Management of idiopathic intracranial hypertension in parturients: anesthetic considerations

  • Iosifina Karmaniolou
  • Georgios Petropoulos
  • Kassiani Theodoraki
Review Article/Brief Review

DOI: 10.1007/s12630-011-9508-4

Cite this article as:
Karmaniolou, I., Petropoulos, G. & Theodoraki, K. Can J Anesth/J Can Anesth (2011) 58: 650. doi:10.1007/s12630-011-9508-4

Abstract

Purpose

Idiopathic intracranial hypertension (IIH) is a rare condition characterized by raised intracranial pressure (ICP) without related pathology in either the brain or the composition of cerebrospinal fluid (CSF). Herein, we provide a brief review of the clinical presentation of IIH and the anesthetic considerations in parturients diagnosed with the disorder.

Source

We conducted a MEDLINE® literature search for all types of articles published in English with restriction for year of publication, and we used the search terms “idiopathic intracranial hypertension”, “pseudotumor cerebri”, “benign intracranial hypertension”, “pregnancy”, “cesarean section”, “labour analgesia”, “epidural”, and “anesthesia”.

Principal findings

Idiopathic intracranial hypertension affects primarily obese women of childbearing age. The main symptom is headache, and the cardinal sign is papilledema. The main goal of management is to preserve visual function. Treatment lies in the administration of diuretics and corticosteroids, control of excessive weight gain, and surgical management, such as cerebrospinal fluid diversion or optic nerve sheath fenestration for refractory cases. For the parturient with IIH, Cesarean delivery is not necessarily indicated. Neuraxial anesthesia has been used uneventfully for both labour analgesia and for Cesarean delivery. There are reports describing successful use of both spinal and epidural anesthesia, even in IIH patients with CSF diversion devices in situ.

Conclusion

Although IIH is rare, there are special considerations for anesthetic management in the parturient. Despite the presence of raised ICP in these patients, there are no specific contraindications to neuraxial techniques, and uncal herniation has not been reported to occur in patients with IIH.

Prise en charge de l’hypertension intracrânienne idiopathique chez la parturiente: considérations anesthésiques

Résumé

Objectif

L’hypertension intracrânienne idiopathique (HII) est une condition rare qui se caractérise par une pression intracrânienne (PIC) élevée sans pathologie connexe au niveau du cerveau ou de la composition du liquide céphalorachidien (LCR). Nous proposons ici une brève synthèse de la présentation clinique de l’HII et quelques considérations anesthésiques chez les parturientes avec un diagnostic de ce trouble.

Source

Nous avons réalisé une recherche de la littérature sur MEDLINE® pour extraire tous les articles publiés en anglais en posant comme contrainte l’année de publication, et avons utilisé les termes de recherche « idiopathic intracranial hypertension » (hypertension intracrânienne idiopathique), « pseudotumor cerebri » (méningite séreuse), « benign intracranial hypertension » (hypertension intracrânienne bénigne), « pregnancy » (grossesse), « cesarean section » (césarienne), « labour analgesia » (analgésie pour le travail obstétrical), « epidural » (péridurale), et « anesthesia » (anesthésie).

Constatations principales

L’hypertension intracrânienne idiopathique affecte principalement les femmes obèses en âge de procréer. Les céphalées sont le symptôme principal, et le symptôme cardinal est l’œdème papillaire. L’objectif principal de la prise en charge est de conserver la fonction visuelle. Le traitement consiste à administrer des diurétiques et des corticostéroïdes, à contrôler une prise de poids excessive, et à effectuer une prise en charge chirurgicale, telle que le détournement du liquide céphalorachidien ou la fenestration de la gaine du nerf optique dans les cas réfractaires. L’accouchement par césarienne n’est pas forcément indiqué chez la parturiente atteinte d’HII. L’anesthésie neuraxiale a été utilisée sans complication pour l’analgésie du travail obstétrical et pour les accouchements par césarienne. Certains cas rapportés décrivent l’utilisation réussie d’anesthésie rachidienne et de péridurale, même chez les patientes atteintes d’HII et chez lesquelles étaient positionnés des appareils de dérivation du LCR.

