Viral Parkinsonism: An underdiagnosed neurological complication of Dengue virus infection.

Dengue virus (DENV) is a flavivirus that is a significant cause of human disease costing billions of dollars per year in medical and mosquito control costs. It is estimated that up to 20% of DENV infections affect the brain. Incidence of DENV infections is increasing, which suggests more people are at risk of developing neurological complications. The most common neurological manifestations of DENV are encephalitis and encephalopathy, and movement disorders such as parkinsonism have been observed. Parkinsonism describes syndromes similar to Parkinson's Disease where tremors, stiffness, and slow movements are observed. Parkinsonism caused by viral infection is characterized by patients exhibiting at least two of the following symptoms: tremor, bradykinesia, rigidity, and postural instability. To investigate DENV-associated parkinsonism, case studies and reports of DENV-associated parkinsonism were obtained from peer-reviewed manuscripts and gray literature. Seven reports of clinically diagnosed DENV-associated parkinsonism and 15 cases of DENV encephalitis, where the patient met the case criteria for a diagnosis of viral parkinsonism were found. Clinically diagnosed DENV-associated parkinsonism patients were more likely to be male and exhibit expressionless face, speech problems, and lymphocytosis. Suspected patients were more likely to exhibit tremor, have thrombocytopenia and low hemoglobin. Viral parkinsonism can cause a permanent reduction in neurons with consequential cognitive and behavior changes, or it can leave a latent imprint in the brain that can cause neurological dysfunction decades after recovery. DENV-associated parkinsonism is underdiagnosed and better adherence to the case definition of viral parkinsonism is needed for proper management of potential sequalae especially if the patient has an ongoing or potential to develop a neurodegenerative disease.

Interaction between coxsackievirus B3 infection and α-synuclein in models of Parkinson's disease.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. PD is pathologically characterized by the death of midbrain dopaminergic neurons and the accumulation of intracellular protein inclusions called Lewy bodies or Lewy neurites. The major component of Lewy bodies is α-synuclein (α-syn). Prion-like propagation of α-syn has emerged as a novel mechanism in the progression of PD. This mechanism has been investigated to reveal factors that initiate Lewy pathology with the aim of preventing further progression of PD. Here, we demonstrate that coxsackievirus B3 (CVB3) infection can induce α-syn-associated inclusion body formation in neurons which might act as a trigger for PD. The inclusion bodies contained clustered organelles, including damaged mitochondria with α-syn fibrils. α-Syn overexpression accelerated inclusion body formation and induced more concentric inclusion bodies. In CVB3-infected mice brains, α-syn aggregates were observed in the cell body of midbrain neurons. Additionally, α-syn overexpression favored CVB3 replication and related cytotoxicity. α-Syn transgenic mice had a low survival rate, enhanced CVB3 replication, and exhibited neuronal cell death, including that of dopaminergic neurons in the substantia nigra. These results may be attributed to distinct autophagy-related pathways engaged by CVB3 and α-syn. This study elucidated the mechanism of Lewy body formation and the pathogenesis of PD associated with CVB3 infection.

Parkinsonism as a Third Wave of the COVID-19 Pandemic?

Since the initial reports of COVID-19 in December 2019, the world has been gripped by the disastrous acute respiratory disease caused by the SARS-CoV-2 virus. There are an ever-increasing number of reports of neurological symptoms in patients, from severe (encephalitis), to mild (hyposmia), suggesting the potential for neurotropism of SARS-CoV-2. This Perspective investigates the hypothesis that the reliance on self-reporting of hyposmia has resulted in an underestimation of neurological symptoms in COVID-19 patients. While the acute effect of the virus on the nervous system function is vastly overshadowed by the respiratory effects, we propose that it will be important to monitor convalescent individuals for potential long-term implications that may include neurodegenerative sequelae such as viral-associated parkinsonism. As it is possible to identify premorbid harbingers of Parkinson's disease, we propose long-term screening of SARS-CoV-2 cases post-recovery for these expressions of neurodegenerative disease. An accurate understanding of the incidence of neurological complications in COVID-19 requires long-term monitoring for sequelae after remission and a strategized health policy to ensure healthcare systems all over the world are prepared for a third wave of the virus in the form of parkinsonism.

Hepatitis E Virus-Associated Acute Encephalitic Parkinsonism.

