Sixth nerve palsy: Difference between revisions
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==Background== | ==Background== | ||
[[File:Gray785.png|thumb|Figure showing the mode of innervation of the recti lateralis from CNII.]] | |||
[[File:Capture2.PNG|thumbnail|Right eye]] | |||
[[File:Extraocular muscle actions and innervation.png|thumb|Eye movements by extra-ocular muscles and cranial nerve innervation]] | [[File:Extraocular muscle actions and innervation.png|thumb|Eye movements by extra-ocular muscles and cranial nerve innervation]] | ||
*Also called 6th cranial nerve (CN VI) or abducens nerve palsy | *Also called 6th cranial nerve (CN VI) or abducens nerve palsy | ||
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*''Neoplastic'': [[brain tumor|Lesions]] in the cerebellopontine angle. In children – pontine glioma | *''Neoplastic'': [[brain tumor|Lesions]] in the cerebellopontine angle. In children – pontine glioma | ||
*''Degenerative/deficiency'': [[vitamin B12 deficiency|Vitamin B deficiency]], [[Wernicke-Korsakoff syndrome]] | *''Degenerative/deficiency'': [[vitamin B12 deficiency|Vitamin B deficiency]], [[Wernicke-Korsakoff syndrome]] | ||
*'' | *''Iatrogenic'': Post-[[lumbar puncture]], status-post surgery involving head | ||
*''Infection'': [[Meningitis]], [[lyme disease]], [[syphilis]] | *''Infection'': [[Meningitis]], [[lyme disease]], [[syphilis]] | ||
*''Congenital'': Rare to find true congenital sixth nerve palsy | *''Congenital'': Rare to find true congenital sixth nerve palsy | ||
Revision as of 21:43, 9 November 2020
Background
- Also called 6th cranial nerve (CN VI) or abducens nerve palsy
- Most common ocular nerve palsy
- Innervates the ipsilateral lateral rectus muscle controlling eye abduction
- Esotropia (eye moves inward) of the affected eye due to the unopposed action of the medial rectus muscle, innervated by the oculomotor nerve (CN III) [1]
Causes
- Nuclear lesion
- Congenital, demyelinating, ischemia, traumatic
- Inflammatory
- Infectious
- Orbital lesions
- Neoplastic
- Inflammatory
- Infectious
Clinical Features
History
- May complain of:[1][2]
- Diplopia (frequent complaint) upon attempting lateral gaze and esotropia at rest
- May have a head turn to help correct their diplopia
- Vision loss
- Hearing loss
- Symptoms of vasculitis, most commonly giant cell arteritis (headache, tenderness of the scalp, jaw claudication, reduced visual acuity, tinnitus, fever_
- +/- history of diabetes, hypertension, stroke, fever, and headache
Examination
- Excluding paresis of the other cranial nerves
- Check ocular muscle movements
- Check for papilledema
- Test pupillary response
- Test ocular motor nerves (CN III, IV, and VI)[3][4]
- Trace a full H-pattern with finger and have the patient follow the finger only with their eyes
- Patients with abducens nerve palsy are unable to move the affected eye laterally
- In order to avoid diplopia, patients will turn their heads away from the lesion so that both eyes are looking sideways
- Check deep tendon reflexes and strength to exclude corticospinal tract involvement
Differential Diagnosis
- Increased intracranial pressure (ICP): Because of its position and intracranial length, increased ICP from any cause can lead to injury and dysfunction
- Vascular: Aneurysm, central venous sinus thrombosis
- Inflammatory: Post-viral, demyelinating, sarcoidosis, giant cell arteritis, Miller-Fisher Syndrome variant of Guillian-Barre Syndrome
- Neoplastic: Lesions in the cerebellopontine angle. In children – pontine glioma
- Degenerative/deficiency: Vitamin B deficiency, Wernicke-Korsakoff syndrome
- Iatrogenic: Post-lumbar puncture, status-post surgery involving head
- Infection: Meningitis, lyme disease, syphilis
- Congenital: Rare to find true congenital sixth nerve palsy
- Autoimmune: Myasthenia Gravis
- Trauma: Especially if a torsional head motion or medial wall orbital fracture (with entrapment of the medial rectus muscle
- Endocrine: Diabetic cranial mononeuropathy - the incidence of palsy in the 3rd, 6th, and 7th cranial nerves is significantly higher in patients with diabetes[1][2] [3][4][5][6][7]
Evaluation
Work-up
- Workup will depend on suspected etiology, may include
- POC glucose
- CBC
- BMP
- ESR
- Lyme titer
- RPR (if suspect syphilis)
- Lumbar puncture to exclude meningitis, Guillain-Barré
- Antinuclear antibody test
- CT head: exclude acute bleed or mass
- MRI: indicated for brainstem findings on the exam and to exclude pontine glioma in children and in adults where the abducens nerve palsy does not improve[3][4]
Management
- Treat by underlying etiology
- Consider neuro/optho consult
- Children: Can be treated with alternating patching to decrease probability of developing amblyopia in the affected eye
- Adults: Lenses can be fogged with clear tape, paint, or nail polish to decrease diplopia. Neurology can prescribe Fresnel prisms as an alternative.
- Giant cell arteritis: treat with prednisone or intravenous Methylprednisolone.
Disposition
- Dispo appropriate to etiology
- Truly isolated cases: often benign, can be followed up by neurologist for serial exams
- Surgery: If patient does not improve within 6 months after treatment and serial check-ups, surgery may be required[3][4]
See Also
External Links
References
- ↑ 1.0 1.1 1.2 Tintinalli JE, Kelen GD, Stapczynski JS, Ma, OJ, Cline DM, editors. Tintinalli’s Emergency Medicine. 7th ed. New York: McGraw-Hill; 2011. 763, 1037, 1546
- ↑ 2.0 2.1 Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013
- ↑ 3.0 3.1 3.2 3.3 Yanoff M, Duker JS. Opthalmology. Mosby International Ltd; 2013
- ↑ 4.0 4.1 4.2 4.3 Gerstenblith AT. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. Lippincott Williams and Wilkins
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/26314216
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/17157701
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/11555800