NCLEX Review Guide: Acoustic Neuroma

Understanding Acoustic Neuroma

• An acoustic neuroma is a benign, slow-growing tumor that develops on the eighth cranial nerve (vestibulocochlear nerve), specifically affecting the vestibular portion.
• The tumor typically arises from Schwann cells and can compress surrounding cranial nerves, brainstem, and cerebellum as it enlarges.
• Most commonly unilateral, but bilateral acoustic neuromas are associated with neurofibromatosis type 2 (NF2).

Clinical Manifestations

• Unilateral sensorineural hearing loss is the most common initial symptom, often gradual and progressive.
• Tinnitus (ringing in the ear) typically accompanies hearing loss and may be the presenting complaint.
• Vertigo and balance problems occur due to vestibular nerve involvement, leading to unsteadiness and dizziness.
• As the tumor grows, facial numbness, weakness, or paralysis may develop from cranial nerve VII compression.

Diagnostic Tests

• MRI with gadolinium contrast is the gold standard for diagnosing acoustic neuroma and determining tumor size and location.
• Audiometry testing reveals characteristic unilateral sensorineural hearing loss pattern.
• Brainstem auditory evoked response (BAER) testing may show prolonged or absent responses on the affected side.

Treatment Options

1. Observation: Small, asymptomatic tumors may be monitored with serial MRIs
2. Stereotactic radiosurgery: Gamma knife or CyberKnife for small to medium tumors
3. Surgical removal: Indicated for large tumors or those causing significant symptoms

Preoperative Care

• Conduct comprehensive neurological assessment including cranial nerve function, hearing acuity, and balance testing.
• Educate patient about potential postoperative complications including facial paralysis, hearing loss, and cerebrospinal fluid leak.
• Prepare patient for possible need for facial nerve monitoring during surgery.

Postoperative Monitoring

• Monitor for signs of increased intracranial pressure: headache, nausea, vomiting, altered level of consciousness.
• Assess for cerebrospinal fluid leak through incision site or nasal drainage (clear, glucose-positive fluid).
• Evaluate facial nerve function and document any weakness or paralysis using House-Brackmann scale.
• Monitor for hearing changes and provide communication assistance as needed.

Potential Complications

• Facial nerve paralysis can be temporary or permanent, requiring eye protection and facial rehabilitation.
• Hearing loss may be complete on the operative side, necessitating hearing aid evaluation or bone-anchored hearing aid.
• Balance problems persist for weeks to months, requiring vestibular rehabilitation therapy.
• Rare but serious complications include stroke, brainstem injury, and meningitis.

Discharge Planning

• Provide education on eye care for facial paralysis: artificial tears, eye patches, and taping eyelid closed at night.
• Arrange referrals for audiologist, physical therapy for balance training, and facial nerve rehabilitation.
• Teach signs of complications requiring immediate medical attention: severe headache, vision changes, or drainage from incision.

Commonly Confused Points

Quick Check Questions