Is cranial computerized tomography useful in the diagnosis of multiple system atrophy?

Cranial computer tomographic (CT) images of 33 patients with multiple system atrophy (MSA) and of 40 age-matched controls were blindly analyzed by two neuroradiologists. All patients had autonomic dysfunction, all but one had parkinsonism, and 13 had cerebellar signs. The scans were judged entirely normal in 21%. Moderate or severe infratentorial atrophy was found in 42%. Cerebellar atrophy was present in 39%, and pontine atrophy was present in 18%. Of the 13 patients with cerebellar signs, only eight had cerebellar atrophy. Of the 20 patients without cerebellar signs, five had cerebellar atrophy. Supratentorial involvement was much less common and less severe. Thus, CT demonstrated system involvement that was not evident clinically in five of 33 cases (15%). However, in all five the clinical diagnosis was already evident from the presence of both autonomic and pyramidal signs in addition to parkinsonism. We conclude that CT imaging is of limited diagnostic use in individual patients with MSA.

Brain swelling and ischaemia in Kenyans with cerebral malaria

Computed tomography was performed on 14 unconscious Kenyan children recovering from cerebral malaria (seven of whom had another scan 12-120 days later) to elucidate the cause of intracranial hypertension and neurological sequelae. Brain swelling, defined as a loss of cerebrospinal fluid spaces, was documented in six children, while a further two had conspicuously small ventricles only. There was severe intracranial hypertension in the two children with definite brain swelling in whom intracranial pressure was monitored. There was no evidence of acute hydrocephalus or vasogenic oedema. Four children with brain swelling also had widespread low density areas suggestive of ischaemic damage. The patterns of damage were not uniform but were consistent with a critical reduction in cerebral perfusion pressure (which was documented in the two in whom this was monitored), hypoglycaemia, or status epilepticus. All four had serious neurological sequelae. These data suggest that brain injury in cerebral malaria may be due in part to secondary systemic and intracranial factors as well as to the direct effect of intravascular sequestration.

Delayed diagnosis of spinal vascular malformations presenting as intermittent myelopathy

We report our recent experience of three male patients, whose clinical diagnosis and subsequent surgery was delayed for 9.25 and 15 months respectively. Initially, they all presented with vague, either sensory or motor lower limb disturbances and intermittency of symptoms was followed by bladder dysfunction or impotence. Extensive laboratory work-up was unrevealing and the non-specific diagnosis of myelopathy further delayed the recognition of the underlying vascular lesion. Finally spinal magnetic resonance imaging (MRI), supine myelography and selective spinal arteriography indicated the presence of a tumor in the first patient and vascular malformation in the other two. Neurosurgery and histology confirmed one cavernous angioma and two arteriovenous malformations, all thoracic and dural. We believe that both the cryptic nature of these lesions and our technical limitations (spinal arteriography and MRI not readily available), accounted for the delayed diagnosis in our three patients, who nevertheless, when treated by surgery showed a satisfactory outcome in the first case, while further deterioration was prevented in the other two.

EEG features of cortical dysplasia in children

Two distinctive electroencephalographic abnormalities, very high amplitude rhythmic activity or prominent fast activity, have been described in children with extensive cortical dysplasia. Cases with cortical dysplasia identified on computerised tomography or magnetic resonance imaging, or a characteristic EEG were selected. One hundred and forty electroencephalograms from 94 cases were reviewed and related to the imaging findings. An EEG with very high amplitude rhythmic activity was found to have high specificity for severe cortical dysplasia but low sensitivity (< 50% cases). Abnormal fast activity was not specific and was seen with very diverse pathologies. The EEG features of most cases with localised cortical dysplasia were very variable. The EEG could be normal even when the cortical dysplasia was extensive.

Brain MRI changes in phenylketonuria. Associations with dietary status

Following the introduction 30 years ago of neonatal screening and early dietary treatment for phenylketonuria there has been a dramatic decrease in the severity of neurological dysfunction associated with this disorder. However, there is evidence that subtle neurological impairment remains common in early treated subjects and in the last 3 years there have been a number of reports of overt neurological impairment with white matter abnormalities on MRI. The frequency of white matter changes in phenylketonuria, and the relation of these changes to dietary management, have remained unclear. The present study examines MRI findings in 34 subjects aged 8-33 years. Twenty-five subjects had been detected by routine neonatal screening and nine had been missed in the screening programme. At the time of the investigation 16 of the early treated and two of the late treated subjects were still receiving a diet low in phenylalanine. All but two of the 34 subjects showed abnormalities on MRI. In the early diagnosed group it could be shown that the severity of MRI changes (graded 1-5) was significantly and independently associated with phenylalanine concentrations at the time of investigation and the time since dietary treatment had been withdrawn. These data are consistent with studies in animals showing that hyperphenylalaninaemia increases myelin turnover in a dose dependent manner. It is suggested that the effects of phenylalanine on myelin pose a lifelong hazard to the nervous system.

