Vasogenic Bilateral Thalamus Lesions:A Retrospective Case Series Study

Objective:The thalamus is a midline structure situated between the cerebral hemispheres and the midbrain,with paired symmetric portions located on either side of the third ventricles.It consists of multiple nuclei that are responsible for relaying sensory and motor signals to and from the cerebral cortex and are involved in regulating consciousness,sleep,and alertness.Hence,lesions affecting the thalamus often result in disorders of consciousness and abnormalities of sensation.The bilateral thalamic lesions(BTL)are not common in clinical practice.According to the etiology,BTL can be classified into vasogenic and non-vasogenic.Vasogenic bilateral thalamic lesions(vasogenic bilateral thalamic lesions,VBTL)refers to the bilateral thalamic infarction or swelling caused by the abnormalities in the thalamic blood supply,and comprises artery of Percheron infarction(AOPI),top of basilar artery syndrome(TOBS),cerebral venous thrombosis(CVT)and dural arterio-venous fistula(DAVF).Various VBTLs overlap in clinical and radiographic features,but they are not identical and are therefore easy to be confused,leading to misdiagnosis.Early diagnosis and proper treatment of various VBTLs can help improve the prognosis of patients.In the current study,we retrospectively analyze clinical data of 29 patients with VBTL,and discuss the etiology,risk factors,clinical manifestations,neuroimaging features,treatment and prognosis of VBTL.Methods:A retrospective review of medical records of 29 patients with VBTL admitted to our neurology ward in the First Affiliated Hospital of Dalian Medical University from January 2011 to December 2016 was performed.We collected data regarding the epidemiological characteristics including gender,age,risk factors,past history and Related risk factors,clinical manifestations including onset state,main symptoms and neurological findings during the course,qualitative diagnosis,results of radiological study,laboratory indicators including lumbar puncture,neuropsychological examination,transthoracic echocardiography and electrocardiogram,treatment methods and short-outcome.All of the 29 patients received neuroimaging examinations,including CT(29 cases),Diffusion weighted imaging(DWI)(21 cases)and vascular imaging(14 cases).Short-outcome was evaluated using the modified Rankin Score(mRS)at the hospital discharge.Results:Among the 29 patients with VBTL,19 were male and 10 were female.The age of onset ranged from 14 to 84 years old,with the mean age of 65.9 years.21 patients were diagnosed with TOBS,5 patients AOPI,2 patients CVT,and one patient DAVF.Of the 21 patients with TOBS,the history of hypertension was the most common in 18 cases(85.7%),followed by atrial fibrillation in 9 cases(42.9%).Among AOPI-related risk factors,hyperlipidemia was the most common(100%),followed by diabetes(60%).The most common mode of onset of arteriogenic BTL is acute onset,accounting for 88.5%;2 cases of CVT patients showed subacute onset;1 case of DAVF patient was chronic onset.Of the 21 patients with TOBS,there were 13 cases(61.9%)with physical weakness,12 cases(57.1%)of language disorder and 11 cases(52.4%)of consciousness disturbance.In 5 cases of AOPI,the eye movement abnormalities and disturbance of consciousness were the most common;seen in 4 cases(80.0%),respectively.2 cases of CVT and 1 case of DAVF patients have headache.The mean NIHSS score at admission was 10.2 in the TOBS group and 5.8 in the AOPI group,the difference was statistically significant(P<0.05).All patients with TOBS showed the bilateral cerebral thalamic infarction,and also had involvement of cerebellum(61.9%),brainstem(57.1%)and occipital lobe(42.9%).All patients with AOPI showed bilateral thalamic infarction,occasionally companied by midbrain involvement(20%).The mean mRS at discharge was 2.7 points in the TOBS group and 0.6 in the AOPI group,the difference between two was statistically significant(P<0.05);TOBS group had 7 case s(33.3%)with mRS<2,and AOPI group had 5 cases(100.0%),the difference between the two groups was statistically significant(P<0.05).2 cases of CVT and 1 case of DAVF patients were discharged mRS were 0 points.Conclusions:(1)VBTL has a variety of etiology,including AOPI,TOBS,CVT and DAVF.(2)Patients with arteriogenic BTL often have stroke risk factors,and acute onset of mode;(3)On neuroimaging,AOPI often reveals the isolated of BTL lesions,but occasionally with the involvement of the midbrain;in addition to BTL lesions,the involvement of the cerebellum,brain stem and occipital involvement are often seen in TOBS.(4)Compared patients with TOBS,patients with AOPI often have the milder symptoms,and the better prognosis.