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SYMPTOMS
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Acute ptosis, diplopia, and possibly retroorbital or periorbital pain
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SIGNS
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Typically unilateral
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3-4mm ptosis (Levator palpebrae superioris paralysis), EOM restriction with involvement of the medial rectus, superior rectus, inferior oblique, and medial rectus, “Down and out” position of the eye, possible fixed and dilated pupil with loss of direct light response and accommodative response (typically seen if etiology is compression or trauma)
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A complete cranial III palsy involves all associated muscles with complete paresis. A partial cranial nerve III palsy involves a few muscles with moderate paresis
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WORK-UP
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Pupils | EOMs | Cover test | Complete eye exam with dilation | Cranial nerve testing | Ptosis testing | Forced duction testing
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TREATMENT
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Children with a cranial nerve III palsy with or without pupil involvement should be referred to a neuro-ophthalmologist/neurologist/pediatric ophthalmologist/pediatrician/ER ASAP
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Adults under 50 years old with a cranial nerve III palsy with or without pupil involvement should be referred to a neuro-ophthalmologist/neurologist/PCP/ER ASAP
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Adults over the age of 50 years old with a cranial nerve III palsy without pupil involvement can be observed and referred to their PCP for a vascular work-up, but strong consideration should be given to referring patient to a neuro-ophthalmologist/neurologist/PCP/ER if cranial nerve III palsy is incomplete, if there is no improvement within 1 month, if there is progression, if there is aberrant regeneration, or if there are other neurological symptoms
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Fresnel prisms can temporarily help with diplopia
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Treatment depends on the underlying etiology of the CN III palsy
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FOLLOW-UP
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Evaluate every day for the first week to make sure there is no pupil involvement. After, monitor monthly until complete resolution
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ADDITIONAL LAB | TESTS
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Neuro-imaging is typically ordered through neuro-ophthalmologist/neurologist/PCP/pediatric ophthalmologist/pediatrician/ER and may include the following: -MRI of the brain with and without contrast | CT of the brain with and without contrast | MRA | CTA
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If etiology is suspected to be due to vascular ischemia, the following should be ordered through the patient’s PCP: Blood pressure evaluation | Fasting blood sugar HbA1c | CBC with differential | ESR | C-reactive protein | ANA
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ETIOLOGY
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Cranial nerve III damage can be secondary to the following: Vascular ischemia from systemic diseases such as diabetes | Trauma | Compression from a tumor or aneurysm | Infiltrative | Congenital due to incomplete development of the nucleus or nerve
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DIFFERENTIAL DX
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Internuclear ophthalmoplegia, Myasthenia gravis, Thyroid eye disease, Chronic progressive external ophthalmoplegia, Orbital fracture, Brown syndrome, Ophthalmic migraine
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NOTES
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If eye with cranial nerve III palsy is fixating, the eye that is not involved may be up and out
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Cranial nerve III palsies due to vascular ischemia typically fully resolve in 3-6 months. If residual diplopia is still present, glasses with prism can be prescribed
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Aberrant regeneration includes pseudo von Graefe’s sign and lid synkinesia
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Different syndromes can be associated with third nerve palsies including Benedikt, Weber, Nothnagel, and Claude
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