Delayed-onset central poststroke pain due to degeneration of the spinothalamic tract following thalamic hemorrhage: A case report

RATIONALE

Recent studies have used diffusion tensor tractography (DTT) to demonstrate that central poststroke pain (CPSP) was related to spinothalamic tract (STT) injury in patients with stroke. However, few studies have been reported about delayed-onset CPSP due to degeneration of the STT following a stroke.

PATIENT'S CONCERNS

A 57-year-old female patient presented with right hemiparesis after stroke. Two weeks after onset, she did not report any pain. At approximately 6 months after onset, she reported pain in the right arm and leg, and the pain slowly intensified with the passage of time. At 14 months after onset, the characteristics and severity of her pain were assessed to be continuous pain without allodynia or hyperalgesia; tingling and cold-sensational pain in her right whole arm and leg (visual analog scale score: 5).

DIAGNOSES

The patient was diagnosed as the right hemiparesis due to spontaneous thalamic hemorrhage.

INTERVENTIONS

Clinical assessment and diffusion tensor imaging (DTI) were performed 2 weeks and 14 months after onset.

OUTCOMES

She suffered continuous pain in her right whole arm and leg (visual analog scale score: 5). On DTT of the 2-week postonset DTI scans, the configuration of the STT was well-preserved in both hemispheres. However, in contrast to those 2-week postonset results, the 14-month postonset DTT results showed partial tearing and thinning in the left STT. Regardless, both the 2-week and 14-month postonset DTT showed that the left STT passed through the vicinity of the thalamic lesion.

LESSONS

Diagnostic importance of performing a DTT-based evaluation of the STT in patients exhibiting delayed-onset CPSP following intracerebral hemorrhage.

Degeneration of paramedian nuclei in the thalamus induces Holmes tremor in a case of artery of Percheron infarction

RATIONALE

Holmes' tremor is an uncommon neurologic disorder following brain insults, and its pathogenesis is undefined. The interruption of the dento-rubro-thalamic tract and secondary deterioration of the nigrostriatal pathway are both required to initiate Holmes' tremor. We used nuclear medicine imaging tools to analyze a patient with concurrent infarction in different zones of each side of the thalamus. Finding whether the paramedian nuclear groups of the thalamus were injured was a decisive element for developing Holmes' tremor.

PATIENT CONCERNS

A 36-year-old woman was admitted to our department due to a bilateral paramedian thalamic infarction. Seven months after the stroke, a unilaterally involuntary trembling with irregularly wavering motions occurring in both her left hand and forearm.

DIAGNOSIS

Based on the distinct features of the unilateral coarse tremor and the locations of the lesions on the magnetic resonance imaging (MRI), the patient was diagnosed with bilateral paramedian thalamic infarction complicated with a unilateral Holmes' tremor.

INTERVENTIONS

The patient refused our recommendation of pharmacological treatment with levodopa and other dopamine agonists based on personal reasons and was only willing to accept physical and occupational training programs at our outpatient clinic.

OUTCOMES

We utilized serial anatomic and functional neuroimaging of the brain to survey the neurologic deficit. A brain magnetic resonance imaging showed unequal recovery on each side of the thalamus. The residual lesion appeared larger in the right-side thalamus and had gathered in the paramedian area. A brain perfusion single-photon emission computed tomography (SPECT) revealed that the post-stroke hypometabolic changes were not only in the right-side thalamus but also in the right basal ganglion, which was anatomically intact. Furthermore, the brain Technetium-99m-labeled tropanes as a dopamine transporter imaging agents scan ( Tc-TRODAT-1) displayed a secondary reduction of dopamine transporters in the right nigrostriatal pathway which had resulted from the damage on the paramedian nuclear groups of the right-side thalamus.

LESSONS

Based on the functional images, we illustrated that a retrograde degeneration originating from the thalamic paramedian nuclear groups, and extending forward along the direct innervating fibers of the mesothalamic pathway, played an essential role towards initiating Holmes' tremor.

Pediatric Thalamic Gliomas: An Updated Review

CONTEXT

- Neoplasms originating in the thalamus are rare overall (1% of all brain tumors); however, they comprise approximately 5% of pediatric intracranial tumors and approach 15% of all malignant pediatric intracranial tumors in some series.

OBJECTIVE

- To update readers about the current understanding of the diverse histology, biology, and behavior of pediatric thalamic tumors. Histologic verification is now thought to be critical for planning treatment, and, as a result, biopsy and total/subtotal resections are much more common today than in the past.

DATA SOURCES

- A PubMed search using the keywords "pediatric + thalamic + glioma" yielded 45 publications with a total of 445 cases of thalamic gliomas in patients less than 18 years of age. We found only 9 substantial institutional series tabulating all encountered thalamic histologic types in children. This survey confirmed a high proportion of astrocytomas, 81% (214 of 265), of which approximately two-thirds were diffuse astrocytomas (146 of 214) and one-third were pilocytic astrocytomas (68 of 214). Of the diffuse astrocytomas, 34% (49 of 146) were low grade (World Health Organization grade II) and 55% (81 of 146) were high grade (World Health Organization grade III or IV), making the latter subgroup the largest single category of all pediatric thalamic tumors. Oligodendrogliomas and ependymomas (mostly anaplastic in both cases) comprised 10% and 3% of all pediatric thalamic tumors, respectively.

