FDG- and Dopa-PET in postencephalitic parkinsonism

Summary. We report a case of a 74-year old woman who following an acute virus encephalitis developed an akinetic-rigid Parkinson syndrome with tremor, hypokinesia, hypomimia, rigidity and cogwheel phenomenon in all four extremities, brady-dysdiadochokinesia as well as myoclonic jerks of the arms. Many of the clinical features of this postencephalitic parkinsonism (PEP) suggested the diagnosis of sporadic encephalitis lethargica, first described by von Economo 1917. Cerebral spinal fluid showed signs of a viral encephalitis, and a positive influenza A IgA-antibody titer (1 : >160) in the viral serologic screen was found. Positron emission tomography (PET) showed an altered pattern of glucose- and dopa-metabolism clearly different from findings in idiopathic Parkinson syndrome (IPS). The acute lack of inhibitory input from the substantia nigra pars compacta to the striatum could explain the different metabolic patterns in our case in comparison to IPS patients. Our findings indicate that PEP may also be caused by influenza A and furthermore that PET clearly distinguishes PEP from IPS. Received January 27, 2000; accepted March 29, 2000     

柯萨奇病毒B3感染的病毒性脑炎小鼠模型的建立

目的建立柯萨奇病毒B3（CVB3）感染的病毒性脑炎小鼠模型。方法BALB/c纯系小鼠分两组,实验组小鼠颅内直接注射滴度为4.5×10^8pfu的柯萨奇病毒B3悬液20μl,对照组颅内注射生理盐水20μl,应用逆转录酶聚合酶链反应（RT-PCR）法测定脑组织中CVB3RNA含量,HE染色观察脑组织病理学的改变。结果与对照组相比,模型组动物于注射后1d开始出现病毒性脑炎的表现;另外脑组织观察到CVB3的阳性条带,并出现大量的炎细胞浸润、充血水肿和片状坏死,皮质细胞排列紊乱,形态不规则,有空泡样改变,出现核固缩、碎裂、溶解等。结论颅内直接注射柯萨奇病毒B3悬液,可快速建立柯萨奇病毒B3感染的病毒性脑炎小鼠模型。     

Bilateral substantia nigra changes on MRI in a patient with encephalitis lethargica

A 33-year-old woman admitted for meningoencephalitis had features of encephalitis lethargica develop on her third day of illness. She had ophthalmoplegia, akinetic mutism, and prominent extrapyramidal signs consisting of lip and hand tremors, cogwheel rigidity, and facial bradykinesia.     

Substantia nigra lesions in viral encephalitis.

Post-encephalitic parkinsonism is a well-known entity, but involvement of the basal ganglia is rarely documented. We describe a 21-year-old man who developed parkinsonism following encephalitic illness presumed to be of viral origin with substantia nigra lesions evident on magnetic resonance imaging scan.     

SPECT in focal enterovirus encephalitis: evidence for local cerebral vasculitis

We report a 4-year-old, left-handed male with focal coxsackievirus A3 encephalitis who presented with seizures and acquired aphasia. Electroencephalography exhibited focal spike discharges over the right frontal regions, but cranial magnetic resonance imaging did not reveal any structural abnormalities. However, brain single-photon emission computed tomography performed during the acute phase disclosed focal hypoperfusion in the right frontal lobe, consistent with decreased regional cerebral blood flow in the territory of some branches of the right cerebral anterior artery. Without specific treatment, the patient recovered completely within 1 month, when brain single-photon emission computed tomography images returned to normal and cranial magnetic resonance imaging still demonstrated no abnormalities. The present case suggests the possible role of transient local cerebral vasculitis in the pathogenesis of focal enterovirus encephalitis.     

Eastern equine encephalitis presenting with a focal brain lesion

Eastern equine encephalitis (EEE) virus causes a severe meningoencephalitis with high morbidity and mortality. Despite numerous clinical reports of EEE, there are only 11 patients in whom cranial computed tomographic (CT) findings are described. In 6 patients, CT was normal and in 5 patients diffuse edema was present; none had a focal brain lesion. Based on these reports, it has been suggested that focal findings on CT support the diagnosis of herpes simplex encephalitis rather than EEE. The first patient with serologically-confirmed EEE and a focal lesion demonstrated by cranial CT and magnetic resonance imaging is described; these findings underscore the importance of including EEE in the differential diagnosis of encephalitides that can cause focal brain lesions on neuroimaging.     

