Intracranial pressure directly predicts headache morbidity in idiopathic intracranial hypertension.

OBJECTIVE: Headache is the predominant disabler in idiopathic intracranial hypertension (IIH). The aim was to characterise headache and investigate the association with intracranial pressure. METHODS: IIH:WT was a randomised controlled parallel group multicentre trial in the United Kingdom investigating weight management methods in IIH. Participants with active IIH (evidenced by papilloedema) and a body mass index (BMI) ≥35 kg/m2 were recruited. At baseline, 12 months and 24 months headache characteristics and quality of life outcome measures were collected and lumbar puncture measurements were performed. RESULTS: Sixty-six women with active IIH were included with a mean age of 32.0 years (SD ± 7.8), and mean body mass index of 43.9 ± 7.0 kg/m2. The headache phenotype was migraine-like in 90%. Headache severity correlated with ICP at baseline (r = 0.285; p = 0.024); change in headache severity and monthly headache days correlated with change in ICP at 12 months (r = 0.454, p = 0.001 and r = 0.419, p = 0.002 respectively). Cutaneous allodynia was significantly correlated with ICP at 12 months. (r = 0.479, p < 0.001). Boot strap analysis noted a positive association between ICP at 12 and 24 months and enabled prediction of both change in headache severity and monthly headache days. ICP was associated with significant improvements in quality of life (SF-36). CONCLUSIONS: We demonstrate a positive relationship between ICP and headache and cutaneous allodynia, which has not been previously reported in IIH. Those with the greatest reduction in ICP over 12 months had the greatest reduction in headache frequency and severity; this was associated with improvement of quality of life measures. TRIAL REGISTRATION: This work provides Class IIa evidence of the association of raised intracranial pressure and headache. ClinicalTrials.gov number, NCT02124486 .

Cerebrospinal fluid opening pressure: The effect of body mass index and body composition.

OBJECTIVES: Idiopathic intracranial hypertension (IIH) is strongly related to obesity. The relationship between intracranial pressure, body mass index (BMI), percentage body fat and distribution of body fat in non-IIH patients remains less clear. The aim of this study was to examine the relationship between intracranial pressure and body type in non-IIH patients. PATIENTS AND METHODS: Lumbar puncture manometry was used to measure cerebrospinal fluid opening pressure (CSFOP). BMI, in addition to neck, waist and hip circumferences were calculated. Air displacement plethysmography (BODPOD) was used to assess body composition. RESULTS: Data was collected from 100 subjects. 11 subjects with conditions known to cause raised intracranial pressure were excluded from analysis. According to Pearson correlation factors displaying a significant relationship with CSFOP included: BMI (R = 0.635, p < 0.0001); waist circumference (R = 0.498, p < 0.0001), hip circumference (R = 0.513, p < 0.0001) and percentage body fat (R = 0.435, p < 0.001). Multivariate analysis indicated that BMI was the only independent factor which predicted CSFOP. Sub-analysis according to gender indicated that BMI was predictive in females and percentage body fat was predictive in males. We did not identify any differences in BMI, percentage body fat or distribution of body fat in 7 IIH patients and 7 wt-matched non-IIH patients. CONCLUSION: BMI and percentage body fat both positively correlated with CSFOP, but BMI was more predictive in women and percentage body fat was more predictive in men. We did not find a relationship between distribution of body fat and CSFOP.

Idiopathic intracranial hypertension.

BACKGROUND: Idiopathic intracranial hypertension or pseudotumour cerebri is primarily a disorder of young obese women characterised by symptoms and signs associated with raised intracranial pressure in the absence of a space-occupying lesion or other identifiable cause. SUMMARY: The overall incidence of idiopathic intracranial hypertension is approximately two per 100,000, but is considerably higher among obese individuals and, given the global obesity epidemic, is likely to rise further. The pathophysiology of this condition is poorly understood, but most theories focus on the presence of intracranial venous hypertension and/or increased cerebrospinal fluid outflow resistance and how this relates to obesity. A lack of randomised clinical trials has resulted in unsatisfactory treatment guidelines and although weight loss is important, especially when used in conjunction with drugs that reduce cerebrospinal fluid production, resistant cases remain difficult to manage and patients invariably undergo neurosurgical shunting procedures. The use of transverse cerebral sinus stenting remains contentious and long-term benefits are yet to be determined. CONCLUSION: An understanding of the clinical features, diagnostic work-up and therapeutic options available for patients with idiopathic intracranial hypertension is important both for neurologists and ophthalmologists as visual loss maybe permanent if untreated.