Idiopathic Intracranial Hypertension (IIH) Treatment & Management

Updated: Jan 02, 2019
  • Author: Mark S Gans, MD; Chief Editor: Andrew G Lee, MD  more...
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Treatment

Approach Considerations

The treatment goal in patients with idiopathic intracranial hypertension (IIH) is to preserve optic nerve function while managing increased ICP. Medical management is multifaceted. Optic nerve function should be carefully monitored with an assessment of visual acuity, color vision, optic nerve head appearance, and perimetry. Weight control is recommended for obese patients. [105] Exogenous agents related to increased ICP should be discontinued.

Patients without visual loss are most often treated with a carbonic anhydrase inhibitor (eg, acetazolamide) to lower the ICP. While, historically, this has been the mainstay of treatment, it has now been corroborated with an NIH-funded study (Idiopathic Intracranial Hypertension Treatment Trial). In patients with severe symptoms, early visual field loss, or poor response to standard medical therapy, some clinicians use a short course of high-dose oral corticosteroids to temporarily postpone the need for surgical intervention.

When new visual field loss is documented, medical management should be coupled with plans for emergency surgical intervention if the visual function continues to deteriorate or does not improve immediately with corticosteroid treatment.

Visual loss in one or both of the eyes can evolve rapidly despite best efforts to arrest the process.

The exact interval within which vision loss can be reversed after symptomatic decline is unknown. Opinions among experts vary as to how rapidly and aggressively any given patient should be treated.

One of the standard teachings regarding this condition has been that pregnancy exacerbates or triggers the onset of symptomatic IIH. At present, however, there is little statistical evidence of a causal association between pregnancy and IIH, beyond the fact that pregnancy is common in the age group and gender that is predominantly affected by IIH. [106, 42]

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Pharmacologic Therapy

Acetazolamide and furosemide

In a 2014 NIH-funded study of 165 patients with IIH and mild vision loss (the Idiopathic Intracranial Hypertension Treatment Trial), researchers found that acetazolamide treatment for 6 months in conjunction with a low-sodium weight-reduction diet modestly improved vision, reduced ICP, improved quality of life, and reduced papilledema. Average improvement in perimetric mean deviation (PMD) was 1.43 dB with acetazolamide and 0.71 dB with placebo. Data showed that the drug’s effect was independent of weight loss. [107, 108] Compared with the placebo group, patients on acetazolamide treatment had statistically significant improvement of retinal nerve fiber layer thickness, total retinal thickness, and optic nerve volume based on OCT measurements. [109]

Acetazolamide appears to be the most effective agent for lowering ICP. Most patients experience adequate relief of symptoms (typically, headache) with this first-line agent. The brand-name formulation Diamox appears to be better tolerated than generic acetazolamide.

Among patients who are able to tolerate acetazolamide, it has been successful in managing symptoms and stabilizing vision in 47%-60% of cases. [110, 111, 112]

A randomized prospective trial assessed headache response to study interventions in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT). Using the Headache Impact Test-6 (HIT-6) questionnaire, the trial showed that a similar amount of improvement occurred in the acetazolamide versus placebo group at 6 months. The lack of correlation between headache disability and CSF pressure at baseline and at the end of the randomized phase of the study implies that headache in IIH may be related to factors other than intracranial hypertension and that specific headache treatment is needed in addition to therapies directed at lowering CSF pressure. [113]

In a long-term follow up study of 54 patients, recurrent episodes of IIH occurred in 38% of cases over a mean period of 6.2 years; no reoccurrences occurred in patients receiving ongoing acetazolamide treatment. [114]

The initial acetazolamide dosage should be 0.5-1 g/day. Although many physicians start patients on 250 mg twice daily, others consider this dosage too low. A 500-mg oral dose of Diamox Sequels twice daily is often preferred; however, some insurers cover only an oral dose of 250 mg 4 times per day. Most patients respond to a dosage of 1-2 g/day. This can be increased to 3-4 g/day, but some patients cannot tolerate the adverse effects (eg, extremity paresthesias, fatigue, metallic taste from carbonated beverages, and decreased libido) that occur at this high dosage. [6, 2] In the Idiopathic Intracranial Hypertension Treatment Trial, of the 86 patients in the acetazolamide treatment group, 38 patients (44.1%) tolerated the maximum dose of 4 g/day. [115] Seventy-seven (89.5%) of the 86 patients taking acetazolamide tolerated dosages of 1 g/day or more. Compared with the 79 patients from the placebo group, the 86 patients taking acetazolamide were more likely to experience paresthesia, dysgeusia (foul or metallic taste), vomiting and diarrhea, nausea, and fatigue. [115]

In the event of intolerance to acetazolamide, furosemide may be used as a replacement diuretic in this group. Unfortunately, it does not appear to be as effective as acetazolamide.