Hepatitis E virus (HEV) is a common infection worldwide and is an emerging infectious disease in the developed countries. The unique characteristics of HEV is that it displays different epidemiological and clinical characteristics between developing and developed countries. Neurological disorders are emerging extra hepatic manifestations of both acute and chronic Hepatitis E virus infection. We report a 17 year old sportsman presenting with acute encephalitic Parkinsonism concurrent with acute hepatitis. Serology was positive for Hepatitis E virus (HEV) and HEV RNA was confirmed. Patient improved completely with symptomatic treatment. We suggest offering diagnostic testing for Hepatitis E virus in patients of neurological disorders with concurrent liver impairment.

Acute Facial Nerve Palsy With Ipsilateral Soft Palate Ulcers.

Ramsay-Hunt syndrome (RHS) is a rare complication of herpes zoster in which reactivation of latent varicella zoster virus (VZV) infection occurs in the geniculate ganglion. Major clinical findings are peripheral facial nerve palsy accompanied by ipsilateral ear pain and erythematous vesicular rash on the external ear (herpes zoster oticus) and in the mouth. Thus, diagnosis of RHS is usually clinical. However, auricular herpetic eruption is not always present, making diagnosis more difficult. This report describes a case of RHS with left facial palsy without skin lesions in 60-year-old woman. Multiple ulcers were found on her left soft palate. Polymerase chain reaction analysis on oral mucosa biopsy samples and serologic assays allowed the identification of VZV as the causal agent. Knowledge of the anatomy of the facial nerve is important for oral and maxillofacial surgeons when dealing with patients with RHS, especially in unusual and clinically misleading forms of this syndrome.

Asymmetry in parkinsonism, spreading pathogens and the nose.

Parkinson's disease, as well as many other parkinsonisms, including most toxic, neurodegenerative and familial types are typically asymmetric. No explanation for this phenomenon exists. A summary of the frequency of asymmetry in a spectrum of parkinsonian disorders is provided. Evidence against asymmetry being the result of normal asymmetries of the substantia nigrais reviewed. Asymmetry either results from a greater susceptibility on one side or a spreading pathology entering or starting on one side of the CNS. With the increasing evidence for spreading pathologies (toxins, viruses, α-synuclein), knowledge of neuroanatomical connections, and literature implicating spreading pathogens from the enteric and olfactory nerves, potential explanations can be theorized and explored, including the possibility of a pathogen preferentially entering or originating in the olfactory bulb on one side, with subsequent involvement of the other side.

Hypothalamic abnormalities and Parkinsonism associated with H1N1 influenza infection.

OBJECTIVE: To describe a case of a young adult with severe H1N1 influenza illness associated with hypothalamic abnormalities and post-influenza parkinsonism. DESIGN: Case report. PATIENT: A 22-year-old woman with H1N1 influenza infection developed encephalopathy followed by diverse hypothalamic dysfunction manifestations, sleeplessness, and persistent parkinsonian features. RESULTS: CSF analysis, brain imaging and EEG ruled out hypoxic brain injury or other illnesses. CONCLUSIONS: A number of viruses have been associated with both acute and chronic parkinsonism. A link between parkinsonism and influenza viruses is somewhat controversial. This is the first reported case of parkinsonism following an H1N1 influenza infection.

Early and reliable detection of herpes simplex virus type 1 and varicella zoster virus DNAs in oral fluid of patients with idiopathic peripheral facial nerve palsy: Decision support regarding antiviral treatment?

Idiopathic peripheral facial nerve palsy has been associated with the reactivation of herpes simplex virus type 1 (HSV-1) or varicella zoster virus (VZV). In recent studies, detection rates were found to vary strongly which may be caused by the use of different oral fluid collection devices in combination with molecular assays lacking standardization. In this single-center pilot study, liquid phase-based and absorption-based oral fluid collection was compared. Samples were collected with both systems from 10 patients with acute idiopathic peripheral facial nerve palsy, 10 with herpes labialis or with Ramsay Hunt syndrome, and 10 healthy controls. Commercially available IVD/CE-labeled molecular assays based on fully automated DNA extraction and real-time PCR were employed. With the liquid phase-based oral fluid collection system, three patients with idiopathic peripheral facial nerve palsy tested positive for HSV-1 DNA and another two tested positive for VZV DNA. All patients with herpes labialis tested positive for HSV-1 DNA and all patients with Ramsay Hunt syndrome tested positive for VZV DNA. With the absorption-based oral fluid collection system, detections rates and viral loads were found to be significantly lower when compared to those obtained with the liquid phase-based collection system. Collection of oral fluid with a liquid phase-based system and the use of automated and standardized molecular methods allow early and reliable detection of HSV-1 and VZV DNAs in patients with acute idiopathic peripheral facial nerve palsy and may provide a valuable decision support regarding start of antiviral treatment at the first clinical visit.