Conclusion

Bien que l’HII soit rare, certaines considérations particulières s’appliquent à la prise en charge anesthésique de la parturiente atteinte de ce trouble. Malgré la présence d’une PIC élevée chez ces patientes, il n’existe pas de contre-indication spécifique aux techniques neuraxiales, et on n’a pas rapporté d’hernie uncinée chez les patientes atteintes d’HII.

Idiopathic intracranial hypertension (IIH) is defined as a neurological disorder characterized by raised cerebrospinal fluid pressure (CSF) in the absence of any intracranial pathology or secondary cause of intracranial hypertension.1 It was first described by Quinke in 1893 under the name of “meningitis serosa”.2 This condition was known as pseudotumor cerebri and benign intracranial hypertension until 1989 when Corbett and Thomson suggested its current term.3

In the general population, IIH occurs at a rate of 0.9/100,000 per year.4 It is more prevalent in women of childbearing age,5 especially obese persons.6-8 In a cohort study in Iowa and Louisiana, the female-to-male ratio was estimated to be 8:1.4 In the same study, the incidence increased to 19.3/100,000 for obese women ages 20 to 44.4 Pregnancy occurs in IIH patients at the same rate as for the general population, and subsequent pregnancies do not seem to increase the risk of recurrence.9,10 Rare cases of familial IIH have been described.11,12

In pregnant women with IIH, normal deliveries are usually expected. Some authors suggest that the second stage of labour can be shortened by instrumental delivery if deemed necessary to avoid a further increase in ICP.13,14 In our view a prolonged second stage labour in these patients is no specific cause for concern; furthermore, IIH is not in itself a specific indication for Cesarean delivery.15

We undertook to review the symptoms, pathogenesis, management, and anesthetic considerations in parturients with IIH. We conducted a MEDLINE® literature search for all types of articles published in English with restriction for year of publication, and we used the search terms “idiopathic intracranial hypertension”, “pseudotumor cerebri”, “benign intracranial hypertension”, “pregnancy”, “cesarean section”, “labour analgesia”, “epidural”, and “anesthesia”. The search identified only 14 articles that specifically addressed the anesthetic management of parturients with IIH. We considered all articles that helped to characterize the nature of IIH and the clinical presentation and management of the disorder. Since randomized prospective data were lacking, we considered case reports, case series, and retrospective studies.

Presentation and pathogenesis of IIH

The most frequent symptom of IIH is headache, occurring in more than 90% of cases.16,17 The headache is usually generalized, worse in the morning, and may be associated with photophobia.18 Also, patients may report neck, back, and shoulder pain, although less frequently.4,13 Other symptoms include nausea, vomiting, and pulsatile tinnitus (in up to 60% of cases).19 Visual disturbances are a common manifestation and include visual field loss, transient visual obscurations, loss of visual acuity, as well as diplopia resulting from sixth nerve palsy.20,21 The cardinal sign is papilledema, although, albeit rarely, it might be absent22,23 or unilateral.24,25 The major risk of IIH is visual loss, which can be permanent despite therapy.26 Untreated papilledema can lead to permanent blindness in up to 10% of patients.27,28 On rare occasions, seventh29 and fourth30 nerve palsies have been reported, the latter in pediatric patients. It seems that symptoms worsen during pregnancy in 50% of patients and usually resolve postpartum.31,32

Although the pathogenesis of raised intracranial pressure in IIH remains unclear, the most widely accepted theory is impaired absorption of CSF in the arachnoid villi. It has been suggested that this might be due to raised venous pressure from venous outflow obstruction.33-35 Sugerman et al. suggested that the raised ICP in obese IIH subjects is secondary to the increased cardiac filling pressures caused by increased abdominal pressure.36 It has recently been suggested that jugular venous insufficiency plays a causal role.37

