Familial idiopathic intracranial hypertension with variable phenotype

A systematic review of surgical and interventional radiology procedures for pediatric idiopathic intracranial hypertension

Background

Idiopathic intracranial hypertension (IIH) is defined as elevated intracranial pressure and consequent symptoms (mainly headache and visual deterioration) occurring in the absence of secondary causes. Surgical and interventional radiology procedures should be considered for refractory IIH and mainly include cerebrospinal fluid (CSF) diversion techniques, optic nerve sheath fenestration (ONSF), and venous sinus stenting (VSS). Our study aims to review the current literature on the application of these techniques in clinical practice.

Methods

A systematic literature review on the surgical and interventional radiology treatment of IIH was conducted, focusing on ONSF, VSS, and CSF diversion techniques. According to PRISMA guidelines, all reports published in PubMed in the last 30 years (1993-2023) were considered, and among 722 papers, 48 were included in the present study, resulting in a total study population of 454 children or adolescents (11 months-17 years old).

Results

Among 454 patients, 193 underwent an invasive approach, divided into CSF diversion (115/193), ONSF (65/193), VSS (11/193), cranial subtemporal decompression (8/193), and internal cranial expansion (9/193). Sixteen of the 193 patients (8%) required reintervention due to relapsing symptoms or surgical complications, particularly those who underwent CSF diversion. Furthermore, 9/115 required shunt revision due to shunt obstruction or malfunction. We extracted data on the outcome of each procedure: of the 193 patients, 71 experienced a positive outcome with symptom resolution or improvement, while 27 demonstrated a negative outcome.

Discussion and conclusions

Severe and refractory cases of IIH are eligible for invasive treatments. CSF diversion is the most frequently used technique, despite its high failure risk and need for reintervention. ONSF has shown good results in terms of outcome and safety, particularly in children with visual symptoms. VSS is the most recent approach, indicated in children with stenosis of the venous sinus. In our study population, VSS demonstrated good results in terms of symptom resolution and need for reintervention, but its use remains limited to a few centers.

Systematic Review Registration

https://www.crd.york.ac.uk/, PROSPERO (CRD42024504244).

Idiopathic intracranial hypertension in two twin sisters

Idiopathic intracranial hypertension (IIH) is a condition of unknown aetiology characterised by an increase in the intracranial pressure. Familial cases of IIH are rare and not well-understood. We present two monozygotic twins who developed IIH two years apart. The case involves two monozygotic female twins developing IIH in their 50s. They presented with a history of blurry vision and headaches. The diagnosis included the neurological, radiological and ophthalmological examination, excluding other causes. Both patients received treatment with acetazolamide, successfully resolving the papilloedema and restoring a normal visual field. This case highlights the occurrence of IIH among twins presenting at similar periods, emphasising the potential genetic influence. Clinicians should alert and educate the family regarding the risk factors and potential symptoms of this condition in the unlikely occurrence that other family members are affected.

Association between RS3763040 polymorphism of the AQP4 and idiopathic intracranial hypertension in a Spanish Caucasian population

Background

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure of unknown aetiology. Principal symptoms are headache, visual disturbances, and obesity, together with elevated intracranial pressure. Unspecified MRI, despite normal ventricle size, suggests alterations in the water flux cellular mediated by the brain water channel aquaporin-4 (AQP4). The association among IIH, cerebral spinal fluid malfunction, reabsorption, and functional or regulatory modifications of AQP4 is a hypothesis not confirmed.

Methods

Blood samples were collected from 72 Spanish Caucasian patients with IIH. A genetic association study was performed with bi-allelic SNPs rs1049305 and rs10244884 in AQ1 and rs2075575, rs3763043, and rs3763040 in AQ4. Genetic data were compared with 94 healthy Caucasian control. Statistics studies were assessed by Pearson's χ 2 tests for 2 × 2 (alleles) or 3 × 2 (genotypes) contingency tables. A P value < 0.05 was considered to be statistically significant.

Results

Statistically significant differences were found when comparing the results of the rs3763040 polymorphism of the AQ4 locus of IIH patients with controls, in genotypic frequencies (P = 0.0442) and allele frequencies (P = 0.0171). Furthermore, a statistically significant difference (P = 0.0207) was found in individuals carrying and not carrying the minor allele (GG + GA individuals vs GG homozygotes). No statistically significant differences were found when comparing allele and genotypic frequencies for SNPs rs1049305 and rs10244884 of AQ1 and rs2075575 and rs3763043 of AQ4.

Conclusions

The association of AQP4 and specifically of its polymorphic variant rs3763040 with IIH should be validated in other ethnic groups in order to assess more precisely the role of AQP4 in the etiopathogenesis of IIH.

