Differential Diagnosis in Lateral Rectus Palsy

Differential Diagnosis in Lateral Rectus Palsy

• 1.
  Differential Diagnosis inLateral Rectus Palsy/Abducens Palsy
• 2.
  CN VI (AbducensNerve) • Longest subarachoid course • Runs from brainstem in posterior fossa, through middle fossa (especially the petrous apex) and orbit • Lesions can affect the nerve via: VI1: the brainstem syndrome VI2: the elevated intracranial pressure syndrome VI3: the petrous apex syndrome VI4: the cavernous sinus syndrome VI5: the orbital syndrome
• 3.
  Anatomical Concerns • Courseof the Abducens Nerve
• 4.
  Brainstem Sources ofAbducens Palsy • Millard Gubler Syndrome • A unilateral lesion of the ventrocaudal pons may involve the basis pontis and the fascicles of cranial nerves VI and VII. Symptoms include: • 1.Contralateral hemiplegia (sparing the face) due to pyramidal tract involvement • 2.Ipsilateral lateral rectus palsy with diplopia that is accentuated when the patient looks toward the lesion, due to cranial nerve VI involvement. • 3.Ipsilateral peripheral facial paresis, due to cranial nerve VII involvement.
• 5.
  Millard Gubler Syndrome
• 6.
  Foville Syndrome: InferiorMedial Pontine Syndrome (Foville Syndrome) • Foville’s syndrome: Sixth nerve paresis Horizontal conjugate gaze palsy Ipsilateral V, VII, VIII cranial nerve palsy Ipsilateral Horner’s syndrome
• 7.
  Foville Syndrome • IpsiPPRF --> Horizontal Gaze palsy • Ipsi CNVII --> LMN facial paresis • contra UMN paralysis of body • contra sensory loss of body • internuclear opthalmoplegia
• 8.
  Anatomical Consideration ofthe Petrous Apex
• 9.
  Petrous Apex Syndrome(Grandenigo’s Syndrome) • retroorbital pain due to pain in the area supplied by the ophthalmic branch of the trigeminal nerve (fifth cranial nerve), • abducens nerve palsy (sixth cranial nerve),[3] and • otitis media
• 10.
  Intracranial Abducens Dorello canalchannels the abducens nerve (CN VI) from the pontine cistern to the cavernous sinus
• 11.
  Increased Intracranial Pressure •Brainstem displacement inferiorly • Diffuse pressure along the subarachnoid course • Traction on CN VI while it is anchored in Dorello’s canal Diplopia--> Horizontal
• 12.
  Extracranial course ofCN VI Note the Abducens in within the cavernous sinus while the CNIII, V1, V2 and Trochlear nerves are in the wall CN VI exists the eye at the superior orbital fissure
• 13.
  Superior Orbital Fissure •Learn • Fauna • To • See • Numerous • Invertebrate • Animals
• 14.
  In adults, themost likely etiology of isolated sixth nerve palsy is ischemic mononeuropathy that may be due to diabetes mellitus, arteriosclerosis, hypertension, temporal arteritis or anemia Isolated 6th Nerve Palsy
• 15.
  Six Mimics ofa CN VI Palsy Thyroid eye diseases Myasthenia gravis Duane’s syndrome Spasm of the near reflex Delayed break in fusion Old blowout fracture of the orbit
• 16.
  Duanes Retraction Syndrome •Defect in genesis of Abducens nucleus • Three components” • Defect AB duction • Some defect in AD duction • Palpebral fissue narrowing and globe retraction often with upshoot