A case of adult onset pure pallidal degeneration. I. Clinical manifestations and neuropathological observations

Pallidal degenerations and related disorders: an update

Neurodegenerative disorders involving preferentially the globus pallidus, its efferet and afferent circuits and/or related neuronal systems are rare. They include a variety of both familial and sporadic progressive movement disorders, clinically manifesting as choreoathetosis, dystonia, Parkinsonism, akinesia or myoclonus, often associated with seizures, mental impairment and motor or cerebellar symptoms. Based on the involved neuronal systems, this heterogenous group has been classified into several subgroups: "pure" pallidal atrophy (PPA) and extended forms, pallidonigral and pallidonigrospinal degeneration (PND, PNSD), pallidopyramidal syndrome (PPS), a highly debatable group, pallidopontonigral (PPND), nigrostriatal-pallidal-pyramidal degeneration (NSPPD) (Kufor-Rakeb syndrome /KRS), pallidoluysian degeneration (PLD), pallidoluysionigral degeneration (PLND), pallidoluysiodentate atrophy (PLDA), the more frequent dentatorubral-pallidoluysian atrophy (DRPLA), and other hereditary multisystem disorders affecting these systems, e.g., neuroferritinopathy (NF). Some of these syndromes are sporadic, others show autosomal recessive or dominant heredity, and for some specific gene mutations have been detected, e.g., ATP13A2/PARK9 (KRS), FTL1 or ATP13A2 (neuroferritinopathy), CAG triple expansions in gene ATN1 (DRPLA) or pA152T variant in MAPT gene (PNLD). One of the latter, and both PPND and DRPLA are particular subcortical 4-R tauopathies, related to progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and frontotemporal lobe degeneration-17 (FTLD-17), while others show additional 3-R and 4-R tauopathies or TDP-43 pathologies. The differential diagnosis includes a large variety of neurodegenerations ranging from Huntington and Joseph-Machado disease, tauopathies (PSP), torsion dystonia, multiple system atrophy, neurodegeneration with brain iron accumulation (NBIA), and other extrapyramidal disorders. Neuroimaging data and biological markers have been published for only few syndromes. In the presence of positive family histories, an early genetic counseling may be effective. The etiology of most phenotypes is unknown, and only for some pathogenic mechanisms, like polyglutamine-induced oxidative stress and autophagy in DRPLA, mitochondrial dysfunction induced by oxidative stress in KRS or ferrostasis/toxicity and protein aggregation in NF, have been discussed. Currently no disease-modifying therapy is available, and symptomatic treatment of hypo-, hyperkinetic, spastic or other symptoms may be helpful.

Pallidopyramidal disease: a misnomer?

The combination of recessive early-onset parkinsonism and pyramidal tract signs caused by pallidopyramidal degeneration is known as pallidopyramidal disease or syndrome (PPD/S). We investigated whether patients diagnosed as Davison's PPD/S showed any definite proof of pyramidal and pallidal involvement, without findings suggestive of other nosological entities. Since Davison's original description, 15 other PPD/S cases have been reported, yet all lack proof of pyramidal or pallidal degeneration. Because of the dopa-responsiveness in all patients subsequent to Davison's report, we argue that these patients probably suffered from early-onset nigral parkinsonism or dopa-responsive dsystonia, rather than pallidal parkinsonism; in such cases, the presumed pyramidal Babinski could be a pseudobabinski ("striatal toe"). Secondary pallidopyramidal syndromes do occur, for example, in multiple system atrophy or Wilson's disease, but in these patients additional findings indicate diseases other than Davison's PPD/S. We conclude that the existence of PPD/S as a distinct clinico-pathological nosological entity, as proposed by Davison, is doubtful. In cases reported as Davison's PPD/S, the description "pallidopyramidal" seems to be a misnomer.

Severe hypokinesis caused by paraneoplastic anti-Ma2 encephalitis associated with bilateral intratubular germ-cell neoplasm of the testes

We report a 40-year-old man with severe hypokinesis as paraneoplastic manifestation of a microscopic "carcinoma in situ" of the testis. The young age of the patient, along with progressive neurologic deterioration, detection of anti-Ma2 antibodies, and ultrasound findings of bilateral microcalcifications, led to bilateral orchiectomy, revealing the tumor in both testes. After orchiectomy, neurological symptoms stabilized, but the patient eventually died of systemic complications caused by his severe neurological deficits. Anti-Ma2 paraneoplastic encephalitis should be considered in patients with severe hypokinesis, and intensive investigation and aggressive approach to treatment is encouraged to prevent progression of the neurological deficits.

Woman with a 26-year history of parkinsonism, supranuclear ophthalmoplegia, and loss of postural reflexes

A woman who had her first serious fall at age 48 years subsequently developed neurological symptoms. Her case is described, differential diagnoses are presented, pathology is discussed, and a final diagnosis is reached.