Diagnosis and treatment of IIH

Diagnosis is based mostly on the “modified Dandy criteria” updated by Friedman and Jacobson in 200238 (Table 1). Imaging of the brain should be carried out before a lumbar puncture, and magnetic resonance imaging (MRI) is the current diagnostic testing of choice.39 Neuroimaging studies are usually normal, although, in some cases, they may demonstrate partially empty sella and perioptic CSF distension or small ventricles.40
Table 1

The Modified Dandy Criteria for diagnosis of IIH38

Symptoms of raised intracranial pressure

No localizing signs with the exception of sixth nerve palsy

CSF pressure of 25 mmHg or greater measured in the lateral decubitus position

Normal CSF composition

Patient awake and alert

Normal neuroimaging studies without evidence of thrombosis, except for an empty sella

No other explanation for the raised intracranial pressure

IIH = idiopathic intracranial hypertension; CSF = cerebrospinal fluid

Therapeutic measures should be focused towards preserving visual function. Medical treatment includes diuretics (mainly acetazolamide), steroids, and serial lumbar punctures. De Simone et al. suggest CSF drainage in increments of 20 mL.41 Cerebrospinal fluid drainage volumes as high as 45 mL have been reported.42 Symptoms may resolve even after a single lumbar puncture, but, if needed, the puncture can be repeated at intervals spaced over several weeks. Generally, the CSF is drained until the pressure falls to normal levels or below 20 mmHg.43,44 Prednisone has been reported to achieve resolution of symptoms in a parturient within three days.45 Parturients should be advised to avoid excessive weight gain.28 A low-calorie diet or weight loss program, generally indicated in non-pregnant patients with IIH, may not be the recommendation of choice in the parturient because of the high nutritional requirements of the parturient and the developing fetus. If these measures fail to improve visual function, then surgical management becomes necessary, including lumboperitoneal shunting46,47 or ventriculoperitoneal shunting procedures48,49 or optic nerve sheath fenestration.50,51 Optic nerve sheath fenestration is usually undertaken when visual loss is prominent.52 An incision is made in the retrobulbar optic nerve dural sheath, thus allowing a reduction in the pressure exerted on the optic nerve.53 Optic nerve sheath fenestration has the advantage of requiring less anesthesia time, which is always an important consideration during pregnancy. All methods of management have a recognized failure rate with frequent need for revisions in some patients.52 Such procedures have been carried out in parturients with IIH without adverse outcome on the pregnancy.54,55

Acetazolamide, a carbonic anhydrase inhibitor, lowers intracranial pressure by reducing the production of CSF. However, carbonic anhydrase inhibitors may be teratogenic and have been associated with forelimb abnormalities in rats and mice.56-58 Within the United States Food and Drug Administration classification of pregnancy risk, the risk is considered category C (meaning that animal studies have shown an adverse effect, but there no adequate and well-controlled studies in pregnant women). Nevertheless, in their review, Lee et al. concluded that there are no well-documented reports of adverse effects of acetazolimade on pregnancy.59 They recommend to consider acetazolamide if there is a high risk of visual loss. Overall, since safety in pregnancy cannot be established, we suggest that carbonic anhydrase inhibitors should be administered with caution, at least during the first trimester or until the 20th week of pregnancy.21

Anesthetic considerations for the parturient with IIH

As mentioned previously, IIH is not in itself an indication for Cesarean delivery; patients diagnosed with IIH might require labour analgesia or anesthesia for Cesarean delivery for indications unrelated to IIH. Although dural puncture is contraindicated in patients with increased ICP resulting from space occupying lesions, a risk of uncal herniation does appear to exist in patients with IIH.60 As described previously, lumbar puncture may be therapeutic in IIH patients as it decreases CSF pressure and consequently improves symptoms. It has been postulated that the uniform swelling and stiffness of the brain in IIH prevents herniation.60 On rare occasions, it has been reported that herniation was associated with an anatomic variation, i.e., low-lying cerebellar tonsils.61 Herniation, on the other hand, is an identified late complication of lumboperitoneal shunts.62,63 In this case, it seems that the lumboperitoneal shunt creates a craniospinal pressure gradient due to the continuous CSF drainage, which acts as a driving force for tonsillar descent and subsequent herniation.64 Moreover, months after placement of the shunt, the brain eventually loses its stiffness to a point that it is compliant enough to herniate.

