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Biomedical subjects

C Kilpatrick

Publications and source records attributed to C Kilpatrick.

18 recordsLinked to original sources

Degree of left hippocampal atrophy correlates with severity of neuropsychological deficits.

The relationship between the degree and distribution of hippocampal atrophy measured by volumetric magnetic resonance imaging and severity of memory deficits in 25 patients with temporal lobe epilepsy secondary to mesial temporal sclerosis was assessed. Hippocampal volumes were expressed as a ratio of smaller to larger, normal ratio greater than 0.95. Neuropsychology tests included: subtests of the WAIS-R, Rey Auditory Verbal Learning Task, Rey Figure and the Austin Maze. Degree of left hippocampal atrophy in patients with left temporal lobe epilepsy was associated with severity of verbal memory deficits as measured by RAVLT total recall (P < 0.05), delayed recall (P < 0.001), story recognition (P < 0.001), list recognition (P < 0.001) and final delayed recall (P < 0.001) and recall of the Rey Figure (P < 0.01). There was no association between degree of right hippocampal atrophy and any of the memory tests. Diffuse left hippocampal atrophy was associated with more severe verbal memory deficits than anterior atrophy. We conclude, the association between degree of left hippocampal atrophy and verbal memory provides further evidence of the predominant involvement of the left hippocampus in verbal memory. The finding of a relationship between degree of left hippocampal atrophy and measures of non-verbal function suggests these tests are dependent on verbal memory, or that mesial temporal sclerosis is a bilateral but asymmetrical condition.

Adolescent

Hippocampal atrophy is not a major determinant of regional hypometabolism in temporal lobe epilepsy.

PURPOSE: The pathophysiologic basis for the [18F]fluorodeoxyglucose positron-emission tomography (FDG-PET) temporal lobe hypometabolism in patients with hippocampal sclerosis (HS) is uncertain. We tested the hypothesis that hippocampal atrophy, which is strongly correlated with hippocampal cell loss, is largely responsible for the regional hypometabolism in HS. METHODS: Regions of interest (ROIs) on FDG-PET scanning were determined in the medial, lateral, and posterior temporal lobe, thalamus, and basal ganglia. A right/left asymmetry index for each ROI was calculated. These results were correlated with hippocampal magnetic resonance imaging (MRI) volume ratios. RESULTS: There was no correlation between the magnitudes of the FDG-PET asymmetry index and the MRI volume ratio for the mesial or lateral temporal regions (r = -0.09, r = -0.04). When the right/left asymmetry index was compared with the right/left hippocampal volume ratio, correlations for the mesial temporal ROI (r = 0.79, p < 0.0001) and lateral temporal ROI (r = 0.57, p < 0.0005) were found. These, however, simply indicated that both tests accurately reflect the side of the epileptogenic region. The concordance of the side of relative hypometabolism of the FDG-PET with the side of the hippocampal atrophy was higher for the mesial temporal region (100%) than for the lateral (77.5%). CONCLUSIONS: The lack of correlation between the magnitudes of the ratios argues against hippocampal atrophy and cell loss having a central role in the FDG-PET temporal hypometabolism.

Adult

Non-invasive investigations successfully select patients for temporal lobe surgery.

OBJECTIVES: There is controversy regarding the need for invasive monitoring in the preoperative assessment of patients with temporal lobe epilepsy. The use of a series of non-invasive investigations in identifying the seizure focus is reported in 75 consecutive adults referred for epilepsy surgery. METHODS: All had video-EEG monitoring using scalp electrodes, high resolution MRI, and neuropsychology assessment. Other investigations included volumetric MRI, PET, and ictal and interictal SPECT. The seizure focus was localised and surgery offered if MRI disclosed unilateral hippocampal atrophy or a foreign tissue lesion and other investigations were either concordant or not discordant. RESULTS: In 68 patients the seizure focus was localised and three patients were inoperable. Sixty five patients have been offered surgery and 50 have undergone temporal lobe surgery and have a follow up of at least 12 months (mean 24 months). All had pathology: hippocampal sclerosis 34, dysembryoblastic neuroepithelial tumour six, cavernoma four, dysplasia two, low grade glioma two, ganglioglioma two. Thirty nine patients (78%) are seizure free postoperatively, 29/34 with hippocampal sclerosis and 10/16 with a foreign tissue lesion. Of the 11 patients with postoperative recurrent seizures, eight have a >90% reduction in seizure frequency and three have <90% reduction in seizure frequency but a worthwhile improvement. CONCLUSIONS: Non-invasive investigations successfully select most patients for temporal lobe surgery.

