Progressive myoclonic ataxia and JC virus encephalitis in an AIDS patient

A review of movement disorders in persons living with HIV

BACKGROUND

The human immunodeficiency virus (HIV) causes movement disorders in persons living with HIV (PLH).

OBJECTIVES AND METHODS

We conducted a systematic review on the spectrum of movement disorders in PLH using standard terms for each of the phenomenologies and HIV.

RESULTS

Movement disorders in PLH were commonly attributed to opportunistic infections (OI), dopamine receptor blockade reactions, HIV-associated dementia (HAD), presented during seroconversion, developed due to drug reactions or antiretroviral therapy (ART) itself and lastly, movement disorders occurred as a consequence of the HIV-virus. Parkinsonism in ART naïve PLH was associated with shorter survival, however when Parkinsonism presented in PLH on ART, the syndrome was indistinguishable from Idiopathic Parkinson's disease and responded to therapy. Tremor was often postural due to HAD, drugs or OI. Generalized chorea was most frequent in HIV encephalopathy and toxoplasmosis gondii caused most cases of hemichorea. Ataxia was strongly associated with JCV infection, ART efavirenz toxicity or due to HIV itself. Dystonia was reported in HAD, secondary to drugs and atypical facial dystonias. Both cortical/subcortical and segmental/spinal origin myoclonus were noted mainly associated with HAD. In patients with HIV related opsoclonus-myoclonus-ataxia-syndrome, seroconversion illness was the commonest cause of followed by IRIS and CSF HIV viral escape phenomenon.

CONCLUSIONS

Aetiology of movement disorders in PLH depend on the treatment state. Untreated, PLH are prone to develop OI and HAD and movement disorders. However, as the number of PLH on ART increase and survive longer, the frequency of ART and non-AIDS related complications are likely to increase.

A practical approach to diseases affecting dentate nuclei

A wide variety of diseases affect the dentate nuclei. When faced with the radiological demonstration of signal changes in the dentate nuclei, radiologists and clinical neurologists have to sieve through the many possibilities, which they do not encounter on a regular basis. This task can be challenging, and therefore, developing a clinical, radiological, and laboratory approach is important. Information on the topic is scattered and the subject has not yet been reviewed. In this review, a combined clinicoradiological approach is presented. The signal changes in T1, T2, fluid-attenuated inversion recovery (FLAIR), diffusion, susceptibility weighted, and gadolinium-enhanced images can give specific or highly suggestive patterns, which are illustrated. The role of computed tomography (CT) in the diagnostic process is discussed. Specific radiological patterns do not exist in a significant proportion of patients where the clinical and laboratory analysis becomes important. In this review, we group the clinical constellations to narrow down the differential diagnosis and highlight the diagnostic clinical signs, such as tendon xanthomas and Kayser-Fleischer rings. As will be seen, a number of these conditions are potentially reversible, and hence, their early diagnosis is desirable. Finally, key diagnostic tests and available therapies are outlined. The practical approach thus begins with the radiologist and winds its way through the clinician, towards carefully selected diagnostic tests defining the therapy options.

Progressive multifocal leukoencephalopathy (PML) associated with HIV Clade C--is not uncommon

Progressive multifocal leukoencephalopathy (PML) is a rare, subacute, demyelinating disease of the central nervous system caused by JC virus. Studies of PML from HIV Clade C prevalent countries are scarce. We sought to study the clinical, neuroimaging, and pathological features of PML in HIV Clade C patients from India. This is a prospective cum retrospective study, conducted in a tertiary care Neurological referral center in India from Jan 2001 to May 2012. Diagnosis was considered "definite" (confirmed by histopathology or JCV PCR in CSF) or "probable" (confirmed by MRI brain). Fifty-five patients of PML were diagnosed between January 2001 and May 2012. Complete data was available in 38 patients [mean age 39 ± 8.9 years; duration of illness-82.1 ± 74.7 days). PML was prevalent in 2.8 % of the HIV cohort seen in our Institute. Hemiparesis was the commonest symptom (44.7 %), followed by ataxia (36.8 %). Definitive diagnosis was possible in 20 cases. Eighteen remained "probable" wherein MRI revealed multifocal, symmetric lesions, hypointense on T1, and hyperintense on T2/FLAIR. Stereotactic biopsy (n = 11) revealed demyelination, enlarged oligodendrocytes with intranuclear inclusions and astrocytosis. Immunohistochemistry revelaed the presence of JC viral antigen within oligodendroglial nuclei and astrocytic cytoplasm. No differences in clinical, radiological, or pathological features were evident from PML associated with HIV Clade B. Clinical suspicion of PML was entertained in only half of the patients. Hence, a high index of suspicion is essential for diagnosis. There are no significant differences between clinical, radiological, and pathological picture of PML between Indian and Western countries.

