What is cystometry and how is it used in the workup of bladder dysfunction?

Updated: Jan 04, 2019
  • Author: Gregory T Carter, MD, MS; Chief Editor: Elizabeth A Moberg-Wolff, MD  more...
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Cystometry is the measurement of bladder volume and intravesical pressure during filling and storage phases for the purpose of evaluating detrusor function. It includes the following:

  • The determination and record of bladder volumes and pressures: The normal adult bladder can contain 400-750 mL of urine, with a maximum bladder pressure of 15 cm water. Abnormal findings include decreased bladder compliance with intravesical pressures exceeding 15 cm water and a steep rising curve in the cystometrogram, possibly due to bladder inflammation, bladder fibrosis, or detrusor hypertrophy. A noncompliant bladder with reduced capacity demonstrates a steep curve associated with neurogenic lesions, inflammation, or severe outlet obstruction.

  • Assesses the leak point (ie, the pressure at which voiding occurs): A leak point in excess of 40 cm water may result in hydronephrosis in children with myelomeningocele.

  • Establishment of the voluntary voiding phase after filling and the efficacy of emptying: Involuntary detrusor contraction (ie, a phasic increase in intravesical pressure during the filling phase) reflects the presence of detrusor hyperreflexia in patients with suprapontine lesions (eg, from a cerebrovascular accident [CVA] or Parkinson disease). This phenomenon also is seen in patients with suprasacral spinal cord disease (eg, spinal cord injury [SCI], multiple sclerosis [MS], or spina bifida). An absence of contractions during attempts to void, as is noted with areflexic bladders, may be seen in patients with sacral lesions. Peripheral neuropathy can also develop from conditions such as diabetes mellitus. [18]

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