Entacapone, a catechol-O-methyltransferase inhibitor, improves the motor activity and dopamine content of basal ganglia in a rat model of Parkinson's disease induced by Japanese encephalitis virus.

Levodopa is the main medication used for the treatment of Parkinson's disease. However, dyskinesia and wearing-off appear after the administration of high-dose levodopa for a long period. To combat the dyskinesia and wearing-off, levodopa is used together with a dopamine (DA) receptor agonist, and the amount of levodopa is decreased. We have reported the monoamine oxidase (MAO)-B inhibitor selegiline to be effective for treating motor dysfunction in Parkinson's disease model rats. We analyzed the improvement in motor functions and catecholamine contents in various brain regions induced by a combination of the catechol-O-methyltransferase (COMT) inhibitor entacapone and a levodopa/dopadecarboxylase inhibitor (DDCI) in Japanese encephalitis virus (JEV) induced Parkinson's disease model rats. Entacapone (10 mg/kg) was administered via a single oral administration with levodopa/DDCI (10 mg/kg). The motor functions of the JEV model rats were significantly worsened, compared with those of the healthy control rats. The motor functions in the Parkinson's disease model rats were significantly recovered to the same levels as the healthy control rats by the combined administration of entacapone and levodopa/DDCI. A significant improvement in motor function was not demonstrated in the case of the administration of levodopa/DDCI alone. The striatal DA concentrations in the model rat brains were significantly increased by using levodopa/DDCI together with entacapone. Motor function was recovered by raising the striatum DA density in the model rats. Thus, COMT inhibitors are useful for decreasing the amount of levodopa administered to Parkinson's disease patients.

Acute reversible parkinsonism in Epstein-Barr virus-related encephalitis lethargica-like illness.

A 10-year-old boy presented with fever, headache, vomiting, and hypersomnolence. An akinetic-rigid syndrome with tremor, dysphagia, dysphonia, and sialorrhea, as well as pyramidal signs, developed. Slightly elevated protein content was found in the cerebrospinal fluid and serological investigations were suggestive of a primary Epstein-Barr virus infection. Magnetic resonance imaging (MRI) showed massive bilateral hyperintense striatal and punctiform periventricular lesions. After 2-month treatment with steroids and antiparkinsonian drugs, all features resolved without sequelae. Control MRI demonstrated only minimal residual lesions in both putamina. Strongly resembling the encephalitis lethargica-like syndrome, this case is an unusual presentation of parainfectious acute disseminated encephalitis.

Levodopa-responsive infantile parkinsonism due to a novel mutation in the tyrosine hydroxylase gene and exacerbation by viral infections.

Autosomal recessive forms of infantile dystonia due to mutations in the tyrosine hydroxylase (TH) gene have been described recently. The main clinical manifestations are Segawa's disease, or infantile hypokinetic rigid Parkinsonism. Here, we report on a patient with hyperrigidity, psychomotor developmental delay, and dystonic posturing of the hands, symptoms that appeared after a viral infection at the age of 14 months. Low homovanillic acid/5-hydroxyindolacetic acid (HVA/5HIAA) ratio in cerebrospinal fluid suggested a TH deficiency. Molecular analysis revealed a novel (H246Y) and a known (D498G) compound heterozygote mutation in the TH gene. The patient showed a remarkable response to treatment with levodopa. The new mutation and the association of viral infections with the onset and worsening of symptoms are discussed.

Variable patterns of varicella-zoster virus reactivation in Ramsay Hunt syndrome.

The mechanism by which reactivation of varicella-zoster virus (VZV) causes facial paralysis in Ramsay Hunt syndrome remains unclear. The relationship between VZV load and the onset of facial paralysis was analyzed in 42 patients with Ramsay Hunt syndrome. The patients were divided into three groups according to the times of appearance of zoster and of facial paralysis; group I (zoster preceding, n = 13), group II (simultaneous, n = 22), group III (paralysis preceding, n = 7). A real-time quantitative PCR assay was used to measure VZV DNA copy number in saliva, and paired sera were assayed for anti-VZV IgG and IgM antibodies. In group I, the VZV DNA-positive rate was low and virus load decreased gradually after the initial hospital visit around the time of onset of paralysis. The level of anti-VZV antibodies had in most cases already increased at that time. In group III, viral load tended to increase after the onset of paralysis and peaked around the time of appearance of zoster. The level of anti-VZV antibodies was low at the onset of paralysis but showed a significant increase when paired sera were tested. In group II, virus load and changes in level of anti-VZV antibodies either resembled group I or group III behavior. These results indicate that facial paralysis in Ramsay Hunt syndrome can occur at various times between the early and the regression phase of VZV reactivation, suggesting that there are variable patterns of development of facial nerve dysfunction caused by VZV reactivation and the progression of neuritis.

