Lesions In Middle Cerebellar Peduncles Research Articles

Stroke pattern in giant-cell arteritis mostly involves watershed areas

ContextStroke related to giant cell arteritis (GCA) is rare and is associated with a poor outcome. One of the putative ischemic mechanisms is narrowing of the arterial lumen due to wall infiltration by inflammation and intimal proliferation, leading to reduced distal blood flow. It was hypothesized that GCA-related stroke could predominate in watershed areas (WA). MethodsLiterature review including all cases of GCA-related stroke with brain images. ResultsAmong 75 cases of GCA-related stroke, the anterior and posterior territories were involved in 48 % and 62.6 %, respectively. Up to 88.9 % of cases of anterior stroke probably involved WA. WA lesions in the posterior territories were as follows: uni/bilateral middle cerebellar peduncle (MCP) lesions in 25.5 %, and with less confidence, non-wedge-shaped cerebellar lesions in 46.8 %, or combined lesions in 61.7 %. Stenosis or occlusion of the afferent artery was almost always observed. A few lesions were not easily explained by low flow. DiscussionDespite the limitations of arterial territory allocation especially in the posterior circulation, ischemic lesions mainly occurred in WA. MCP lesions, which were typically WA, were highly characteristic of GCA. Low flow downstream focal stenosis was the main, but not the unique, ischemic mechanism of GCA stroke.

Middle Cerebellar Peduncle Lesions and Their Relation to Affective and Cognitive Impairment in Multiple Sclerosis

Background: Cerebellum has long been known to modulate not only motor coordination but also affective and cognitive functions. This study aimed to assess the impact of middle cerebellar peduncle (MCP) lesions on affective and cognitive function in patients with multiple sclerosis (MS). Methods: This was a cross-sectional study conducted on patients with relapsing-remitting MS (RRMS). All patients were subjected to 3-Tesla magnetic resonance imaging (3T MRI), brief international cognitive assessment for MS (BICAMS), and Depression, Anxiety, and Stress Score-21 (DASS-21) upon recruitment. Results: Of the 30 patients recruited, 33.3% and 36.7% had right and left MCP lesions, respectively. Patients with right MCP lesions had significantly worse symbol digit modality test (SDMT) scores (P=0.036), worse California verbal learning test (CVLT) immediate recall scores (P=0.011), and worse CVLT delayed free recall scores (P=0.049), whereas patients with left MCP lesions had lower DASS-21 scores (P<0.005). On multivariate regression analysis, the presence of left MCP lesion was associated with an 8.9-point reduction in DASS-21 scores (CI: -16.985- -0.805, P=0.033), whereas right MCP lesions did not have an independent effect on BICAMS scores after adjustment for age and educational level. Conclusion: Left MCP lesions were associated with significantly lower DASS-21 scores, whereas none of the MCP lesions had an independent impact on cognition.

