Fatal hydrocephalus in a patient with neurofibromatosis

A retrospective regional study of aqueduct stenosis and fourth ventricle outflow obstruction in the paediatric complex neurofibromatosis type 1 population; Aetiology, clinical presentation and management

OBJECTIVES

Aqueduct stenosis (AS) and fourth ventricle outflow obstruction are rare associations of neurofibromatosis type 1 (NF1), resulting in ventriculomegaly and hydrocephalus requiring surgical treatment. This study aims to identify the prevalence of AS and its patterns of clinical presentation, aetiology and treatment in the paediatric complex NF1 population.

PATIENTS AND METHODS

Patients with NF-1 aged 0-18 years were recruited from the Regional Genetic Family Register, following institutional review board approval. Magnetic resonance imaging data and clinical documents were reviewed with respect to clinical presentation, degree of ventriculomegaly, aetiological factors and management of AS and fourth ventricle outflow obstruction.

RESULTS

24 of the 233 paediatric patients seen within the NHS highly specialised service for complex NF1 were found to have AS or and fourth ventricle outflow obstruction. This included 13 males and 11 females with a mean age of 9 years 5 months (range 8 months - 17 years). The majority of patients with AS or fourth ventricle outflow obstruction presented with symptoms of raised intracranial pressure associated with ventriculomegaly and/or hydrocephalus (n = 18). However, in 25 % of patients, AS was an incidental finding on MRI and was observed both in the presence (n = 2) and absence (n = 4) of ventriculomegaly. In the majority of cases a single cause of AS was identified (n = 16), of which tectal plate thickening (n = 7) was most frequently observed. The remaining 8 patients had multiple causes of AS, in which tectal plate thickening (n = 7) and aqueductal webs (n = 5) were the most common observations. Surgery was performed on all patients with evidence of raised pressure (n = 8) by performing endoscopic third ventriculostomy (ETV) (n = 5) or ventriculoperitoneal (VP)-shunting (n = 3). Tectal plate thickening was most frequently observed in patients who underwent ETV (n = 3), followed by aqueductal web (n = 1) and T2-signal changes in the tectal plate (n = 1). Patients treated with VP-shunt had 4th ventricle outflow obstruction (n = 2) and a tectal plate tumour (n = 1).

CONCLUSION

This study identifies that AS is more prevalent amongst the paediatric complex NF-1 population than previously reported, occurring in 10 % of cases. Our findings demonstrate that AS is most commonly symptomatic in presentation but can be asymptomatic in 25 % of paediatric complex NF1 patients. In this population, AS can occur both in the presence and absence of ventriculomegaly and therefore requires careful monitoring for development of hydrocephalus. In this study, over one third of patients (9 of 24 patients) with AS eventually required treatment.

Brain gliomas, hydrocephalus and idiopathic aqueduct stenosis in children with neurofibromatosis type 1

PURPOSE

To evaluate the incidence and clinical importance of brain gliomas - optic pathway gliomas (OPGs) and especially gliomas outside the optic pathway (GOOP) for children with neurofibromatosis type 1 (NF1), additionally, to assess the causes of obstructive hydrocephalus in NF1 children with an emphasis on cases caused by idiopathic aqueduct stenosis.

SUBJECTS AND METHODS

We analysed data from 285 NF1 children followed up on our department from 1990 to 2010 by the same examination battery.

RESULTS

We have found OPGs in 77/285 (27%) children and GOOPs in 29/285 (10,2%) of NF1 children, of who 19 had OPG and GOOP together, so the total number of brain glioma was 87/285 (30,5%). GOOPs were significantly more often treated than OPGs (p > 0.01). OPGs contain clinically important subgroup of 14/285 (4.9%) spreading to hypothalamus. Spontaneous regression was documented in 4/285 (1.4%) gliomas and the same number of NF1 children died due to gliomas. Obstructive hydrocephalus was found in 22/285 (7.7%) patients and 14/22 cases were due to glioma. Idiopathic aqueduct stenosis caused hydrocephalus in 6/22 cases and was found in 2.1% of NF1 children. Two had other cause.

CONCLUSIONS

The total brain glioma number (OPGs and only GOOPs together) better reflected the overall brain tumour risk for NF1 children. However, GOOPs occur less frequently than OPGs, they are more clinically relevant. The obstructive hydrocephalus was severe and featuring frequent complication, especially those with GOOP. Idiopathic aqueduct stenosis shows an unpredictable cause of hydrocephalus in comparison with glioma and is another reason for careful neurologic follow up.