The Droopy Eye
The chief complaint was "Swollen puffy eye. Saw optometrist yesterday." Great, I thought. I get to try to figure out something that a specialist couldn't. As it turned out, it wasn't that difficult.
Her eye wasn't really puffy or swollen, but she was unable to open it. "I saw my doctor two days ago, and he gave me some antibiotics. Then I saw my optometrist yesterday and he said my eye was OK." Well, it wasn't really OK. She looked sort of like this:
Her pupils were equal in size and reacted equally to light, but she had double vision especially when she would look upward and to the left. Double vision occurs when the two eyes cannot work together properly. The rest of her cranial nerves were intact, and there were no other neurological deficits. Her blood pressure was quite elevated, however, and she did admit to a headache in the back of her head on the same side as the involved eye.
So it appeared that she had an isolated and partial third cranial nerve palsy. It really isn't that difficult of a diagnosis to make if you know what to look for. Anyone presenting with the new onset of ptosis (droopy eye) should have a thorough eye examination including pupillary response and extraocular movements, among other things.
Because her pupil was not affected, my presumptive diagnosis was infarction of the third cranial nerve. The third cranial nerve innervates the muscle which lifts the eyelid, as well as several of the muscles that control eye movement. In addition, the nerve fibers which innervate the pupillary constrictor muscles are found on the outer surface of the nerve, so a compressive lesion like an aneurysm or tumor typically causes dilation of the pupil (which is usually a sign of a true emergency). A stroke can occlude the blood supply to the nerve, which is located deep inside the nerve itself and thus can leave the pupil unaffected. This is an important distinction.
Myasthenia gravis would be another less likely consideration but not one that I pursued in the ER. I'll provide an update next week.
Her eye wasn't really puffy or swollen, but she was unable to open it. "I saw my doctor two days ago, and he gave me some antibiotics. Then I saw my optometrist yesterday and he said my eye was OK." Well, it wasn't really OK. She looked sort of like this:
Her pupils were equal in size and reacted equally to light, but she had double vision especially when she would look upward and to the left. Double vision occurs when the two eyes cannot work together properly. The rest of her cranial nerves were intact, and there were no other neurological deficits. Her blood pressure was quite elevated, however, and she did admit to a headache in the back of her head on the same side as the involved eye.So it appeared that she had an isolated and partial third cranial nerve palsy. It really isn't that difficult of a diagnosis to make if you know what to look for. Anyone presenting with the new onset of ptosis (droopy eye) should have a thorough eye examination including pupillary response and extraocular movements, among other things.
Because her pupil was not affected, my presumptive diagnosis was infarction of the third cranial nerve. The third cranial nerve innervates the muscle which lifts the eyelid, as well as several of the muscles that control eye movement. In addition, the nerve fibers which innervate the pupillary constrictor muscles are found on the outer surface of the nerve, so a compressive lesion like an aneurysm or tumor typically causes dilation of the pupil (which is usually a sign of a true emergency). A stroke can occlude the blood supply to the nerve, which is located deep inside the nerve itself and thus can leave the pupil unaffected. This is an important distinction.
Myasthenia gravis would be another less likely consideration but not one that I pursued in the ER. I'll provide an update next week.
posted by scalpel at 1:37 AM
11 Comments:
Um most of that was over my head, but I hope she gets better, cos it looks horrid to me.
Isolated Third cranial nerve palsy with sparing of the pupil could be diabetic mononeuropathy. If this patient is non-diabetic then probably ur diagnosis of infarction makes more sense.
Man, that's awesome. I can't wait until I have the knowledge to understand everything you just said. Maybe I'll be that good someday.
De-myelination of CN 3? I'm just a 1st year med student, so I don't really know what I'm talking about.
This stuff is from the first year of medical school. I had to get a book to read about it, lol.
I doubt it's de-myelination. That would have expressed over a longer period of time (months, at least), and probably wouldn't be isolated to a single nerve or area.
Myasthenia would probably be bilateral as well.
you're probably right! i just did a rotation in internal med and we had a super good neurology tutor who expounded on neurology emergencies, that was one of them that came up.
demyelination of 3rd n is unlikely, it'd be progressive and much more obvious.
myasthenia seems unlikely cos it's unilat.
quick update please please! really interesting case =D
As near as I can tell, the patient was discharged without a clear etiology of her palsy. The MRI revealed a 3mm posterior circulation aneurysm on the opposite side, felt to be not clinically significant. Tensilon test was negative. The patient was discharged on valtrex and steroids.
Thanks for the update, was curious what the dx was.
Neuro has always been the bane of my existence - my neuro pathology education was minimal and clinical exposure the same, so am always impressed when clinicians can localize sx based on an H&P.
CardioNP
As someone who suffers from Myasthenia Gravis (and studied medicine) I just want to point out you can throw the medical books out the window... Myasthenia does not have to be equal on both sides. I personally suffer with my right side/eye than left...
So what was the diagnosis?
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