Idiopathic Intracranial Hypertension (IIH) and Papilledema Grading
Title: Idiopathic Intracranial Hypertension (IIH) and Papilledema Grading
Author (s): Cole Swiston MSIV, Meagan Seay MD
Photographer: Danielle Princiotta, Becky Weeks
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Keywords/Main Subjects: papilledema, idiopathic intracranial hypertension, IIH, papilledema grading
Subcategory: Decreased Vision > Optic Neuropathy
Diagnosis: Idiopathic Intracranial Hypertension
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History of present illness: The patient is a 27-year-old woman, 5 ½ weeks pregnant, who presented to the neuro-ophthalmology clinic with a one-week history of peripheral vision loss in both eyes. She also experienced a left sided throbbing headache, pain behind her eye, and associated neck pain. She had nausea and vomiting during the same time frame. The patient originally presented to an urgent care facility 2 days prior, where the physician noted possible papilledema on exam and transferred her to the emergency room for evaluation. In the ER, the patient underwent lumbar puncture with an opening pressure of 56 cm H2O. CSF glucose, protein, and WBCs were within normal limits. She then underwent an MRI of her head which revealed no structural lesions, acute hemorrhage or infarct though this did show signs of elevated intracranial pressure including bilateral flattening of the posterior sclera and an “empty sella”. An MRV was also performed which showed no evidence of venous outflow obstruction. She was prescribed Diamox but did not begin taking the medication out of fear that it would harm her baby. She had no diplopia, flashers, or floaters in her vision, and had no history of blood clots, though she had 4 prior miscarriages. She was taking an 81 mg aspirin per the recommendation of her obstetric provider and had been on progesterone for the last three weeks during this pregnancy. The patient had no history of doxycycline, tetracycline, steroid, lithium, or Vitamin A derivative use. The last time she was on an oral contraceptive was eight years ago. She weighed 220 pounds and her weight was stable for the past year.
Neuro-ophthalmology examination: The patient’s visual acuity was 20/20 in each eye; her pupils were reactive without a relative afferent pupillary defect. Extraocular movements were full in both eyes, and visual fields performed by confrontation revealed partial inferonasal defect in the right eye. She performed Humphrey 24-2 Visual Field testing which revealed significant peripheral field loss in both eyes, the left eye more so than the right. She identified 11.5/15 Ishihara plates correctly in the right eye, 12.5/13 in the left eye. Slit lamp exam of the anterior segment was unremarkable, and fundus exam revealed grade 4 papilledema in both the right and left (Figure 1) with mild vascular tortuosity. OCT-RNFL confirmed bilateral optic disc swelling.
Clinical Course: The patient was diagnosed with papilledema secondary to idiopathic intracranial hypertension (IIH). After discussing with maternal fetal medicine, it was decided that the benefits of Diamox (Pregnancy Category C) outweighed the risk and the patient agreed to begin taking 500 mg twice a day, increasing to 1000 mg twice a day after two days. Given the severity of her papilledema and visual field defects, the patient was admitted for lumbar drain placement, at which time her opening pressure was 32 cm H2O. The lumbar drain was removed after four days in the hospital. On the day of drain removal, the patient was discharged and seen for follow-up in neuro-ophthalmology clinic. At that time, her visual acuity remained 20/20 in each eye. Papilledema was still present on fundus exam and by RNFL but improved in both eyes, and her objective visual field testing (Humphrey 24-2) showed significantly improved peripheral defects. The patient was continued on Diamox 1000 mg twice a day and was scheduled for close follow up for management of this new diagnosis of IIH.
Discussion: Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a condition of increased intracranial pressure (ICP) of unknown etiology. The disease primarily affects obese women of child bearing age, but other risk factors include obstructive sleep apnea, hypothyroidism, anemia, autoimmune conditions, and specific medication use. These medications include steroids, lithium, oral contraceptives, tetracyclines, and vitamin A derivatives. Common non-ocular symptoms include headache, nausea, vomiting, and pulsatile tinnitus (the sensation of blood flow and “whooshing” in the ears). Ocular symptoms are variable, but generally include visual disturbance, either transient episodes of visual loss with position changes or Valsalva maneuver, or peripheral field defects. Central vision is usually spared until very late in the disease. Diplopia may occur if increased intracranial pressure leads to a unilateral or bilateral sixth cranial nerve palsy.1 The main ocular sign of IIH and increased ICP is papilledema, characterized by bilateral optic disc swelling, elevation, blurring of the disc margins, and obscuration of optic disc blood vessels. The modified Frisén scale has been used to grade the severity of papilledema, summarized in Figure 2.2 If IIH is suspected based on presenting clinical symptoms, the first step in diagnosis is fundoscopy to assess for papilledema. Optical coherence tomography (OCT) can be used to quantify the optic disc swelling, and visual field testing is useful to assess for the degree of peripheral field loss. The next steps in diagnosis involve establishing objective evidence of increased ICP and ruling out other potential etiologies. This is accomplished with neuroimaging, usually an MRI, which excludes structural causes (i.e. mass lesions, hemorrhage, or obstructive hydrocephalus), and MRV to rule out venous outflow obstruction (i.e. dural sinus thrombosis). A lumbar puncture with opening pressures confirms elevated ICP and evaluates for alternative etiologies of elevated ICP, including infection, inflammation, or neoplasm.3 Based on these results, the modified Dandy criteria can be used to establish a diagnosis of IIH:
- Signs and symptoms of increased ICP
- Absence of localizing findings on the neurologic exam, other than sixth nerve palsy
- Awake and alert patient
- Normal neuroimaging findings except for signs of elevated ICP
- Increased CSF opening pressure (>25 cm H2O) with normal CSF composition
- No other cause of elevated ICP found4
The management of IIH consists of both medical and surgical/intervention options depending on the severity of papilledema and symptoms. The mainstay of treatment consists of weight reduction and medical management, usually with acetazolamide. Other diuretics including furosemide are sometimes used alone or in combination with acetazolamide. Interventional options range from large volume lumbar punctures and lumbar drains, which are more temporary measures, to lumboperitoneal (LP) or ventriculoperitoneal (VP) shunts, venous sinus stenting, and optic nerve sheath fenestrations.3
- Markey KA, Mollan SP, Jensen RH, Sinclair AJ. Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions. Lancet Neurol. 2016;15(1):78-91. doi:10.1016/S1474-4422(15)00298-7
- Diagnosis and Grading of Papilledema in Patients With Raised Intracranial Pressure Using Optical Coherence Tomography vs Clinical Expert Assessment Using a Clinical Staging Scale | Neuro-ophthalmology | JAMA Ophthalmology | JAMA Network. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/425762. Accessed September 15, 2018.
- Jensen RH, Radojicic A, Yri H. The diagnosis and management of idiopathic intracranial hypertension and the associated headache. Ther Adv Neurol Disord. 2016;9(4):317-326. doi:10.1177/1756285616635987
- Friedman DI, Liu GT, Digre KB. Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology. 2013;81(13):1159-1165. doi:10.1212/WNL.0b013e3182a55f17
Faculty Approval by: Griffin Jardine, MD
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Disclosure (Financial or other): The authors have no financial disclosures.