A review on JC virus infection in kidney transplant recipients

The polyomavirus (PyV), JC virus (JCV), is a small nonenveloped DNA virus that asymptomatically infects about 80% of healthy adults and establishes latency in the kidney tissue. In case of immunodeficient hosts, JCV can lytically infect the oligodendrocytes, causing a fatal demyelinating disease, known as progressive multifocal leukoencephalopathy (PML). Although the reactivation of another human PyV, BK virus (BKV), is relatively common and its association with the polyomavirus associated nephropathy (PyVAN) following renal transplantation is proven, JCV replication and its impact on graft function and survival are less well studied. Here we describe the biology of JCV and its pathological features and we review the literature regarding the JCV infection analyzed in the setting of transplantations.

Progressive multifocal leukoencephalopathy: an unexpected complication of modern therapeutic monoclonal antibody therapies

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disorder of the central nervous system, caused by the reactivation of the ubiquitous JC virus. PML usually occurs during severe immunosuppression, and the most common causes are represented by human immunodeficiency virus infection, lymphoproliferative disorders and other forms of cancer. Recently, the introduction of monoclonal antibodies (e.g. natalizumab, rituximab, efalizumab) in the treatment of several dysimmune diseases such as multiple sclerosis, rheumatoid arthritis, psoriasis and systemic lupus erythematosus, has led to an increased incidence of PML. This phenomenon has had severe consequences, leading, for example, to the withdrawal from the market of Efalizumab, and important restrictions in the use of the other compounds, all of which are characterized by high efficacy in improving prognosis and quality of life. In this review we will discuss clinical, laboratory and imaging findings of PML. In addition, proposed pathogenetic mechanisms promoting the reactivation of JC virus in the context of treatment with monoclonal antibodies will be described.

Progressive multifocal leukoencephalopathy: clinical and molecular aspects

The fatal CNS demyelinating disease, progressive multifocal leukoencephalopathy (PML), is rare and appears to occur almost always as a consequence of immune dysfunction. Thus, it is associated with HIV/AIDS and also as a side effect of certain immunomodulatory monoclonal antibody therapies. In contrast to the rarity of PML, the etiological agent of the disease, the polyomavirus JC (JCV), is widespread in populations worldwide. In the 40 years since JCV was first isolated, much has been learned about the virus and the disease from laboratory and clinical observations. However, there are many aspects of the viral life cycle and of the pathogenesis of the disease that remain unclear, and our understanding is constantly evolving. In this review, we will discuss our current understanding of the clinical features of PML and molecular characteristics of JCV and of how they relate to each other. Clinical observations can inform molecular studies of the virus, and likewise, molecular findings concerning the life cycle of the virus can guide the development of novel therapeutic strategies.

Myoclonus

Myoclonus can be classified as physiologic, essential, epileptic, and symptomatic. Animal models of myoclonus include DDT and posthypoxic myoclonus in the rat. 5-Hydrotryptophan, clonazepam, and valproic acid suppress myoclonus induced by posthypoxia. The diagnostic evaluation of myoclonus is complex and involves an extensive work-up including basic electrolytes, glucose, renal and hepatic function tests, paraneoplastic antibodies, drug and toxicology screens, thyroid antibody and function studies, neurophysiology testing, imaging, and tests for malabsorption disorders, assays for enzyme deficiencies, tissue biopsy, copper studies, alpha-fetoprotein, cytogenetic analysis, radiosensitivity DNA synthesis, genetic testing for inherited disorders, and mitochondrial function studies. Treatment of myoclonus is targeted to the underlying disorder. If myoclonus physiology cannot be demonstrated, treatment should be aimed at the common pattern of symptoms. If the diagnosis is not known, treatment could be directed empirically at cortical myoclonus as the most common physiology. In cortical myoclonus, the most effective drugs are sodium valproic acid, clonazepam, levetiracetam, and piracetam. For cortical-subcortical myoclonus, valproic acid is the drug of choice. Here, lamotrigine can be used either alone or in combination with valproic acid. Ethosuximide, levetiracetam, or zonisamide can also be used as adjunct therapy with valproic acid. A ketogenic diet can be considered if everything else fails. Subcortical-nonsegmental myoclonus may respond to clonazepam and deep-brain stimulation. Rituximab, adrenocorticotropic hormone, high-dose dexamethasone pulse, or plasmapheresis have been reported to improve opsoclonus myoclonus syndrome. Reticular reflex myoclonus can be treated with clonazepam, diazepam and 5-hydrotryptophan. For palatal myoclonus, a variety of drugs have been used.

