Hydrocephalus caused by a venous varix

Gamma knife radiosurgery cured hydrocephalus in non-hemorrhagic brain stem arteriovenous malformation

A 13-year-old boy, with a history of intermittent headache and transient diplopia, was found to have non-hemorrhagic cerebral arteriovenous malformation in the midbrain tegmental region associated with hydrocephalus. Gamma knife radiosurgery was performed at 16 Gy with 75% marginal dose. Posttreatment course was uneventful. Follow-up MR imaging at one year after the treatment revealed complete disappearance of the abnormal vascular flow voids. The size of each ventricle at the treatment and at one year after treatment were as follows; 60.2 cc and 20.9 cc in the lateral ventricles, 3.7 cc and 2.7 cc in the third ventricle. The hydrocephalus might be caused by obstructive mechanism but mostly by high venous pressure due to the shunt blood flow. The goal of treatment for hydrocephalus should be nidus obstruction and normalizing the vascular flow.

Obstructive Hydrocephalus Due to Unruptured Brain Arteriovenous Malformation: Demonstrating Transcranial Color Duplex Confirmation of Cerebral Venous Hemodynamic Alterations and Color Duplex Ultrasound Confirmation of Shunt Patency

Given the rarity of arteriovenous malformations of the brain (bAVMs) with concomitant obstructive hydrocephalus, few papers have commented on the resultant hydrodynamic perturbations. To date, no study has specifically investigated the effect of ventricular shunting on intracranial venous parameters as measured by transcranial color duplex ultrasound (TCCD). This study investigates whether TCCD and color duplex ultrasound are useful modalities to elucidate the physiological and hemodynamic changes in a patient with bAVM following ventricular shunting.

Using TCCD, this study demonstrates that preoperatively, there is a decrease in cerebral capacitance, manifesting in a decrease in cerebral inflow and reduced venous outflow. Following shunt insertion, intracranial compliance is increased, resulting in the dilatation of previously compressed capacitance vessels and restoration of venous compliance. Color duplex ultrasound (CDU) was a useful determinant of shunt patency in the neck.

We report the first TCCD assessment of hemodynamic changes of the intracranial circulation in a patient with bAVM following ventricular-peritoneal shunting. The results lend conceptual support of a pressure gradient change with high pressure that occurs in the veins as compared to the subarachnoid space.

Unruptured brain arteriovenous malformations and hydrocephalus: Case series and review of the literature

OBJECTIVE

Hydrocephalus is an uncommon presentation of unruptured brain arteriovenous malformations (AVMs). The goal of this case series and literature review is to present possible pathological mechanisms, management strategies and outcomes in patients with hydrocephalus due to unruptured AVMs.

METHODS

Three consecutive patients with hydrocephalus caused by unruptured AVMs as well as all cases previously reported in the literature were retrospectively reviewed to determine clinical symptoms, AVM location, nidus size, venous drainage, mechanism of hydrocephalus, level/cause of obstruction, and degree of hydrocephalus. Management of hydrocephalus, AVM treatment, and follow-up length were evaluated.

RESULTS

Of 350 patients unruptured AVMs, 3 presented with hydrocephalus (0.8%). In the literature review we found an additional 22 patients for a total of 25 cases. Eighteen patients had mechanical obstruction by the draining vein or the AVM nidus, usually at the level of the aqueduct (52%). Impaired cerebrospinal fluid resorption secondary to venous congestion led to hydrocephalus in 7 patients. Ten patients were treated for both the AVM and hydrocephalus, 13 patients underwent treatment of either hydrocephalus, or the AVM alone. Treatment of hydrocephalus, with or without associated treatment of the brain AVM, resulted in improvement of symptoms in 92% of patients. No rupture of the AVM was reported at follow-up.

CONCLUSIONS

The most common cause of hydrocephalus in unruptured brain AVMs is mechanical obstruction by the draining vein if it is located in a strategic position. Treatment of hydrocephalus alone or with associated treatment of the AVM is safe and effective.