St Louis encephalitis: a review of 11 cases in a 1995 Dallas, Tex, epidemic

OBJECTIVE: To update some of the clinical features of St Louis encephalitis (SLE), a common arboviral infection that occurs in epidemic patterns in the south-central and midwestern United States. METHODS: Eleven patients with SLE from a 1995 epidemic in Dallas, Tex, were studied clinically, radiologically, neurophysiologically, and neuropathologically (in 1 case). RESULTS: The electroencephalograms and magnetic resonance imaging (MRI) scans of our patients revealed features that have received little attention in previous studies. Of the 9 patients who were examined with electroencephalography, all 9 had seizures or other abnormalities, and 1 had nonconvulsive status epilepticus. Two of 6 patients who had MRIs showed substantia nigra edema. Finally, 2 (18%) of our patients had coinfection with the human immunodeficiency virus. CONCLUSIONS: The MRI findings of substantia nigra edema in patients with SLE have not been previously reported. Nonconvulsive status epilepticus can occur in patients with SLE and should be considered in patients with prolonged encephalopathy. Finally, human immunodeficiency virus coinfection may be a risk factor for symptomatic SLE infection.     

Neuromelanin magnetic resonance imaging of locus ceruleus and substantia nigra in Parkinson's disease

We carried out an investigation to identify neuromelanin-containing noradrenergic and dopaminergic neurons in the locus ceruleus and substantia nigra pars compacta of healthy volunteers and patients with Parkinson's disease using a newly developed magnetic resonance imaging technique that can demonstrate neuromelanin-related contrast. The high-resolution neuromelanin images obtained by a 3-T scanner revealed high signal areas in the brain stem and these corresponded well with the location of the locus ceruleus and substantia nigra pars compacta in gross specimens. In Parkinson's disease patients, the signal intensity in the locus ceruleus and substantia nigra pars compacta was greatly reduced, suggesting depletion of neuromelanin-containing neurons. We conclude that neuromelanin magnetic resonance imaging can be used for direct visualization of the locus ceruleus and substantia nigra pars compacta, and may help in detecting pathological changes in Parkinson's disease and related disorders.     

T1‐Weighted MRI shows stage‐dependent substantia nigra signal loss in Parkinson's disease

Depigmentation of the substantia nigra is a conspicuous pathological feature of Parkinson's disease and related to a loss of neuromelanin. Similar to melanin, neuromelanin has paramagnetic properties resulting in signal increase on specific T1‐weighted magnetic resonance imaging. The aim of this study was to assess signal changes in the substantia nigra in patients with Parkinson's disease using an optimized neuromelanin‐sensitive T1 scan. Ten patients with Parkinson's disease and 12 matched controls underwent high‐resolution T1‐weighted magnetic resonance imaging with magnetization transfer effect at 3T. The size and signal intensity of the substantia nigra pars compacta were determined as the number of pixels with signal intensity higher than background signal intensity + 3 standard deviations and regional contrast ratio. Patients were subclassified as early stage (n = 6) and late stage (n = 4) using the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr Parkinson's disease staging scale. The T1 hyperintense area in the substantia nigra was substantially smaller in patients compared with controls (?60%, P < .01), and contrast was reduced (?3%, P < .05). Size reduction was even more pronounced in more advanced disease (?78%) than in early‐stage disease (?47%). We present preliminary findings using a modified T1‐weighted magnetic resonance imaging technique showing stage‐dependent substantia nigra signal reduction in Parkinson's disease as a putative marker of neuromelanin loss. Our data suggest that reduction in the size of neuromelanin‐rich substantia nigra correlates well with postmortem observations of dopaminergic neuron loss. Further validation of our results could potentially lead to development of a new biomarker of disease progression in Parkinson's disease. © 2011 Movement Disorder Society     

Coxsackie B meningoencephalitis in a patient with acquired immunodeficiency syndrome and a multiple sclerosis-like illness

