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Answers: 2006 Series -  April 11, 2006 Lecture 38 of 52  NEXT»

question

A 58-year-old patient with anisocoria has the following pupil measurements:

Light  room    OD:  3.5mm     OS: 5.5mm
Dark room     OD:  4.0mm        OS: 8.0mm

You administer 4% cocaine and no dilation occurs in the right eye.  After 48 hours, you re-test  the patient with 1% hydroxyamphetamine (Paradrine) and the pupil does not dilate. 

The most likely diagnosis is:  

  c -- Hornerís syndrome: third order neuron

When evaluating a patient with anisocoria it is important to look at the asymmetry in pupil size both in light and dark conditions. This patient has a Hornerís syndrome- a third-order (post-ganglionic) lesion.

Topical cocaine helps diagnose a Hornerís syndrome and paradrine is used to help localize the lesion. Paradrine releases norepinephrine (NE) from the nerve terminal and is used to distinguish pre- and post-ganglionic lesions.

 


Lecture 38 of 52 «Previous Lecture   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52    Next»