Biomedical subjects
Publications and source records attributed to Y L Yu.
A patient with Claude's syndrome (ipsilateral fascicular third nerve palsy with contralateral ataxia) in whom computed tomography demonstrated a discrete infarct in the paramedian rostral mesencephalic tegmentum is reported. The vascular supply of the rostral mesencephalon is discussed.
The clinical manifestations, immunological, chromosomal, and multimodal electrophysiological studies of five Chinese patients with ataxia telangiectasia are described. One died of hepatocellular carcinoma not associated with Hepatitis B-antigenaemia. Another died of respiratory failure. Two siblings are free of sinopulmonary infections although they are wheelchair bound. Computed tomography of the brain showed cerebellar atrophy in four cases. Nerve conduction studies showed evidence of axonal neuropathy in all cases with the earliest detection at six years. Electromyography showed mild denervation changes in two cases. Two patients had abnormal somatosensory evoked potentials and one had abnormal visual and brain stem auditory evoked potentials. The level of alpha foetal protein was elevated whereas the serum carcino-embryonic antigen was normal in all patients.
A 32-year-old Chinese woman with bilateral occipital aspergilloma was treated successfully with high dose ketoconazole (1200 mg/day) for six months in conjunction with amphotericin B and 5-fluorocytosine. No unacceptable side effects occurred. The use of high dose ketoconazole could be considered in CNS aspergillosis unresponsive to conventional anti-fungal therapy.
A review of the extensive literature on cervical spondylotic myelopathy and radiculopathy shows that the clinical picture and pathology are well defined, and the complex pathogenetic mechanisms are better understood. With recent advances in investigative procedures: computed tomography, magnetic resonance imaging and somatosensory evoked potentials, the diagnosis can be more accurate and the assessment more complete. Careful selection of patients for the appropriate treatment modality (conservative, anterior or posterior surgery) is crucial to the success in management.
Seven patients with cerebral necrosis after radiotherapy for carcinoma of the nasopharynx are presented. The clinical features included seizures and a varying degree of intellectual impairment. In spite of significant mass effect on CT scan, the patients remained alert, ambulatory and independent. We believe that some cases of cerebral necrosis following radiotherapy for extra-cranial neoplasms present in a more benign fashion than has been portrayed in the literature, and in the absence of clinical evidence of raised intracranial pressure, surgical intervention is unnecessary. The importance of careful fractionation of an optimum radiation dose as a preventive measure is emphasised.
Forty five patients with clear sensorium and no neurological deficits other than unilateral motor and sensory impairment underwent computed tomography (CT). Twenty patients had sensorimotor stroke with impairment of all sensory modalities (type 1). Eight had only impairment of nociceptive sensation (type 2) and 15 had only proprioceptive impairment (type 3). Two patients had sensory impairment in one limb only (type 4). Lacunes were found in patients in the first three groups. However, 80% of those who had hemiparesis and incomplete sensory loss were found to have a lacune or normal CT scan whilst only 33% of those with complete motor or sensory impairment had lacunes. It is proposed that sensorimotor stroke as a lacunar syndrome be best restricted to those with only mild to moderate hemiparesis and sensory impairment in both upper and lower limbs. The degree and extent of sensory and motor involvement may vary, however, possibly dependent on whether the thalamo-geniculate, anterior choroidal or lateral lenticulostriate artery is affected.
Ninety-three Chinese patients with cutaneous herpes zoster were seen during a 4-year period. Thoracic zoster occurred most commonly, followed by ophthalmic, cervical and lumbosacral zoster. Neurological complications were present in eleven patients (11.8%), the commonest being Ramsay-Hunt syndrome and segmental limb paresis. The clinical picture, pathogenesis, treatment and outcome of segmental limb paresis, myelitis and delayed contralateral hemiparesis following zoster ophthalmicus are discussed. Nine immunocompromised patients received intravenous adenine arabinoside (vidarabine) or acycloguanosine (acyclovir), and no cutaneous or visceral spread occurred in these patients.
Two cases of dystrophia myotonica, a mother and her newborn child, are reported. The diagnosis in the mother was only made after seven years and two eventful deliveries. The obstetrical and anaesthetic complications, as well as the neonatal form of dystrophia myotonica, are reviewed.