Both Coxsackie infection and multiple sclerosis (MS) are rare in human immunodeficiency virus (HIV) infection. We report a 35-year-old woman with known HIV infection of 12 years’ duration and a clinical illness of 4 years’ duration consistent with MS. The latter was characterized by optic neuritis, bilateral abducens palsies, recurrent Bell’s palsy, hemiparesis, and ataxia coupled with white matter abnormalities on magnetic resonance imaging (MRI). Autopsy revealed Coxsackie B meningoencephalitis; no other infectious disease were detected and no histopathological features of MS were evident. We suggest that the relapsing-remitting neurological disease in this patient was the consequence of Coxsackie B meningoencephalitis. This is the first case report, to the best of our knowledge, of an enteroviral meningoencephalitis complicating human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS).     

Japanese encephalitis virus antigen in the human brain and its topographic distribution

This study reports the pathological findings and the distribution of viral antigen in the brains of 13 confirmed and autopsied cases of Japanese encephalitis (JE) in correlation with other virus-specific immunological parameters measured in the cerebrospinal fluid (CSF) antemortem. Japanese encephalitis virus (JEV)-specific antibodies were detected in the CSF of 10 of 13 patients, JEV antigen was detected in the CSF of 7 of 13 and JEV-specific immune complexes were detected in the CSF of 3 of 11 patients. Viral antigen was localised immunocytochemically in the brain tissue of 11 of 13 cases, indicating, that viral antigen could not be cleared from the tissues by the antibody. The topographic distribution of the tissue-associated antigen in the thalamus, hippocampus, substantia nigra and medulla oblongata explain the evolution of post JE sequelae.     

In vivo detection of hepatitis C virus (HCV) RNA in the brain in a case of encephalitis: evidence for HCV neuroinvasion

We report here a 27-year-old woman who presented with encephalitis of unknown origin. Magnetic resonance imaging (MRI) of the brain revealed leukoencephalopathy, cerebrospinal fluid showed signs of inflammation. Serum and brain biopsy tissue was tested positive for hepatitis C virus (HCV). Neuropathological investigation supported the hypothesis of viral encephalitis. C3, C4 and cryoglobulins as well as cerebral MR-angiography were normal. Neurological complications of HCV infection other than hepatic encephalopathy are generally attributed to parainfectious phenomena. This is the first case of HCV-RNA detection in vivo in human brain in literature and it raises the possibility that HCV is able to induce encephalitis caused by neurotrophism. This is supported by the fact that there is a growing body of literature on HCV-induced cerebral dysfunction and laboratory findings indicating HCV neuroinvasion.     

A case of Japanese encephalitis demonstrating characteristic changes in MRI]

A 40-year-old woman developed high fever and headache. Five days later, she was admitted because of consciousness disturbance and tremulous movements in upper extremities. The paired sera showed more than fourfold elevation in complement fixation titer to Japanese encephalitis virus. She was diagnosed as Japanese encephalitis from the clinical features and serological tests. Magnetic resonance imaging (MRI), which was performed about seven months after the onset, revealed abnormal intensity areas bilaterally in the thalamus, hippocampus, substantia nigra, globus pallidus and white matter around the lateral ventricle. Eight months after the onset, she was left with bradykinesia, disturbance of rightening reflex, emotional lability and impairment of recent memory with a long period of amnesia, including not only her illness and subsequent events but also about several years before her illness. The characteristic memory dysfunction seems to be due to disorder of bilateral hippocampus, where MRI revealed abnormal intensity areas. And disorder of medial thalamic nucleus would be related to emotional liability. The relation between the clinical features and MRI findings is also discussed.     

Correlation of in vivo neuroimaging abnormalities with postmortem human immunodeficiency virus encephalitis and dendritic loss