CONCLUSIONS

- Tissue diagnosis is now thought crucial for prognostication and treatment, particularly as more potentially therapeutic molecular targets are discovered. Secure diagnosis allows identification of tumors for which resection is more feasible and beneficial.

H3F3A K27M mutations in thalamic gliomas from young adult patients

INTRODUCTION

Mutations in H3F3A, which encodes histone H3.3, commonly occur in pediatric glioblastoma. Additionally, H3F3A K27M substitutions occur in gliomas that arise at midline locations (eg, pons, thalamus, spine); moreover, this substitution occurs mainly in tumors in children and adolescents. Here, we sought to determine the association between H3F3A mutations and adult thalamic glioma.

METHODS

Genomic H3F3A was sequenced from 20 separate thalamic gliomas. Additionally, for 14 of the 20 gliomas, 639 genes--including cancer-related genes and chromatin-modifier genes--were sequenced, and the Infinium HumanMethylation450K BeadChip was used to examine DNA methylation across the genome.

RESULTS

Of the 20 tumors, 18 were high-grade thalamic gliomas, and of these 18, 11 were from patients under 50 years of age (median age, 38 y; range, 17-46), and 7 were from patients over 50 years of age. The H3F3A K27M mutation was present in 10 of the 11 (91%) younger patients and absent from all 7 older patients. Additionally, H3F3A K27M was not detected in the 2 diffuse astrocytomas. Further sequencing revealed recurrent mutations in TP53, ATRX, NF1, and EGFR. Gliomas with H3F3A K27M from pediatric or young adult patients had similar, characteristic DNA methylation profiles. In contrast, thalamic gliomas with wild-type H3F3A had DNA methylation profiles similar to those of hemispheric glioblastomas.

CONCLUSION

We found that high-grade thalamic gliomas from young adults, like those from children and adolescents, frequently had H3F3A K27M.

Connectivity-based parcellation of the thalamus explains specific cognitive and behavioural symptoms in patients with bilateral thalamic infarct

A novel approach based on diffusion tractography was used here to characterise the cortico-thalamic connectivity in two patients, both presenting with an isolated bilateral infarct in the thalamus, but exhibiting partially different cognitive and behavioural profiles. Both patients (G.P. and R.F.) had a pervasive deficit in episodic memory, but only one of them (R.F.) suffered also from a dysexecutive syndrome. Both patients had an MRI scan at 3T, including a T1-weighted volume. Their lesions were manually segmented. T1-volumes were normalised to standard space, and the same transformations were applied to the lesion masks. Nineteen healthy controls underwent a diffusion-tensor imaging (DTI) scan. Their DTI data were normalised to standard space and averaged. An atlas of Brodmann areas was used to parcellate the prefrontal cortex. Probabilistic tractography was used to assess the probability of connection between each voxel of the thalamus and a set of prefrontal areas. The resulting map of corticothalamic connections was superimposed onto the patients’ lesion masks, to assess whether the location of the thalamic lesions in R.F. (but not in G. P.) implied connections with prefrontal areas involved in dysexecutive syndromes. In G.P., the lesion fell within areas of the thalamus poorly connected with prefrontal areas, showing only a modest probability of connection with the anterior cingulate cortex (ACC). Conversely, R.F.’s lesion fell within thalamic areas extensively connected with the ACC bilaterally, with the right dorsolateral prefrontal cortex, and with the left supplementary motor area. Despite a similar, bilateral involvement of the thalamus, the use of connectivity-based segmentation clarified that R.F.’s lesions only were located within nuclei highly connected with the prefrontal cortical areas, thus explaining the patient’s frontal syndrome. This study confirms that DTI tractography is a useful tool to examine in vivo the effect of focal lesions on interconnectivity brain patterns.

Bilateral central pain sensitization in rats following a unilateral thalamic lesion may be treated with high doses of ketamine

BACKGROUND

Central post-stroke pain is a neuropathic pain condition caused by a vascular lesion, of either ischemic or hemorrhagic origin, in the central nervous system and more precisely involving the spinothalamocortical pathway responsible for the transmission of painful sensations. Few animal models have been developed to study this problem. The objectives of this study were to evaluate different modalities of pain in a central neuropathic pain rat model and to assess the effects of ketamine administered at different doses. Animals were evaluated on the rotarod, Hargreaves, Von Frey and acetone tests. A very small hemorrhage was created by injecting a collagenase solution in the right ventral posterolateral thalamic nucleus. Following the establishment of the neuropathy, ketamine was evaluated as a therapeutic drug for this condition.

RESULTS

Histopathological observations showed a well localized lesion with neuronal necrosis and astrocytosis following the collagenase injection that was localized within the VPL. No significant change in motor coordination was observed following surgery in either the saline or collagensae groups. In the collagenase group, a significant decrease in mechanical allodynia threshold was observed. A sporadic and transient cold allodynia was also noted. No thermal hyperalgesia was seen following the collagenase injection. Ketamine was then tested as a potential therapeutic drug. A significant decrease in motor coordination was seen only following the administration of 25 mg/kg of ketamine in both groups. An alleviation of mechanical allodynia was achieved only with the high ketamine dose. The minimal effective ketamine serum concentration (150 ng/mL) was only achieved in animals that received 25 mg/kg.

CONCLUSIONS

An intrathalamic hemorrhage induced a bilateral mechanical allodynia in rats. Cold hyperalgesia was observed in 60% of these animals. Mechanical allodynia was alleviated with high doses of ketamine which corresponded with therapeutic plasmatic concentrations.

