The idiopathic intracranial hypertension prospective cohort study: evaluation of prognostic factors and outcomes

Abstract

Background There are limited longitudinal data evaluating outcomes in idiopathic intracranial hypertension (IIH). We aimed to evaluate the long-term outcomes in a real-world cohort of patients with IIH and sought to establish the prognostic factors. Methods A longitudinal prospective cohort study was conducted over 9 years (2012–2021). Data included demographics and disease status. All consenting patients with IIH were recruited. Visual outcomes included visual acuity, Humphrey visual field and optical coherence tomography (OCT) imaging measurements. Headache frequency, severity, and impact were noted. We analysed the key variables impacting visual and headache outcomes. Results The cohort contained 490 patients with a confirmed IIH diagnosis. 98% were female with a mean body mass index (BMI) of 38 kg/m2. Those with the highest OCT retinal nerve fibre layer had the worst visual outcomes. We noted a delayed decline, in the visual field and OCT ganglion cell layer after 12 months. In the medically managed cohort (n = 426), we found that disease duration and change in BMI had the greatest influence on visual outcomes. There was a high burden of headache, with a daily headache at presentation and prior migraine history influencing long-term headache prognosis. Conclusions There is a delayed decline in visual outcomes in those with the most severe papilloedema. Disease duration and change in BMI were the key visual prognostic factors, therefore those with the more acute disease may require closer monitoring. Improving prognosis in IIH should focus on the potentially modifiable factor of weight management.

Modelling idiopathic intracranial hypertension in rats: contributions of high fat diet and testosterone to intracranial pressure and cerebrospinal fluid production

“…The observed ICP of the HFD-fed rats was approximately 65% higher than that of the control animals, which aligns with the earlier reports on such rat models [35, 70]. However, this ICP elevation is lower than the (minimum) doubling of the mean lumbar opening pressure observed in IIH patients compared to healthy control subjects [72]. Therefore, although these overweight rats appear to recapitulate the cardinal phenotype of IIH symptomatology, elevated ICP, this model cannot mimic the magnitude of ICP change seen in IIH.…”

“…However, when mimicking the elevated testosterone environment, as observed in patients with IIH, we observed CSF hypersecretion in the experimental rats. Synergic effects of obesity and hyperandrogenism may thus, if sustained for prolonged time and potentially associated with other IIH-promoting factors [28, 59, 72], provide a mechanistic coupling to the elevated ICP observed in the IIH patients. Future in vivo animal studies combining obesity and androgen excess may reveal further pieces of the IIH etiology, and androgen blockade, in the context of obesity, may elucidate avenues for therapeutic targeting in IIH.…”

Disease Course and Long-term Outcomes in Pregnant Women With Idiopathic Intracranial Hypertension

“…42,43 These data show marked variability in headache outcomes, which reflects what has been found in the IIH population as a whole. 37 Headache frequency was high at baseline (Figure 3) in groups 2, 3, and 4 with either mild improvement or stability over time (Table 2). This plateau was also seen for migraine-like headache frequency, headache severity, and HIT-6 score and highlights the need for new treatment options for the management of persistent post-IIH headache, which has been called for by patients and physicians.…”

“…In group 1, we also noted a trend toward declining PMD and worsening papilledema measured by OCT imaging (Figure 2). We have previously shown that acute IIH has more severe papilledema than chronic IIH, 37 so there is the possibility that newly diagnosed IIH in pregnancy would have more severe papilledema than those with more chronic IIH who become pregnant. Those patients with IIH diagnosed in pregnancy (group 1) were interesting in that papilledema worsened during the 12 months following diagnosis.…”

“…This contrasts with patients with newly diagnosed IIH who are not pregnant who gradually improve over time. 37 This poses a significant treatment dilemma as in pregnancy there are more limited treatment options, including the potential teratogenicity of carbonic anhydrase inhibitors, 12 although 1 study showed the safety of acetazolamide in pregnancy. 38 The mechanism to explain why new-onset IIH may deteriorate during pregnancy is not known.…”