CEREBELLAR DIFFUSE LARGE B CELL LYMPHOMA IN IMMUNOCOMPETENT FEMALE PATIENT

Diffuse large B cell lymphoma (DLBL) is the most common type of lymphoma worldwide, representing about 25% of all non-Hodgkin lymphomas. Among these lymphomas, primary DLBL of the central nervous system (CNS) is a rare category listed at 2016 revision of the World Health Organization classication of lymphoid neoplasms. First line treatment is based on methotrexate (MTX), with studies showing complete remission rates of 30 to 60% in patients who receive high-dose MTX, alone or in combination with other agents. The rarity of primary CNS lymphomas makes randomized trials dicult to do, but regimens usually include MTX plus one of the following drugs: cytarabine, procarbazine, temozolomide or rituximab in CD20 positive tumors. to present a case of primary CNS lymphoma presenting as multiple lesions in the cerebellum. We present a case of a 57-year-old female patient, without comorbidities or HIV seropositivity, diagnosed with diffuse large B cell lymphoma with cerebellar origin. During a period of 4 months the patient presented progressive difficulties to accomplish everyday activities quickly evolved, and were accompanied by aphasia, dysarthria, lack of motor coordination, nausea and vomiting. Her handwriting was unintelligible. A brain MRI showed enhanced leptomeningeal area associated with middle cerebellar peduncle lesions on both sides. Biopsy confirmed the diagnosis of lymphoma with immunohistochemistry showing positivity for CD20 and 40% Ki67. Bone marrow biopsy was normal and the serology for HIV, Epistein-Barr virus and hepatitis B and C viruses were negative. She was treated high dose induction immunochemotherapy with methotrexate (four doses of 3.5 g/m 2 ), cytarabine (two cycles of 2 g/m 2 , twice a day for 2 days) and rituximab (four doses of 375 mg/m 2 ). After the first cycle, the patient developed foreign accent syndrome (FAS) changing from her Brazilian accent to a Portuguese accent (within the same language). Despite FAS, other neurological symptoms ameliorated and the patient can once again write with her normal handwriting, have conversations and read. She was referred to complementary whole-brain radiotherapy. Literature on cerebellar primary central nervous system lymphoma is scarce. 1 A review of PCNSL reported only 9% of tumors with cerebellar involvement. The addition of high-dose cytarabine to high-dose methotrexate seems to be associated with improved response in patients with primary CNS lymphoma. However, cerebellar toxicity is a dose-dependent adverse effect of cytarabine and a concern in cases with previous cerebellar syndrome. FAS may be related to involvement of ’linguistic cerebellum’ 2 but apparently not associated with cytarabine. We showed that this combination was possible, without major neurologic events. Early diagnosis and treatment is important for the successful management of this aggressive and uncommon cerebellar tumor. Symptomatic improvement was fast after MTX initiation and the addition of cytarabine is feasible.

COVID-19 LEUKOENCEPHALOPATHY: THE MIDDLE CEREBELLAR PEDUNCLE SIGN

TOPIC: Imaging TYPE: Medical Student/Resident Case Reports INTRODUCTION: Although the pulmonary manifestations of the coronavirus disease 2019 (COVID-19) are commonly recognized, a rapidly accumulating body of evidence also supports multiple neurological manifestations. In addition to nonspecific headache and myalgia, complications include cranial/peripheral neuropathy, meningoencephalitis, and acute demyelination. We now present a case of acute encephalomyelitis associated with COVID-19. CASE PRESENTATION: A 69-year-old male with a history of diabetes mellitus and was admitted to the intensive care unit. He initially presented to the emergency room four days prior for fevers at which time COVID-19 PCR rapid antigen testing was positive. He was discharged home given the absence of other symptoms. Four days later he was found unresponsive and intubated for airway protection. On arrival to the hospital, the patient was unresponsive with roving eye movements but withdrew to stimulation in all extremities. He was started on dexamethasone and remdesivir. Computed tomography head demonstrated mild chronic small vessel ischemic periventricular leukomalacia. Given the degree of his encephalopathy, an magnetic resonance imaging (MRI) T2 of the brain was obtained demonstrating bilaterally symmetric restricted diffusion at the middle cerebellar peduncles and corticospinal tracts without microbleeds (Figure 1). FLAIR hyperintense lesions in the dorsal aspects of the internal capsules extending into the corticospinal tracts at the midbrain were also noted. A lumbar puncture was remarkable for 100% lymphocytic predominance cell count with normal glucose and protein. Steroid therapy was transitioned to methylprednisolone 1 gram daily for 5 days. Although repeat MRI (Figure 2) one week later showed lessened restriction diffusion without new pathology, the patient remained profoundly encephalopathic. Given the stability on MRI, intravenous immunoglobulin was deferred. He was started on a prednisone taper. He subsequently had a tracheostomy and percutaneous gastrostomy tube placed and transferred to a long-term acute care hospital. DISCUSSION: This case highlights an important finding of middle cerebellar peduncle lesions on MRI in the setting of COVID-19. Neurologic symptoms from COVID-19 are becoming better understood, with multiple recent papers examining neurological sequelae. The mechanism by which COVID-19 causes demyelination is not entirely clear. One idea is that leukocytes that become infected can serve as a reservoir and a vector of the disease that are subsequently able to enter the CNS through the bloodstream. Another theory is that viruses will infect peripheral neurons and then using axonal transport machinery will access the central nervous system. CONCLUSIONS: More research needs to be done to identify a precise mechanism of how demyelination occurs, but it is clear that demyelination is an unfortunate outcome of infection with respiratory viruses, like COVID-19. REFERENCE #1: Kremer S et al (Neurology 2020; 95: e1868-e1882) reported radiographic ADEM with COVID-19; MCP involvement reported as well as meningeal enhancement. REFERENCE #2: Desforges M, Coupanec AL, Dubeau P, et al. Human Coronaviruses and Other Respiratory Viruses: Underestimated Opportunistic Pathogens of the Central Nervous System? Viruses. 2019, 12, 14. DISCLOSURES: No relevant relationships by HANAD BASHIR, source=Web Response No relevant relationships by Mark Metry, source=Web Response No relevant relationships by Aidan Neustadtl, source=Web Response No relevant relationships by Christopher Newey, source=Web Response