Vaginal delivery and anesthesia

During routine vaginal delivery, the uterus empties approximately 300 mL of blood into the circulation with each myometrial contraction. Cerebrospinal fluid pressure increases in response to myometrial contractions and is associated with increases in central venous pressure, stroke volume, cardiac output, and arterial blood pressure.32 Although such increases in CSF pressure are independent of pain, pain may exaggerate the response. Specifically, elevations in ICP are related to skeletal muscle contractions in response to pain, so that epidural analgesia might in fact attenuate rises in ICP.65 Neuraxial analgesia for labour has been carried out without complications in parturients with IIH66,67 (Table 2). However, there have been concerns that large volumes of local anesthetic administered epidurally might elevate intracranial pressure even more in patients with intracranial hypertension.68 Using a porcine model, Grocott et al. demonstrated that the elevation in ICP is significantly greater in the presence of intracranial hypertension.68 Similarly, Hilt et al. have recorded a great increase in ICP in a patient with intracranial hypertension following lumbar extradural injection of bupivacaine 10 mL, even though the study was not specific for IIH.69

Accordingly, cerebral blood flow is reduced markedly for a short time after injection. For this reason, vaginal delivery using an intrathecal catheter has also been suggested.27 In fact, Aly et al. claim that an intrathecal catheter creates the possibility of therapeutic CSF drainage if symptoms deteriorate during labour.27 Similarly, in an effort to minimize abrupt increases in ICP, epidural infusion has been suggested instead of intermittent bolus dosing.70 Analgesic drugs that might cause respiratory depression and a consequent rise in ICP, mainly opioids, are best avoided.
Table 2

Anesthetic techniques for vaginal delivery in patients with IIH

First AuthorRef

Presence of LP shunt / Interspace

Anesthetic technique Interspace / Needle

Volumes of local anesthetic (duration)

Level

Complications

Other comments

Kaul14

Yes / L2-3

Epidural L1-2 / 17G Hustead

t.d. 1.5% lidocaine 3 mL (20 min) lidocaine 10 mg (15 min)

T5 motor

Hypotension/Accidental spinal catheter (left in place and used)

Forceps used;

Prior radiograph to locate the shunt

Aly27

No

Epidural catheter intrathecally L3-4 / 18G Tuohy

0.5% hyperbaric bupivacaine 1 mL

Infusion: 1 mL /3 hr for 13 hr

Motor block T7 sensory

Postpartum headache for two days (not PDPH)

Drainage of 25 mL of CSF before anesthesia

Palop66

No

Epidural L3-4 / 17 G Tuohy

t.d. 0.5% bupivacaine 2 mL

0.5% bupivacaine 6 mL

After 70 min: 0.5% bupivacaine 8 mL

N/A

No

No

Douglas80

No

Epidural / NA

Bolus: 0.25% bupivacaine 8 mL

Infusion: 0.125% bupivacaine 8 mL·hr−1

+ fentanyl 2 μg·mL−1 for 9 hr

N/A

No

No

IIH = idiopathic intracranial hypertension; LP = lumboperitoneal; t.d. = test dose; PDPH = postdural puncture headache; CSF = cerebrospinal fluid

Anesthesia for Cesarean delivery

Neuraxial anesthesia, epidural or spinal, has been used successfully for Cesarean delivery in patients with IIH70-72 (Table 3). Since lumbar puncture for CSF drainage is a therapeutic modality for IIH, there is no indication to withhold spinal anesthesia in these patients.71 However, when using epidural techniques for Cesarean delivery, one should consider that the large volumes of drugs administered into the epidural space for surgical anesthesia possibly may carry a risk of raising intracranial pressure in these patients.27 On the other hand, special consideration should be given for parturients who have been subjected to recent CSF removal, as the risk of a higher than anticipated block or even a total spinal may be present.27
Table 3

Anesthesia for Cesarean delivery in patients with IIH

First AuthorRef

Presence of LP shunt / Interspace

Anesthetic technique

Volumes of local anesthetic (duration)

