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  #1  
Old 04-22-2013
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Eye Pupillary Reflexes Abnormal

A 34 year old woman comes to the physician complaining of double vision. She first experienced difficulty while at work yesterday. Upon waking up this morning her vision progressed to frank diplopia. Shining light in right eye causes constriction in right pupil but no left eye constriction. Shining light in left eye causes constriction in right pupil only. Which of the following additional physical findings are likely to be found?
A) Absence of left corneal reflex
B) Dropping of the left eye lid
C) Inability to close the left eye
D) Inward deviation of left eye
E) Visual loss in left eye

What is the answer and why??
Someone please explain...
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  #2  
Old 04-22-2013
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I guess it is lesion of oculomotor nerve
B
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Old 04-22-2013
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B due to a lesion in the Occulomotor nerve III.
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Old 04-22-2013
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Why is it not A??? The left corneal reflex is not working.
Please explain why A does not make sense
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Old 04-22-2013
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Quote:
Originally Posted by OMGStep View Post
Why is it not A??? The left corneal reflex is not working.
Please explain why A does not make sense
Absence of left corneal reflex

it is formed by afferent (CN5) and efferent (CN7)
responds to touch and not light
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  #6  
Old 04-22-2013
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Correct Answer

Double vision/diplopia->there is an eye deviation, but we don't know which nerve is impaired, it could be CN III, IV or VI.

Shining light in the right eye causes constriction in right pupil only--> Light sends signal via CN II to pretectal nucleus then activates Edinger-Westphal nuclei and then the constriction signal travels bilateral in both CN III (left and right), in these case left eye doesn't constrict so it's probably a left CN III problem.

Shining light in left eye causes constriction in right pupil only--> these confirms a CN III impairment in left eye.

A) Absence of left corneal reflex----> no because the corneal reflex is mediated by ophthalmic branch of trigeminal nerve (V1) is the afferent and the facial VII is the efferent. The pupilary constriction has nothing to do with CN VII and CN V.
B) Dropping of the left eye lid----> CN III damage symptoms: ptosis, eye look down and out, loss of accommodation
C) Inability to close the left eye---> CN III damage ptosis
D) Inward deviation of left eye----> eye it is going to look down and out
E) Visual loss in left eye----> we now that CN II is working perfect in both eyes because there was a pupillary response when they shine the light in both eyes.
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Old 04-23-2013
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Quote:
Originally Posted by pablogarcia View Post
Double vision/diplopia->there is an eye deviation, but we don't know which nerve is impaired, it could be CN III, IV or VI.

Shining light in the right eye causes constriction in right pupil only--> Light sends signal via CN II to pretectal nucleus then activates Edinger-Westphal nuclei and then the constriction signal travels bilateral in both CN III (left and right), in these case left eye doesn't constrict so it's probably a left CN III problem.

Shining light in left eye causes constriction in right pupil only--> these confirms a CN III impairment in left eye.

A) Absence of left corneal reflex----> no because the corneal reflex is mediated by ophthalmic branch of trigeminal nerve (V1) is the afferent and the facial VII is the efferent. The pupilary constriction has nothing to do with CN VII and CN V.
B) Dropping of the left eye lid----> CN III damage symptoms: ptosis, eye look down and out, loss of accommodation
C) Inability to close the left eye---> CN III damage ptosis
D) Inward deviation of left eye----> eye it is going to look down and out
E) Visual loss in left eye----> we now that CN II is working perfect in both eyes because there was a pupillary response when they shine the light in both eyes.
Guys why is it not C but B!
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Old 04-23-2013
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Quote:
Originally Posted by OMGStep View Post
A 34 year old woman comes to the physician complaining of double vision. She first experienced difficulty while at work yesterday. Upon waking up this morning her vision progressed to frank diplopia. Shining light in right eye causes constriction in right pupil but no left eye constriction. Shining light in left eye causes constriction in right pupil only. Which of the following additional physical findings are likely to be found?
A) Absence of left corneal reflex
B) Dropping of the left eye lid
C) Inability to close the left eye
D) Inward deviation of left eye
E) Visual loss in left eye

What is the answer and why??
Someone please explain...
Oh ok I got the question now!
The problem of this patient is problem with consensual light reflex.
Which is mediated through parasympathetic innervation via Occulomotor nerve (Ed-W nucleus). The only option in the answer for cn 3 is B.
A. Is for CN5 via CN7
C is for CN7
D is defect of abducens nerve ( medial/internal strabismus) CN 3 gives external strabismus.
E is defect in CN2. CN 2 not involved directly in consensual light reflex but involved in the visual pathway.
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Old 04-23-2013
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B............because left occolomotor doesnt work......
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Old 04-24-2013
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I guess it is lesion of oculomotor nerve B
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Old 05-13-2013
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it should be option B, cuz all others are unrelated to occulomotor,
and the patient shows left occulomotor leison
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