A Highly Uncommon Variation of “Top of the Basilar” Syndrome

Case Report

Austin J Radiol. 2015;2(1): 1009.

A Highly Uncommon Variation of “Top of the Basilar” Syndrome

Ying Cheng1, Feng Bai2*, Yi Xin Zhu2 and Zhi Jun Zhang2

1Medical School of Southeast University, China

2Department of Neurology, Southeast University, China

*Corresponding author: Feng Bai, Department of Neurology, Affiliated ZhongDa Hospital of Southeast University, The Institute of Neuropsychiatry of Southeast University, Nanjing, Jiangsu 210009, China

Received: December 03, 2014; Accepted: January 26, 2015; Published: February 04, 2015


Stroke is a leading cause of death and acquired disability worldwide. Top of the Basilar Syndrome (TOBS), is a relatively uncommon subtype of stroke, and it has a wide spectrum of clinical presentations (abnormalities of alertness, inversion of the sleep–wake cycle, and abnormal oculomotor or pupillomotor functions) due to anatomic variations of posterior circulation, raising diagnostic challenges. In this case study, A 78-year-old man was admitted to our hospital with sudden-onset hemi paralysis and stupor followed by central facial palsy, dysphasia and dysarthria. He also revealed a blepharoptosis of the right eyelid, impairment of abduction on left side. He appeared hypersomnic, exhibited a reversed sleep–wake cycle, and was disoriented in space and time. It was also noticed that, he also had a personality change. Cerebral Magnetic Resonance Imaging (MRI) showed a bilateral thalamic stroke with extension to the right midbrain, temporal and occipital lobes. This unique case represents a highly uncommon variant of the “top of the basilar” syndrome because of a special anatomic arterial variation named Artery of Percheron (AOP).

Keywords: Artery of Percheron; Bilateral thalamic infarction; Top of the basilar syndrome



Stroke is one of the most common causes of death and acquired disability in the world. In China, stroke136.64 /100,000 has exceeded malignant tumor (135.88/100,000) and become the first cause of death. The incidence rate of stroke is approximately 205-584/100,000, the morbidity rate is approximately 400-700/100,000. Approximately two thirds of the 6000,000 people who survive a stroke are left with severe disabilities, which place a heavy economic burden on our society [1,2].

Bilateral thalamic infarction, a relatively uncommon subtype of stroke, combined with infarctions in the posterior circulation territories, results in a constellation of symptoms and signs that is generally referred to as “top of the basilar” syndrome [3,4]. Here, a highly uncommon variation of TOBS is discussed with the aim of increasing diagnostic awareness.

Case Report

A 78-year-old man with an unremarkable medical history experienced sudden weakness of his left leg and simultaneously had difficulty lifting his left arm when he was jogging in the early morning. His gait was unsteady, and he deviated to the left. He also felt dizzy and experienced an overwhelming feeling of drowsiness. He then quickly fell asleep after he was sent home by his neighbors. Approximately seven hours later, his family came home from work and found that he was not very responsive. He was disoriented, his speech was slurred, and the left side of his mouth was drooping when he was finally admitted to the emergency department of our hospital.

Clinical findings

On clinical examination, he was in a stupor. His Glasgow coma score was 12/15; he was able to obey simple commands, but he was disoriented in time and place. His blood pressure was 150/102 mmHg, his pulse rate was 62 beats per minute, respiratory rate was 20 per minute, and his SpO2 was 94%. An emergency cerebral Computed Tomography (CT) scan without contrast was performed at hospital admission and ruled out an intracerebral hemorrhage. No lowdensity focus was responsible for his staggered symptoms and signs.

The patient was soon transferred to our neurology department. A neurological examination was performed. A physical examination of cranial nerve function revealed blepharoptosis of the right eyelid, impairment of abduction on the left side, left central facial palsy, dysarthria, and dysphagia. The muscle strength of his left extremities was scored at 2/5. Oppenheimer and Babinski signs were present on the left. No sensory deficits were present. A cardiopulmonary examination was unremarkable.

Results of Auxiliary Examinations

Extensive laboratory tests, including a complete blood count, biochemical analyses and fibrinolysis and cardiac troponin measurements, were normal. Holter Electrocardiograph monitoring revealed atrial fibrillation and arrhythmias. Transthoracic echocardiography was unremarkable, and transesophageal echocardiography was contraindicated by persistent arousal disorder. Duplex sonography of the carotid and vertebral arteries revealed light stenosis due to the presence of extensive atheromatous plaques. A chest CT scan revealed mild pneumonia. A cerebral MRI performed on the third day after admission revealed a bilateral thalamic stroke with extension to the right midbrain and the right temporal and occipital lobes (Figure 1). Because the patient became agitated and uncooperative during the latter part of the MRI scan, we were unable to perform cerebral MRA.

Citation: Cheng Y, Bai F, Zhu YX and Zhang ZJ. A Highly Uncommon Variation of “Top of the Basilar” Syndrome. Austin J Radiol. 2015;2(1): 1009. ISSN :2473-0637