Benign Intracranial Hypertension And Pregnancy

Author Information

Desai A*, Desai G**, Hatkar PA***, Warke HS***

(* Second year Resident, ** Assistant Professor, *** Associate Professor, Department of Obstetrics and Gynecology, Seth GS Medical College and KEM Hospital, Mumbai, India.)

Abstract

Benign intracranial hypertension (BIH) (or idiopathic intracranial hypertension) is commonly seen in women of reproductive age group with obesity. A successfully managed case of pregnancy with BIH, who had features of papilledema but no visual deterioration, and delivered by cesarean section is presented here. A multidisciplinary approach involving ophthalmologists and neurologists helped in the management of the patient.

Introduction

IIH is characterized by the presence of papilledema, headache, and raised intracranial pressure without any specific neurologic abnormality in otherwise healthy individuals. The diagnostic criteria include papilledema, visual loss and lumbar CSF opening pressure > 250 mm of water when the patient is in the lateral decubitus position with legs extended. Annual incidence of IIH is about 0.9/ 100,000 persons.  It is higher (3.5/ 100,000) in females of reproductive age group.[1]

It can occur in any trimester during pregnancy. Pregnancy does not cause worsening or recurrence of symptoms and thus therapeutic abortions are not indicated and also the number of spontaneous abortions is also not affected by BIH. The pregnancy rates and outcome is not different from that of general population and the incidence of papilledema is not affected by pregnant state. Risk of recurrence is not very clear, although recurrent IIH in successive pregnancies has been reported.[2] The symptoms worsen during pregnancy and usually resolve after abortion or delivery.

Case Report

A 30 year old G5P1L1MTP1SA2 antenatally registered with us at 8 weeks of gestation with seven uneventful antenatal follow-up visits is presented here. 

Four years back she had history of severe headache and vomiting episodes not responding to medications for which she consulted a neurologist. MRI brain showed mild short segmental narrowing at the junction of transverse and sigmoid sinuses bilaterally. As the MRI findings were mild and not specific, a diagnosis of BIH was made and she was started on acetazolamide and oral potassium supplements. There was no other significant past medical or surgical history. There was no history of tuberculosis. She had one full term vaginal delivery and underwent one medical termination of pregnancy prior to detection of this neurological problem. After this, she had two spontaneous abortions, for which curettage was done and neurology review suggested continuation of same management. In current pregnancy, she was on regular neurological and ophthalmologic consultation.  Continuation of acetazolamide was advised. Fundus examination was not suggestive of papilledema. Ultrasonography showed no fetal malformations. She was admitted at 39 weeks of gestation in early labor.  

Her BMI was normal. Her blood pressure was 130/ 80 mm Hg and she had no complaints of headache or visual blurring then. Ophthalmologists reviewed her and features of early papilledema with blurring of disc margins superiorly and nasally were found. Neurologists opined that in view of grade 1 papilledema, it would be preferable to deliver by cesarean section, to avoid the risks of increased intracranial tension during Valsalva maneuver that occurs in labor. She was taken up for lower segment cesarean section under general anesthesia after adequate preoxygenation. The surgery was uneventful, she delivered a healthy male child of 3.4 kg with Apgar of 9/ 10, and post-operative course was uneventful. Neurologists and ophthalmologists reviewed and advised to continue the same treatment (tablet acetazolamide) in view of persistence of early signs of papilledema.

Discussion

IIH is a disease of unknown etiology. Two mechanisms that have been postulated are vasogenic extracellular brain edema and a reduced conductance of cerebrospinal fluid outflow at arachnoid villi. PCOS, exogeneous estrogen and pregnancy can all worsen IIH. Hypofibrinolysis, exacerbated by thrombophilic exogenous estrogens, seen in PCOS is considered a treatable causal factor for BIH.[3] Vitamin A toxicity may play a role in the pathogenesis of BIH and doxycycline use has been shown to aggravate BIH.[4]

Acute management depends on the immediate risk to vision. The treatment goal is to preserve vision and improve symptoms as blindness may develop in 10 % of pregnant women with BIH. Visual loss in BIH may be permanent despite medical treatment. In 50 % of pregnant females, the symptoms of visual loss may worsen however it improves in postpartum period.[5] Our patient did not have any specific visual complaint throughout pregnancy. Most therapies used during the non-pregnant state can also be used during pregnancy. Treatment includes analgesics, diuretics, steroids, and serial lumbar punctures. Surgical procedures may be options in severe cases resistant to medical therapy. However, our patient was well controlled with only medical management with diuretics. Steroids was not required in our patient. 

A weight gain of 5–9 kg during the pregnancy is recommended (0.22 kg/ week in the second and third trimester) in those with a BMI of ≥30 kg/m2.[6] Disease-modifying therapy is weight loss, but significant caloric restriction is not a recommended approach during pregnancy to avoid ketosis. Our patient had a normal BMI and hence approaches of weight loss and caloric modification was not required. 

Obesity can cause IIH. Central obesity raises intra-abdominal pressure, causing increased pleural pressure and cardiac filling pressures, which impedes venous return and causes raised intracranial venous pressure and in turn increased intracranial pressure.

Glucocorticoids, diuretics, carbonic-anhydrase inhibitors (acetazolamide), and lumbar punctures are treatment options. Though rare occurrence of sacrococcygeal teratoma has been reported with acetazolamide use, this is the preferred agent. In our patient, acetazolamide was continued for maternal benefit, and is justifiable.[2] 

Though IIH is not a very rare condition, the dilemma regarding mode of delivery remains. Uterine contractions and bearing down efforts with associated increased BP, cardiac output, central venous pressure, and consequently, increased CSF pressure can cause onset of or worsening of preexisting papilledema. Labor analgesia is recommended in vaginal delivery. Even though the increase in CSF pressure is independent of pain, it can be exaggerated by it.  So, epidural analgesia can minimize these hemodynamic changes caused by pain.[7] Second stage of labor may be shortened by instrumental delivery.[8] However, our patient had newly developing papilledema detected during admission at term, which was not present during the prior antenatal visits, and hence vaginal trial was avoided. 

Our patient underwent cesarean section under general anesthesia. However, regional anesthesia can be used if papilledema is absent and per se, BIH is not a contraindication.[9]  Majority of patients with BIH remain stable and a normal vaginal delivery is possible. 

Conclusion

BIH is a relatively rare condition seen in women of reproductive age. Pregnancy in these patients can be successfully managed with a multidisciplinary approach in tertiary center involving obstetricians, neurologists, ophthalmologists and anesthesiologists. Vaginal delivery is permitted unless signs of raised intracranial pressure exist (absence of papilledema in cases of BIH under treatment). In presence of papilledema elective caesarean section is indicated.

References

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Citation

Desai A, Desai G, Hatkar PA, Warke HS. Benign Intracranial Hypertension And Pregnancy. JPGO 2018. Volume 5 No.3. Available from: http://www.jpgo.org/2018/03/benign-intracranial-hypertension-and.html