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Neurologic Causes Of Stransimus


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Neurologic Causes Of Stransimus

  1. 1. Neurological causes of StrabsimusRaed Behbehani , MD FRCSC
  2. 2. Strabismus• Ocualar misalignment of the visual axes.• Childhood strabimus. » Congenital strabsimus » Accomodative esotropia/ refractive non-accomodative » Abnormal visual development » Neurologic
  3. 3. Neurologic Strabismus• Pure neurologic strabismus can mimick other causes of childhood strabismus.• Diagnostic difficulty.• Comitant vs incomitant.• History : Ask about : » acute onset, head trauma, perinatal history, variability with ptosis, other neurological signs, old photographs , previous history of head tilt
  4. 4. Neurological Strabismus• Cranial Nerve Palsies ( III, IV, IV CN Palsy)• Neurological diseases ( Myasthenia, mitochondrial encephalomyopthy, Botulism, Miller Fisher Synrome).• Posterior Fossa tumors / malformations ( Chiari).• Raised intracranial pressure (hydrocephalus, idiopathic, tumor-related).
  5. 5. Paralytic Strabismus Third nerve palsy• Nucleus in midbrain tectum anterior to cerebral aqueduct.
  6. 6. Third nerve palsy• Palsy can be complete or partial.• Complete : complete ptosis, eye is deviated out and pupillary dilation. No depression, elevation or adduction.• Partial : Superior or inferior branch.
  7. 7. Third nerve palsy
  8. 8. Causes of third nerve palsy• Ischemia ( diabetis, hypertesnion, hyperlipedemia)• Vascular • Pcom artery aneyrysm ( adults with pulillary involvment) , but rare in children (posteior comunicating artery).• Inflammatory • Post-viral , auto-immune , Miller-Fisher syndrome• Neoplastic • Astrocytoma , meingioma, schwanommas.• Congenital – Forceps deivery , underlying neurinoma of the third nerve , midbrain hypoplasia.
  9. 9. Third NP
  10. 10. Differential Diagnosis of Third Nerve Palsy• Myasthenia.• Orbital Fractures.• Brain stem syndrome (Inter-nuclear ophthalmoplegia).• Duane Syndrome.
  11. 11. Trochlear Nerve Palsy• The most common cause of isolated acquired cranial nerve palsy.• Congenital or traumatic.• Vertical diplopia.
  12. 12. Anatomy of the Forth Nerve
  13. 13. Fourth Nerve Palsy• Head tilt ( in congenital palsy , it can be overlooked).
  14. 14. Trochlear Palsy• Look at old photos ! (FAT scan)
  15. 15. Trochlear Palsy
  16. 16. Postive Head Tilt• Hypertropia increases when head is tilted to the ipsilateral side.
  17. 17. Trochlear Palsy• Hypertropia of the affectd eye (eye is higher than contralateral).• Facial asymmetry (ipsilateral face less developed).
  18. 18. Superior oblique palsy in Case 1. Kim J H , Hwang J Br J Ophthalmol 2010;94:346-350©2010 by BMJ Publishing Group Ltd.
  19. 19. Bilateral SO Palsy
  20. 20. Torchlear Palsy Causes• Congenital• Ischemic (adults)• Craniofacial anamolies – Plagiocephaly• Head trauma. • Most common cause of acquired unilateral. • Presume bilateral.• Brain tumors • Posteior fossa tumors , post-resection , hydrocepahlus.
  21. 21. Abducens Nerve Palsy• Limited abducation.• Esotropia.• Head turn.
  22. 22. Abducens Palsy Anatomy Lateral ponto-meduallary junction
  23. 23. Abducens Anatomy
  24. 24. Cavernous Sinus
  25. 25. Causes of Abducens Palsy• Ischemic (adults)• Tumor • Pontine gliomas • Extra-axial clival or petrous ridge tumors.• Raised intra-cranial pressure • Pseudotumor cerebri • Hydrocephalus• Trauma • Closed head truama , basal skull fractures• Inflammation. • Post-viral or vaccination
  26. 26. Always examine the fundus
  27. 27. Differential Abducens Palsy• Duane syndrome.• Myasthenia.• Long standing esotropia.• Thyroid eye disease.• Fractures of the medial orbital wall.
  28. 28. Duane Syndrome• Congenital duction deficit due to absence innervation of the lateral rectus.• Co-contraction of the lateral rectus muscle in adducion.• Narrowing of the papebral fissure in adduction and widening in adduction.