BACKGROUND: In the absence of significant opportunistic infection, the most common alterations on neuroimaging in the brains of patients with AIDS include enlarged cerebrospinal fluid spaces, white-matter loss, volume loss in striatal structures, and white-matter signal abnormalities. Although previous studies have linked brain viral levels to these alterations, other neuropathological mechanisms might also contribute to them. OBJECTIVE: To examine the relationship between findings on premortem magnetic resonance images and postmortem neuropathologic evidence of human immunodeficiency virus (HIV) encephalitis and neurodegeneration. DESIGN: Morphometric analysis of magnetic resonance imaging in seropositive cases with matched seronegative controls, and the correlation of these volumes to neuropathological measures in autopsied seropositive cases. SETTING: University of California, San Diego, HIV Neurobehavioral Research Center. SUBJECTS: Twenty-one seropositive subjects studied at autopsy and 19 seronegative cases. MAIN OUTCOME MEASURES: In vivo structural magnetic resonance imaging data analyzed by quantitative methods, with comparison of volumes from magnetic resonance imaging and neuropathological data from autopsies. RESULTS: The HIV-seropositive subjects demonstrated cerebrospinal fluid increases relative to seronegative controls. These increases were associated with a significant decrease in the volumes of cerebral and cerebellar white matter, caudate nucleus, hippocampus, and, to a lesser extent, cerebral cortex. The volume of cerebral white-matter tissue with elevated signal was also increased. This signal elevation in white matter predicted the autopsy diagnosis of HIV encephalitis, as well as the extent of dendritic loss as assessed by analysis of microtubule-associated protein 2 immunoreactivity. CONCLUSIONS: White-matter and cortical damage resulting from HIV disease are closely related. In vivo magnetic resonance imaging may be a valuable adjunct in the assessment of patients at risk for developing HIV encephalitis.     

Clinical study in 28 patients with infection-related acute onset encephalitis]

Of the 75 patients with infection-related acute encephalopathy or encephalitis treated by us in the last 10 years, 28 had acute onset encephalitis. The results of clinical studies on these 28 patients were as follows: (1) The number of cases who exhibited CNS manifestations during (A) and after pyrexia (B) were 15 and 13, and the ages of predilection were infancy and school age, respectively. (2) MRI studies in cases of A revealed multifocal CNS lesions in 1 case, localized lesions in 7 and normal findings in 7. In B, there were 3 cases with multifocal lesions, 8 of focal lesions and 2 of normal findings. (3) The 7 cases of localized lesions in A were divided into 5 of herpes encephalitis and 2 of suspected vasculitis. Vasculitis was suspected in 3 of 8 cases of localized lesions in B. Thus, vasculitis is considered to be an important cause of encephalitis. (4) Brain lesions in the 5 cases of herpes encephalitis were occipital dominant in 4. Only one case had a temporal lesion. (5) All cases with focal MRI lesions and CSF pleocytosis, having evidence of direct viral invasion, were herpes encephalitis. Direct viral invasion was not proven in any other cases. (6) Although the term encephalitis is often used in clinical practice, the process by which the CNS lesions occur in acute viral infection is still unknown. Therefore it is not easy to establish the diagnosis. The diagnostic criteria of encephalitis should be reconsidered. New specific methods to analyze the cause of CNS lesions are necessary.     

Detecting dopaminergic neuronal degeneration using diffusion tensor imaging in a rotenone-induced rat model of Parkinson's disease: fractional anisotropy and mean diffusivity values

Dopamine content in the basal ganglia is strongly associated with the degree of dopaminergic neuron loss in the substantia nigra pars com-pacta. Symptoms of Parkinson's disease might not arise until more than 50% of the substantia nigra pars compacta is lost and the dopamine content in the basal ganglia is reduced by more than 80%. Greater diagnostic sensitivity and specificity would allow earlier detection of Parkinson's disease. Diffusion tensor imaging is a recently developed magnetic resonance imaging technique that measures mean diffusiv-ity and fractional anisotropy, and responds to changes in brain microstructure. When the microscopic barrier (including cell membranes, microtubules and other structures that interfere with the free diffusion of water) is destroyed and extracellular fluid volume accumulates, the mean diffusivity value increases; when the integrity of the microstructure (such as myelin) is destroyed, fractional anisotropy value decreases. However, there is no consensus as to whether these changes can reflect the early pathological alterations in Parkinson's disease. Here, we established a rat model of Parkinson's disease by injecting rotenone (or sunflower oil in controls) into the right substantia nigra. Diffusion tensor imaging results revealed that in the stages of disease, at 1, 2, 4, and 6 weeks after rotenone injection, fractional anisotropy value decreased, but mean diffusivity values increased in the right substantia nigra in the experimental group. Fractional anisotropy values were lower at 4 weeks than at 6 weeks in the right substantia nigra of rats from the experimental group. Mean diffusivity values were mark-edly greater at 1 week than at 6 weeks in the right corpus striatum of rats from the experimental group. These findings suggest that mean diffusivity and fractional anisotropy values in the brain of rat models of Parkinson's disease 4 weeks after model establishment can reflect early degeneration of dopaminergic neurons. The change in fractional anisotropy values after destruction of myelin integrity is likely to be of greater early diagnostic significance than the change in mean diffusivity values.     

