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Disorders of Ocular Motility 2
Topic: AdultCreated on Thursday, August 31 2006 by jdmiles
Last modified on Friday, December 15 2006.
A 499 year-old female presents with recent abrupt onset of abnormal eye movements. On exam, you see the movements shown in the image above as she follows your finger down and then up.
Of the following options, which is the most likely site of the lesion?
A) Bilateral medial longitudinal fasciculi B) Right cranial nerve VI C) Right medial longitudinal fasciculus D) Left medial longitudinal fasciculus E) Posterior commissure
This question was created on August 31, 2006 by jdmiles.
This question was last modified on December 15, 2006.
ANSWERS AND EXPLANATIONS
A) bilateral medial longitudinal fasciculi
This answer is incorrect.
A lesion of both medial longitudinal fasciculi would present as bilateral impairment of adduction, with nystagmus in the abducted eye on congugate lateral gaze. ( See References)
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B) right cranial nerve VI
This answer is incorrect.
A lesion affecting the abducens nerve (CN VI) would result in impaired abduction of the eye ipsilateral to the lesion. This patient has impaired adduction of the right eye, with normal abduction. ( See References)
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C) right medial longitudinal fasciculus
This answer is incorrect.
A lesion of the right medial longitudinal fasciculus would present as impaired adduction of the right eye, with nystagmus in the left eye when it is abducted. ( See References)
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D) Left medial longitudinal fasciculus
This answer is incorrect.
A lesion of the left medial longitudinal fasciculus would present as impaired adduction of the left eye, with nystagmus in the right eye when it is abducted. ( See References)
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E) posterior commissure
This answer is correct.
This patient has Parinaud syndrome, a palsy of vertical gaze which can result from a lesion of the posterior commissure. When the patient tries to look up, her eyes converge and retract; this is known as conversion-retraction nystagmus. ( See References)
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References:
1. Victor, M., and Ropper, A.H. (2001). Adams and Victor's Principles of Neurology, 7th Edition. McGraw-Hill, New York. Pp. 289. | |
2. Wall, M. (2004). Brainstem Syndromes. In In Bradley, W.G., Daroff, R.B., Fenichel, G.M., and Jankovic, J. (Eds.). Neurology in Clinical Practice, 4th Edition. Butterworth Heinemann, Philadelphia. Pp. 273-286. | |
3. Leigh, R.J., and Zee, D.S. (2006). The Neurology of Eye Movements, 4th Edition. Oxford University Press, Oxford. | |
4. Bickley, L.S., and Hoekelman, R.A. (1999). Bates' Guide to Physical Examination and History taking, 7th Edition. Lippincott, Philadelphia. Pp. 163-244. | |
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adult
Disorders of Ocular Motility 2
Question ID: 831200602
Question written by J. Douglas Miles, (C) 2006-2009, all rights reserved.
Created: 08/31/2006
Modified: 12/15/2006
Estimated Permutations: 600
1 user entries
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