A case of pure agraphia due to left thalamic hemorrhage

Pure agraphia is an isolated writing disturbance without intellectual impairment, aphasia, alexia, or apraxia. The authors report a case of pure agraphia following left thalamic hemorrhage. The patient showed impairment in the writing of both kanji and kana. The most frequent error in the writing of kanji was substitution (46%) followed by no reaction (23%) and partial omission or addition of characters (21%). The copying of kanji by hand was normal. Even when the patient was unable to write a kanji character, he understood the meaning and correctly recited the other readings. He complained that he could not recall the graphic image of the kanji. When we cued the patient by writing a part of a kanji he initially failed to recall, he correctly completed the character. The kanji and kana he was unable to write were inconsistent over time: in some cases he was unable to write words he had successfully written a week before, and vice versa. These findings suggested that the patient's pure agraphia resulted from combined impairments in recalling and selecting letters. While the thalamic lesion might have influenced the manifestation of pure agraphia, the dysfunction seemed to originate from the secondary negative effect of the lesion on the function of the left cerebral cortex.

Bilateral thalamic necrosis following ingestion of ridge gourd infested with coelomycete fungi (Diplodia)

Bilateral thalamic lesions detected on magnetic resonance imaging have a wide differential diagnosis. This report describes a previously healthy young man who developed bilateral thalamic necrosis with seizures, vomiting, hepatitis, neutrophilic leukocytosis and metabolic acidosis following consumption of raw dried fruits of the ridge gourd plant (Luffa acutangula) prescribed by a traditional medicine practitioner. These fruits were subsequently shown to be infested with spores and conidiomata of Diplodia, a coelomycete fungus known to cause neurotoxicity in farm animals. The patient made a partial recovery with supportive care, and has persistent deficits consistent with bilateral medial thalamic damage. This is the first report of neurological toxicity attributable to Diplodia in humans, and this entity should be considered in the differential diagnosis of bilateral thalamic lesions in the appropriate clinical setting.

[Déjerine-Roussy syndrome of an ischaemic origin in an adolescent with patent foramen ovale]

INTRODUCTION

Déjerine-Roussy syndrome, or thalamic syndrome, is characterised by transient mild hemiparesis, hemichoreoathetosis, hemihypoesthesia, hyperalgesia, allodynia and hemiataxia with astereognosia that varies in intensity, and it appears in the presence of lesions in the posterior nuclei of the thalamus. It can be produced by strategic cerebral infarction, reported in elderly patients with vascular risk factors. Patent foramen ovale has been suggested as a risk factor for ischaemic stroke in young people, especially when associated to aneurysm of the auricular septum and above all to a procoagulating status.

CASE REPORT

An 18-year-old male with a family history of Behçet's disease, who presented right-side thalamic and hippocampal cerebral infarction; following an exhaustive study, patent foramen ovale with septal aneurysm was found as the only risk factor. At that time he did not satisfy criteria for Behçet's disease, and thorough systemic screening did not reveal direct or indirect signs of venous thrombosis. Percutaneous closure of the foramen was performed.

CONCLUSIONS

This is the first reported case of Déjerine-Roussy syndrome as a manifestation of cryptogenic cerebral infarction associated to patent foramen ovale in an adolescent. Taken as a whole, the clinical and complementary data enable us to reconstruct the pathophysiological sequence that position foramen ovale with an associated septal 'aneurysm' as the only detectable risk factor, which, when linked to the stress of the patient and the family, triggered its early closure.

Clinical features of sporadic fatal insomnia

Recent advances in neuropathology, genotyping, and physiochemical characterization of proteins have allowed for the classification and verification of MM2-thalamic Creutzfeldt-Jakob disease (CJD). CJD is a fatal neurodegenerative illness belonging to the transmissible spongiform encephalopathies, also known as prion diseases. Sporadic CJD is generally classified by the genotype at codon 129 of the prion protein gene and the distinct physiochemical features of the pathologic prion protein (PrP(sc)). The entity is characterized by methionine homozygosity at codon 129, type 2 PrP(sc), and, primarily, thalamic pathology (MM2-thalamic CJD). It shares clinical and pathologic similarities with the genetic prion disorder fatal familial insomnia; the MM2-thalamic phenotype has therefore been called sporadic fatal insomnia (SFI). SFI may also present like other neurodegenerative diseases, and common diagnostic findings that are seen in other forms of sporadic CJD may be absent.

The germinomas arising from the basal ganglia and thalamus

OBJECTIVE

To introduce the features of germinomas arising from the basal ganglia (BG) and thalamus.

METHOD

Retrospective analysis was done with the clinical cases of germinomas in BG and thalamus from 1996 to 2000. The data included the symptoms, signs, neuroimaging findings, treatment, and outcomes.

RESULT

Fourteen cases were included, only one female was included. The main symptoms are disorder of numbness and weakness in limbs. Neuroimaging showed no or mild peritumor high signal in T2 weighted imaging of magnetic resonance, accompanied with cyst, calcification or bleeding. Total gross resection was obtained in nine cases, subtotal resection in four. Follow-up data were available in 11 cases with average of 56 months. Eight cases underwent only postoperative radiotherapy, one underwent only chemotherapy, and two underwent both. One case died of complication 6 months after chemotherapy, the rest lived good life.

CONCLUSION

Germinoma in BG and thalamus predominate in a boy. The neuroimaging features are very informative for diagnosis. Surgical resection should not be the first choice although it is has lesser complications. The long-term outcome is favorable.