Open interconnected model of basal ganglia-thalamocortical circuitry and its relevance to the clinical syndrome of Huntington's disease

The early stages of Huntington's disease (HD) present with motor, cognitive, and emotional symptoms. Correspondingly, current models implicate dysfunction of the motor, associative, and limbic basal ganglia-thalamocortical circuits. Available data, however, indicate that in the early stages of the disease, striatal damage is mainly restricted to the associative striatum. Based on an open interconnected model of basal ganglia-thalamocortical organization, we provide a detailed account of the mechanisms by which associative striatal pathology may lead to the complex pattern of motor, cognitive, and emotional symptoms of early HD. According to this account, the degeneration of a direct and several indirect pathways arising from the associative striatum leads to impaired functioning of: (1) the motor circuit, resulting in chorea and bradykinesia, (2) the associative circuit, resulting in abnormal eye movements, "frontal-like" cognitive deficits and "cognitive disinhibition," and (3) the limbic circuit, resulting in affective and psychiatric symptoms. When relevant, this analysis is aided by comparing the symptomatology of HD patients to that of patients with mild to moderate Parkinson's disease, since in the latter there is similar dysfunction of direct pathways but opposite dysfunction of indirect pathways. Finally, we suggest a potential novel treatment of HD and provide supportive evidence from a rat model of the disease.

Pallido-Luysio-Nigral atrophy revealed by rapidly progressive hemidystonia: a clinical, radiologic, functional, and neuropathologic study

Pallido-luysio-nigral atrophy (PLNA) is a rare neurodegenerative disease in which the clinical and radiologic correlates have not yet been clearly established. A 62-year-old man insidiously developed dystonic postures, choreoathetoid movements, slowness, and stiffness, which initially affected the right hand and foot and progressively spread to the entire right side. T2-weighted magnetic resonance imaging showed increased signal intensity in both left and right medial pallida and in the left substantia nigra. Tests using HMPAO-SPECT and FDG-PET demonstrated left cortical hyperperfusion and hypermetabolism, whereas the left lenticular nucleus was slightly hypometabolic. At age 65, abnormal movements and postures involved all four limbs and the axis causing major gait disturbances, and facial and bulbar muscles atrophied resulting in dysarthria, dysphagia, and impaired breathing. Diffuse amyotrophy and fasciculations also appeared. Death occurred at age 66, 4 years after onset. At autopsy, severe bilateral neuronal loss and gliosis restricted to the pallidum, the subthalamic nucleus, the substantia nigra, and the hypoglossal nucleus were noted, accounting for the diagnosis of PLNA with lower motor neuron involvement. Progressive hemidystonia with adult onset represents an unusual clinical presentation for this disorder. Moreover, this observation indicates that a diagnosis of PLNA should be considered for specific magnetic resonance imaging, SPECT, and/or PET data, and suggests that in PLNA, pallidal dysfunction might play a key role in the dystonic presentation.

Electrolytic lesion of globus pallidus ameliorates the behavioral and neurodegenerative effects of quinolinic acid lesion of the striatum: a potential novel treatment in a rat model of Huntington's disease

Bilateral electrolytic pallidal lesion ameliorated the deleterious effects of bilateral quinolinic acid (QA) lesion to the striatum on post-surgery weight, activity level, and performance in a water maze task, and reduced the extent of striatal damage. Given that the neurodegenerative and behavioral effects of QA striatal lesion are thought to mimic those seen in Huntington's disease, these results may point to a potential novel treatment for this disease.

The connections of the primate subthalamic nucleus: indirect pathways and the open-interconnected scheme of basal ganglia-thalamocortical circuitry

The current view of basal ganglia organization holds that functionally corresponding subregions of the frontal cortex, basal ganglia and thalamus form several parallel segregated basal ganglia-thalamocortical circuits. In addition, this view states that striatal output reaches the basal ganglia output nuclei (the substantia nigra pars reticulata (SNR) and the internal segment of the globus pallidus (GPi)) via a 'direct' pathway, and via an 'indirect pathway' which traverses the external segment of the globus pallidus (GPe) and the subthalamic nucleus (STN). However, the topographical relationships of GPe and STN, and their topographical relationships with the basal ganglia-thalamocortical circuits are still unclear. The present work reviewed primate data on the topographical organization of STN afferents from GPe, and STN efferents to the pallidum, striatum and SNR, and examined these data with respect to a tripartite (motor, associative and limbic) functional subdivision of the striatum and pallidum. This examination indicated the following. (1) On the basis of its efferent connections, the STN may be divided into a motor and an associative territories, as well as a smaller limbic territory, each projecting to corresponding areas in the pallidum and striatum. (2) Efferents from GPe are in a position to contact subthalamic cells projecting to GPi/SNR, thus providing anatomical support for the existence of indirect pathways. (3) Moreover, given the tripartite division of the striatum, pallidum, and STN, the available data indicate the existence of indirect pathways connecting functionally corresponding subregions of the striatum, pallidum, and STN, as well as indirect pathways connecting functionally non-corresponding subregions. On the basis of the above we suggested that there may be two types of indirect pathways, one which terminates in the same subregion in GPi/SNR as the direct pathway arising from the same striatal subregion, and another which terminates in a different GPi/SNR subregion than the direct pathway arising from the same striatal subregion. We termed the former a 'closed indirect pathway' and the latter an 'open indirect pathway'. The application of these concepts to the surveyed data suggested the existence of three closed indirect pathways, each connecting the corresponding functional (motor, associative, and limbic) regions of the striatum, pallidum, STN, and SNR, as well as of two open indirect pathways, one connecting the associative striatum to the motor subregions of the basal ganglia, and the other connecting the associative striatum to the limbic subregions of the basal ganglia. While the organization of the closed indirect pathways fits the closed segregated arrangement of basal ganglia-thalamocortical circuitry, the organization of the open indirect pathways fits the recently suggested open interconnected scheme of basal ganglia thalamocortical circuitry. The clinical implications of this scheme for Huntington's disease are discussed.

