Dihydroergocriptine in Parkinson's disease: clinical efficacy and comparison with other dopamine agonists

The present paper reviews clinical studies on the use of dihydroergocriptine (DHEC), an ergot derivative with dopamine agonist activity, for the treatment of Parkinson's disease. This compound is a hydrogenated ergot derivative structurally quite similar to bromocriptine, from which it differs because of the hydrogenation in C9 C10 and the lack of bromine in C2. DHEC has a potent D2-like receptor agonist and a partial D1-like receptor agonist activity; because of this biochemical profile, it has been suggested that DHEC may produce fewer side-effects and have clinical efficacy equal to that of a classical dopamine agonist. Several open-label and double-blind studies indicate that DHEC is an efficacious remedy for parkinsonian signs and symptoms. Further studies are necessary to compare DHEC to new dopamine agonists (pergolide, cabergoline, ropinirole, and pramipexole) which have been more recently marketed.

Direct demonstration of long latency cortico-cortical inhibition in normal subjects and in a patient with vascular parkinsonism

OBJECTIVE

The motor evoked potential to a single suprathreshold transcranial magnetic stimulus (TMS) is suppressed by a preceding stimulus given 100-200 ms before (long latency intracortical inhibition, LICI). The effect is enhanced in patients with Parkinson's disease. Although previous studies have agreed that the effect is cortical, there is disagreement over exactly which cortical mechanisms are involved. The aim of this study was to provide further evidence for cortical involvement in LICI.

METHODS

Recordings of corticospinal volleys evoked by the TMS stimulation were made from electrodes inserted into the cervical epidural space of 4 conscious subjects. Three of the patients had received the electrodes for treatment of lumbo-sacral pain; the other patient had vascular parkinsonism, and had the electrode implanted to evaluate its effect on cerebral blood flow. The number and amplitude of the volleys were compared with and without a conditioning stimulus.

RESULTS

In 3 pain patients, a conditioning stimulus suppressed the later components of the corticospinal volley (I2 and later waves) when the interval between stimuli was 100-150 ms; at 50 ms the responses were enhanced. Early components of the volley were not affected. Inhibition was much more pronounced and involved all descending volleys except the D wave in the patient with vascular parkinsonism.

CONCLUSIONS

LICI, which is conventionally described in EMG recordings, is also evident in recordings of descending corticospinal volleys and appears enhanced in a patient with vascular parkinsonism.

The symptomatic treatment of multiple system atrophy

Multiple system atrophy (MSA) is a neurodegenerative disease of undetermined aetiology that occurs sporadically and manifests itself as a combination of parkinsonian, autonomic, cerebellar and pyramidal signs. Despite the lack of any effective therapy to reverse this condition, some of the symptoms may be, at least temporarily, improved with adequate symptomatic therapies. Medical treatment is largely aimed at mitigating the parkinsonian and autonomic features. The therapeutic results of levodopa therapy in cases of MSA are difficult to interpret because of their variability. Nevertheless, the statement that patients with MSA are non or poorly levodopa-responsive is misleading. Clinical and pathologically proven series document about 40-60% levodopa efficacy in patients with MSA presenting with predominant parkinsonian features. Unfortunately, other antiparkinsonian compounds (dopamine agonists, amantadine) are not more effective than levodopa. Orthostatic hypotension (OH) can be suspected from the patient's history and subsequently documented in the clinic by measuring lying and standing blood pressure. The diagnosis ideally should be confirmed in the laboratory with additional tests to determine the cause and evaluate the functional deficit, so as to aid treatment. A variety of pharmacological agents with different mechanisms of action have been used in MSA to reduce OH when this is symptomatic. OH can also be alleviated by avoiding aggravating factors, such as the effects of food, micturition, exposure to a warm environment and physiological diurnal changes and by using other non-pharmacological strategies. The treatment of the very common genito-urinary symptoms (incontinence, retention, impotence) should also be considered in order to improve the quality of life of these patients.

