Authors: Caberry W. Yu, Ethan Waisberg, Jason M. Kwok, Jonathan A. Micieli.

Disclosure Block: C.W. Yu: None. E. Waisberg: None. J.M. Kwok: None. J.A. Micieli: None.

Abstract Body:

Purpose: Idiopathic intracranial hypertension (IIH) is a multifactorial condition typically seen in young, obese women. While anemia is recognized as a risk factor for IIH from case reports, their relationship remains controversial as several comparative studies showed no significant association. The goal of this study was to describe cases with a fulminant IIH presentation and significant anemia, and systematically review the literature on the relationship between IIH and anemia.
Study Design: Retrospective study of consecutive patients with IIH and anemia seen at tertiary neuro-ophthalmology clinics at the University of Toronto between 2018 and 2020; meta-analysis of prevalence and association between anemia and IIH.
Methods: Patients were included in the study if they had a fulminant IIH presentation and met the inclusion criteria of i) IIH according to modified Dandy criteria, ii) hemoglobin <80g/L, and iii) less than 4 weeks between symptom onset and severe visual loss. The systematic review followed PRISMA guidelines. MEDLINE, EMBASE, Cochrane Library, and grey literature were searched to September 2020. Primary studies on patients with diagnoses of anemia of any kind and IIH were included.
Results: Four female patients had a fulminant course of IIH associated with severe anemia. Frisen grade 3 to 4 with severe cotton wool spots around the nerve, and opening pressure was >55 centimetre of water for all. The etiology of anemia was iron-deficiency (n=4). The average hemoglobin was 71g/L (range 63 to 78). All patients had resolution of papilledema and symptoms within 3 months using a combination of acetazolamide and intravenous or oral iron. Optic nerve sheath fenestration was used for one patient.
From literature, 74 cases and 5 comparative studies were included. Pooled incidence of anemia among IIH patients was 195/1073 (18.2%). IIH patients (n=747) had a significantly higher prevalence of anemia compared to controls (n=230,981) (RR 1.44 [95% CI 1.08, 1.92]). Patients were 63.5% female and had a mean age of 20.1 years. Overall, 53% of patients showed improvement or resolution with anemia treatment only, 8% with intracranial pressure-lowering therapy only, and 29% with a combination.
Conclusions: Anemia was 44% more common in IIH patients compared to control patients. A complete blood count should be ordered in all cases of papilledema, particularly in atypical presentations or in treatment-refractory IIH. Our 4 cases and the literature suggest a direct relationship between anemia and IIH, with symptoms resolving in half of all cases with anemia treatment only without acetazolamide or surgery.