Headache prophylaxis

In patients with stable visual function but inadequate headache relief with first-line pressure-lowering drugs, primary headache prophylaxis should be considered. Patients with IIH may experience headaches that have many of the features of migraine. These headaches can often be controlled with amitriptyline, propranolol, or other commonly prescribed migraine prophylaxis agents. Topiramate is also an excellent choice, in that one of its side effects is weight loss (a common association in IIH), which can help put the disease in remission. One open-label study suggested that topiramate appears to have similar efficacy to acetazolamide in terms of visual field improvement and symptom relief. [116]

Corticosteroids

Corticosteroids are effective in lowering ICP in patients whose IIH has an inflammatory etiology. In addition, they may be used as a supplement to acetazolamide to hasten recovery in patients who present with severe papilledema. Because of their significant adverse effects, corticosteroids should not be considered as a long-term solution in patients with IIH. In addition, a rebound in the ICP may occur during the tapering of the corticosteroid dosage. [2]

Digoxin and furosemide have been advocated by some investigators, but these are on the same level of effectiveness as acetazolamide and are not appropriate as sole therapy in patients who are losing vision.

If a moderately severe new visual field loss is detected on a routine office visit and the patient is not experiencing progressive symptoms, outpatient management can continue.

If the patient presents with symptomatic vision deterioration and the examination documents worsening of visual field despite adequate standard medical therapy, the patient should be admitted to the hospital for consideration of emergency surgical decompression. Visual field examination should be performed daily, and surgical decompression should be performed if no improvement or further worsening is noted.

Serial lumbar puncture

Serial lumbar puncture has fallen out of favor as CSF reforms within 6 hours, it is uncomfortable for patients, it can have complications, and is technically difficult to perform in obese patients. [117]

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Optic Nerve Sheath Fenestration, CSF Diversion, and Venous Sinus Stenting

Patients with IIH should be closely monitored while on medical treatment. The frequency of visits is determined by the initial state of the patient’s visual function and the response to medical treatment. Despite close follow-up care and maximum medical treatment, some patients experience deterioration of visual function. Others fail to respond, are noncompliant, are intolerant to medication, or have intractable headache or progressive visual loss. In this situation, surgical intervention may be considered. Such intervention most often takes 1 of the following 2 general approaches:

  • Optic nerve sheath fenestration (decompression)
  • Cerebrospinal fluid (CSF) diversion (ie, via a lumboperitoneal or ventriculoperitoneal shunt)

Intracranial venous sinus stenting has also been investigated (see below).

Optic nerve sheath fenestration

The ophthalmic surgical approach to managing progressive vision loss and papilledema involves cutting slits or rectangular patches in the dura surrounding the optic nerve immediately behind the globe. [118] This allows direct egress of CSF into the orbital fat, where it is absorbed into the venous circulation.

Optic nerve sheath fenestration (ONSF) has been demonstrated to reverse optic nerve edema and to bring about some recovery of optic nerve function. In addition, it may decrease headache in many patients. The approach to the optic nerve may be from either the medial or the lateral aspect of the orbit; each approach has its benefits and drawbacks. [119] . ONSF has also been shown to be safe and effective in children. [120, 121]

Although ICP typically remains elevated in these patients postoperatively, the local filtering effect of the fenestration acts as a safety valve and keeps the pressure from being transmitted to the optic nerve. Despite the general lack of an ICP-lowering effect, unilateral surgery occasionally has a bilateral curative effect on the papilledema. However, if this is not the case, the opposite nerve must undergo the same procedure.

Complications (not life-threatening) related to optic nerve sheath fenestration occur in 40%-45% of cases and include diplopia (29%-35%); optic nerve injury; vision loss (1.5%-2.6%), typically due to vascular occlusion; direct operative traction and trauma; orbital hematoma; sheath hematoma; tonic pupil (11%); and hemorrhage and infection (risks inherent to intraconal surgery). [122, 121, 123, 124, 125, 126, 127]

Unfortunately, ONSF may not have lasting benefits. In most cases, visual function stabilizes or improves postoperatively, [128] but, in at least one third of cases, secondary visual decline may occur within 3-5 years and may necessitate repeat surgery or an alternative treatment; Spoor and McHenry found the long-term success rate of this operation to be only 16%. [129]

A study of ONSF performed in 41 eyes among 21 patients with vision loss due to either IIH or intracranial hypertension caused by cerebral venous thrombosis found best-corrected visual acuity and visual field to be stabilized or improved in 32 of 34 eyes (94%) over a 3-month follow-up interval. [130] Transient benign complications were apparent in 4 eyes. Only marginal improvement was shown in 4 eyes with no light perception vision; these were not analyzed with the remainder of the group.