Glasgow Coma Scale and hematoma volume as criteria for treatment of putaminal and thalamic intracerebral hemorrhage

BACKGROUND

The decision to administer conservative or surgical treatment for putaminal and thalamic ICH is still a controversial issue. This study was undertaken to examine the decision-making criteria for these 2 treatments.

METHODS

In a retrospective study, case records of 400 patients with spontaneous putaminal and thalamic hemorrhage who underwent conservative treatment (n = 201) and surgical treatment (n = 199) over the past 5 years were examined. Conservative treatment included hypertonic solution treatment and hypertension control. Surgical treatments included endoscopic surgery, craniotomy, and stereotactic aspiration. Preoperative GCS score and ICH volume were the major evaluating factors, and comparison of the 30-day mortality rate and 6-month BI score was used for outcome evaluation.

RESULTS

In patients with a GCS score of 13 to 15, there was no difference in mortality between conservative and surgical treatments. At a GCS score of 9 to 12 and ICH volume of less than 30 mL, the mortality rate with surgical treatment (10.5%) was lower than that with conservative treatment (20.0%, P < .05). At a GCS score of 3 to 8 and ICH volume of at least 30 mL, surgical treatment was for life saving. Mortality rates were lower for conservative treatment than for surgical treatment when the GCS score was 3 to 12 and ICH volume less than 30 mL. Endoscopic surgery had a better functional outcome compared with craniotomy and stereotactic aspiration when the GCS score was at least 9 (P < .001 and P < .02, respectively). Those in conservative treatment received a better BI score than those in surgical treatment did when the ICH volume was less than 40 mL (P < .001).

CONCLUSIONS

Intracerebral hemorrhage volume is probably more important than GCS score in determining treatment. Our nonrandomized data could be interpreted to show that conservative treatment is suggested at GCS score of at least 13 or when ICH volume is less than 30 mL, regardless of GCS score. Surgical treatment could be recommended at GCS score of less than 12 with ICH volume of at least 30 mL for life saving. Endoscopic surgery may improve the functional outcomes because it is less invasive and effectively removes the ICH at GCS score of at least 9.

Occult infarct with acute hemorrhagic stroke in juvenile diabetic ketoacidosis

Diabetes ketoacidosis (DKA) is one of the common complications of type I insulin-dependent diabetes mellitus. Neurological deterioration during an episode of DKA is usually assumed to be caused by cerebral edema and cerebral vascular accidents. However, hemorrhagic stroke is a very rare complication of juvenile DKA. We describe a girl who had newly diagnosed insulin-dependent diabetes mellitus with juvenile DKA developed intracerebral hemorrhage.

Feeling sounds after a thalamic lesion

OBJECTIVE

The ventrolateral nucleus of the thalamus (VL), based on its connectivity with the cerebellum and motor cortex, has long been considered to be involved with motor functions. We show that the human VL also plays a prominent role in sensory processing.

METHODS

Structural magnetic resonance imaging and diffusion tensor imaging were used to localize a small lesion restricted to the right VL in a patient with contralesional sensory processing deficits. Systematic assessments of anatomic brain organization and behavioral measurements of somatosensory and visual processing were conducted at several time points after stroke.

RESULTS

Initially, the patient was more likely to detect events on the contralesional side when a simultaneous ipsilesional event was presented within the same, but not different, sensory modality. This perceptual phenomenon, which we refer to as unisensory antiextinction, persisted for several months before transforming into a form of synesthesia in which auditory stimuli produced tactile percepts. Tractography performed on the diffusion tensor imaging data showed altered connections from the lesioned thalamus to the cerebral cortex, suggesting a neural basis for these sensory changes.

INTERPRETATION

These results demonstrate a role for the VL in sensory processing and suggest that reorganization of thalamocortical axonal connectivity can lead to major changes in perception.

Germinoma with synchronous involvement of midline and off-midline structures associated with progressive hemiparesis and hemiatrophy in a young adult

INTRODUCTION

Cerebral germinomas, the most common and least malignant intracranial germ cell tumors, usually arise in the pineal or suprasellar region and have characteristic clinical and radiological features. Germinomas more rarely occur in the thalamus, basal ganglia, and internal capsule, causing sometimes cerebral hemiatrophy and hemiparesis. More rarely, other clinical features can be fever of unknown origin, visual disturbance, and neuropsychiatric symptoms. Cerebral hemiatrophy can precede the imaging depiction of the off-midline mass.

CASE

The authors present the first case of cerebral germinoma with synchronous involvement of the midline and off-midline structures, with unusual clinical and radiological presentation.

DISCUSSION

The literature is reviewed, and the pathogenesis, the clinical findings, the imaging, and the therapy are discussed.

Bilateral Isolated Lateral Geniculate Body Lesions in a Patient with Pancreatitis and Microangiopathy

An 18-year-old woman developed pancreatitis and a thrombotic microangiopathy but no electrolyte abnormalities. She required intubation hours after admission and was not able to communicate for 8 days. Upon recovering consciousness, she reported severely impaired vision in both eyes, but ophthalmologic evaluation and neuroimaging were not obtained until several days later. Ophthalmologic examination documented retinal infarcts and profound binocular vision loss with hourglass bilateral homonymous hemianopic visual field loss. MRI showed signal abnormalities restricted to the area of the lateral geniculate bodies (LGBs) with characteristics most suggestive of hemorrhagic infarction. Very few cases of isolated bilateral LBG lesions have been reported. Damage has been attributed to myelinolysis from osmotic demyelination or to infarction from microvascular occlusion. This case conforms more to microvascular infarction. The vulnerability of the LGB to selective microvascular infarction may be based on a combination of its unique architecture and high metabolic demand.

