Idiopathic Intracranial Hypertension in Pregnancy

A 27-year-old white woman presented to the clinic with headaches and decreased vision through her reading glasses while performing near tasks. Her medical history was significant for herpes simplex, hyperlipidemia, and migraine headaches with aura. Her migraines began following an earlier motor vehicle accident, and her most recent magnetic resonance imaging (MRI) showed no abnormalities. Her current medications included prophylactic acyclovir for herpes and acetaminophen and caffeine tablets as needed for headache. She reported no other trauma or surgery and no known allergies. The patient’s best-corrected Snellen visual acuities in both eyes were 20/20 (distance) and 20/30 (near).

Preliminary testing, including pupils, extraocular motilities, confrontation fields, and color vision, were all within normal limits. Her slit-lamp examination was unremarkable. A dilated fundus examination revealed crowded, elevated discs without vessel obscuration, hemorrhage, hyperemia, or drusen (Figure 1). The fundus examination was otherwise unremarkable. Optical coherence tomography of the optic nerves showed increased nerve fiber layer thickness in both eyes (Figure 2). Her blood pressure (BP) at this visit was 
106/77 mm/Hg.

The diagnosis based on these findings was bilateral optic nerve elevation with long-standing migraine headaches. The plan was for the patient to return to the clinic for repeat visual field testing and B-scan ultrasonography to rule out buried optic nerve head drusen.

Two months later, the patient presented to the clinic 19 weeks pregnant and reported that her headaches had increased in frequency, but she had no diplopia. All preliminary testing, including visual acuities, pupil reaction, color vision, and slit-lamp examination remained normal. Fundus examination showed the patient’s nerves were unchanged in appearance from the initial presentation. Visual fields revealed an enlarged blind spot in the right eye and paracentral defects in the left eye. The B-scan testing was negative for optic nerve drusen. Due to the increased frequency of headaches, pregnancy, and suspicious optic nerves, an urgent consult was placed to neurology.

At the neurology appointment 
1 month later, the patient was diagnosed with migraine headache syndrome and idiopathic intracranial hypertension (IIH). The neurologist believed her headaches might have been resulting from analgesic rebound. He suggested that the patient discontinue or decrease use of oral butalbital, acetaminophen and caffeine tablets, and other forms of caffeine. It was decided that divalproxen sodium and verapamil were not feasible due to pregnancy. The neurologist started her on oral acetazolamide 
500 mg twice daily.

The patient returned to her obstetrician 1 month later for a routine 
follow-up; the headaches had worsened and were now accompanied by nausea and vomiting twice daily on average. Her medications still included acetaminophen and caffeine tablets, although it had been recommended she discontinue them, prochlorperazine, and acetazolamide. Due to the worsening of her symptoms and visual fields (eFigure 1), the obstetrician recommended that the patient deliver by cesarean section at 38 to 39 weeks.

(eFigure 1.Visual Fields at Follow-up 1 and 2)
Right eye

Left Eye

Following an uncomplicated cesarean delivery at 38 weeks, the patient returned to the clinic for visual field testing. Humphrey visual fields were full in the right eye and showed some scattered central depressions in the left. Both eyes were significantly improved from previous fields (eFigure 2) . The patient had discontinued acetazolamide and reported minor tension headaches she believed were due to lack of sleep but stated that she was no longer having migraines. There was no papilledema noted on fundus examination, and Snellen distance visual acuity measured 20/20 in both eyes. An MRI had been performed after delivery and was negative for intracranial hemorrhage, mass, or hydrocephalus).

(eFigure 2. Visual Fields Postpartum)
Right eye

Left eye

Three months later, the patient returned for her yearly comprehensive examination. At that visit, she reported a decrease in frequency of the migraine headaches. Optical coherence tomography was performed and showed a significant decrease in optic nerve head swelling.

Related: Diabetes on the Rise Among Other Pregnancy Problems

Clinical Picture

Idiopathic intracranial hypertension presents clinically with signs and symptoms of increased intracranial pressure (ICP). Headache is the most common symptom, usually presenting as daily and pulsatile.1 Nausea may be associated with the headache, although vomiting is rare, and the headache may awaken the patient. The headache may remain after resolution of elevated ICP (Table).²

Papilledema is the most common sign of IIH.^1,2 Visual loss associated with papilledema is generally mild at first but progressive. Transient blur lasts usually 30 seconds and may be monocular or binocular.¹ The cause is thought to be related to transient ischemia of the optic nerve.¹ Vision loss is typically reversible with resolution of optic nerve swelling, but 25% of patients may develop optic atrophy, which results in permanent vision loss.² Common patterns of visual abnormalities include enlargement of the physiologic blind spot, inferonasal and arcuate defects, and eventually severe peripheral constriction.^1,2 It is imperative that all patients with IIH have visual field testing performed.