Biomedical subjects
Publications and source records attributed to I Bone.
Three cases of cortical blindness complicating eclampsia are described, with magnetic resonance imaging (MRI) and X-ray computed tomography (CT). The correspondence of MRI lesions (hyperintense on T2 weighted, and hypointense on T1 weighted sections) and low attenuation lesions on CT scan indicated ischaemia rather than haemorrhage as the pathological mechanism.
Bilateral chorda tympani section is an accepted treatment for troublesome sialorrhoea. Nevertheless the effects of this operation have been poorly studied. Twenty patients were studied with unilateral chorda tympani section and a healthy contralateral ear. The effects on ipsilateral and contralateral stimulated submandibular and parotid flow and taste recognition and detection thresholds were measured. Stimulated submandibular flow accounted for only 27% of the total salivary flow. Chorda tympani section had no effect on submandibular flow in seven patients and only reduced submandibular flow by approximately 54% in the remaining 13 patients. No significant effect was observed on ipsilateral parotid flow rate. Electrogustometric taste detection thresholds were more than twice the accepted upper limit of normal on the lesioned side and taste recognition thresholds were also markedly abnormal. Chorda tympani section alone is a poor method of reducing stimulated salivary flow.
Three cases are reported in which an initial misdiagnosis of multiple sclerosis was made. In each of these a single central nervous system lesion with space occupying effect was present. These lesions caused confusion because multiple closely running neurological tracts were affected, and there was relapse and remission in the neurological signs and symptoms produced. We conclude that such cases need careful assessment to determine whether a single structural lesion could explain the presentation. Early imaging may show remediable lesions or prevent unnecessary steroid therapy.
The neurological features of 10 patients with HIV-related disease seen in Glasgow between July 1984 and May 1988 are described. Two of these patients presented with ARC and eight with AIDS. Six patients showed features consistent with a diagnosis of AIDS-dementia complex, one had cerebral toxoplasmosis, one had CNS lymphoma, one had a probable drug-induced encephalopathy and one patient had a meningoencephalitis of undetermined cause. Seven of these patients have now died. The implications of these findings are discussed.
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Accurate measurements of CSF volumes would assist in the diagnosis of several important neurological conditions. Using Magnetic Resonance Imaging (MRI) we have devised a method to measure both total intracranial CSF volume and ventricular volume. This initial study, in normal humans, provides an answer to two longstanding questions: first, do these volumes differ between the sexes; second, do both total and ventricular CSF volumes increase with normal aging? We found that the total cranial CSF volume and skull size of males were significantly greater than those of females, but that there was not a statistically significant difference between the ventricular volumes of the sexes. Total cranial CSF volume increased steeply with age in both sexes but although there was an increase in ventricular volume with age in males, no significant increase with age could be demonstrated in females.
No standardised method for taste threshold measurement is available and therefore comparison between clinical studies is difficult. An electrogustometer was evaluated in normal subjects. No sex difference in taste threshold was noted; however, there was a significant elevation in detection threshold with age and smoking. Electrogustometric values both in patients before and after surgery for trigeminal neuralgia and in patients with trigeminal sensory neuropathy were determined. Many patients with trigeminal nerve disorders had abnormal electrogustometric detection thresholds suggesting that there is possibly an accessory taste pathway through the trigeminal nerve, although in some individuals the site of lesion may be in the brain stem. Electrogustometry is a convenient method for clinically assessing taste.
Clinical improvement in epilepsy following temporal lobectomy is more often obtained when an abnormality is found on subsequent histological examination. Pre-operative MRI demonstrated an abnormal signal in the temporal lobe of a patient with pathologically proven mesial temporal sclerosis with microvascular anomaly. MRI may therefore be helpful in the selection of patients for temporal lobectomy. MRI findings of 12 patients with resistant focal epilepsy are reviewed. A wide range of T1 and T2 weighting is suggested to maximise selection of patients.