Surgical resection of thalamic tumors in children: approaches and clinical results

OBJECTIVES

Thalamic tumors are uncommon, and although gross total removal (GTR) is a prospective goal, its interest is debated because the thalamus constitutes a highly functional region. The relation of choice of the surgical approach, achievability of GTR, and operative morbidity to the anatomic location of the tumor has received little attention in the medical literature.

MATERIALS AND METHODS

We reviewed retrospectively the cases of pediatric patients treated for thalamic tumor, with pre- and postoperative magnetic resonance imaging, and who were operated with the aim of maximal surgical removal.

CONCLUSION

We reviewed 16 cases operated between 1992 and 2003. The clinical presentation was dominated by intracranial hypertension and hemiparesis. Fifteen children were operated through transcortical approaches: transfrontal in six cases, transparietal in six, and transtemporal in three. The remaining patient was operated through an infratemporal approach. All operations performed since 1998 used intraoperative neuronavigation. Complete or near-total resection was achieved in 11 cases; only subtotal resection was achieved in the remaining five cases. The most common postoperative morbidity was visual field defect. Hemiparesis was unchanged or improved in all the cases. Seven children died of tumor progression, in relation with high histological grade, and one died of acute hydrocephalus. The approach to thalamic tumors needs to be planned according to the location of critical neural structures. GTR of thalamic tumors in children bears acceptable morbidity and may even improve preoperative deficits. Surgery alone can be curative in low-grade tumors; in high-grade or infiltrating tumors, GTR is only part of the overall oncological management.

Granulomatous tissue response in germinoma, a diagnostic pitfall in endoscopic biopsy

We report a case of a 24-year-old man with a right thalamic germinoma that initially mimicked a granulomatous inflammation, compatible with neurosarcoidosis based on clinical symptoms, imaging results and histology of an endoscopically navigated biopsy. A second biopsy, prompted by clinical course, and performed openly from parieto-lateral revealed the underlying germinoma, obscured in the first biopsy by a granulomatous tissue response, particularly at the tumor edge. The present case highlights granulomatous inflammatory tissue response on the tumor edge of germinoma as a tumor-immanent diagnostic challenge. This diagnostic problem is aggravated by stereotactic and endoscopic approaches. We conclude that granulomatous inflammation in a specimen obtained by biopsy of a midline lesion should always be considered for the differential diagnosis of germinoma. Stereotactic and endoscopic surgery should sample several different target points within the lesion. Because of tumor heterogeneity of germinoma, the open biopsy approach is advantageous compared to endoscopic or stereotactic techniques for germinoma and should be considered if a germinoma is in the differential diagnosis and if allowed by the clinical situation.

CNS germ cell tumor (CNSGCT) of childhood: presentation and delayed diagnosis

OBJECTIVE

To describe the relationship between symptomatology and time to diagnosis of an institutional series of patients with CNS germ cell tumor (CNSGCT) over a 16-year period.

METHODS

Thirty consecutive patients newly diagnosed with CNSGCT (mean age 10.9 years; range 6 to 17 years; 70% boys) were evaluated at our institution between 1990 and 2006.

RESULTS

Duration of symptoms prior to diagnosis ranged from 5 days to 3 years (mean 8.4 months). Tumor location included pineal (14), suprasellar (8), pineal/suprasellar (3), pineal/thalamic (4), and basal ganglionic/thalamic (3). Five patients had disseminated disease at the time of diagnosis. Features including headache, nausea, vomiting, and visual changes led to earlier diagnosis. Symptoms including movement disorders, enuresis, anorexia, and psychiatric complaints delayed diagnosis in 9 of 30 patients, diagnosed 7 months to 3 years (mean 22.3 months) from symptom onset. In 7 of 9 patients with delayed diagnosis, enuresis was present. Seventeen of 30 patients had signs of endocrine dysfunction at presentation that included diabetes insipidus (4), hypothyroidism (8), and growth hormone deficiency (4). Ophthalmologic findings of decreased visual acuity, visual field deficits, or ocular abnormalities were present in 13 patients. Duration of symptoms did not correlate with tumor subtype or event-free survival. In three patients with basal ganglionic/temporal lobe, thalamic, or pineal/suprasellar signal abnormalities on MRI, neuroradiographic diagnosis was difficult.

CONCLUSIONS

Diagnosis of CNS germ cell tumor is often delayed, and presentation may include movement disorders or mimic psychiatric disease. MRI interpretation can be challenging and may require serum/CSF markers and biopsy for diagnosis.

Rapid relief of thalamic pain syndrome induced by vestibular caloric stimulation

Central post-stroke pain syndrome develops in a minority of patients following a stroke. The most usual causative lesion involves the lateral thalamus. The classic presentation is of severe, unrelenting pain that involves the entire contralateral half of the body. It is largely refractory to current treatments. We found that in two patients with this condition their pain was substantially improved by vestibular caloric stimulation, whereas placebo procedures had no effect. We proposed that this is because vestibular stimulation activates the posterior insula, which in turn inhibits the generation of pain in the anterior cingulate.