Familial non-obese idiopathic intracranial hypertension

Purpose

To report a series of cases of non-obese familial idiopathic intracranial hypertension.

Observation

One father and three offsprings (two brothers and one sister) with idiopathic intracranial hypertension and different phenotypic presentations.

Conclusion and Importance

Familial idiopathic intracranial hypertension may underrecognized and may not be associated with obesity. Symptomatic family members may need to be screened for IIH in some cases.

Familial Idiopathic Intracranial Hypertension in Two Non-obese Chinese Sisters

Background: Familial idiopathic intracranial hypertension (FIIH) is a rare condition, the etiology of which is unclear.

Aims: To describe two non-obese Chinese sisters who met the criteria of FIIH and to analyze the clinical features and prognosis of FIIH.

Methods: The clinical course, treatment, and prognosis of these two patients were analyzed retrospectively. Meanwhile, all the literature of familial IIH (FIIH) was reviewed.

Results: These two sisters presented with headaches and visual impairment in their mid-thirties. Magnetic resonance imaging (MRI) of the brain was unremarkable except for partial empty sella. No comorbidities or defined causes were detected. Headaches were partially relieved by dehydrated medicine, whereas the visual impairment persisted.

Conclusion: In cases where patients present with headaches, empty sella are found on an MRI, and there is visual impairment with or without papilla edema, intracranial hypertension should be excluded. Furthermore, we should pay more attention to the relatives of those patients with increased intracranial hypertension.

Familial Intracranial Hypertension in 2 Brothers With PTEN Mutation: Expansion of the Phenotypic Spectrum

PTEN (Phosphatase and Tensin Homolog on chromosome TEN) encodes a vastly expressed tumor suppressor protein that antagonizes the PI3 K signaling pathway and alters the MTOR pathway. Mutations in PTEN have been described in association with a number of syndromes including PTEN hamartoma-tumor syndrome, macrocephaly/autism, and juvenile polyposis of infancy. Although there is a wide variability in the clinical and radiologic presentations of PTEN-related phenotypes, the most consistent features include macrocephaly and increased tumorigenesis. Intracranial hypertension may be idiopathic or secondary to multiple etiologies. We describe 2 siblings harboring a PTEN mutation who presented with macrocephaly and intracranial hypertension. Repeat brain MRIs were normal in both. Acetazolamide treatment normalized intracranial pressure, but several trials of medication tapering led to recurrence of intracranial hypertension symptoms. The clinical presentation of our patients expands the PTEN-related phenotypes. We discuss the possible pathophysiology in view of PTEN function.

Pediatric Intracranial Hypertension: a Current Literature Review

PURPOSE OF REVIEW

The purpose of this review is to provide an update on pediatric intracranial hypertension.

RECENT FINDINGS

The annual pediatric incidence is estimated at 0.63 per 100,000 in the USA and 0.71 per 100,000 in Britain. The Idiopathic Intracranial Hypertension Treatment Trial found improvement in visual fields, optical coherence tomography, Frisen grade, and quality of life with acetazolamide compared to placebo in adult patients, and these findings have been translated to the pediatric population. Pediatric intracranial hypertension is a disorder that if left untreated can lead to poor quality of life and morbidity. There are no current treatment studies in pediatrics, but adult data suggests acetazolamide remains an acceptable first-line medication.

Pediatric Intracranial Hypertension

Primary (idiopathic) intracranial hypertension has been considered to be a rare entity, but with no precise estimates of the pediatric incidence in the United States. There have been attempts to revise the criteria over the years and adapt the adult criteria for use in pediatrics. The clinical presentation varies with age, and symptoms tending to be less obvious in younger individuals. In the prepubertal population, incidentally discovered optic disc edema is relatively common. By far the most consistent symptom is headache; other symptoms include nausea, vomiting tinnitus, and diplopia. Treatment mainstays include weight loss when appropriate and acetazolamide. Furosemide may exhibit a synergistic benefit when used in conjunction with acetazolamide. Surgical interventions are required relatively infrequently, but include optic nerve sheath fenestration and cerebrospinal fluid shunting. Pain and permanent vision loss are the two major complications of this disorder and these manifestations justify aggressive treatment. Once intracranial hypertension has resolved, up to two thirds of patients develop a new or chronic headache type that is different from their initial presenting headache.

Manifestations of Pediatric Intracranial Hypertension From the Intracranial Hypertension Registry

OBJECTIVE

The purpose of this study was to examine the presenting symptoms, demographics, and interventions in pediatric patients enrolled in the Intracranial Hypertension Registry.

