Evaluation and Diagnostic Testing
What you must know
Evaluation moves from history to focused exam to confirmatory tests. Know the standardized terminology: symptom, sign, urodynamic diagnosis, and condition are distinct. Understand a voiding diary's purpose (frequency, volume, nocturia, polyuria), pad tests, and validated questionnaires.
For the office: post-void residual by catheter or bladder scan (normal generally <100–150 mL), urinalysis with culture when indicated, cough stress test at comfortable bladder volume, and simple cystometry. Know multichannel urodynamics: filling cystometry (detrusor overactivity, compliance, capacity, sensation), pressure-flow study (detrusor pressure at maximum flow, obstruction nomogram), and urethral pressure profilometry. Understand Valsalva leak point pressure and detrusor leak point pressure as measures of sphincter competence.
For prolapse, know POP-Q points (Aa, Ba, C, D, Bp, Ap, gh, pb, tvl) and staging. For anorectal symptoms, know anorectal manometry, endoanal ultrasound, and defecography indications.
Traps
Questions confuse detrusor overactivity (involuntary contraction during filling) with stress incontinence, or mistake a low Valsalva leak point pressure for obstruction. Remember urodynamics is not required before conservative therapy but is valuable before surgery in complex cases. Don't over-interpret a single PVR - measure and repeat.
Rule of thumb
Match the test to the question: "Is it stress?" → cough test/uDS; "Is it overactive?" → cystometry; "Is it retention?" → PVR and pressure-flow; "Is it prolapse?" → POP-Q.
Worked example: A patient with mixed symptoms and prior continence surgery needs surgery planning. The right step is multichannel urodynamics to assess detrusor overactivity, sphincter function (VLPP), and obstruction - not empiric repeat surgery.