Adolescent

Temporal lobe epilepsy caused by mesial temporal sclerosis and temporal neocortical lesions. A clinical and electroencephalographic study of 46 pathologically proven cases.

This study aims to determine whether there are important clinico-electrical differences between patients with temporal lobe epilepsy (TLE) secondary to mesial temporal sclerosis (MTS) and those with TLE secondary to a discrete temporal neocortical lesion (NL). The case histories, interictal EEG, seizure semiology, ictal EEG and postoperative outcome of 46 pathologically proven patients (31 MTS and 15 NL) were compared. A history of febrile convulsions (FC) was more common in MTS patients (58% versus 26%, P < 0.05), as was a history of a significant cerebral event at < 4 years of age (22% versus 0%, P < 0.05). There were no statistically significant differences in the incidence or nature of auras. No statistically significant differences between the groups were found in the interictal-EEG. With ictal semiology dystonic posturing occurred more frequently in MTS patients (mean 52% versus 26%, P < 0.05). Facial grimacing/ twitching occurred earlier in the seizures of NL patients (median 19 s versus 35 s, P < 0.05). There was an increased frequency of fast rhythmic sharp waves (> 4 Hz) in the ictal-EEG of MTS patients (mean 81% versus 60%, P = 0.05). The patients with NL developed bilateral ictal EEG changes more often (mean 55% versus 26%, P < 0.05) and more rapidly (mean 23 s versus 74 s, P < 0.005). The onset of ictal EEG seizure activity was bilateral more often in patients with NL (20% versus 4%, P < 0.005). There were no significant differences between the two groups for any of the video-EEG features, in terms of whether or not the feature occurred at least once in an individual patients. There was a tendency for MTS patients to have a higher seizure-free postsurgical outcome (87% versus 60%, P = 0.057). However, all the NL patients who were not free of seizures had had an incomplete lesion resection. We conclude that there are a number of clinico-electrical differences between patients with mesial TLE (MTLE) and patients with neocortical TLE (NCTLE), but that none of these are sufficient to allow a distinction to be made in an individual patient.

Adolescent

Imaging in epilepsy.

Neuroimaging in epilepsy now includes magnetic resonance imaging, positron emission tomography (PET), single-photon emission tomography (SPECT), magnetoencephalography, and magnetic resonance spectroscopy. Recent advances in neuroimaging include improved rates of detection of lesions on structural imaging using quantitative methods, identification of metabolic patterns on functional imaging with PET, and recognition of the value of ictal SPECT in seizure localization.

Brain

Reversal of a neurologic paraneoplastic syndrome with octreotide (Sandostatin) in a patient with glucagonoma.

A 69-year-old woman with classic glucagonoma syndrome had associated progressive neurologic disease manifest as dementia, ataxia, optic atrophy, and lower limb weakness. Visual evoked responses (VERs) were absent bilaterally. After an attempt at resection was unsuccessful, therapy was started with somatostatin analogue (Sandostatin, SMS 201-995). Over the ensuing 3 months, there was a decrease in the plasma glucagon level, resolution of the rash, weight gain, reversal of the dementia, and an improvement in coordination and limb weakness. Subsequent VERs revealed bilateral delayed responses.

Aged

Cerebrospinal fluid biochemistry in the diagnosis of multiple sclerosis.

The Poser criteria for diagnosing multiple sclerosis (MS) includes clinical, paraclinical and laboratory information. We studied the influence of cerebrospinal fluid (CSF) biochemistry results on the categorisation of patients with suspected MS. A retrospective study was made of 138 patients who had CSF samples sent over a 1 year period to the laboratory for examination for oligoclonal bands. Using the Poser criteria, 23 patients were diagnosed as having definite MS and one patient as probable MS. Cerebrospinal fluid biochemistry upgraded the categorisation from probable to definite MS in 16 of these 24 patients (66%). In this study, we found oligoclonal bands to be more sensitive in the diagnosis of MS (96%) than either the concentration of IgG in the CSF (43.5%) or the IgG expressed as a percentage of the total protein in the CSF (71%). We conclude that CSF biochemistry is a valuable investigation in the evaluation of patients with suspected MS.

Adolescent

Clobazam in the treatment of epilepsy.

