmolar Hyperglycemic Nonketotic Syndrome, multiple organ dysfunction syndrome, urinary obstruction/urinary retention, DKA, pre-eclampsia, and urinary tract infections, among other conditions.
Contents
Beyond oliguria is anuria, which represents an absence of urine, clinically classified as below 80 or 100 ml/day.
Definition
Oliguria is defined as a urine output that is less than 1 mL/kg/h in infants, less than 0.5 mL/kg/h in children, and less than 400 mL or 500 mL per 24h in adults - this equals 17 or 21 mL/hour. For example, in an adult weighing 70 kg it equals 0.24 or 0.3 mL/hour/kg. Alternatively, however, the value of 0.5 mL/kg/h is commonly used to define oliguria in adults as well.
Olig- (or oligo-) is a Greek prefix meaning small or few.
Anuria is clinically defined as less than 50mL urine output per day.
Diagnostic approach
Perform ultrasound examination of the kidney to rule out obstructive processes.
The mechanisms causing oliguria can be categorized globally in three different categories:
Postoperative oliguria
Patients usually have a decrease in urine output after a major operation that may be a normal physiological response to:
Oliguria in infants
Oliguria, when defined as less than 1 mL/kg/h, in infants is not attributed to kidney failure.