Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 5, 2010, pp. 797-799

Neurology India, Vol. 58, No. 5, September-October, 2010, pp. 797-799

Letter to Editor

Stroke-like episodes in Sturge-Weber syndrome

Neeraj N Baheti¹, Syam Krishnan¹, Bejoy Thomas², Chandrasekharan Kesavadas², Ashalatha Radhakrishnan¹

¹ Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
² Department of Neuroimaging and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India

Correspondence Address:
Syam Krishnan
Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala
India
drsyam@sctimst.ac.in

Date of Acceptance: 22-Jul-2010

Code Number: ni10224

PMID: 21045522

DOI: 10.4103/0028-3886.72185

Sir,

Sturge-Weber syndrome (SWS) is a rare sporadic neurocutaneous syndrome, characterized by leptomeningeal and cutaneous angiomas of the face, typically in the ophthalmic and maxillary distributions of the trigeminal nerve. ^[1] Transient stroke-like episodes are a rare presentation in SWS. The occurrence of such episodes, if unaware of, poses a diagnostic challenge to the clinician.

A 6-year-old girl was noted to have a port wine nevus in V1 and V2 division of bilateral trigeminal nerves at birth. Psychomotor development was normal. At the age of three years, the child had brief seizures, characterized by deviation of head and eyes to the left with clonic jerking of left upper and lower limbs. She was initiated on carbamazepine with no further seizures. She presented to us with sudden-onset holocranial persistent headache of four days' duration and acute onset left sided weakness of six hours duration prior to presentation. Examination showed left hemiparesis. Computerized tomography scan head (done at the age of 3 years) showed calcification in right subcortical parietal white matter. Brain magnetic resonance (MR) imaging done during this admission showed mild gyral edema over the right temporo-occipital region and bilateral (right>left) posterior cerebral hemispheres pial angiomatosis [Figure - 1]. Contrast-enhanced MR angiogram and digital subtraction angiogram showed no evidence of arterial or venous thrombosis. Electroencephalogram (EEG) showed excess of slow wave-activity (1-1.5 Hz) over the right hemisphere without any epileptiform activity [Figure - 2]. The child was given IV lorazepam without any improvement in limb power or change in EEG. She was initiated on aspirin (3 mg/kg); and over the next one week, her neurologic deficit improved completely and she was discharged home. A follow-up susceptibility-weighted imaging at the time of discharge showed reappearance of susceptibility artifacts over the region of angiomatosis [Figure - 2].

Transient focal deficits (stroke-like episodes) are a unique feature in SWS. These symptoms can be caused by temporary ischemia of the cortex underlying the vascular malformation or postictal depression of the brain activity. ^[2] Adequate differentiation between epileptic and ischemic origins of these events is of utmost importance, as this will have consequences on management. Advanced MR imaging techniques can potentially help to differentiate between the two. However, these have never been tried in this setting. Classically these episodes have been attributed to venous stasis within the leptomeningeal malformation causing repeated thrombosis, resulting in recurrent infarction. ^[2] Angiographic studies, however, have documented patent venous channels, suggesting stasis at a microvascular level. ^[3] Abnormalities of the microcirculation in angioma cause stasis and anoxia of the underlying brain, leading to disruption of the blood-brain barrier, increased capillary permeability, focal alterations in pH, calcium deposition and neuronal dysfunction. ^[3] This corresponds to the gray matter edema, as seen on MR imaging in our patient

About 75% to 90% of children with SWS develop seizures by three years of age. ^[4] Ictal epileptiform activity or postictal depression of activity can be another cause of transient neurological dysfunction. Rarely focal inhibitory motor status manifests as hemiplegia without any change in sensorium, and EEG shows focal slowing without epileptiform abnormalities. ^[5] Clinical and electrographic improvement after intravenous lorazepam can resolve this issue. Perfusion imaging in our patient [Figure - 3] showed decreased relative cerebral blood flow and volume with prolonged mean transit time, thus ruling out inhibitory motor seizures. ^[6]

Despite weakness persisting and progressing over days, repeat diffusion MR imaging showed no restriction, suggesting a reversible pathology. Our patient consistently showed decreased artifacts, suggesting deficient oxygen utilization with increased ratio of oxyhemoglobin to deoxyhemoglobin. ^[7] The above changes reverted once deficit improved, suggesting some reversible cause. Although the exact reason is unknown, it may represent preferential dilatation of abnormal venous channels with increase blood flow.

The value of aspirin in the treatment of such transient weakness in SWS has been suggested previously. In a study of 14 patients, a 65% decrease of stroke-like events was found after administration of low-dose aspirin (2-3 mg/kg/d). ^[8] Our patient also stabilized after being initiated on aspirin, and weakness improved completely over a week. Therefore, we suggest that low-dose aspirin should be considered for individuals with manifestations of a paroxysmal hemiparesis without ictal epileptiform activity on EEG.

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