No brain lesion

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Obtain lumbar puncture with opening pressure (Class II)

Workup

IIH is definitively diagnosed when there are signs and symptoms of increased ICP with normal neuroimaging, normal CSF composition, elevated LP opening pressure (≥28 cm H2O in children; ≥25 cm H2O if the child is not obese or sedated), and a normal neurologic examination except for potential cranial nerve abnormalities.$^{45}$ It must be noted that papilledema and cranial nerve defects are not always present.$^{43}$ If this is the case, an elevated ICP with at least 3 of the following neuroimaging criteria must be met for diagnosis: (1) an empty sella, (2) flattening of the posterior aspect of the globe, (3) distention of the perioptic subarachnoid space with or without a tortuous optic nerve, and (4) transverse venous sinus stenosis.$^{45}$ Magnetic resonance venography or CT venography may be obtained to help distinguish IIH from elevated ICP caused by CVT.$^{60}$ Early consultation with ophthalmology and neurology is essential.

Initial Treatments

The goal of treatment in IIH is to prevent vision loss and to alleviate symptoms of elevated ICP. Some patients with mild symptoms and findings may need no treatment acutely in the ED. For patients with more severe disease, therapeutic LPs and IV acetazolamide may be used. There is currently no evidence-based guideline that recommends how much CSF should be drained or what the optimal closing pressure should be in pediatric patients.$^{63}$ Acetazolamide is a carbonic anhydrase inhibitor that decreases the production of CSF and thus helps to prevent the buildup of CSF leading to increased ICP. Second-line treatments include furosemide, topiramate, corticosteroids, and surgical intervention (shunt). These second-line therapies are likely to be guided by neurology, ophthalmology, and/or neurosurgery, rather than being initiated unilaterally by emergency clinicians.$^{44,45,64}$