Diagnosis of idiopathic intracranial hypertension - the importance of excluding secondary causes: A systematic review

Background: Idiopathic intracranial hypertension is characterized by increased intracranial pressure without any pathological findings on neuroimaging, except for signs of high intracranial pressure. Before diagnosing idiopathic intracranial hypertension secondary causes of increased intracranial pressure should be excluded. Objective: to characterize the phenotype of patients with secondary intracranial hypertension and to identify possible risk factors for secondary intracranial hypertension. Methods: We have systematically searched the PubMed database. The publications were analyzed according to the patient phenotype, age, gender, comorbidities, body mass index/weight status, and additional medication. The results are summarized in four categories: medication, infection, hormonal induced intracranial hypertension and miscellaneous groups of diseases related to sIH. Results: We identified 105 eligible papers which included 272 cases. There were 49.6% pediatric cases. Among the adult group,70.9% were women. A total of 40.4% of all cases were obese or overweight, 27% among adults and 13.4% among pediatric cases. Increased BMI and recent weight gain, anemia, renal diseases and hypertension were the most frequent comorbidities related to sIH. Conclusion: Among sIH patients, 40.4% were obese or overweight; two thirds were women. We recommend that even patients with a typical IIH phenotype should be screened for secondary causes.