Concurrent West Nile Virus Infection in Pneumococcal Meningitis: Clinical and MRI Features

We report the clinical and neuroimaging findings of an immunocompetent patient with concurrent pneumococcal and West Nile virus meningoencephalitis with relapsing clinical course despite a full course of antibiotic treatment. The patient developed acute oculomotor nerve palsy with pupillary involvement and bilateral hearing loss, and delayed right leg monoparesis. We speculate that coexisting bacterial and viral neuroinvasive infections contributed to the unusual clinical and imaging manifestations, and that overwhelming laboratory and clinical features of bacterial meningitis masked the typical features of CNS viral infection. Therefore, atypical presentations of bacterial meningitis should raise a high index of suspicion for coexisting infections, even in immunocompetent patients, and evolving neuroimaging findings may be helpful in substantiating clinical suspicion and guiding further management.     

α-Synuclein accumulation in a case of neurodegeneration with brain iron accumulation type 1 (NBIA-1, formerly Hallervorden-Spatz syndrome) with widespread cortical and brainstem-type Lewy bodies

We studied a 27-year-old woman who died after a 6-year history of progressive dementia, dystonia, ataxia, apraxia, spasticity, choreoathetosis, visual and auditory hallucinations, and optic atrophy. Magnetic resonance imaging showed decreased intensity in the globus pallidus, substantia nigra, and dentate nuclei in T2-weighted images, supporting the clinical diagnosis of neurodegeneration with brain iron accumulation type 1 (NBIA-1; formerly known as Hallervorden-Spatz syndrome). At autopsy the brain showed mild frontotemporal atrophy and discoloration of the globus pallidus and the substantia nigra pars reticularis. Histologically, features typical of NBIA-1 were found including widespread axonal spheroids and large deposits of iron pigment in the discolored regions. Additionally, excessive numbers of Lewy bodies (LBs) were found throughout all examined brain stem and cortical regions. LBs of both types, as well as Lewy neurites in this case of NBIA-1, were strongly labeled by antibodies against α-synuclein. These findings give further evidence that accumulation of α-synuclein is generally associated with LB formation, i.e., in Parkinson’s disease, dementia with Lewy bodies and NBIA-1. The case presented here is particularly notable for its high number of LBs in all areas of the cerebral cortex. Received: 26 November 1999 / Revised: 11 February 2000 / Accepted: 14 February 2000     

A case of Balamuthia mandrillaris meningoencephalitis

Balamuthia mandrillaris is a newly described pathogen that causes granulomatous amebic encephalitis, an extremely rare clinical entity that usually occurs in immunosuppressed individuals. We report a case of pathologically proven Balamuthia encephalitis with unusual laboratory and radiologic findings. A 52-year-old woman with idiopathic seizures and a 2-year history of chronic neutropenia of unknown cause had a subacute illness with progressive lethargy, headaches, and coma and died 3 months after the onset of symptoms. Cerebrospinal fluid (CSF) glucose concentrations were extremely low or unmeasurable, a feature not previously described (to our knowledge). Cranial magnetic resonance imaging scans showed a single large temporal lobe nodule, followed 6 weeks later by the appearance of 18 ring-enhancing lesions in the cerebral hemispheres that disappeared after treatment with antibiotics and high-dose corticosteroids. The initial brain biopsy specimen and analysis of CSF samples did not demonstate amebae, but a second biopsy specimen and the postmortem pathologic examination showed Balamuthia trophozoites surrounded by widespread granulomatous inflammation and vasculitis. The patient's neutropenia and antibiotic use may have caused susceptibility to this organism. Amebic meningoencephalitis should be considered in cases of subacute meningoencephalitis with greatly depressed CSF glucose concentrations and multiple nodular lesions on cerebral imaging. Arch Neurol. 2000;57:1210-1212