Magnetic resonance imaging of metastatic disease to the brain with gadobenate dimeglumine

Seventy-four patients with one to eight proven intraaxial brain metastases received a total cumulative dose of 0.2 mmol/kg bodyweight gadobenate dimeglumine, administered as sequential injections of 0.05, 0.05 and 0.1 m mol/kg over a 20-min period. MR imaging was performed before the first administration (T2- and T1-weighted sequences) and after each injection of contrast agent (T1-weighted sequences only). Quantitative assessment of images revealed significant (P <0.01) dose-related increases in lesion-to-brain (L/B) ratio and percent enhancement of lesion signal intensity. Qualitative assessment by two independent, blinded assessors revealed additional lesions in 22%, 25% and 38% (assessor 1) and 29%, 32% and 34% (assessor 2) of patients after each cumulative dose when compared with combined T1- and T2-weighted pre-contrast images. Significantly more lesions (P < 0.01) were noted by both assessors after the first injection and by one assessor after each subsequent injection. For patients with just one lesion observed on unenhanced T1- and T2-weighted images, additional lesions were noted in 12%, 16% and 28% of patients by assessor 1 following each dose and in 24%, 27% and 30% of patients by assessor 2. Contemporaneously, diagnostic confidence was increased and lesion conspicuity improved over unenhanced MRI. For patients with one lesion observed after an initial dose of 0.05 mmol/kg, additional lesions were noted by assessors 1 and 2 in 9.1% and 11.8% of patients, respectively, after a cumulative dose of 0.1 mmol/kg and in a further 9.1% and 5.9% of patients, respectively, after a cumulative dose of 0.2 mmol/kg. No safety concerns were apparent.

Dopamine transporter immunoreactivity in peripheral blood lymphocytes in Parkinson's disease

There is increasing interest in the identification of biological markers for the early diagnosis of Parkinson's disease (PD). Previous studies indicate changes of dopamine content, tyrosine hydroxylase immunoreactivity and dopamine receptors in peripheral blood lymphocytes (PBL) in PD. Here we demonstrate a reduction of dopamine transporter immunoreactivity in PBL in the early clinical stages of the disease. These findings contribute to our understanding of the peripheral dopamine system in PD.

Surgical treatment of cervical intramedullary spinal cord tumors

The aim of this study is to determine if radical microsurgical removal of cervical intramedullary spinal cord tumors (CIMSCT) is achievable without causing respiratory, motor and sphincter deficits. Sixteen consecutive patients, who underwent surgical removal of a cervical intramedullary spinal cord tumor between 1988 and 1997, are presented. Surgical findings and results are analyzed. Patients' pre- and postoperative neurological conditions were evaluated using the clinical/functional scale of McCormick et al. The tumor was totally removed in 15 patients (93%). An improvement in sensory and motor functionality was obtained in 10 patients (63%), five patients (31%) remained stable and only one patient (6%), in whom partial removal was performed, presented a worsening of motor and sphincter functions. None of the patients who underwent total removal have shown MR signs of recurrence. The only patient in whom a partial removal was realized, presented a bulbar diffusion of the tumor and died. Microsurgical total removal can be considered the treatment of choice for CIMSCT. An accurate dissection between tumoral mass and normal spinal cord may allow, in the majority of cases, a total removal of tumor with preservation of spinal cord. Potential alterations of the spine stability must be prevented using internal or external stabilization.

Gadobenate dimeglumine-enhanced magnetic resonance imaging of intracranial metastases: effect of dose on lesion detection and delineation

Seventy-four patients with one to eight proven intraaxial metastatic lesions to the brain received a total gadobenate dimeglumine dose of 0.3 mmol/kg of body weight, administered as three sequential bolus injections of 0.1 mmol/kg, at 10-minute intervals over a 20-minute period. Quantitative and qualitative assessments of efficacy were performed after each injection and a full evaluation of safety was conducted. Cumulative dosing produced significant (P < 0.01) dose-related increases in lesion-to-brain (L/B) ratio and lesion signal intensity (SI) enhancement. Two independent, blinded assessors noted additional lesions, compared to unenhanced images in 31% and 33%, 49% and 42%, and 50% and 48% of patients after each cumulative dose, respectively. Significantly more lesions were noted after the first injection, compared to unenhanced images (P = 0.002 and P < 0.001; assessors 1 and 2, respectively), and after a second injection, compared to the first (P < 0.001 and P = 0.039; assessors 1 and 2, respectively). Neither assessor noted significantly more lesions after the third injection. For patients with just one lesion observed on unenhanced T1- and T2-weighted images, additional lesions were noted by assessors 1 and 2 for 27% and 26%, 48% and 35%, and 42% and 41% of patients, respectively, following each injection. Contemporaneously, diagnostic confidence was increased and lesion conspicuity improved over unenhanced magnetic resonance imaging (MRI). For patients with one lesion observed after 0.1 mmol/kg of gadobenate dimeglumine, additional lesions were noted for 24% and 17% of patients (assessors 1 and 2, respectively) following a second 0.1 mmol/kg injection. Only assessor 2 noted additional lesions following the third 0.1 mmol/kg injection. The findings of on-site investigators concurred with those of the two off-site assessors. No safety concerns were apparent.

