To differentiate between stress incontinence and detrusor instability investigation done is
**Core Concept**
Stress incontinence and detrusor instability are two distinct lower urinary tract disorders. Stress incontinence is characterized by involuntary urine leakage during physical stress or increased abdominal pressure, whereas detrusor instability is marked by uncoordinated bladder contractions leading to urine leakage. The primary goal of the investigation is to accurately diagnose and differentiate between these conditions.
**Why the Correct Answer is Right**
A urodynamic study, specifically a filling cytometry, is the most appropriate investigation to differentiate between stress incontinence and detrusor instability. During a filling cytometry, the bladder is gradually filled with saline, and the pressure within the bladder is monitored. This study helps to assess the bladder's ability to store urine and the presence of detrusor instability, characterized by involuntary contractions of the bladder muscle. Additionally, urodynamic studies can also evaluate the urethral closure mechanism and the effects of stress on the bladder.
**Why Each Wrong Option is Incorrect**
**Option A:** Filling cytometry is the correct answer, making option A incorrect as it is not the best choice.
**Option B:** Ultrasound may provide some information about bladder fullness, but it is not sufficient to diagnose detrusor instability and differentiate it from stress incontinence.
**Option C:** Cystoscopy is primarily used to visualize the inside of the bladder and urethra, and while it may be useful in some cases, it is not the best investigation for differentiating between stress incontinence and detrusor instability.
**Clinical Pearl / High-Yield Fact**
Urodynamic studies, particularly filling cytometry, are essential in the evaluation of patients with lower urinary tract symptoms, as they provide valuable information about bladder function and help guide treatment decisions.
**Correct Answer: C. Cystoscopy is primarily used to visualize the inside of the bladder and urethra, and while it may be useful in some cases, it is not the best investigation for differentiating between stress incontinence and detrusor instability.**