Cranial Nerves

Review of Cranial Nerves

Cranial Nerve

Major Function

I Olfactory

Smell

II Optic

Vision

III Oculomotor

Eyelid and eyeball movement

Pupil constriction

IV Trochlear

Downward, inward eye movement

V  Trigeminal

Chewing

Sensation in the face

VI Abducens

Lateral Eye Movement

VII Facial

Taste from anterior tongue

Control of muscles of face

VIII Vestibulocochlear (Acoustic)

Hearing

Equilibrium

Nerve

Function

IX Glossopharyngeal

Taste from posterior tongue

Secretion of saliva

Swallowing

X Vagus

Monitors oxygen, carbon dioxide, and pH levels in the blood

Senses blood pressure

Inhibits cardiac action and extensive

Stimulates digestive organs

Swallowing and Speaking

 XI Spinal accessory

Voice production

Movement of head and shoulders

XII Hypoglossal

Movements of tongue during speech and swallowing

  • Cranial nerves are responsible for vision, hearing, movement

  • Brain stemic cranial nerves are responsible

  • EMG - electromyogram and MRI used for brains stem and cranial nerves

Mnemonics -

Trigeminal Neuralgia

  • Formerly known as tic douloureux (painful twitch)

  • Condition of the 5th cranial nerve

  • Etiology is unknown possible causes: vascular compression and pressure

    • Sudden pain in the area innervated by any of the three branches( which are?)

      • Across the forehead, across the cheek bone, and down the jaw line

      • 1st branch (forehead), 2nd branch (cheek bone), 3rd branch (down the jaw line)

    • Abrupt pain - unilateral shooting, stabbing, and burning sensation in nature

    • Involuntary contraction of facial muscles - closing of eye, twitching mouth

  • Occurs most often as people age between 50-60

    • More common in women and people with MS (muscularslorosis)

    • Before age 50, evaluate for MS

  • Painful intervals; more painful as you age. Can be from mins, secs, hours, etc

  • Washing face, shaving, brushing teeth, eating, and drinking can cause stimulations of the terminals of the affected nerve branches

  • Certain areas are considered trigger points - avoid doing the above because of an attack

  • Even cold air or slight touch can cause an episode

  • Medical Management

    • Pharmacological

      • Anticonvulsant - Carbamazepine (Tegretol) - take with food - serum levels monitor;

        • S/S: nausea, dizziness, drowsiness, aplastic anemia, bone marrow suppression

        • Diagnostics: have CBC’s drawn frequently. Monitor bone marrow, just stop medication if bone marrow suppression begins.

      • Gabapentin and baclofen - also used for pain control; phenytoin may be used as an adjunctive therapy

    • Nursing Management

      • Preventing Pain

        • Preop management on an outpatient basis

        • Recognize factors that are aggravating

        • Provide education on preventive strategies

        • Recognize anxiety, depression, and insomnia - use appropriate referrals

    • Providing Postoperative Care

      • Standard post op care

      • Neuro assessments - detect for facial or sensory deficits

      • Artificial tears

      • Observe for difficulty swallowing or eating

      • Factors - foods too hot or too cold or jarring of the patient’s bed or chair, washing the face, combing hair, or brushing the teeth

      • Preventive strategies - provide cotton pads, room temp water for face washing, rinsing with mouthwash after eating, perform personal hygiene during pain free intervals

      • Take food and fluids at room temp, chew on unaffected side

  • Surgical

    • Only used if pharmacological ways fail

    • Depends on patient’s preference and health status

      • Microvascular decompression of the trigeminal nerve

      • Radiofrequency thermal coagulation

      • Percutaneous Balloon Microcompression

    • Surgery complications:

      • permanent numbness, paralysis permanent droop

         

Distribution of the Trigeminal Nerve Branches

Distribution of the Facial Nerve

Bell’s Palsy

  • Most patients recover completely in 3 to 5 weeks, and the disorder rarely recurs

  • May be a type of pressure paralysis

  • The nerve is inflamed and edematous becomes compressed which leads to necrosis due to blood supply being occluded

  • Patient may exhibit drooping of the mouth, drooling, excessive lacrimation, painful sensations in face, behind ear and eye

    •Majority recover completely and rarely recurs

  • Inability to close eyelids

  • Drooping of the mouth

  • Facial nerve

  • Patho

    • Idiopathic facial paralysis caused by unilateral inflammation of the seventh cranial nerve

    • Reactivation of a dormant virus (herpes) or autoimmune syndromes

    • Usually between ages 15 and 45 years old

  • Manifestations: unilateral facial muscle weakness or paralysis with facial distortion, increased lacrimation, and painful sensations in the face; may have difficulty with speech and eating

  • Medical Management

    • Objective: maintain muscle tone of the face and to prevent or minimize denervation 

      • Reassure of no stroke, spontaneous recovery occurs within 3 to 5 weeks

    • Corticosteroid therapy (prednisone)

      • Start within 72 hours

    • Analgesics

    • Electrical stimulation

    • Surgical decompression is controversial

    • Steroids – reduce inflammation and edema, reduces vascular compression and permits restoration of blood circulation to the nerve

      Start early- highly effective in diminishing the severity of the disease, relieving pain, and preventing or minimizing denervation

      Electrical stimulation- prevents muscle atrophy

  • Nursing Management

    • Protect eye from injury

      • Eyelid not closing –foreign particles- corneal irritation

      • Alteration of proper drainage of tears

      • Eye patch at night

      • Eye ointment at HS

      • Close eye manually

      • Sunglasses or goggles

    • Maintaining muscle tone

      • Massage area after pain decreases

      • Facial exercises

      • Avoid exposure to cold drafts to face