Symptomatic myoclonus

A huge number of neurological disorders are associated with myoclonus. This paper describes these disorders whose diagnosis partly relies on the presence of myoclonus. The diagnostic approach is related to certain clinical features of myoclonus, which, after their integration in the clinical context, help orientate towards diagnosis. Myoclonus is frequent during dementia. Although its presence is well-known to take part in the diagnosis of Creutzfeldt-Jakob disease (CJD), myoclonus can also be present to a significant degree in Alzheimer's disease and Lewy body dementia (LBD), which raises a diagnostic issue. Both its clinical and electrophysiological features may help differential diagnosis, given that myoclonus with fast-evolving dementia and focal neurological signs should favor the diagnosis of CJD. Myoclonus in a context of progressive ataxia suggests one clinical form of the Ramsay-Hunt syndrome (progressive myoclonic ataxia, PMA), whose most frequent causes are: coeliac disease, mitochondriopathies, some spino-cerebellar degenerations, and some late metabolic disorders. In addition to ataxia and myoclonus, the presence of opsoclonus directs diagnosis toward the opsoclonus-myoclonus syndrome (OMS), whose origin, in adult, is idiopathic or paraneoplastic. Palatal tremor (myoclonus) with ataxia may represent either a sporadic pattern, which often reflects the evolution of degenerative or lesional disorders, or a familial pattern in some degenerative affections or metabolic diseases. Of more recent knowledge is the association of progressive ataxia, myoclonus, and renal failure, which corresponds to a recessive autosomic disease. In a context of encephalopathy, myoclonus is frequent in metabolic or hydro-electrolytic disorders, and in brain anoxia. One should distinguish these various forms of myoclonus which may occur in the acute post-anoxic phase, from those occurring as sequels at a later stage, i.e. the Lance and Adams syndrome whose clinical aspects are also multiple. Myoclonus is less frequent during toxic or drug exposures. Irrespective of its acute or insidious onset, Hashimoto's encephalopathy is accompanied by myoclonus and tremor. Myoclonus may also be present during encephalic and/or spinal infectious disorders. Myoclonus with focal neurological signs may be observed in thalamic lesions, responsible for unilateral asterixis or unilateral myoclonus superimposed on dystonic posture. Segmental spinal myoclonus or propriospinal myoclonus may be associated with several spinal-cord disorders. Myoclonus associated with peripheral nerve lesions is exceptional or even questionable for some of these.

Head tremor and progressive multifocal leukoencephalopathy in AIDS patients: report of two cases

Progressive multifocal leukoencephalopathy (PML) is caused by replication of JC virus in oligodendrocytes of immunocompromised patients. Common manifestations are focal motor and sensory deficits, gait abnormalities, speech and language disturbances, cognitive disorders, headache, and visual impairment. Although the occurrence of movement disorders is rare in PML, bradykinesia, rigidity, dystonia, myoclonic jerks and myoclonic ataxia have been described. Head tremor associated with PML has not been previously reported. We report two cases of PML in whom head tremor was present.

Movement disorders and AIDS: a review

Movement disorders are a potential neurologic complication of acquired immune deficiency syndrome (AIDS), and may sometimes represent the initial manifestation of HIV infection. Dopaminergic dysfunction and the predilection of HIV infection to affect subcortical structures are thought to underlie the development of movement disorders such as parkinsonism in AIDS patients. In this review, we will discuss the clinical presentations, etiology and treatment of the various AIDS-related hypokinetic and hyperkinetic movement disorders, such as parkinsonism, chorea, myoclonus and dystonia. This review will also summarize current concepts regarding the pathophysiology of parkinsonism in HIV infection.