METHODS

We analyzed confirmed intracranial hypertension patients ≤18 years at the time of initial diagnosis who were enrolled in the registry.

RESULTS

A total of 203 patients met the criteria for inclusion; 142 (70%) were considered primary intracranial hypertension. Females made up 72.5% (103 of 142) and 75.8% (47 of 61) in the primary intracranial hypertension and secondary intracranial hypertension groups, respectively. There were no clinically significant differences in age, body mass index, or opening pressure between the primary intracranial hypertension and secondary intracranial hypertension groups. Symptoms most often reported were headache and blurred vision. Bilateral optic disc edema occurred in 89.3% of primary intracranial hypertension and 78.7% of secondary intracranial hypertension patients. When divided into pre- and postpubertal status, 32.5% of patients were classified prepubertal; 77.3% of these had primary intracranial hypertension. This resulted in a female to male ratio of 1:1.04 for prepubertal and 6:1 for postpubertal primary intracranial hypertension patients. The body mass index was significantly higher in the postpubertal primary intracranial hypertension group (P = 0.0014). There was no significant difference in opening pressure.

CONCLUSIONS

The common symptoms of intracranial hypertension, including headache, optic disc edema, and vision changes, occurred with similar frequencies in our cohort to those reported in the literature. In separate subanalyses, we found significantly higher rates of obesity in postpubertal females with primary intracranial hypertension. The female-to-male ratios in the postpubertal primary intracranial hypertension and secondary intracranial hypertension groups were higher than reported in the literature.

[Idiopathic intracranial hypertension and spontaneous cerebrospinal fluid fistula. Usefulness of intracranial pressure monitoring]

Spontaneous cerebrospinal fluid (CSF) fistulas are rather common in daily practice. The aim of the surgical treatment is closure of the leak, but recurrences are quite frequent. The association between spontaneous CSF fistulas and idiopathic intracranial hypertension (IIH) is not uncommon, and this is probably the cause of the low rate of success of the surgical treatment. Symptoms of IIH associated with spontaneous CSF fistula are atypical, and diagnosis is often missed. Continuous intracranial pressure monitoring is very useful in the diagnosis of chronic IIH and in patients with spontaneous CSF fistula, as it helps in making decisions on the treatment of these patients.

Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions

Idiopathic intracranial hypertension is a disorder characterised by raised intracranial pressure that predominantly affects young, obese women. Pathogenesis has not been fully elucidated, but several causal factors have been proposed. Symptoms can include headaches, visual loss, pulsatile tinnitus, and back and neck pain, but the clinical presentation is highly variable. Although few studies have been done to support evidence-based management, several recent advances have the potential to enhance understanding of the causes of the disease and to guide treatment decisions. Investigators of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) reported beneficial effects of acetazolamide in patients with mild visual loss. Studies have also established weight loss as an effective disease-modifying treatment, and further clinical trials to investigate new treatments are underway. The incidence of idiopathic intracranial hypertension is expected to increase as rates of obesity increase; efforts to reduce diagnostic delays and identify new, effective approaches to treatment will be key to meeting the needs of a growing number of patients.

Is the brain water channel aquaporin-4 a pathogenetic factor in idiopathic intracranial hypertension? Results from a combined clinical and genetic study in a Norwegian cohort

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure of unknown aetiology. Patients with IIH usually suffer from headache and visual disturbances. High intracranial pressure despite normal ventricle size and negative MRI indicate perturbed water flux across cellular membranes, which is provided by the brain water channel aquaporin-4 (AQP4). IIH could be associated with malfunctioning intracerebral water homeostasis and cerebrospinal fluid (CSF) reabsorption based on functional or regulatory alterations of AQP4.

METHODS

Clinical data, blood and CSF samples were collected from 28 patients with IIH. Clinical characteristics were assessed, and a genetic association study was performed by sequencing the AQP4 gene on chromosome 18. Genetic data were compared with 52 healthy controls and matched by age, sex and ethnicity. Chi-square test and linear discriminant analysis (LDA) were used in the search of a genotype-phenotype association.

RESULTS

While the majority of patients responded to medical treatment, four required shunt application. All, except one, had a good visual outcome. The 24 AQP4 gene SNPs showed no association with IIH. Full cross-validation of the LDA modelling resulted in only 55.1% correct classification of the cases and controls, with a corresponding estimated p-value 0.37.

CONCLUSIONS

Our genetic case-control study did not indicate an association between AQP4 gene variants and IIH. However, the theory of an etiopathogenic link between IIH and AQP4 is tempting, and discussed in this article. Association studies with large sample size are difficult to perform owing is the rarity of the condition.