Alexander's disease: clues to diagnosis

The clinical, radiologic, neurophysiologic, and pathologic findings in 10 children with histologically proven Alexander's disease are described, and the presence of two broad clinical subgroups is confirmed. Macrocephaly, regression, and seizures are found in the infantile form, whereas bulbar signs predominate the so-called juvenile form. None of the clinical or neurophysiologic findings is pathognomonic, and radiologic features suggesting the diagnosis are not present in all cases. However, the combination of abnormalities may suggest the diagnosis and justify histologic confirmation.

Anterior pituitary function and computed tomography/magnetic resonance imaging in patients with Langerhans cell histiocytosis and diabetes insipidus

In order to document anterior pituitary dysfunction in patients with biopsy-proven Langerhans cell histiocytosis (LCH) and diabetes insipidus and to correlate this with structural changes on imaging, we performed an insulin tolerance test, enhanced computed tomography (CT), and unenhanced magnetic resonance imaging (MRI) in nine patients. Six of the nine patients had growth hormone deficiency, which in two patients was part of panhypopituitarism and in one was associated with poor cortisol response to insulin hypoglycemia. One patient had an exaggerated growth hormone response and one who had had neck irradiation as an infant, had a high resting thyroid stimulating hormone (TSH) suggesting compensated primary hypothyroidism. All enhanced CTs were abnormal, bony defects being the only abnormality in two patients and opaque mastoids in one. The remaining six patients all had structural changes in the hypothalamic/pituitary region. Unenhanced MRI confirmed the CT findings except in one child who had been treated with radiotherapy in the intervening period, but, in addition, confirmed diabetes insipidus by showing absence of the posterior pituitary bright signal and picked up white matter changes in a child with clinical neurological dysfunction. Our findings indicate that the development of diabetes insipidus in LCH is commonly associated with anterior pituitary dysfunction and is usually associated with structural changes in the hypothalamic/pituitary axis.

Magnetic resonance imaging of the central nervous system in Behçet's disease

Magnetic resonance imaging (MRI) was performed in 25 patients with Behçet's disease, of whom 15 had clinical involvement of the central nervous system (CNS). Brain MRI was abnormal in 11/15 with and in 1/10 without CNS involvement. The most common sites of MR lesions were the cerebral white matter and brainstem. Lesions were also seen in the basal ganglia, cerebellum, optic nerves and spinal cord. The cerebral white matter lesions were always asymptomatic and usually small, whereas the brainstem lesions were often symptomatic and sometimes extensive. Follow-up MRI in 2 patients presenting with brainstem syndromes and treated with immunosuppression showed resolution of a large lesion in 1 patient in whom there was clinical remission, and the development of marked brainstem atrophy in the other who became severely disabled. The pattern of MRI abnormalities may assist the diagnosis and suggests a role for MRI in monitoring the effect of treatment in patients with neurological Behçet's disease.

Magnetic resonance imaging in the assessment of craniosynostosis

Modern interest in craniosynostosis began when clinicians, regardless of their individual specialty but united in their interest in the problems raised by patients with this condition, first realised that if treatment was confined simply to opening up the fused sutures of the skull vault, success in terms of both function and the restoration of a more normal appearance was likely to be limited. Indeed, the grouping together of such specialists into formal craniofacial units was tacit recognition of this, as was the acceptance that many affected children had evidence of clinical problems that could not be explained on simple mechanical grounds alone. It is not surprising, therefore, that the advent of any new method of investigation has been welcomed by craniofacial surgeons eager to learn anything that might lead to an improvement in management, particularly of the more complex syndromes.