[Differential diagnosis of bilateral thalamic lesions]

A multitude of different diseases can result in bilateral thalamic lesions. These include vascular pathologies requiring prompt therapeutic intervention, such as basilar thrombosis or thrombosis of the internal cerebral veins, as well as tumors, infectious or demyelinating diseases, and toxic-metabolic lesions. Therefore, detailed knowledge of the typical radiological findings for the various diseases is essential for determining the correct diagnosis. This review provides a synopsis of the radiological findings for the most important bithalamic lesions and an overview of the literature.

Stereotaxic gamma knife surgery in treatment of critically located pilocytic astrocytoma: preliminary result

Background

Low-grade gliomas are uncommon primary brain tumors, located more often in the posterior fossa, optic pathway, and brain stem and less commonly in the cerebral hemispheres.

Case presentations

Two patients with diagnosed recurrent cystic pilocytic astrocytoma critically located within the brain (thalamic and brain stem) were treated with gamma knife surgery. Gamma knife surgery (GKS) did improve the patient's clinical condition very much which remained stable later on. Progressive reduction on the magnetic resonance imaging (MRI) studies of the solid part of the tumor and almost disappearance of the cystic component was achieved within the follow-up period of 36 months in the first case with the (thalamic located lesion) and 22 months in the second case with the (brain stem located lesion).

Conclusion

Gamma knife surgery represents an alternate tool in the treatment of recurrent and/or small postoperative residual pilocytic astrocytoma especially if they are critically located

Diffuse bilateral thalamic astrocytoma

Diffuse astrocytoma with bilateral thalamic involvement is extremely rare. We present a case of 10 years old female who presented with decreased mentation, dysarthria, decreased performance at school and later on with seizures. MRI scans were performed twice and were reported as Leigh's disease and hemimegalencephaly respectively. Patient presented again with complaint of unconsciousness, vomiting and chest congestion. No further imaging was performed. Biopsy showed grade III Astrocytoma with bilateral thalamic involvement. Patient was admitted to intensive care unit but could not survive and expired.

Bithalamic lesions of butane encephalopathy

Butane inhalation can cause serious medical complications and is particularly toxic to the nervous system. This is a report of an acutely encephalopathic youth with prominent abulia. MRI revealed severe bithalamic injury attributed to butane toxicity. Clinical issues, including particular radiologic findings, related to butane inhalation are reviewed.

Allodynia in the flank after thalamic stroke

Lesions responsible for thalamic pain are often thought to involve the ventral posteromedial nucleus and ventral posterolateral nucleus of the thalamus. We describe two patients with allodynia and hyperpathia in the contralateral flank caused by a small lesion in the posteroventral part of the thalamus. When considered with the literature, involvement of the ventral posteroinferior nucleus may be responsible for this unique post-stroke pain syndrome.

Les astrocytomes pilocytiques du diencéphale de l’enfant

BACKGROUND AND PURPOSE

Pilocytic astrocytoma (PA) is a WHO grade I tumor of the central nervous system mostly arising in children and young adults. Management of diencephalic PA is a difficult challenge. Surgical treatment has to cope with both the difficulties of deep location and eloquent area tumors.

MATERIALS AND METHODS

We retrospectively reviewed seven pediatric cases (female: 4, male: 3) of diencephalic PA. Opto-chiasmatic tumors were excluded from the series. Mean age at diagnosis was 108 months (9 years) (range: 4 month-18 years), median age was 111 months. Median follow-up for the series was 125 months. Tumor locations were as followed: right thalamus: 2, both thalami: 1, hypothalamus: 3, and right basal ganglia: 1. At the onset, the first symptom was mostly raised intracranial pressure. The delay in diagnosis ranged from 48 hours up to 6 years.

TREATMENT

a shunting procedure was performed in 3 patients, a direct surgical approach in 5 patients (gross total removal: 2; partial removal: 3) and one patient had only a biopsy. Three children were re-operated. Three patients were treated by radiationtherapy (RT) after surgery. Chemotherapy was delivered for 4 children.

RESULTS

The overall survival rate was 71.4 months (almost 6 years) (range: 3-184 months). Median survival rate was 42 months (3.5 years). Three children died, two by tumor progression and one death related to late side-effects of RT. Four patients have a good quality of life with GOS I (n = 3) or II (n = 1). We observed tumor regression in two patients at 1 and 17 years after the beginning of treatment. Correct diagnosis was only made for two cases at the initial pathological examination.

CONCLUSION

The course of diencephalic PA is still unpredictable. The tumor can be controlled by a partial surgical removal, and a residual tumor can sometimes decrease in size after surgery. Gross total removal of these tumors, although difficult, may be performed. With cranial navigation systems, the risk is low. Pathological diagnosis is sometimes difficult to assess.

Novel Representation of Astasia Associated With Posterior Cingulate Infarction

Background and Purpose— The representation elicited in the cingulate motor area has been demonstrated in animals, but remains unclear in humans. In particular, the representation and pathogenic mechanisms of the posterior cingulate cortex are poorly understood, especially in humans. We describe a case of posterior cingulate infarction associated with contralateral astasia.

Case Description— A 67-year-old right-handed man with a 10-year history of hypertension suddenly presented with right-sided pulsion on attempting to stand or sit. On the following day, he could not maintain a sitting position. The patient immediately fell to the floor because of instability, characterized by marked right-sided pulsion despite no muscle weakness, sensorial deficits, or cerebellar ataxia. Magnetic resolution imaging of the brain showed abnormal intensity in the posterior parts of the cingulate, with no other clinically significant lesions.

