Aqueductal stenosis presenting as isolated tremor: case report and review of the literature

How growing tumour impacts intracranial pressure and deformation mechanics of brain

Brain is an actuator for control and coordination. When a pathology arises in cranium, it may leave a degenerative, disfiguring and destabilizing impact on brain physiology. However, the leading consequences of the same may vary from case to case. Tumour, in this context, is a special type of pathology which deforms brain parenchyma permanently. From translational perspective, deformation mechanics and pressures, specifically the intracranial cerebral pressure (ICP) in a tumour-housed brain, have not been addressed holistically in literature. This is an important area to investigate in neuropathy prognosis. To address this, we aim to solve the pressure mystery in a tumour-based brain in this study and present a fairly workable methodology. Using image-based finite-element modelling, we reconstruct a tumour-based brain and probe resulting deformations and pressures (ICP). Tumour is grown by dilating the voxel region by 16 and 30 mm uniformly. Cumulatively three cases are studied including an existing stage of the tumour. Pressures of cerebrospinal fluid due to its flow inside the ventricle region are also provided to make the model anatomically realistic. Comparison of obtained results unequivocally shows that as the tumour region increases its area and size, deformation pattern changes extensively and spreads throughout the brain volume with a greater concentration in tumour vicinity. Second, we conclude that ICP pressures inside the cranium do increase substantially; however, they still remain under the normal values (15 mmHg). In the end, a correlation relationship of ICP mechanics and tumour is addressed. From a diagnostic purpose, this result also explains why generally a tumour in its initial stage does not show symptoms because the required ICP threshold has not been crossed. We finally conclude that even at low ICP values, substantial deformation progression inside the cranium is possible. This may result in plastic deformation, midline shift etc. in the brain.

Clinical analysis of aqueductal stenosis in patients with hydrocephalus in a Kenyan setting

Introduction

Aqueductal stenosis is the commonest cause of congenital hydrocephalus. The scope of this paper is to highlight the disease burden of hydrocephalus attributed to aqueductal stenosis which still remains unknown in our setting.

Methods

In a descriptive cross-sectional study, 258 records of patients diagnosed with hydrocephalus were analyzed after ethical approval from Kenyatta National Hospital- University of Nairobi (KNH-UON) ethics and research committee from January 2010 to May 2016. Patients with a diagnosis of hydrocephalus due to aqueductal stenosis were included in this study. Patients age, sex, mode of delivery, associated comorbidities, presenting complaints, neurosurgical intervention performed, Kafarnosky score were recorded. Data were divided into 2 sets based on the patient's age i.e. whether < 1 year or > 12 years. Data were recorded on google data collection form and analyzed using Google spreadsheets.

Results

Out of 258 cases of hydrocephalus, 52 had aqueductal stenosis. Male to female sex ratio for this condition was 3:2. There were 25 cases < 1year and 27 cases > 12 years old who were diagnosed with hydrocephalus due to aqueductal stenosis. Associated conditions were bilateral congenital talipes equinovarus, spina bifida, Arnold Chairi malformations, meningitis and HIV. The presenting complaints differed according to the age groups. Neurosurgical interventions included Endoscopic Third Ventriculostomy (ETV) in 21 cases, insertion of Ventriculoperitoneal (VP) shunt and ETV were done in 3 cases while the rest had only insertion of VP shunt. The Kafanosky score improve from < 50 pre-op to 19 cases achieving a score of 100, six months post-op.

Conclusion

Aqueductal stenosis contributes a significant burden of morbidity in patients with hydrocephalus. Clinical presentation differs according to patients age. Accurate diagnosis and treatment remain a cardinal to improving patient outcome.

Hidden aqueductal stenosis associated to bilateral idiopathic foramina of Monro stenosis mimicking a Chiari I malformation? Case report

A 39-year old man came to our outpatient clinic with long history of unspecific symptoms and signs. Cerebral MRI showed herniation of the cerebellar tonsils of more than 1 cm below the foramen magnum and a triventricular hydrocephalus. A diagnosis of Chiari I malformation was retained. After an osteo-dural decompression of the posterior fossa, post-operative MRI revealed an aqueductal stenosis with triventricular hydrocephalus. An endoscopic-third- ventriculostomy showed an idiopathic stenosis of the right foramen of Monro. Residual symptoms and persistence of biventricular hydrocephalus justified a ventriculo-peritoneal shunt. Aqueductal and foramina of Monro stenosis can mimick a Chiari I malformation.