Headaches and visual disturbances are the most obvious symptoms in IIH and the main reason why IIH patients present to the neurologist or the ophthalmologist. In our study, more than 75% of the participants reported visual disturbances and headaches severely impacting their daily lives. In addition to these cardinal symptoms of IIH, almost 50% of the participants reported relevant sleep disturbances and depression. Since sleep disorders and depression are not described as being related to the disease, they might be insufficiently addressed in current clinical practice.
Marcus et al. considered sleep disturbances as a key risk factor for IIH and suggested that nocturnal hypercapnia is responsible for increased intracranial pressure and secondary papilledema [16]. Although obstructive sleep apnea syndrome (OSAS) is often described in IIH patients, it is not clear whether this is induced by IIH or due to the co-occurrence of obesity in IIH patients, which is a known risk factor for OSAS [17]. Daniels et al. showed a correlation between BMI and the risk of IIH [18], furthermore Kesler at al. demonstrated that increased weight is associated with recurrence of the disease [19]. In line with these findings, our survey revealed a strong interaction between a higher BMI and sleep disturbances. In addition, the study showed that in many cases, the onset of the disease was preceded by weight-gain.
Depression has an estimated lifetime prevalence of 15-20% and severe depression has been identified in 37% of IIH patients [20, 21]. An even higher rate of depression (56%) was (self-) reported in our survey, with one third of the participants under an antidepressant medication. Important of note, topiramate (which 86 of the participants reported among their medication) may worsen depression and induce cognitive decline [22]. While the correlation of obesity and depression has been recognized earlier [23], depression also correlates with headaches and sleep disturbances. In our survey obesity, severe impact of headache in daily life and sleep disturbances were confirmed as independent predictors for depression.
60% of the participants complained about a lack of information on IIH and 80% claimed that physicians had insufficient knowledge about the disease. This suggests that physicians focus too much on LP OP and tend to perform procedures rather than consider psychological aspects. Repeated LP was perceived uncomfortable by many and post-lumbar puncture headaches may be understimated in IIH patients. Indeed, in a recent study by Yiangou et al., the authors pointed out that LP should only be performed in severe headaches or to prevent visual loss [24].
Depression and sleep disturbances can impair the ability to treat IIH and may particularly hamper weight loss. Weight gain and lack of exercise in turn promote the development of headache, sleep disturbances and depression. Patients thus find themselves in a vicious circle, with symptoms driving each other; an effect that may be exacerbated by the lockdown measures during the current pandemic [25]. We therefore strongly recommend the use of standardized questionnaires to assess patients' symptoms, followed by multidisciplinary diagnosis and treatment, including referral to psychologists, psychiatrists and sleep physicians.
There are some limitations to our study that should be noted. First there was no external verification of the IIH diagnosis other than self-report and the same applies to all medical data, including symptoms and LP values. Second, the survey contained open questions, representing a subjective and individual view on the collected parameters. Further, there might be a selection bias, as patients with a higher level of suffering might be more likely to participate in the survey.