  29. 29. Duane Syndrome
  30. 30. Duane Syndrome• Sproadic (90%) , familial (10%).• Females > males.• Left side > right side.• Systemic associations • Hearing loss (10%) • Cervical malformations (Klippel-Feil anamoly) • Okihiro syndrome (AD , thenar hypoplasia, deafness)
  31. 31. Etiology of Duane Syndrome• Aberrant innervation of the lateral rectus muscle by a branch of the third nerve.• Lateral rectus muscle is fibrotic.• Absence of the sixth nerve.• Hypoplasia of the sixth nerve nucleus.
  32. 32. Other Neurologic Causes of Strabimus• Mitochondrial encephalopathy (CPEO, MELAS)• Brain stem tumors.• Hydrocephalus.• Miller-Fisher Syndrome.• Myasthenia Gravis.• Botulism
  33. 33. Chronic Progressive External Ophthalmoplegia• Mitochondrial encephalmoypathies.• 50% are sporadic , AD and AR in 15%.• Mutations in the mitochondrial Genome.• Slowly progressive Ophthalmoplegia and ptosis.• Many differenet clinical phenotypes (Kearnes- Sayer Syndrome, MELAS).• Most patients do not complain of diplopia.
  34. 34. Kearne-Syre SyndromeCPEO + Pigmentary degeneration of the retina + heart block
  35. 35. Myasthenia• Auto-immune neurologic disease.• Failure of neuromascular transmission.• Ophthalmologic symptoms in 50% (Ptosis and Ophthalmoplegia).• MG can mimick any ocular motility disorder !• Fatiguable ptosis, orbicularis weakenss, variable strabismus.
  36. 36. Myasthenia• Ice test , sleep test• Tensilon test ( used less often now ).• Serum Ach-receptor antibodies (50% of ocular MG).• Anti-MUSK antibodies• Clinical electophysiological tests • Reptetive nerve stimulation ( in generalized MG) • Single fiber EMG ( the most sensitive test for MG)• CT scan of the chect (thymoam).
  37. 37. Myasthenia Before ice testAfter ice test 2 min
  38. 38. Botulism• Total ophthalmoplegia + pupillary dilataion + dry mouth + descending paralysis + obstipation - Think of Botulsim.• Clostridium botulinum produce different toxins A, B , and E.• Interfer with release of acetychilne by preventing exocytosis.• Food poisoning , contaminated wounds, or colonization of the GIT “infant botulism”.
  39. 39. Hydrocephalus• Uni- or Bilateral Abducens Palsy.• Comitant esotropia or exotropia.• Uni- or Bilateral Trochlear Palsy ( compression of the superior medullary velum).• Third Nerve Palsy.• Dorsal midbrain syndrome (upgaze palsy, lid retraction, pupillary light-near dissociation, convergence retraction nystagmus).
  40. 40. Dorsal Midbrain Syndrome
  41. 41. Chiari Malformation• Hernation of the posterior forssa contents below the foramen magnum.• Chiari I-III ( I most common).• Occipital headache (with coughing), pain, sensory loss and weakness.• Hydrocephalus (lack of CSF flow between the spinal and cranial subarachnoid space).• Nystagmus and ataxia.
  42. 42. Chiari
  43. 43. Esotropia in Chiari• Acute comitant esotropia can occur.• Vertical strabismus.• Strabimsus improves with sub-occipital decompression.
  44. 44. Miller-Fisher Variant of GBS• Ataxia, ophthalmoplegia, and arelfexia.• Viral prodrome , URTI 1-3 weeks prior to onset of the symptoms.• Pupillary involevement.• CSF shows mild protein elevation at 2-3 weeks.• Resolve spontaneously in 1-3 months.• Corticosteroids, plasma exchange or IV immuno-globulins.
  45. 45. Miller-Fisher Variant of GBS• Anti-GQ1b ganglioside antibodies target the pre-synaptic motor terminal complement- mediated injury.• Ganglioside epitopes on C Jeujeni is key to antibody production.• Need to rule out posterior fossa tumors, Botulism, brain stem stroke, and Wenick Encephalopathy.
  46. 46. Summary• Neurologic causes of strabismus are less common than other forms of strabismus.• Can mimick other common types of childhood strabismus.• Most cases can be identified by history and physical examination.• In certain cases, especially posterior fossa tumors, hydrocephalus chiari malforation, ancillary test (MRI) are needed.