When patients with syringomyelia fail to improve after operation, factors such as incomplete cyst decompression or type of operation are often implicated. MRI has been used to confirm adequate syrinx decompression post-operatively and to compare the degree of collapse with the type of operation. Foramen magnum decompression was at least as effective in reducing cyst size as syringo-subarachnoid shunting. MRI may also provide a better classification of syringomyelia.
The severity and distribution of symptoms and signs in patients with syringomyelia is considered to be dependent on the longitudinal and transverse dimensions of the syrinx and it is thought that clinical examination can identify the extent of the cyst. Magnetic resonance imaging has made the anatomical localisation of intramedullary spinal lesions more exact and probably more specific than previous methods of investigation. Syrinx length, diameters, cyst:cord and cord:canal ratios have been studied in 12 patients with syringomyelia to assess whether the dimensions of the syrinx relate to the clinical findings. The length of syrinx appeared to be related to cyst diameter, cyst:cord and cord:canal ratios. Patients with a small syrinx tended to have a small cyst diameter, and small cyst:cord and cord:canal ratios. No significant relationship was found between muscle wasting or weakness, distribution of sensory loss, degree of disability or distress and the dimensions of the syrinx. These findings should be borne in mind when surgical management is being considered.
A 50-year-old man, who had previously been well, presented with symptoms and signs of progressive cauda equina compression. This was shown to be due to an extradural lesion which on biopsy was found to be a non-Hodgkin's lymphoma of the small cell lymphocyte type. There was no evidence of lymphoma deposits elsewhere. Non-Hodgkin's lymphoma rarely affects the central nervous system except as a late feature of widely disseminated disease. This case demonstrates that isolated spinal infiltration in the absence of widespread disease can be a mode of presentation of a non-Hodgkin's lymphoma. Accordingly primary extradural non-Hodgkin's lymphoma should be considered in the differential diagnosis of spinal cord and root compression.
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Resting cerebral blood flow (CBF) and the response to inhalation of 7 per cent CO2 was measured in 74 patients with symptoms of cerebrovascular disease. In order to evaluate their role in the identification of patients with significant arterial lesions, these measurements were correlated with the angiographic appearances, the clinical picture and the presence or absence of infarction on CT scan. Patients with carotid stenosis of 60 per cent or more had normal resting flows, but reduced responsiveness to CO2 inhalation. Patients with carotid occlusion had both reduced resting flow and reduced CO2 responsiveness. Infarcts were visible in 25 per cent of the hemispheres studied, and were more common in patients with fixed neurological deficits, but were also present in 17 per cent of patients with transient ischaemic attacks (TIAs). Reduction in the collateral supply from the contralateral carotid artery via the Circle of Willis further reduced CO2 responsiveness with ipsilateral internal carotid occlusion. The normal increase in CBF which occurs with the inhalation of carbon dioxide is diminished with increasingly severe bilateral disease, with infarction and with a fixed neurological deficit.
A unique illness consisting largely of quadriplegia in an 18-year-old woman with neurogenic and psychogenic seizures is described and discussed in detail. The precise nature of the illness remains obscure, although it was predominantly hysterical. The concept of hysteria is reappraised and examined in terms of the mind-brain problem of philosophy.
The non-invasive xenon-133 inhalation technique was used to measure regional cerebral blood flow in 61 patients with cerebrovascular disease in whom carotid angiography had been performed before carotid endarterectomy or extracranial/intracranial arterial bypass were considered. Hemispheric cerebral blood flow (CBF) was significantly lower in patients with an ipsilateral internal carotid artery occlusion than in those with a patent vessel. CBF values were also influenced by disease of the contralateral carotid artery. The cerebrovascular response to hypercapnia was a more sensitive index of carotid disease; a significant reduction in CO2 responsiveness was found both with occlusion and stenosis of the ipsilateral internal carotid artery. These data suggest that CBF measurements may be clinically useful in selecting patients for angiography and surgery.
A case of mutism due to left hemisphere infarction is described. Recovery revealed mild motor dysphasia. Review of the literature showed that the case resembles aphemia but is unique by virtue of its duration, and the absence of associated apraxia and paresis.