The 5 Cs of Urodynamics
Capacity: volume
Compliance: DLPP
Contractility: DO, DUA, BOO
Coordination: DESD
Continence: VLPP
Tips for Diagnostic Categories
SUI and Prolapse
- UDS is not required if a patient has uncomplicated SUI
- If no SUI, remove catheter and repeat test (may be obstructing) - up to 50% women (and 35% men) with SUI symptoms but no SUI on UDS show SUI once catheter removed
- If prolapse present, reduce (pessary, vaginal pack) and repeat stress testing
OAB, UUI, and Mixed Incontinence
- Consider UDS prior to surgical or irreversible treatments for OAB
- Consider if new or persistent urge symptoms after bladder outlet procedure
- Increased filling sensation decreases patient's functional bladder capacity
- Presence of BOO and SUI may complicate treatment decisions
- Absence of detrusor overactivity does not mean it is not clinically present
Neurogenic Bladder
- Measure post-void residual and assess for underlying cause
- Assess for elevated DLPP (> 40) to determine whether upper tracts are at risk for injury
- Consider vUDS when concerned about anatomic obstructions
- Consider EMG if concerned about detrusor/sphincter dyssynergia
Lower Urinary Tract Symptoms
- Check post-void residual, use UDS to differentiate obstructed versus non-obstructed patients
Definitions
- Autonomic dysreflexia: exaggerated sympathetic response to afferent visceral/painful stimulation, causes flushing, sweating, headache, HTN, and reflex bradycardia
- Bladder outlet obstruction (BOO): PdetQmax - 2 x Qmax > 40
- Cough leak point pressure (CLPP): urinary leakage with cough, considered superior to VLPP
- Cystometry: pressure/volume relationship of the bladder during filling, measures sensation, compliance, capacity, and presence of detrusor activity
- Detrusor External Sphincter Dyssynergia (DESD): involuntary external sphincter contraction during detrusor contraction
- Detrusor overactivity (DO): urodynamic diagnosis, involuntary detrusor contraction during filling phase
- Detrusor Underactivity (DUA): ***
- Electromyography (EMG): measurement of sphincter (and pelvic) muscle depolarization
- Filling (irritative) LUTS: frequency, urgency, nocturia, incontinence
- Increased filling sensation: increased sensation at low volumes in absence of involuntary contractions, leads to decreased “functional” but not anatomic bladder capacity
- Intrinsic sphincter deficiency (ISD): leak point pressure less than 60cm water or MUCP less than 20cm water
- Maximum urethral closure pressure (MUCP): max difference between urethral and intravesical pressures
- Neurogenic bladder (NGB): abnormal bladder function due to neurologic disease
- Occult SUI: SUI only after reduction of co-existent prolapse
- Overactive bladder (OAB): urgency +/- frequency, nocturia, incontinence
- Pelvic organ prolapse (POP): descent of anterior/posterior vaginal wall, uterus, vaginal apex
- Post Void Residual: amount of urine left in bladder after urination, no universal definition, elevated PVR caused by DUA and/or BOO
- Pressure-flow studies: bladder pressure and urine flow rate during emptying
- Stress urinary incontinence (UDS): involuntary leakage during filling associated with increased intraabdominal pressure in the absence of detrusor contraction (AKA low VLPP)
- Stress urinary incontinence (symptom): complaint of involuntary urine leakage w/ effort, physical exertion, sneeze, cough
- Stress urinary incontinence (sign): observation of involuntary urine leakage w/ effort, physical exertion, sneeze, cough
- Urgency: sudden urge to void, difficult to defer
- Urinary incontinence: sudden urge to void with associated incontinence
- Uroflowmetry: measurement of urine flow rate
- Urethral pressure profile: fluid pressure needed to open a closed urethra
- Valsalva leak point pressure (VLPP): intravesical pressure at which urine leakage occurs in the absence of a detrusor contraction
- Video UDS: fluoroscopy during UDS
- Voiding (obstructive) LUTS: slow stream, hesitancy, intermittency, incomplete emptying, postvoid dribbling
Sources
- Winters, J. Christian, et al. "Urodynamic studies in adults: AUA/SUFU guideline." The Journal of urology 188.6 (2012): 2464-2472.