Conclusions— Because the cingulate motor area is connected to the vestibulocerebellar system through the thalamic nuclei, disruption of this connection by posterior cingulate infarction may result in astasia.

Thalamic dementia: an example of primary astroglial dystrophy of Seitelberger

Pure thalamic dementia is highly uncommon and typically demonstrates widespread loss of neurons throughout the thalamus associated with reactive gliosis. This report describes an autopsy case in which there is widespread gliosis of subcortical white matter, focal hippocampal sclerosis and a unique proliferation of protoplasmic astrocytes in the thalamus, with limited bilateral focal loss of neurons. The alterations of the protoplasmic astrocytes consist of proliferation of perivascular feet surrounding blood vessels and velate sheets which surround individual neurons. It is proposed that the astrocytic alterations, or astrocytic dystrophy, constitute the primary and critical pathologic-change, sufficiently severe to produce dementia in the presence of a relatively intact neuronal population.

The syndrome of combined polar and paramedian thalamic infarction

BACKGROUND

Occlusion of the polar or the paramedian arteries of the thalamus usually leads to distinct infarcts with specific clinical and imaging correlates. However, vascular variation is such that in up to one third of humans, the polar artery is missing and its territory taken over by the paramedian arteries.

OBJECTIVE

To provide attention to the corresponding stroke syndrome of combined polar and paramedian thalamic infarction.

METHODS

We studied combined polar-paramedian thalamic infarction in 12 patients (6 right-sided lesions, 3 left-sided lesions, and 3 bilateral lesions) who were selected from 208 consecutively registered patients with thalamic strokes in the Lausanne Stroke Registry.

RESULTS

The clinical manifestation included executive dysfunction, apathy, and memory impairment in all patients, with eye movement disturbances in 10 patients (5 with right-sided lesions, 2 with left-sided lesions, 3 with bilateral lesions); acutely impaired consciousness in 11 patients (5 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions); aphasic disturbances in 8 patients (2 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions), including nonfluent aphasia in 1 patient (with left-sided lesions); dysarthria in 5 patients (4 with right-sided lesions, 1 with bilateral lesions); constructional apraxia in 5 patients (with right-sided lesions); mild hemiparesis in 4 patients (2 with right-sided lesions, 2 with left-sided lesions); dyscalculia in 3 patients (1 with left-sided lesions,1 with right-sided lesions, 1 with bilateral lesions); limb dystonia or asterixis in 2 patients (1 with right-sided lesions, 1 with bilateral lesions); mild hemisensory loss in 2 patients (1 with right-sided lesions, 1 with left-sided lesions); hemiataxia in 1 patient (with right-sided lesions); and ideomotor apraxia in 1 patient (with left-sided lesions). Follow-up showed severely disabling, persistent amnesia in 7 patients (4 with right-sided lesions, 3 with bilateral lesions) and persistent eye movement dysfunction in 5 patients (2 with right-sided lesions, 1 with left-sided lesions, 2 with bilateral lesions). The most common etiology appeared to be cardioembolism, followed by artery-to-artery embolism and presumed small-artery disease.

CONCLUSIONS

Key features of this syndrome included amnesia preceded by a period of altered consciousness, and vertical eye movement disturbances. The severe and persistent amnesia may be due to coexisting damage to the anterior and dorsomedial nuclei.

Caudothalamic groove cysts in Zellweger syndrome

The cerebro-hepato-renal syndrome of Zellweger is the most severe peroxisome biogenesis disorder. Zellweger syndrome is caused by a disturbance in the peroxisomal protein import machinery and leads to multiple organ defects and death usually within the first year of life. Here we report a 3-month-old girl with Zellweger syndrome who was found to have cysts in the caudothalamic groove on cranial magnetic resonance imaging.

Motor cortex excitability after thalamic infarction

OBJECTIVE

We examined 8 patients with hemihypesthesia due to an ischemic thalamic lesion to explore the effects of a central sensory dysfunction on motor cortex excitability.

METHODS

Motor excitability was assessed using transcranial magnetic stimulation techniques and electrical peripheral nerve stimulation. Motor function was evaluated by the Nine-Hole-Peg Test and measurement of hand grip strength. The affected side was compared with the non-lesioned side and with an age-matched control group.

RESULTS

Patients had a loss of inhibition and an increase of facilitation in the motor cortex of the affected side. The silent period was prolonged and motor function was impaired on the affected side.

CONCLUSIONS

A thalamic lesion can modulate motor cortical excitability.

SIGNIFICANCE

This study suggests that, under normal conditions, somatosensory afferents influence inhibitory and excitatory properties in the motor cortex.

Dural arteriovenous fistulas with aggressive course: clinical and angiographic correlations in two patients

Cranial dural arteriovenous fistulas (DAVFs) usually present with non-aggressive symptoms. We here report two patients who presented a peculiar clinical picture related to DAVFs, with focal neurological signs and haemorrhagic (case 1) or ischaemic lesions (case 2) respectively. The clinical and angiographic findings and putative pathophysiological mechanisms are discussed.