Intra-axial dermoid/epidermoid tumors of the brainstem in children

BACKGROUND

Epidermoid and dermoid cysts are rare intracranial space-occupying lesions, which account for about 1% of all intracranial tumors; they are even rarer in the pediatric age group. Among the various locations, that inside the brain stem is quite exceptional (only 12 cases reported to date in the literature). We report two additional cases occurring in children, underlining their clinical characteristics, the difficulties faced in the diagnostic work-up, and the surgical treatment adopted (which consisted of removal of the cyst contents and partial resection of the cyst membrane, because of its adherence to the surrounding nervous and vascular structures).

METHODS

We report two cases of intraaxial dermoid/epidermoid cysts observed within the last 5 years. Both patients complained of cervico-nuchal pain, with a remittent/intermittent character in one of them; this patient also exhibited transient 6th and 7th cranial nerve deficit. One lesion was approached through the floor of the fourth ventricle, the second one through the ventrolateral aspect of the brainstem.

RESULTS

Subtotal tumor resection was achieved in both cases. Both patients had a smooth postoperative course without permanent neurological deficits. In the first patient residual tumor remains stable on follow-up MRI. In the second one, early tumor regrowth necessitated a second operation, after which the residual tumor has remained stable.

CONCLUSIONS

Based on our experience we suggest that a cautious surgical approach ("conservative" resection) to these lesions is the best choice. In fact, attempts at radical removal carry unacceptably high morbidity and mortality rates.

Management of recurrent craniopharyngioma

Although histologically benign, craniopharyngioma can regrow either from macroscopic remnants of the tumour left behind at operation, or even after an apparently gross total removal. Recurrence rates vary significantly in the literature, depending on the efficacy of surgical treatment and also on the growth potential of the tumour itself. The main factor influencing tumour regrowth is obviously the extent of surgical resection, as total removal carries a much lesser risk of recurrence compared to subtotal or partial resections (although in such cases radiation therapy can lower this risk significantly). Other factors involved are the duration of follow-up and patient's age at operation, as children tend to relapse more frequently than adults. Even in the "microsurgery" era, characterized by high percentages of total resections, recurrences remain high and continue to represent a major problem of craniopharyngioma treatment. Twenty-seven children and adolescents were operated on for craniopharyngioma at the Department of Neurosurgery, Section of Pediatric Neurosurgery, Catholic University Medical School, Rome between June 1985 and June 1997. Total tumour resection was achieved in 18 cases, subtotal in 7 and partial in 2 instances. One patient died post-operatively. Post-operative neuroradiological investigations confirmed the operative findings, although 3 children with an apparently gross total removal showed a residual non-enhancing calcium fleck adherent to the hypothalamus (which remained stable at the following examinations). Three of the 9 patients with less than total removal underwent post-operative radiation therapy. Out of the 26 surviving patients 6 presented a recurrence of their craniopharyngioma, 2 after an apparently gross total removal and 4 after a subtotal or partial resection (one of them had received radiation therapy). The diagnosis was merely neuroradiological in 5 cases, as only one child presented a clinical picture suggestive of tumour regrowth. Surgery was the first therapeutic option in all the cases. Total tumour resection was accomplished in 3 cases, subtotal in 2 and partial in the last one. One child died post-operatively. Four of the 5 survivors received radiation therapy. All the patients are presently alive and stable (mean follow-up: 5.6 yrs). The authors conclude that surgery should be the first therapeutic option in case of recurrent craniopharyngioma and that radiation therapy should also be considered but only as adjuvant therapy.

