occur or there is no urine in the drainage bag when a catheter is in place, the catheter may be blocked by blood, thick sediment, or a kink in the catheter or drainage tubing. Sometimes spasms are caused by the catheter irritating the bladder, prostate or penis. Such spasms can be controlled with medication such as butylscopolamine, although most people eventually adjust to the irritation and the spasms go away. Diagnosis Diagnosis of OAB is made primarily on the person's signs and symptoms and by ruling out other possible causes such as an infection. Urodynamics, a bladder scope, and ultrasound are generally not needed. Additionally, urine culture may be done to rule out infection. The frequency/volume chart may be maintained and cystourethroscopy may be done to exclude tumor and kidney stones. If there is an underlying metabolic or pathologic condition that explains the symptoms, the symptoms may be considered part of that disease and not OAB. Psychometrically robust self-completion questionnaires are generally recognized as a valid way of measuring a person's signs and symptoms, but there does not exist a single ideal questionnaire. 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