The Importance of Video Urodynamic Study in the Diagnosis of Voiding Dysfunction  

Case: A 28-year-old woman with voiding difficulty with a previous history of tethered cord

This patient has an approximately 6-year history of voiding difficulty. While jogging she noticed urinary frequency and urgency. Measurement of the residual urine volume showed 150ml. The patient was referred for urologic consultation. Office urodynamic study was performed and she was instructed to begin CIC which she did. She voided occasionally, but gradually the voiding problem progressed until she was unable to void and needed to rely on CIC.

She was referred to Neurosurgery and they found a lipoma and a tethered cord, and this resulted in a neurosurgical operative procedure. Since then, the patient has had some cutaneous numbness and tingling, occasional difficulty with bowel function which is not constant, and difficulty with urination which essentially is total urinary retention.

Because of the complex nature of the condition and because the patient has had previous urodynamics, we thought we would do video urodynamics and try to define bladder function. Video urodynamic study [VIDEO] was done and to our surprise the bladder is nontrabeculated. The bladder neck is tightly closed, normally closed. There is some guarding reflex activity elicited from the external sphincter in response to filling. The bladder is normal with respect to compliance during the early phase of filling, but at approximately 200mL there is a precipitous drop in external sphincter activity (marked as # in the cystometry) and within 2 to 3 seconds after that there is a slow smooth rise in bladder pressure culminating in a pressure of approximately 45 to 50 cm of water. With the initial drop in external sphincter pressure (marked as * in the cystometry) and the rise in bladder pressure, the beginning rise plus the plateau rise, there is no opening of the bladder neck whatsoever. There is some later increase in external sphincter activity as the patient finds bladder behavior somewhat disconcerting. The bladder is inhibited by the contraction and the pressure rapidly returns to normal.

This video urodynamic study demonstrates an isolated bladder neck obstruction. There is no evidence of any neural dysfunction with respect to this bladder and urethra at all. Bladder and external sphincter activity is coordinate. The bladder stores urine normally. There is reflex activity present. A volitional contraction of the external sphincter effectively inhibits reflex bladder contractility.

In summary, this is not a neurogenic bladder. It is a surprisingly abnormal bladder related to bladder outlet obstruction which ought to be remediable with recovery of normal voiding. She is given a prescription for an alpha-blocking agent terazosin 1 mg to be taken at bedtime.

Comments: It was assumed that the patient had a decentralized bladder resulted to a tethered cord which was released.  This study clearly shows reflex bladder contractility, with a coordinate external sphincter, but failure of the bladder neck to open. This is a very rare condition, probably congenital and is in essence a bladder outlet obstruction at the level of the proximal smooth sphincter. She has normal bladder sensation and she feels the bladder contraction. This is not a lower motor neuron lesion in fact this is non-neurogenic.

Please also refer to this.

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