The first systematic attempt to define hepatorenal syndrome was made in 1994 by the International Ascites Club, a group of liver specialists. The more recent history of HRS has involved elucidation of the various vasoactive mediators that cause the splanchnic and kidney blood flow abnormalities of the condition. == References ==
These surveys can be divided into two groups: general surveys of lower urinary tract symptoms and surveys specific to overactive bladder. General questionnaires include: American Urological Association Symptom Index (AUASI), Urogenital Distress Inventory (UDI), Incontinence Impact Questionnaire (IIQ), and Bristol Female Lower Urinary Tract Symptoms (BFLUTS). Overactive bladder questionnaires include: Overactive Bladder Questionnaire (OAB-q), Urgency Questionnaire (UQ), Primary OAB Symptom Questionnaire (POSQ), and the International Consultation on Incontinence Questionnaire (ICIQ). OAB causes similar symptoms to some other conditions such as urinary tract infection (UTI), bladder cancer, and benign prostatic hyperplasia (BPH). Urinary tract infections often involve pain and hematuria (blood in the urine) which are typically absent in OAB. Bladder cancer usually includes hematuria and can include pain, both not associated with OAB, and the common symptoms of OAB (urgency, frequency, and nocturia) may be absent. BPH frequently includes symptoms at the time of voiding as well as sometimes including pain or hematuria, and all of these are not usually present in OAB. Diabetes insipidus, which causes high frequency and volume, though not necessarily urgency. Classification
There is some controversy about the classification and diagnosis of OAB. Some sources classify overactive bladder into two different variants:  "wet" (i.e., an urgent need to urinate with involuntary leakage) or "dry" (i.e., an urgent need to urinate but no involuntary leakage). Wet variants are more common than dry variants.