Idiopathic Intracranial Hypertension in Pregnancy

In patients with rapidly progressive vision loss but with minimal headache, optic nerve sheath fenestration (ONSF) is the surgical treatment of choice.^2,3,6 In this procedure, a window or series of slits are created behind the globe in the optic nerve sheath.¹ About 50% of patients achieve adequate headache control with ONSF, especially for frontal headaches.^1,2

For patients with vision loss, papilledema, and headache that do not respond to medical therapy, a CSF diversion procedure is the preferred treatment. Cerebrospinal fluid diversion with ventriculoperitoneal or lumboperitoneal shunts may prevent progressive loss of vision.^1,4,6 However, variable response rates and shunt failure requiring subsequent revisions are common and may occur in as many as half of patients undergoing these procedures.¹

Increased intracranial venous pressure due to stenosis of the venous sinuses has been thought to be a possible cause of IIH. Stenting of the transverse venous sinus stenosis has been shown to reduce cerebral venous pressure, reduce ICP, and improve symptoms in patients with IIH.^1-3 It is unclear whether elevations in ICP cause transverse sinus stenosis or whether transverse sinus stenosis causes increased ICP.² Regardless, stents have a high rate of complications, including subdural hemorrhage, venous sinus perforation, in-stent thrombosis, and recurrent stenosis proximal to the stent.²

Steroids have been used to treat IIH in the past, although their mechanism of action remains unclear.² There may be recurrence of papilledema if they are tapered too quickly. Due to their association with long-term AEs, including weight gain, they should be avoided.²

Management in Pregnancy

Several studies agree that vision loss occurs in the same frequency in pregnant and nonpregnant patients with IIH.^4,7 Idiopathic intracranial hypertension can occur in any trimester in pregnancy. It has been found that patients have the same spontaneous abortion rate and visual outcomes as the general population.^6-8 It has also been concluded that treatment should be the same in both patient populations with slight variability in the use of acetazolamide.^4,6,7

The use of dilating drops during pregnancy is controversial. Although there have been no teratogenic 
effects reported with use of topical anesthetics and dilating drops, all drugs should be avoided during the first trimester.^7-10 Guidelines have been established by the American Congress of Obstetricians and Gynecologists for X-ray examination and exposure during pregnancy. It has been determined that exposure from a single diagnostic X-ray procedure does not result in harmful fetal effects.¹¹ Magnetic resonance imaging is not associated with any known adverse fetal effects and is a better imaging option during pregnancy, because it is not associated with the use of ionizing radiation.¹¹

The use of CAIs in the first trimester is controversial.^4,7 Some believe it should be avoided because it is a Pregnancy Category C drug. However, a single case of sacrococcygeal teratoma has been reported in humans; therefore, some believe this is not a strong basis for withholding the medication in patients with the potential risk for severe vision loss.^4,7 In this case, a consult to the patient’s obstetrician was made, and the use of acetazolamide had no effect on the health of the baby.

In pregnant women with IIH with progressive vision loss, failed treatment, or nonadherence, surgery may be necessary. Optic nerve sheath fenestration is preferred due to lower morbidity and mortality compared with shunting procedures.^1,2,4,6 The growing fetus may be affected by the peritoneal end of the shunt.⁴

Related: 49-Year-Old Woman With a Broken Heart

Conclusions

Vision loss associated with IIH can be severe and permanent if left untreated. The best treatments and often the most effective involve weight loss and lumbar puncture. Acetazolamide has been a proven effective treatment in some patients, but some debate exists over the safety of its use during pregnancy. This patient did not have any AEs from its use; however, it did not prove valuable in her treatment. Studies often disagree on the use of acetazolamide in pregnancy; however, all agree that proper patient counseling on potential AEs and management by an obstetrician are important. With proper management, pregnant women with IIH have had outcomes similar to those of the general population.

Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.