cystometria

Cystometria, or cystometry, is a urodynamic test used to evaluate bladder function by measuring pressure and volume during bladder filling and, optionally, during voiding. It assesses bladder capacity, compliance, detrusor pressure, and sensation, helping to diagnose storage and voiding disorders such as detrusor overactivity, detrusor underactivity, neurogenic bladder, and various forms of incontinence.

During the test, a sterile catheter is inserted into the bladder to fill it with saline at a controlled rate while intravesical pressure is recorded. A second catheter may be used to measure abdominal pressure, allowing calculation of detrusor pressure (Pdet = Pves − Pabd). The patient reports sensations of filling, and the filling phase continues to determine capacity and the presence of involuntary contractions. Some protocols include a voiding phase to assess flow and pressure during micturition. Key measurements include maximum cystometric capacity, bladder compliance, presence of detrusor overactivity, and detrusor–sphincter interactions.

Indications for cystometry include evaluation of lower urinary tract symptoms, assessment of urinary incontinence, suspected neurogenic bladder, preoperative assessment before pelvic surgery, and pediatric dysfunctional voiding. Results should be interpreted within the context of the full urodynamic study and clinical history, as measurements such as reduced capacity or high detrusor pressure influence management decisions.

Risks are mainly related to catheterization and may include transient discomfort, urethral irritation, or a temporary risk of urinary tract infection. Cystometry is typically part of a broader urodynamic evaluation that may also include uroflowmetry and electromyography.