Tuesday, March 28, 2017

Vein of Galen malformation

The pregnancy with this female neonate was complicated by a diagnosis of a large intracranial arteriovenous malformation in the fetus, as well as fetal heart failure with a dilated right atrium and right ventricle and cardiomegaly on fetal echocardiogram. There was also mildly decreased cardiac contractility, and a dilated superior vena cava. Fetal ultrasound examinations did not show evidence of hydrops, and demonstrated normal growth.

A planned cesarean section delivery was performed due to the intracranial arteriovenous malformation. The membranes were ruptured at delivery. The amniotic fluid was normal in quantity and was clear. The neonate was in vertex presentation. She was then intubated for a preplanned angiogram. Her  birth weight was 2060 grams.

There was mild dilatation of both lateral and 3rd ventricles. The 4th ventricle was normal in size. Findings consistent with a large (slightly greater than 2 cm) vein of Galen aneurysm were noted.
MR angiography as well as routine sequences demonstrated that there were both anterior and posterior circulation feeding arteries. There are abnormally enlarged basilar and vertebral arteries as well as the posterior cerebral arteries and branches. Both posterior communicating arteries are markedly enlarged as are the anterior communicating arteries and anterior cerebral arteries and their branches. Middle cerebral arteries appear normal in caliber. The abnormally enlarged vein of Galen drains through an enlarged straight sinus and torcula into bilateral large transverse sinuses and sigmoid sinuses. Jugular veins are also seen to be abnormally enlarged.

The posterior fossa had a normal appearance. The supratentorial brain, however, appeared markedly atrophic with prominent extra-axial fluid spaces in a symmetric pattern. There was a diminished quantity of white matter. Brain parenchyma had an  abnormally heterogeneous signal intensity.

A postnasal echocardiogram obtained on the neonate demonstrated a widely patent aortic arch with significant diastolic reversal. There was a stretched foramen ovale with right-to-left shunting. There was aneurysmal right-to-left bowing of the atrial septum. The right ventricle was markedly enlarged with reduced systolic function. There was mild right ventricular hypertrophy. There was mild-to-moderate tricuspid valve insufficiency. There was prominent flow in the right superior vena cava and innominate vein.

She was transitioned from amplitude integrated EEG, which showed intermittent seizures, to conventional EEG and ongoing frequent focal electrographic seizures were noted. These were much more frequent from the left hemisphere than the right hemisphere.  These were typically brief, and lasted less than 1 minute.  Some of the longer ones lasted up to 2 minutes before resolving spontaneously.  Again, the patient probably had 2 to 3 (sometimes more) electrographic seizures per hour during this recording.  With some electrographic seizures, she would desaturate, but not with everyone.  Otherwise, there was no clinical correlate.  Age-anticipated markers of state modulation and sleep architecture were not appreciated.  This was a diffusely suppressed record (voltages of 10 microvolts or less), consistent with diffuse cerebral dysfunction.

The seizures were refractory to treatment with phenobarbital, fosphenytoin and levetiracetam.  Ultimately, the parents decided to pursue palliative care and limitation of support.  Shortly thereafter, the patient passed away.

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