Bilateral middle cerebellar peduncle lesions: Neuroimaging features and differential diagnoses.

ObjectivesLesions limited to the bilateral middle cerebellar peduncles (MCPs) are uncommon. This retrospective study investigated diseases with a proclivity for the bilateral MCPs and explored the associations between their neuroimaging features and clinical findings for the differential diagnosis of such lesions.MethodsWe enrolled 26 patients who were admitted to our department between January 2016 and March 2019 with bilateral MCP abnormalities on magnetic resonance imaging (MRI). The demographic, clinical, and neuroimaging characteristics, and the biomarkers and diagnoses were evaluated.ResultsAlthough all patients exhibited symmetrical bilateral MCP hypointensities on T1‐weighted imaging and hyperintensities on T2‐weighted and fluid‐attenuated inversion recovery imaging, they were diagnosed with different conditions. Diagnoses included acute cerebral infarction (ACI) (n = 9, 34.62%), Wallerian degeneration (WD) (n = 8, 30.77%), multiple system atrophy (MSA) (n = 6, 23.08%), neuromyelitis optica (NMO) (n = 1, 3.85%), heroin‐induced leukoencephalopathy (n = 1, 3.85%), and primary central nervous system lymphoma (PCNSL) (n = 1, 3.85%). Patients with ACI exhibited bilateral MCP‐restricted diffusion hyperintensities on diffusion‐weighted imaging and corresponding stenosis or occlusion of the vertebrobasilar system. The initial MRI of patients with WD depicted pontine infarctions, while symmetrical MCP lesions were observed on follow‐up MRI. Symmetrical MCP lesions, cruciform hyperintensity, and marked atrophy in the posterior fossa were characteristic manifestations of MSA. Longitudinally extensive myelitis affecting more than three vertebral segments on cervical MRI and positive serum AQP4‐IgG may be indicative of NMO. Heroin‐induced leukoencephalopathy was characterized by extra‐symmetrical lesions in the posterior limbs of the internal capsules, while the anterior limbs were spared. PCNSL was indicated by a significant and characteristic “fist” sign on contrast‐enhanced MRI.ConclusionsBilateral MCP lesions were most frequently observed in cerebrovascular diseases, followed by neurodegenerative diseases, inflammatory diseases, toxic encephalopathies, and lymphomas. Our findings demonstrate that bilateral MCP signal abnormalities are more common in patients with ACI and WD, with fewer degenerative processes than previously believed. The high frequency of WD may be attributed to the specific awareness of this pathology. WD can also present with stage‐related restricted diffusion and should not be mistaken for a new infarction. The symmetrical bilateral MCP hypointensities on T1‐weighted imaging and hyperintensities on T2‐weighted imaging often raise concern regarding a demyelinating process. Our findings emphasize that neurologists should consider the aforementioned conditions and correlate the specific neuroimaging characteristics and medical history before arriving at the final diagnosis.