Clobazam, a 1,5-benzodiazepine, is a potent anticonvulsant but the development of tolerance limits its use. It has been suggested that low dose clobazam may prevent or delay the onset of tolerance. This study aimed to assess, by an open trial, the anticonvulsant activity of low dose clobazam in 11 adult patients with frequent intractable seizures. Serum clobazam and N-desmethylclobazam levels were assayed and correlated with clinical effect, adverse effects, drug dose and the development of tolerance. Clobazam was given in addition to conventional antiepileptic therapy, beginning with a dose of 20 mg at night. A 50% or greater reduction in the frequency of seizures was noted, at least transiently, in all patients. In 8 of the 11 patients there was a subsequent deterioration in control of epilepsy and in all patients this relapse occurred within 3 months of commencing treatment. There was a relationship between plasma concentrations of N-desmethylclobazam (but not of clobazam) and therapeutic and toxic effects. Tolerance was not associated with a fall in plasma levels. It is concluded that clobazam is of limited value as a long term anticonvulsant and that the high incidence of tolerance is not reduced by the use of low doses.

Administration, Oral

Antagonistic activity of tiotidine and ranitidine on guinea-pig and rabbit atria.

Isolated, spontaneously beating atrial pairs from rabbits and guinea-pigs were used to determine and to compare the activity of ranitidine and tiotidine as antagonists of histamine stimulated chronotropic activity. Ranitidine produced a classical competitive, reversible antagonism of histamine effects with a pA2 in rabbit atria of 8.2. In contrast, tiotidine produced both a dextral shift of the log dose-response curve, as well as a previously unreported suppression in the maximal response produced by histamine. In accordance with receptor theory, this type of activity represents a dualistic antagonism of histamine chronotropic responses.

Animals

Computed tomography of rhinocerebral mucormycosis.

Rhinocerebral mucormycosis is a rare fungal infection which is frequently fatal. Survival depends on early diagnosis and immediate aggressive treatment. Previously described radiological changes have been non-specific. The CT features of two cases are described. Non-enhancement of the superior ophthalmic vein and ophthalmic artery appears to be a CT sign specific to this disease.

Adolescent

Spontaneous dissection of the internal carotid artery.

Spontaneous dissection of the internal carotid artery has been considered a relatively rare cause of carotid artery occlusion. It is postulated this condition may not be uncommon and that some cases are not recognised. The condition is characterised by typical clinical and radiological features which should suggest the diagnosis. Despite these suggestive features it appears that recognition of this condition is not widespread and the diagnosis may not be made. Three cases of spontaneous dissection are reported. The clinical and radiological features will be emphasised and pathogenesis and treatment discussed.

Adult

Identical twins with Alzheimer's disease.

Genetically proven identical twin sisters with Alzheimer's disease are reported. Both sisters at the age of fifty years developed a dementing illness. Their mother and maternal grandmother developed at the same age a similar illness. It is suggested that in some cases of familial Alzheimer's disease the condition is inherited by a single mutant gene.

Aged

Forearm arterial vascular responsiveness in insulin-dependent diabetic subjects.

The vascular reactivity of forearm arterioles was measured in 16 control subjects (C) and 30 insulin-dependent diabetic (IDDM) subjects, 16 of whom were shown to have microvascular and/or neuropathic complications (DC) including 8 with autonomic neuropathy (DCa) and 14 were shown to be free of complications (DNC). Forearm blood flow was measured by strain gauge plethysmography basally, following a cold pressor stress and following a period of arterial occlusion (reactive hyperaemia). The tests were repeated 24 h later following aspirin treatment. Both C and DNC showed a significant reduction in blood flow in the cold pressor test (C 0.64 +/- 0.12, DNC 0.89 +/- 0.22 ml/100 ml forearm tissue/min reduction in flow P < 0.005), while DC showed no significant response. Reactive hyperaemia was significantly greater in C than in DNC or DC (8.37 +/- 1.14, 5.51 +/- 1.27 and 4.95 +/- 0.75 ml/100 ml tissue/min, respectively, P < 0.02). In the DC group, DCa had significantly less response than those without autonomic neuropathy. Aspirin treatment restored the response of DNC but not DC to normal, suggesting that the abnormality in the former group may have been due to overproduction of a vasoconstrictive cyclooxygenase product (such as thromboxane A2). It is concluded that the abnormalities of vasomotor responses in diabetic subjects are complex and are apparently dependent on autonomic neuropathy, humoral and perhaps structural changes.

Adult