CSF diversion procedures

CSF diversion procedures are highly effective in lowering ICP. [131] In some facilities, they remain the procedures of choice for treating patients with IIH who do not respond to maximum medical treatment. [2, 4, 119] Shunts are also indicated in patients with intractable headaches, patients in regions where there is no access to a surgeon comfortable with optic nerve sheath fenestration, and patients in whom optic nerve sheath fenestration has failed.

Lumboperitoneal shunting is the traditional method for providing prompt reduction of ICP in patients with IIH. [132] However, this procedure has a high one-year failure rate. Some neurosurgeons currently prefer ventriculoperitoneal or ventriculoatrial shunting over lumboperitoneal shunting. The main reason why these neurosurgeons prefer ventricular shunts is that such shunts can be monitored for function by using an extracranial subcutaneous compressible bulb and a one-way valve (permitting intracranial-to-abdominal flow) in series with the intracranial and abdominal ends of the shunt. The bulb resists digital compression if the distal (abdominal or atrial) end is obstructed. It collapses under digital pressure but fails to reinflate if the intracranial end is obstructed.

However, Woodworth et al reported that, with a frameless stereotactic approach, they were able to place ventricular shunts in a single pass in all patients, even into slit ventricles, with good long-term viability. [133]

Sinclair et al found that, although CSF diversion minimizes visual decline and improves visual acuity, 68% of patients continued to have headaches and 28% had low-pressure headaches that complicated surgery. Shunt revision was required in 51% of patients, with most requiring multiple revisions. In patients with otherwise untreatable rapidly declining vision, CSF diversion shunting should be conducted as a last resort. Other treatments, such as weight reduction, may be more effective and may have less associated morbidity. [134]

Uncontrolled studies report shunting causes alleviation of headache, diplopia, papilledema, and visual loss. Stabilization and remission of visual remission was reported up to 95%-100% in some studies, while one study showed up to 32% reported worsen vision. [132, 135, 136, 137, 138, 139] One case series reported that headache relief was not sustained, with nearly 50% of patients experiencing recurring severe headaches despite a working shunt. [140]

Intracranial venous sinus stenting

Venous stenting is a relatively new intervention and remains somewhat controversial.

A literature review of 143 patients treated with venous stenting showed that 88% of patients experienced improved headache and 87% reported improved visual symptoms. Follow-up was limited, effects on vision were not consistent, and complications were reported in 6% of cases. [141]

Comparison of visual outcomes

In a meta-analysis of the literature comparing visual outcomes after optic nerve sheath decompression, ventriculoperitoneal and lumboperitoneal shunting, and intracranial venous sinus stenting, Feldon reported the following findings [142] :

  • Optic nerve sheath decompression: Visual defects were improved or resolved in 80% of 252 cases.
  • Ventriculoperitoneal (VP) shunt placement: Visual defects were improved or resolved in 38.7% of 31 cases.
  • Lumboperitoneal (LP) shunt placements: Visual defects were improved or resolved in 44.6% of 44 cases.
  • Intracranial venous sinus stent placement: Visual defects were improved or resolved in 47% of 17 cases.

Visual worsening was rare for all procedures. The author concluded that visual outcome was best documented for optic nerve sheath fenestration, which appeared to be the best surgical procedure for vision loss in IIH. While optic nerve sheath decompression improves visual defects, many patients continue to have significant headaches that require CSF shunt placement. [121]

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Bariatric Surgery

Reduction of body weight by 5%-10% was found to be effective hastening improvement of papilledema and visual fields. [74]

In a literature review of bariatric surgery for obese patients with IIH, Fridley et al found a total of 62 patients, of whom 52 (92%) experienced resolution of the presenting symptoms. [143] Of 35 patients who underwent postoperative funduscopy, 34 had resolution of papilledema. Of 12 patients who underwent preoperative and postoperative visual field examinations, 11 showed resolution of visual field defects.

Among 13 patients in whom CSF pressures were measured preoperatively and postoperatively, there was an average postoperative decrease of 254 mm water. [143] The authors called for prospective controlled studies to confirm the effectiveness of this surgical approach for patients with IIH in long-term follow-up.

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Admission Criteria

Admission for pain management

Even for initial diagnosis, most patients do not require inpatient care, because lumbar puncture is usually performed in the ambulatory care setting. An occasional patient may develop an intractable low-tension headache after lumbar puncture and may require a short hospital stay for intravenous (IV) hydration and analgesic management. A blood patch (by an anesthesiologist) is sometimes indicated if the post–lumbar puncture headache does not subside spontaneously within a few days.