Ataxia and middle cerebellar peduncle lesions in hepatic encephalopathy

Sir,Brain MRI in patients with hepatic encephalopathy (HE)shows hyperintensity in the globus pallidus on T1-weightedimages, which is thought to reflect manganese andammonia accumulation in situ [1, 2]. Those patientscommonly have asterexis, disturbed consciousness, andextrapyramidal features [1, 2]. In contrast, ataxia in HE israre [3], and MRI correlates for ataxia have not beenentirely clear [4, 5]. We recently had a woman who, duringa course of HE, presented with bilateral, middle cerebellarpeduncle lesions and ataxia, both of which ameliorated afterbranched amino acid treatment.A 57-year-old woman suffered from primary biliarycirrhosis and hepatocellular carcinoma for the past 7 years.One year after the onset of diseases, she developedasterexis and disorientation to time and place. An intrave-nous administration of branched amino acid ameliorated hersymptoms. She was then started on kanamycin andlaxatives. However, 1 month before admission to ourhospital, an abdominal MRI revealed a recurrence ofhepatocellular carcinoma; in addition, she developedunsteadiness of the gait but without flapping tremor. Onadmission, she had slight disorientation to place. She hadcerebellar ataxia on finger to nose test, diadochokinesis,and heel-to-knee test. She had no extrapyramidal features orflapping tremor. Blood tests showed increased serum levelsof ammonia 183μg/dl (30–80) and total bilirubin 1.5 mg/dl(0.2–1.0). Brain MRI revealed high signal intensity in theglobus pallidus on T1-weighted image, and markedly highsignal intensity in the middle cerebellar peduncle bilaterally(Fig. 1a) and slightly high signal intensity in the cerebralwhite matter on T2-weighted image. We started her on anintravenous administration of 500 ml/day (valine 0.84%,leucine 1.10%, isoleucine 0.90%) intravenous branchedamino acid and low protein diet. Three weeks later, herataxia ameliorated significantly, and serum ammonia levelsdecreased to 113μg/dl. A post-treatment MRI scan, whichwas performed 1 month later, showed reduction inhyperintense signal (Fig. 1b).Previously, four reports of brain MRI imaging for ataxiain HE are available [4–7]. Park and Heo [4] reported a46-year-old man with acquired hepatocerebral degenerationwho developed ataxia and bilateral, middle cerebellarpeduncle lesions. In a review article, Uchino and colleagues[5] showed similar MRI findings. Nagura and colleagues[6] reported a 66-year-old man with portal-systemic shunt,with irreversible middle cerebellar peduncle involvement,attributed to hyperammonemia. Deguchi and colleagues [7]reported a 58-year-old woman with similar MRI findings,which improved by intravenous branched amino acids. Todate, no pathology studies are available accounting for theMRI abnormalities in the middle cerebellar peduncle.However, in cases of HE, demyelination has been demon-strated in the cerebral white matter [8], pontine base [9],and corticospinal tract [10]. Since myelinated axon is themain histological constituent in the cerebellar peduncle, theMRI findings in the middle cerebellar peduncle mightreflect demyelination. Since intravenous branched aminoacid soon ameliorated ataxia and the MRI lesions, togetherwith reversal of serum ammonia levels, cytotoxic edema

Lesions of the middle cerebellar peduncle disrupt acquisition and retention of the rabbit's classically conditioned nictitating membrane response.

Rabbits were classically conditioned to emit a nictitating membrane response (NMR) to either a light or tone conditioned stimulus (CS) paired with an eye shock unconditioned stimulus (UCS). They then received lesions of the middle cerebellar peduncle (MCP) or served as unoperated controls. Following surgery, they were given separate presentations of tone, light, and vibratory CSs, each paired with the eye shock UCS. In this way, conditioned responses (CR) to the previously trained light or tone served as a test of retention, whereas CRs to the remaining two conditioned stimuli (tone and vibratory or light and vibratory) served as a test of acquisition. The results of the study revealed that rabbits with complete lesions of the MCP showed disrupted acquisition and retention of the conditioned NMR to all stimuli, rabbits with partial MCP lesions also showed disrupted acquisition and retention to all CSs, but to a lesser degree, and animals with lesions that missed the MCP and unoperated controls both showed normal acquisition and retention of the conditioned NMR. These data are consistent with the view that the cerebellum is an essential part of the circuit for classical conditioning of the NM response and that information about CSs in the auditory, visual, and tactile modalities reach the cerebellum by way of the MCP.