Level

ComplicationsComments

Interspace / Needle

Bagga31

No

GA

 

 

No

Palop66

No

Epidural L3-4 / NA

Initially for labour: t.d. 0.5% bupivacaine 2 mL + 4 doses of 6 mL in 5 hr

For CD: 0.5% bupivacaine 10 mL

T10 sensory

T6 sensory

CD due to non progression of vaginal delivery

Bedson70

No

CSE L2-3 / 16G Tuohy 27G Whitacre

Spinal: bupivacaine 11 mg + fentanyl 25 μg volume: 2.7 mL

T3 sensory

No

Abuleish71

Case 1

Case 2

Yes / NA

No

Spinal L3-4 /22G

GA - RSI

5% lidocaine 60 mg in 7.5% D/W + epinephrine 0.2 mg (4 segment regression in 120 min)

T4 sensory

No

Hypotension

Kim72

Yes / L4-5

Epidural L1-2 / NA

For vaginal: 0.2% ropivacaine 5-7 mL·hr−1 (for 19 hr)

For CD: 2% lidocaine + 1:200,000 epinephrine + HCO3-, volume: 15 mL (1 ½ hr)

T4 sensory

CD due to non progression of vaginal delivery

Epidurogram before removal of the catheter

Bédard73

Yes L3-4

Epidural L4-5 /NA

Initially for labour: t.d lidocaine 3 mL + epinephrine 5 μg·mL−1 + 3 bolus doses

Infusion: 0.125% bupivacaine 10 mL·hr−1 + fentanyl 2 μg·mL−1 for 7 hr

Motor weakness

T10 sensory right

T8 sensory left

Failure after 7 hr of infusion replacement

Epidural T12-L1 (replacement)

For CS: t.d. 1.5% lidocaine 3 mL + epinephrine 5 μg·mL−1, 2% lidocaine 15 mL + fentanyl 100 μg (90 min)

T8 sensory before drapes were placed

CD due to non progression of vaginal delivery

Heckathorn74

No

Spinal catheter in place used for drainage L4-5

bupivacaine 11.25 mg + fentanyl 10 μg + morphine 0.3 mg (90 min)

T5 sensory

Catheter clamped throughout the procedure

IIH = idiopathic intracranial hypertension; LP = lumboperitoneal; YES CSE = combined spinal-epidural; GA = general anesthesia; RSI = rapid sequence induction; t.d. = test dose; CD = Cesarean delivery; D/W = Dextrose in Water

Anesthesia for IIH patients with shunts

There are special considerations for IIH patients with a lumboperitoneal shunt where there are conflicting recommendations to use either general or neuraxial anesthesia. Some authors advocate the use of general anesthesia without evidence of adverse effects with neuraxial techniques,31,71 while others report use of epidural or spinal anesthesia without complications.14,72,73 A primary issue of concern is potential damage to the shunt catheter by the epidural or spinal needle.10,71 Heckathorn et al. used a spinal catheter that had been inserted ten days prior for CSF drainage, withdrawing the catheter from 20 to 15 cm. The patient received hyperbaric bupivacaine 11.25 mg, fentanyl 10 μg, and morphine 300 μg with the catheter clamped throughout the procedure.74 The location of the catheter tip is important when using such an approach. While some authors advocate radiographic imaging before placement of an epidural catheter in patients with a shunt in situ,14 others do not find it necessary.73,74 In support of the second opinion, Bedard states there is no need for imaging studies if the interspace selected for epidural anesthesia is either above or below the scar of the shunt and the midline approach is followed, since the shunt catheter is directed laterally just underneath the skin.73 Nevertheless, attention must be given while removing the epidural catheter because there is always the theoretical risk of shunt entanglement. If abnormal resistance is felt during attempts to remove the catheter, imaging studies should be carried out before further manipulation.73 Another issue that arises in patients with a shunt in situ is the possible loss of local anesthetic into the peritoneal cavity, which could result in inadequate anesthesia. Bedson et al. claim that spinal anesthesia is unsuitable if a lumboperitoneal shunt is in situ; spread of local anesthetic is possible due to indeterminate circulation of CSF between the intrathecal space and the peritoneal cavity.70 In fact, Kaul et al. have reported a pattern of quick offset of the block after repeated doses of lidocaine intrathecally, possibly due to rapid washout of lidocaine through the shunt into the peritoneal cavity.14 On the other hand, a functioning shunt might limit the risk of raising intracranial pressure with large volumes of local anesthetic. The last matter of concern is the possibility of infection of the shunt catheter.

