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Abnormal urodynamics

Abnormal findings

• Autonomic dysreflexia: exaggerated sympathetic response to afferent visceral/painful stimulation, causes flushing, sweating, headache, HTN, and reflex bradycardia
• Detrusor External Sphincter Dyssynergia (DESD): involuntary external sphincter contraction during detrusor contraction
• 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
• 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
• Reduced filling sensation: decreased sensation throughout bladder filling
• 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
• Voiding (obstructive) LUTS: slow stream, hesitancy, intermittency, incomplete emptying, postvoid dribbling

Detrusor overactivity (DO)

• Definition: urodynamic finding, may (not) be unrelated to OAB symptoms
• Prevalence: seen in 14-18% normal patients, 50% who report urge incontinence may not demonstrate DO on UDS, only 60-70% men and 40-50% with dry OAB demonstrate DO, whereas 90+% men with wet OAB will demonstrate DO
• Bladder outlet obstruction: coexistent BOO may affect efficacy of OAB treatments (cause urinary retention), but OAB symptoms may improve if BOO is treated
• Terminal: occurs at cystometric capacity resulting in incontinence and possible bladder emptying, most likely predictor that OAB symptoms will persist after treating BOO

Tips for Diagnosing certain diseases

Female SUI and Prolapse

• Uncomplicated stress incontinence: urodynamics is not required prior to surgical intervention
• Indications: prior SUI surgery, prior prolapse surgery, significant LUTS, significant OAB symptoms, elevated PVR, unconfirmed SUI, neurogenic LUTS
• If no SUI demonstrated: 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 (occult SUI)
• Mixed incontinence without DO: shows greater improvement after SUI surgery compared with OAB treatment

OAB, UUI, and Mixed Incontinence

• Indications: prior to surgical or irreversible treatments for OAB, new or persistent urge symptoms after bladder outlet procedure
• Complicating factors: 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
• OAB symptoms more likely to resolve after TURP if patient has terminal DO (as opposed to phasic DO)

Neurogenic Bladder

• Measure post-void residual and assess for underlying cause
• Elevated DLPP: > 40 increases concern for upper tract injury
• Video UDS: consider when concerned about anatomic obstructions
• EMG:consider if concerned about detrusor/sphincter dyssynergia - the higher the spinal lesion, the more likely DESD is to occur

Lower Urinary Tract Symptoms

• Indications: helps differentiate outlet obstruction, detrusor underactivity, detrusor overactivity, and sensory urgency, consider UDS prior to considering surgical or irreversible treatments
• Elevated post-void residual: differentiate obstructed versus non-obstructed patients
• Significantly impaired compliance: the only urodynamic indication for treating BOO

Expected findings based on level of neurologic injury

Level of injury	Overall picture	Bladder	Sphincter	Synergy?	Lower limbs	Bulbocavernosus Reflex
Suprapontine	Detrusor overactivity	Spastic	Normal	Yes	Normal	Present
Suprasacral cord	Detrusor/sphincter dyssynergia		Spastic	No	Spastic
Sacral cord or below	Acontractile detrusor	Flaccid	Flaccid		Flaccid	Absent