Consensus statement on the role of acute dopaminergic challenge in Parkinson's disease

Available evidence on the practice of acute pharmacological challenge tests in parkinsonian patients was reviewed by a committee of experts, which achieved a general consensus. The published data deal mainly with the acute administration of levodopa and apomorphine in Parkinson's disease. Such challenge may serve different purposes, e.g., research, diagnosis, or tailoring of treatment. Unique protocols describing the clinical setting and practice parameters are not available. The present paper describes the scientific background and supplies practical guidelines, whenever possible, to perform and evaluate acute challenge tests in parkinsonian syndromes. With the appropriate indication and setting, acute challenge tests are useful in diagnosis and therapy of Parkinson's disease and related disorders.

Detection of intracranial metastases: a multicenter, intrapatient comparison of gadobenate dimeglumine-enhanced MRI with routinely used contrast agents at equal dosage

RATIONALE AND OBJECTIVES

To compare gadobenate dimeglumine (MultiHance) with other commercially available MRI contrast agents for the detection of intracranial metastases.

METHODS

A retrospective assessment was performed on MR images from 22 patients enrolled in a prior phase II clinical trial of gadobenate dimeglumine. Each patient underwent two examinations: a first examination with one of three "comparator" agents (gadopentetate dimeglumine, gadodiamide, and gadoterate meglumine) at a dosage of either 0.1 or 0.2 mmol/kg, and then a similar examination with gadobenate dimeglumine at equal dosage. All images were evaluated randomly for lesion number and location in unpaired and then paired fashion by two independent, masked neuroradiologists. A third assessor performed quantitative assessments on the available complete sets of digitally recorded images (10 cases).

RESULTS

The findings for the comparator agents were pooled. Sensitivity for lesion detection with gadobenate dimeglumine (93%-100%) was markedly superior to that of comparator-enhanced examinations (65%-73%). The increase of lesion-to-brain contrast of the main lesion was consistently greater with gadobenate dimeglumine than with comparator agents relative to unenhanced contrast (+43% vs. +27%).

CONCLUSIONS

Gadobenate dimeglumine proved to be a more efficacious agent than comparator contrast agents for the detection of intracranial metastatic lesions: superior efficacy was noted by both reviewers for total lesion count as well as for sensitivity and positive predictive value for lesion detection. The higher relaxivity of gadobenate dimeglumine might explain the superior sensitivity of gadobenate dimeglumine-enhanced MRI for the detection of central nervous system metastases.

Epidemiology of progressive supranuclear palsy. ESGAP Consortium. European Study Group on Atypical Parkinsonisms

Progressive supranuclear palsy (PSP) is a rare form of parkinsonism. The incidence rates are about 0.3-1.1 cases per 100,000 persons. The only two case-control studies performed up to now show conflictual results as regards education and residence in rural areas. Recently, a cluster of PSP and atypical parkinsonism has been observed in French Antilles. The hypothesis is that a consumption of both tropical fruit and herbal tea may be associated with PSP onset. Some PSP families with a probably autosomal dominant transmission have been described. A high frequency of a tau haplotype (H1/H1) associated with PSP is reported by some authors. The significance of this association is still not clear. We have performed a case-control study on 58 PSP cases, 116 hospital controls and 58 population controls.

Epidemiology of multiple system atrophy. ESGAP Consortium. European Study Group on Atypical Parkinsonisms

Multiple system atrophy (MSA) is a form of atypical parkinsonism with unknown etiology. The epidemiological studies conducted up to now on this disease are scarce. The incidence rate is about 0.6 cases per 100,000 persons per year. The prevalence rates show 4-5 cases per 100,000 persons. In Italy, about 4,900 prevalent cases have been estimated. The mean onset age is about 54 years; the median survival is 7-9 years. Only one case-control study has been performed on this disease. This study showed an increased risk of MSA associated with occupational exposure to organic solvents, plastic monomers and additives, pesticides and metals. Smoking habits seem to be less frequent in MSA cases (as in Parkinson's disease cases) than in healthy controls. Quinn's clinical criteria and those of the Consensus Conference promoted by the American Academy of Neurology are in fair agreement. We have performed a case-control study on 73 MSA cases, 146 hospital controls and 73 population controls.

