Urinary and cranial nerve dysfunction

1. What sort of incontinence is seen with TBI patients?
2. How is bladder dysfunction in TBI treated?
3. Which cranial nerves are most frequently affected by blunt head trauma?
4. How does damage to the olfactory nerve usually occur? What is the prognosis?
5. Why is the facial nerve especially vulnerable to being damaged?

Answers:
1. There is disinhibited detrusor reflex with small bladder volume that empties completely, resulting in small voids and normal PVRs.
2. Timed voids, and possibly anticholinergic meds to increase bladder capacity.
3. CN I (highest rate), VII, VIII more frequently. CN II, III, IV, and VI with intermediate frequency.
4. Displacement of the brain with tearing of the olfactory nerve filaments at the cribiform plate. It is associated with CSF rhinorrhea. Recovery occurs in >1/3 of cases, usually during the first 3 months.
5. Due to its long, tortuous course through the temporal bone.