EyeNet Magazine


 
A Perinatal Predicament

By Chandak Ghosh, MD, MPH
Edited by Thomas A. Oetting, MD
 
 

The obstetrician on call was frantic: “I have a woman who is about to deliver a baby any minute now, and her eyes aren’t straight!” I headed for the delivery ward, where I met Megan Lipton,* a healthy 32-year-old woman who was 40 weeks pregnant—and who was complaining of horizontal diplopia, which had begun several hours previously. The vision in her left eye was blurred, and she also felt some pain behind that eye. Up until this point, her pregnancy had been uneventful and uncomplicated, and she was now in early labor with her first child.

An Easy Diagnosis?
When I examined her, Mrs. Lipton’s vital signs, including her blood pressure, were normal. Her vision was 20/20 in her right eye and 20/50 in her left. Her right pupil was 3 millimeters and briskly reactive. However, her left was 5 mm and sluggish. No afferent pupillary defect was apparent. Color vision and confrontational visual fields were normal. Her extraocular muscle movements were full in her right eye. Her left eye showed limitations in up-gaze, down-gaze and medial gaze but was full in lateral gaze. She had a mild ptosis in that eye as well.

The patient complained of blurred vision and pain behind her left eye.
Caption: What's your diagnosis? The patient was
in early labor with her first child—and was complaining
of horizontal diplopia and blurred vision and pain behind
her left eye.

My initial diagnosis was incomplete third nerve palsy, involving the pupil. The most worrisome cause of this condition would be a posterior-communicating artery aneurysm. In particular, the strong Valsalvas during delivery could complicate the situation gravely.

I recommended radiological imaging studies to see whether an aneurysm was truly the culprit. After much discussion with the radiology department, it was decided that they would perform a cerebral angiogram; the dye used in the angiogram was not expected to adversely affect the baby. (In addition, the baby would be carefully shielded from the x-rays.) Mrs. Lipton was rushed to the angiogram suite while the obstetrician prepared to deliver the child by Cesarean section if an aneurysm was detected. The neurosurgeon on call was also alerted to stand by.

Sudden Change in Course
The cerebral angiogram was negative for aneurysm. The next day, Mrs. Lipton delivered a healthy baby boy vaginally; there were no complications.

I re-examined Mrs. Lipton the day of the delivery. The findings of this exam matched those of the initial exam, except for better pupillary reaction in her left eye. One day later, her vision in that eye returned to 20/20, the pupil came down to 3 mm and reacted normally and all gazes were full. The remaining ptosis resolved a day later, completing the transition back to normal.

Many Possibilities
There are a number of possible causes of a painful ophthalmoplegia, including posterior-communicating and basilar artery aneurysms, trauma, carotid-cavernous and cavernous sinus fistulas, tumors, infectious or inflammatory conditions (including Tolosa-Hunt syndrome), giant cell arteritis, ischemic conditions (such as diabetes and hypertension) and ophthalmoplegic migraine.

Upon further detailed questioning, Mrs. Lipton recounted two episodes of migraine headaches in her preteen years. Each was preceded by some neck numbness. In addition, she reported that she noted mild neck numbness before this current event. She had attributed this to lying on her back and thus did not mention it during the initial eye exam.

Nearly all patients who experience ophthalmoplegic migraines will have their first attack in early childhood. First cases have only rarely been reported in adults. The third cranial nerve is almost always involved, and the fourth and sixth nerves are sometimes affected as well. Bilateral involvement has been noticed in some patients. The majority of cases involve the pupil, leaving it mid-dilated and slow to react.

The accompanying headache usually begins ipsilateral to the eye and then becomes bilateral. While it isn’t always severe, the headache can last from a few hours to several days. Resolution usually occurs completely but often requires weeks to months. With its swift normalization, Mrs. Lipton’s case was not typical—thus, it was probably triggered specifically by labor. Some reports speak of people who have suffered up to 30 attacks; about 10 percent of these patients have to deal with unresolving ptosis and ophthalmoplegia.

Criteria to Meet
To classify an event as ophthalmoplegic migraine, the following criteria must be met:

  • The patient must have prior history of “classic” migraine (migraine with preceding aura).
  • Ophthalmoplegia occurs during the migrainous attack and is usually on the same side as the initial pain.
  • Other causes, particularly aneurysm or other compressive phenomena, must be excluded by radiological studies.

There are many theories about why eye signs occur during migraine attacks. The ischemic theory blames the swelling and narrowing of the small nutrient arteries supplying the third nerve. The compression theory points to a possible swelling of the intracavernous carotid or basilar artery against the third nerve. The final guess points to some MRI reports of thickening of the third nerve itself along its full course from the midbrain to the cavernous sinus.

Treatment
Treatment usually consists of watching the migraine follow its natural course. Steroids have been used successfully in children with ophthalmoplegic migraine. Importantly, there is no need to rule out aneurysm in symptomatic children who are younger than age 10, as no aneurysms have ever been reported in that age range.

Mrs. Lipton went home with her new baby boy and has not had any subsequent migraine episodes.

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Dr. Ghosh is a medical consultant for the U.S. Department of Health and Human Services and an attending physician at Queens Hospital Center, Mount Sinai School of Medicine, New York.

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* Patient name is fictitious.

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