Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

A patient who has sustained an injury to the conus medullaris will usually exhibit which of the following bladder symptoms?

1. Hypertonicity, frequent urination, urinary retention

2. Hypotonicity, no voiding reflex, overflow dribbling

3. Normal voiding, urgency, nocturia

4. Increased urgency, bladder spasm, constant leaks

The correct answer is: Hypotonicity, no voiding reflex, overflow dribbling

The injury to the conus medullaris typically results in a loss of both voluntary and reflex control over the bladder, leading to characteristic symptoms related to bladder function. In this case, the correct answer highlights hypotonicity of the bladder, which means the bladder lacks sufficient tone to effectively contract. This can lead to the absence of a voiding reflex, which is the body's natural response to empty the bladder. As a result, urinary retention becomes an issue since the bladder does not contract strongly enough to facilitate normal urination. Additionally, overflow dribbling occurs because although the bladder may be full and unable to empty, small amounts of urine can escape due to over-distension. This combination of symptoms - hypotonicity leading to the loss of the voiding reflex and the presence of overflow dribbling - is commonly seen in patients with conus medullaris injuries. This contrasts with the symptoms associated with other options, which do not fit the expected outcomes of such an injury.