Admission for surgical management of increased intracranial pressure

Patients who report progressive visual loss (typically, constriction of peripheral vision or dimming of vision in one or both eyes) and have documented new visual field loss may respond to high-dose corticosteroid therapy. They should be considered for hospital admission and should undergo daily monitoring of visual function. Patients with fulminant IIH should also be considered for admission and rapid surgical intervention.

If the visual field worsens or does not recover promptly (ie, within 24-48 hours) with corticosteroid therapy, emergency CSF shunting (lumboperitoneal, ventriculoperitoneal, or ventriculoatrial) or optic nerve sheath fenestration should be performed.

If any delay in implementing surgical decompression of the failing optic nerve is anticipated, the patient should be moved to the ICU or a stepdown unit for lumbar CSF drainage until the definitive procedure can be performed. Another short-term treatment option is intravenous mannitol, but definitive pressure-lowering surgery must still be performed within 2-3 days.

A very small number of patients with normal visual fields may require surgical relief of CSF pressure because of intractable headache. Optic nerve sheath fenestration does not provide reliable CSF pressure normalization or headache relief; thus, these patients require a shunting procedure. Because patients with IIH frequently have other types of headaches, the decision to choose ventriculoperitoneal shunting over optic nerve sheath fenestration should not be made based on headache alone.

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Diet and Activity

Most patients with IIH are females who are overweight. Weight loss is a cornerstone in the long-term management of these patients. As little as a 5%-10% weight loss has been demonstrated to yield a reduction in ICP with accompanying resolution of papilledema. [75, 74, 6] Unfortunately, weight reduction generally proves to be a difficult task for these patients. [144] To formalize the process of weight reduction, referral to a dietitian is appropriate.

On initial diagnosis, a weight-reduction diet should be strongly recommended to all patients with IIH. Often, a formal weight-loss program is required. No activity restriction is required in managing IIH. In fact, exercise programs are strongly recommended in conjunction with the weight-reduction diet.

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Consultations

Diagnosis and long-term management of IIH requires lumbar puncture, which is typically performed by neurologists or internists, and careful monitoring of visual status (in particular, peripheral visual field and fundus photography). Vision examination and fundus photography are the domain of ophthalmologists, and neuro-ophthalmologists are especially expert in examining visual fields. A team approach is therefore needed for most, if not all, patients with IIH.

Neurosurgical consultation is required for ventriculoperitoneal shunting when patients are losing visual field and medical management does not arrest or reverse the process promptly (ie, within hours to days). Consultation with an orbital plastic surgeon is required for optic nerve sheath fenestration for the same clinical indications.

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Long-Term Monitoring

The frequency of the follow-up visits is determined by a number of factors, to include the following:

  • Initial visual function of the patient
  • Underlying disease causing increased ICP
  • Perceived compliance of the patient with medical therapy

Once the initial diagnosis has been established, investigations have been performed, and therapy has been initiated, the patient can be observed every 3-4 weeks.

If, however, the patient presents with a significant visual function deficit or marked papilledema, daily monitoring for 1 week is appropriate until some improvement and subsequent stability in visual function can be demonstrated. The clinician should be prepared to titrate the patient’s treatment to the status of visual function and should not hesitate to refer the patient for surgical treatment (optic nerve sheath fenestration or CSF diversion) if visual function does not stabilize.

During follow-up visits, the best-corrected visual acuity for distant and near vision, color vision (with pseudoisochromatic plates), static perimetry, and optic nerve appearance (including the status of spontaneous venous pulsations) should be recorded. Patients who do not perform well on static perimetry testing may be better monitored with kinetic perimetry testing.

Spontaneous pulsation of large retinal veins generally indicates a normal ICP. If the patient continues to remark on the persistence of a significant headache despite the presence of spontaneous venous pulsations, a source other than IIH for the headache should be considered.

In a clinical trial of acetazolamide as treatment for IIH (Idiopathic Intracranial Hypertension Treatment Trial at NORDIC Clinical Trials), risk factors for treatment failure included male sex, high-grade papilledema, low baseline visual acuity, and increased number of transient visual obscuration episodes per month. Among patients with these risk factors, the study group recommends closer monitoring while considering more aggressive treatment options. [145]

When a patient appears to have stabilized with respect to visual function and treatment, the frequency of follow-up visits can be extended to once every 2-4 months.

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Prevention

IIH has no known cause and no known methods of prevention. Among patients who have been diagnosed with IIH, the goal is to prevent further visual loss and comorbid symptoms, including headache. Progression of IIH is prevented through medical and surgical treatment, as well as diet and lifestyle modifications.

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