The rate of lumboperitoneal shunt infection is approximately 1% per year.75 Controversy exists regarding the need for antibiotic prophylaxis. Prophylactic vancomycin and gentamicin have been administered for shunt infection.72 In contrast, the most relevant, though retrospective, study by Landwehr et al. included eight patients with 25 pregnancies over 16 years; they suggested that antibiotics are unnecessary for uncomplicated vaginal delivery in patients with either lumboperitoneal or ventriculoperitoneal shunts.54 Considering the reported experience to date, in our view, neuraxial anesthesia is feasible and a reasonable option in patients with lumboperitoneal shunts in situ. Spinal anesthesia has also been described recently in a parturient with a ventriculoperitoneal shunt, as there is no contraindication for neuraxial block in this set of circumstances.76 Physicians must bear in mind the possibility of shunt malfunction during pregnancy due mainly to uterine enlargement,77,78 while malfunction might also occur after operative delivery, possibly due to obstruction from blood clots.79

General anesthesia in pregnant women with IIH

General anesthesia for Cesarean delivery in parturients with IIH is recommended only when absolutely necessary, since the aim of treatment lies in minimizing increases in ICP.9,31 If a parturient with IIH requires general anesthesia, the planned approach should minimize the risk of a rise in intracranial pressure associated with rapid sequence induction and laryngoscopy.27 Another problem associated with pregnancy that arises is the increased risk of difficult intubation, probably because of fluid retention81 and the possible aspiration of gastric contents, since, as already discussed, these patients are often obese. Beta-blockers or hydralazine can be used to attenuate rises in ICP. Hyperventilation is not indicated as it reduces uterine blood flow and may cause fetal hypoxia and acidosis due to maternal hypocarbia.82 Hypoxia must also be avoided. If a central line is required, the internal jugular vein seems to be a safe approach in patients with elevated ICP.83

Postdural puncture headache in IIH

Postdural puncture headache (PDPH), a well-known complication of accidental dural puncture, is attributed to “low CSF pressure syndrome” after CSF volume loss, which causes a downward pull on pain-sensitive structures, such as the meninges, vessels, and nerves.84,85 Cerebrospinal fluid hypotension is extremely uncommon in patients with IIH, even following dural puncture. As a consequence, this subgroup of parturients rarely develops PDPH. In fact, PDPH is so rare in patients with IIH that it is considered a paradoxical complication. In two cases wherein PDPH has been reported, the headache was managed successfully with an epidural blood patch.14,86 Clinicians should bear in mind that symptoms of IIH, such as headache and diplopia, might be confused with PDPH.

Conclusions

In conclusion, although IIH is rare, there are special considerations for anesthetic management in parturients with this disorder. Even though these patients have an elevated ICP, the most important consideration is the fact that there is no contraindication to either spinal or epidural anesthetic techniques since uncal herniation does not occur in these patients. Special attention must be given to IIH parturients with lumboperitoneal or ventriculoperitoneal shunts in whom, under special precautions, neuraxial anesthesia might also be performed. In all cases, the main goal is to avoid further increases in ICP.

Competing interests

None declared.

Copyright information

© Canadian Anesthesiologists' Society 2011

Authors and Affiliations

  • Iosifina Karmaniolou
    • 1
    • 2
  • Georgios Petropoulos
    • 1
  • Kassiani Theodoraki
    • 1
  1. 1.Department of AnesthesiaAretaieio Hospital, Medical School, University of AthensAthensGreece
  2. 2.AthensGreece

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