Serial gadolinium-enhanced MRI in relapsing/remitting multiple sclerosis of varying disease duration

In the planning of MRI protocols to monitor disease activity in multiple sclerosis (MS), the clinical subtype needs to be considered. In this serial gadolinium-enhanced MRI study, we demonstrated differences between patients with early relapsing/remitting MS and benign MS in both the production of new lesions and the occurrence of enhancement.

CT and MR imaging in lateral sinus thrombosis

Establishing a pre-operative diagnosis of lateral sinus thrombosis can be difficult, as the clinical features are non-specific and laboratory tests unhelpful. CT may demonstrate abnormal high density of the lumen of the sinus, which does not enhance after intravenous contrast medium. Enhancement of the dura surrounding the sinus may be prominent, causing the 'empty triangle' or 'delta sign' which may suggest the diagnosis. Magnetic resonance (MR) imaging may show both lack of flow and abnormal signal from the sinus, thus providing definitive evidence of thrombosis.

The clinical significance of seizures in critically ill young infants requiring intensive care

The aetiology, severity of systemic and biochemical abnormalities, seizure duration, EEGs and CT scans have been reviewed in previously normal young infants with an acute critical illness occurring after the first week of life; none of whom had birth asphyxia. Findings were related to outcome in an attempt to evaluate the significance of seizures during the acute phase of severe illness. In three years seizures occurred in 54/251 (22%) young infants requiring ventilatory support. In these patients the acute illness was most commonly infection and encephalitis/encephalopathy. Twenty-one died, 24 had good or moderate outcome and 9 poor outcome (follow-up 6-27 months). The outcome was not directly related to diagnosis, but to systemic and biochemical changes, the most important being severe hypotension (40/54). After correction of these factors, in survivors, increasing number of days over which seizures occurred during the acute phase of illness was related to worsening outcome (tau(c) = 0.66, p less than 0.0001). In many of these patients one of three abnormal low density changes (generalized, boundary zone and focal) were seen on CT scan and were not uncommonly associated with focal/multifocal clonic seizures and characteristic type, distribution and evolution of EEG discharge. In the 45 patients with EEGs from presentation, severity of encephalopathy assessed by predominant background EEG activity was most closely related to outcome, irrespective of aetiology and seizures. There was a significant relationship between graded severity of background EEG activities and outcome both in the initial and serial recordings (tauB = 0.70, p less than 0.0001 and 0.75, p less than 0.0001 respectively). Seizures are a common occurrence in the previously well young infant with an acute critical illness necessitating intensive care. Prompt recognition and treatment may influence outcome in patients with a potentially reversible encephalopathy. However, in many patients seizures reflect severe, often multifactorial cerebral insult with variable morphological changes, EEG patterns and clinical outcome.

Intracranial neurenteric cysts. Report of two cases

Two cases of intracranial neurenteric cysts are reported and the literature is reviewed. Neurenteric cysts are rare congenital lesions that tend to occur in the spinal intradural space. An intracranial location is exceptional.

Neuroradiology

Posterior fossa cysts have been reclassified, migrational defects have been matched with histology, and new abnormalities have been described in neurofibromatosis, tuberous sclerosis and ceroid lipofuscinosis. Normal myelination, progressive hydrocephalus, infantile neoplasms, cryptic angiomas and irreversible anoxic brain damage are reviewed. The distribution of grey matter changes in subacute necrotizing encephalomyelitis is discussed and the superiority of magnetic resonance imaging in partial epilepsy and neurological acquired immune deficiency syndrome is confirmed.

Pelizaeus-Merzbacher disease: classical or connatal?

The clinical features and investigation results of 7 patients with Pelizaeus-Merzbacher disease (PMD) are described; one patient had a brain biopsy and two patients had an autopsy. This paper tries to differentiate the clinical features of the connatal and classical types of PMD. Transient stridor and nystagmus were early signs in both types of PMD. Our findings support the view that the more severe connatal form shows rapid neurological deterioration from an early age leading to death usually in the first decade. In younger patients in whom the evolution is still unclear, severe feeding problems and extrapyramidal features may suggest the connatal form. By contrast, in the classical form of PMD, cerebellar signs and cognitive deterioration are more prominent with a more slowly progressive course. Nuclear magnetic resonance imaging and brainstem auditory evoked potentials were very helpful in supporting the diagnosis of PMD either in a known affected family or in sporadic cases, but were not useful in distinguishing between the two types of PMD. Genetic counseling in this condition is difficult, particularly in the connatal form in which inheritance may be either X-linked or autosomal recessive.