Persistent neuroleptic-induced rigidity and dystonia in AIDS dementia complex: a clinico-pathological case report

Patients with AIDS dementia complex (ADC) appear to have an increased likelihood of developing acute onset parkinsonism and dystonia when treated with dopamine antagonists. It has been hypothesized, based on clinical evidence, that hypersensitivity to these drugs in ADC is probably related to direct invasion of the basal ganglia by the HIV virus and a secondary alteration in dopaminergic mechanisms. We report the first pathological description of a patient with ADC who developed acute onset, generalized rigidity and dystonia after a brief trial of low dose neuroleptic therapy administered for psychotic symptoms. An unusual clinical feature of this case was the persistence of his movement disorder. Pathological examination revealed a generalized encephalitic process with substantial neuronal loss observed primarily in the medial and lateral globus pallidus. Correlation with a current model of basal ganglia pathophysiology and other disorders with pallidal lesions is discussed. Clinical and pathological features of this case confirm the previous contention and indicate that dopamine antagonists should be utilized with extreme caution in patients with ADC.

Axial motor disturbances after hypoxic lesions of the globus pallidus

Four subjects aged between 29 and 60 years were examined because of axial motor impairment after hypoxic brain injury. Magnetic resonance imaging revealed circumscribed lesions of the globus pallidus in every case. The association of freezing of the gait, speech disorders, axial bradykinesia, and postural disturbances, with no rigidity or tremor and little or no distal akinesia, suggests a role of the globus pallidus in controlling axial motion.

Cell loss in supraoptic and paraventricular nucleus in Alzheimer's disease

Previous studies have shown an activation of the hypothalamo-neurohypophyseal system (HNS) in normal aging and in senile dementia. Among other explanations, this activation might be secondary to cell loss in the supraoptic (SO) and paraventricular (PV) nuclei. This study reports a 63% loss in the SO and a 56% loss in the PV in a group of Alzheimer disease (AD) patients. The remaining neurons undergo a compensatory hypertrophy that is more pronounced in the SO, affecting cell and nuclear size as well as nucleolar volume. The group of patients with a diagnosis of moderate dementia showed the greatest hypertrophy, as compared to the severely demented patients. Our results suggest that there is a compensatory capacity in the earlier stages of the dementia, that is lost in the final stages of Alzheimer's disease.

A case of adult onset pure pallidal degeneration. II. Analysis of neurotransmitter markers, with special reference to the termination of pallidothalamic tract in human brain

We analyzed neurotransmitter markers in a brain of a very rare case of pathologically confirmed adult-onset pure pallidal degeneration (PPD) as compared with 16 controls. Neurotransmitter concentrations are significantly altered in the globus pallidus (GP), subthalamic nucleus (ST) and the thalamic nuclei. Concentrations of gamma-aminobutyric acid (GABA) in the external segment (GPe) and internal segment (GPi) of GP and ST are decreased to 62, 45 and 55% of the control mean, respectively. Concentrations of glutamic acid are increased in GPi (144%) and ST (134%). Choline acetyltransferase (ChAT) activities are increased in GPe (232%), GPi (218%), ST (161%), and ventroanterior (VA, 210%) and ventrolateral nucleus (VL, 193%) of the thalamus. Noradrenaline (NA) concentrations in GPe and GPi are 56 and 43% of the control mean, respectively. Dopaminergic and serotonergic systems show no remarkable change. The grid microdissection analysis demonstrates a patchy GABA distribution in the thalamus of 3 controls, whereas a small GABA-rich area in the ventro-oral nucleus (VO) according to the atlas of Hopf disappears in adult onset PPD. These results strongly suggest that (1) GP GABAergic neurons are selectively degenerated and striatopallidal GABAergic nerve terminals are hypoactive; (2) ChAT activities in GP, ST, VA and VL are increased; (3) the subthalamopallidal glutamatergic system is not hypoactive; (4) activity of the noradrenergic system in GP is decreased; and that (5) VO in the thalamus specifically receives GABAergic nerve terminals from GP in human brain.