Donepezil in the treatment of progressive supranuclear palsy

OBJECTIVES

To evaluate the effect of 3 month therapy with donepezil, a centrally acting cholinesterase inhibitor, on cognitive performances, motor function and daily living activities in progressive supranuclear palsy (PSP).

MATERIALS AND METHODS

Six patients with a diagnosis of PSP were evaluated at baseline and after 3 months of treatment with donepezil, 10 mg given at bedtime. Cognitive functions, motor symptoms and daily activities were evaluated by means of appropriate rating scales.

RESULTS

Donepezil was not effective on cognitive dysfunction and did not change ratings of daily living. Parkinsonian symptoms were unaffected by donepezil treatment.

CONCLUSIONS

Cholinergic replacement therapy alone is not likely to improve symptoms in a disorder characterized by a more widespread impairment of monoaminergic systems. Larger studies may be necessary to confirm the lack of effect of donepezil in this disorder.

Craniopharyngiomas of the third ventricle: trans-lamina terminalis approach

OBJECTIVE

Craniopharyngiomas usually grow on the cisternal surface of the hypothalamic region; these tumors can also grow from the infundibulum or tuber cinereum on the floor of the third ventricle, developing exclusively into the third ventricle. The aim of the present work was to establish the usefulness of the pterional trans-lamina terminalis approach for the removal of these tumors.

METHODS

Eight patients who were surgically treated for craniopharyngiomas located exclusively within the third ventricle were considered. The initial symptoms were acute hydrocephalus in two cases, psychological disturbances in two, amenorrhea in two, headaches in one, and hypopituitarism in one. The diagnoses were established, in all cases except one, with magnetic resonance imaging. In all cases, the tumor completely filled the third ventricle.

RESULTS

Total removal of the lesion was achieved in seven cases. One patient underwent partial removal. In the immediate postoperative period, no major complications were observed. Five patients required replacement hormonal therapy. All patients returned to a normal life. Many months after surgery, two patients exhibited psychological disturbances and died, the first because of voluntary withdrawal of replacement therapy (12 mo after surgery) and the second because of a severe imbalance in body fluids and electrolytes, with a subsequent hyperosmolar coma (27 mo after surgery). Only one patient who underwent initial total removal experienced a small recurrence of the lesion (30 mo after surgery); after 3 years, the lesion exhibited unchanged size.

CONCLUSION

In our experience, the trans-lamina terminalis approach is a valid choice for the removal of purely intraventricular craniopharyngiomas. These tumors can be removed without significant sequelae related to the surgical approach. The proximity to the hypothalamus requires accurate neuroendocrine and electrolyte control in the postoperative period, in some cases even years after surgery.

Occipital condylar fractures: a review

The purpose of this review article is to summarize the epidemiology, pertinent anatomy, mechanisms of injury, and classification systems of occipital condylar fractures (OCFs), as well as their clinical presentation and screening, the importance of computed tomography (CT) for detection, and current treatment options. The authors emphasize the rate of occurrence of OCFs, which may be detected in as many as 16% of patients with craniocervical injury. Clinical presentation is not specific, and OCF is not readily diagnosed at physical examination. Failure to diagnose may result in substantial morbidity, and thus accurate diagnosis is mandatory for both therapeutic and medicolegal implications. The diagnosis is most likely to be made with CT. Thin-section CT technique is the method of choice to evaluate the traumatized craniocervical junction. OCFs should be suspected in all patients sustaining high-energy blunt trauma to the head and/or upper cervical spine, resulting from axial loading, lateral bending and/or rotation, and/or direct blow. Besides a CT study assessing potential intracranial injuries, these patients require CT of the craniocervical junction. Radiologists should be aware of the types of OCFs and associated injuries.

Restrictive limitation of sursumduction caused by an anomalous muscular structure

We report a peculiar case of congenitally restricted sursumduction caused by an anomalous band-like structure within the right orbit which was completely distinct from the extraocular muscles. Imaging (static and dynamic ultrasound studies of the orbit and globe, CT and MRI) revealed the origin of the anomalous structure in Zinn's ring, its intraconal course and bulbar insertion. The ultrasound characteristics were similar to those of the extraocular muscles and optic nerve, and contractile activity appeared to occur during eye movements. The seemingly muscular nature of this structure and its total autonomy with respect to the normal extraocular muscles distinguish this case from previously reported cases of congenital restrictive strabismus.