[Herpes simplex encephalitis originating from bilateral thalamic lesions with hemorrhagic component]

A 71-year-old woman with hypertension and hypothyroidism was transferred to our hospital from a nearby hospital because of right thalamic hemorrhage evident on CT. She had been suffered from fever and headache for five days. Neurological examination on admission revealed somnolence, rigidity in the neck and extremities, and bilateral Babinski signs. Then she developed decorticate rigidity in a day. On brain MRI four hours after admission, T2-hyperintese lesions were demonstrated in the bilateral thalamus in addition to hemorrhagic change of the right thalamus on the initial CT. No pleocytosis was evident on cerebrospinal fluid examination at admission. Follow-up MRI on the fifth hospital day, however, revealed expansion of the lesions bilaterally to the medial temporal lobes including amygdala, hippocampus and insular cortex. The diagnosis of herpes simplex encephalitis was established by PCR of cerebrospinal fluid on the same day. After immediate treatment with acyclovir and ara-A, she gradually became conscious and could respond to simple conversation. This was an unusual case of herpes simplex encephalitis originating from bilateral thalamic lesions on brain imaging. We should consider thalamus as a primary lesion in herpes simplex encephalitis.

Thalamic infarct presenting with thalamic astasia

Astasia, inability to stand unsupported despite good strength, resembles the marked balance impairment of patients with vestibulocerebellar disease. We describe a patient with unilateral thalamic infarct that presented with astasia. A 76-year-old hypertensive woman was admitted to our hospital because of marked unsteadiness. On neurological examination, she could not stand unsupported and the woman's body swayed back and forth markedly. The swaying was not compensated for by her taking a step forward or backward, and she frequently collapsed when support was withdrawn. Diffusion-weighted magnetic resonance image revealed a discrete infarct within the right posterolateral thalamus. Brain single photon emission computerized tomography revealed markedly decreased regional cerebral blood flow within in the right thalamus with concomitant left superior cerebellar region. We discuss the possible pathomechanisms of thalamic astasia.

Dysexecutive syndrome following anterior thalamic ischemia in the dominant hemisphere

In the article, we describe a rare case: a 52-year-old male patient with an isolated lesion of the anterior thalamic nuclei in the dominant hemisphere due to an ischemic stroke. The patient's syndrome of disordered verbal fluency, working memory, learning and executive functions is seen as a part of a lesion in the dorsolateral complex circuit. During the following 6 months, we observed significant improvement in visual learning, recent memory and categorisation of subjects, while verbal learning and visuospatial planning remained insufficient. In this context, the preservation of thalamic structures in different types of cognitive deterioration is discussed.

Analysis of the electroencephalographic activity associated with thalamic tumors

A physiologically based model of corticothalamic dynamics is used to investigate the electroencephalographic (EEG) activity associated with tumors of the thalamus. Tumor activity is modeled by introducing localized two-dimensional spatial non-uniformities into the model parameters, and calculating the resulting activity via the coupling of spatial eigenmodes. The model is able to reproduce various qualitative features typical of waking eyes-closed EEGs in the presence of a thalamic tumor, such as the appearance of abnormal peaks at theta ( approximately 3Hz) and spindle ( approximately 12Hz) frequencies, the attenuation of normal eyes-closed background rhythms, and the onset of epileptic activity, as well as the relatively normal EEGs often observed. The results indicate that the abnormal activity at theta and spindle frequencies arises when a small portion of the brain is forced into an over-inhibited state due to the tumor, in which there is an increase in the firing of (inhibitory) thalamic reticular neurons. The effect is heightened when there is a concurrent decrease in the firing of (excitatory) thalamic relay neurons, which are in any case inhibited by the reticular ones. This is likely due to a decrease in the responsiveness of the peritumoral region to cholinergic inputs from the brainstem, and a corresponding depolarization of thalamic reticular neurons, and hyperpolarization of thalamic relay neurons, similar to the mechanism active during slow-wave sleep. The results indicate that disruption of normal thalamic activity is essential to generate these spectral peaks. Furthermore, the present work indicates that high-voltage and epileptiform EEGs are caused by a tumor-induced local over-excitation of the thalamus, which propagates to the cortex. Experimental findings relating to local over-inhibition and over-excitation are discussed. It is also confirmed that increasing the size of the tumor leads to greater abnormalities in the observable EEG. The usefulness of EEG for localizing the tumor is investigated.

Thalamic reductions in children with chromosome 22q11.2 deletion syndrome

Children with chromosome 22q11.2 deletion syndrome (22q) suffer from physical and behavioral dysfunctions, including neuroanatomical anomalies, visuo-spatial processing deficits, and increased risk for psychopathology. Reduced total brain volume, parietal lobe volume, and cerebellar volumes, enlarged ventricles, and increased basal ganglia volumes have been reported. Since previous literature has related the pulvinar nucleus of the thalamus to visuo-spatial processing, we compared the thalamic volume in children with 22q to typically developing controls. Children with 22q showed a significant reduction of the thalamus compared with normally developing children, specifically in the posterior portion of the thalamus, including the pulvinar nucleus. These results provide the first evidence for a potential relationship between posterior thalamic reductions and the characteristic visuo-spatial deficits demonstrated in this group.

A syndrome of bilateral hemorrhage of the thalamus and myocarditis with fatal course

We report the case of a 41-year-old patient with bilateral hemorrhage of the thalamus, leading to death. Post-mortem examination showed acute myocarditis. Neuropathological study showed perivascular infiltrates in affected thalamic regions. Laboratory investigation failed to find any causal agent. We hypothesize an infective agent, affecting the heart and thalamus, as the cause of this syndrome. Diaschisis due to the strategic anatomical position of the thalamus may have been responsible for coma state and death.