Acyclovir in the treatment of Ramsay Hunt syndrome.

Ramsay Hunt syndrome is an herpetic disease with ominous prognosis regarding the facial nerve. Treatment with acyclovir, a well-known virostatic agent, has been given in a small number of patients in recent years with excellent results. We report on the administration of acyclovir intravenously for 7 days in 31 patients with Ramsay Hunt syndrome, with overall recovery rate of 82.6%. There were no side effects regarding this treatment.

Isatin, an endogenous MAO inhibitor, improves bradykinesia and dopamine levels in a rat model of Parkinson's disease induced by Japanese encephalitis virus.

Isatin, an endogenous monoamine oxidase (MAO) inhibitor, has an important role in the control of neurotransmitter concentration. We previously reported that exogenously administered isatin significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. In order to test the possibility of treating Parkinson's disease by isatin, we evaluated DA levels in the striatum and bradykinesia using a rat model of Parkinson's disease induced by the Japanese encephalitis virus (JEV).We have already reported that in adult Fischer rats infected with JEV at day 13, there was a marked decrease of tyrosine hydroxylase-positive neurons in the bilateral substantia nigra after 12 weeks. Effects of isatin were investigated in JEV-induced post-encephalitic parkinsonism rats by a pole test and high performance liquid chromatograph (HPLC) with an electrochemical detector (ECD). Isatin (100 mg/kg per day for 1 week, intraperitoneal injection) improved the bradykinesia observed in the JEV-induced parkinsonism rats. Dopamine (DA) concentrations in the JEV-infected rats were profoundly reduced in the striatum as compared with controls. Isatin also increased DA in the striatum of parkinsonism rats. These results suggest that isatin could be a possible treatment for Parkinson's disease as well as for post-encephalitic parkinsonism.

Parkinsonism in HIV dementia.

A great number of human immunodeficiency virus (HIV)-infected patients develop a central nervous system disorder, commonly called HIV dementia or AIDS dementia complex (ADC). HIV dementia is independent of opportunistic infections and is due to the virus itself. Symptoms include psychomotor slowing, apathy and motor disorders similar to the bradykinesia and postural and gait abnormalities observed in late Parkinson's disease. Consequently, HIV has been discussed during the last few years as an additional cause for parkinsonism, and parkinsonian syndromes as manifestations of HIV dementia. Moreover, the early phase of HIV infection gains increasing interest because of studies which report subtle neurological symptoms at this stage. Accordingly, we found in SIV-infected monkeys that dopamine is reduced by 44% within as few as two months of infection, indicating that changes during early infection must be thoroughly evaluated. In this short review, we discuss alterations in the nigrostriatal dopaminergic system during early and late immunodeficiency virus infection and the common clinical and biochemical features shared by HIV dementia and Parkinson's disease.

Parkinsonism due to predominant involvement of substantia nigra in Japanese encephalitis.

OBJECTIVE: To study the clinical correlates of lesions seen predominantly in the substantia nigra in some patients with Japanese encephalitis (JE). BACKGROUND: JE typically involves thalamus, brainstem, spinal cord, and cerebral cortex. Rarely, basal ganglia and cerebellum may be affected. Lesions are often widespread and discrete. Predominant involvement of substantia nigra in JE has not been previously reported. METHODS: Of 52 patients with JE seen in an endemic zone, five were selected on the basis of isolated lesions in the substantia nigra on MRI; all were subjected to detailed clinical and laboratory evaluation. RESULTS: Presenting symptoms were fever, alteration of consciousness, neck stiffness, and decreased body movements. Examination during acute illness revealed restricted eye movements, opsoclonus, upbeating nystagmus, and cogwheel rigidity. There was early and complete recovery of consciousness and eye signs. Parkinsonian features such as positive glabellar tap sign, masklike face, bradykinesia, tremors, and postural instability became apparent as these patients started walking. Reversible mutism was observed in three patients during the acute phase. Response to levodopa, amantadine, and trihexiphenedyl was partial. Three patients were followed for more than 1 year, during which time their parkinsonian features recovered completely. Substantial recovery was also observed in the two other patients 2 months after regaining consciousness. CONCLUSIONS: Some patients with Japanese encephalitis may have lesions predominantly in the substantia nigra. After recovery from acute encephalitic illness, they manifest clinically with typical parkinsonian features. Although several viruses are known to cause parkinsonism, this is the first demonstration of a virus producing lesions predominantly in the substantia nigra and causing parkinsonism.