Hypothyroid myopathy has so far been reported in long standing cases of hypothyroidism. We describe two adult patients with myopathy associated with acute transient hypothyroidism. Both presented with severe muscle aches and cramps, stiffness and spasms. Muscle enzymes were markedly elevated and electromyography in one patient showed myopathic features. Histological changes were absent in muscle biopsy, probably because of the short duration of metabolic disturbance. The myopathy subsided promptly when the hypothyroid state was reversed.
Two patients with toxaemia of pregnancy presented with cortical blindness. Immediate cranial computed tomography (CT) demonstrated bilateral hypodense areas in the occipital lobes. Both patients underwent Caesarean section for delivery. There was gradual and complete recovery of vision, together with CT documentation of resolution of the cerebral changes, indicative of the reversible nature of the ischaemic lesion.
A patient with apoplectic intracerebral hemorrhage from delayed cerebral radionecrosis is reported. The histological changes of abnormal telangiectatic vessels account for the unusual clinical presentation. The pathogenesis and treatment of radionecrosis are discussed, and massive hemorrhage as a complication is emphasized.
A patient is reported who developed a brain abscess due to Listeria monocytogenes while on long-term steroid therapy and who was successfully treated medically without surgical intervention. The literature on listeria brain abscess is reviewed, and the importance of early recognition of this infection in any immunocompromised patient who develops focal cerebral dysfunction is emphasised.
A 52 year old patient with a right thalamic haemorrhage is described. She suffered from anterograde amnesia and memory impairment for both visual and verbal material. At follow-up after 3 months, despite being fully oriented and having good concentration, her memory impairment was still evident. Reassessment 3 years afterwards showed persistent deficits and no further improvement.
The case of an adult patient with acute hydrocephalus due to a vein of Galen malformation is reported. Ventricular shunting, apart from relieving the hydrocephalus, also resulted in shrinkage of the malformation and of the visual field defect. The possible mechanisms involved in this phenomenon are discussed.
Although metrizamide is now being superseded by other contrast media, the mechanisms of its side effects may be of fundamental importance. One hundred and four consecutive patients with suspected cervical cord or root lesion were studied prospectively for factors which might influence the side effects of metrizamide myelography. Elderly patients were more prone to develop mental confusion. An earlier onset of dizziness and/or vertigo was associated with the lumbar route of intrathecal injection. Perhaps surprisingly, phenobarbitone prophylaxis shortened the duration of confusion and delayed the onset of headaches. Other factors, viz. sex, excess intracranial flow of metrizamide and myelographic blockage were not shown to have a significant influence on the adverse reactions.
Sixty-nine patients with cervical spondylotic myelopathy (CSM), radiculopathy (CSR), or both (CSMR) were studied with computed tomography (CT). Computer-assisted myelography (CAM) accurately determines the site and nature of spondylotic protrusions and provides good visualisation of the subarachnoid space and cord deformities even in areas with dilute metrizamide. However, excessive vertebral movement and bulging ligamenta flava with their effects on cord deformity, so easily visualised in myelograms, are completely or partially missed. In the assessment of CSM, metrizamide myelography (MM) followed by CAM should be performed, particularly when the myelographic images are unsatisfactory due to contrast dilution or blockage, when cord compression cannot be ascertained with MM and when cord atrophy is suspected. In CSR, the diagnostic information from MM and CAM is comparable. The diagnostic criteria in CAM are, however, less direct and since MM is adequate in uncomplicated cases, CAM is generally not necessary. The APD, APD/TD ratio, area and circularity are sensitive indices of cord deformity and the first two should be used more often to assist visual assessment of cord deformity. The relation between cord parameters and treatment response is better reflected in CSM cases managed conservatively and the results suggest that the degree of cord deformity is helpful in determining the outcome and hence the choice between surgical and conservative treatment. In plain CT, the osteophytes and calcified discs are adequately visualised and canal dimensions measured with accuracy, but the cervical cord and roots cannot be properly assessed and the diagnosis of CSM or CSR cannot be ascertained. At present, its role in cervical spondylosis is therefore limited.
Two Chinese patients with spontaneous spinal epidural haematoma are presented. The clinical picture and the possible site of bleeding are discussed.
A total of 53 patients with cervical spondylotic myelopathy and/or radiculopathy were studied with computer-assisted myelography following metrizamide myelography. Cervical cord deformities resulting from spondylotic protrusions were classified into four groups. The A shape (anterior central concavity) is the commonest and is often associated clinically with bilateral anterolateral and posterior column deficits. In the B shape (lateral deformity on one side), unilateral anterolateral column and root signs, usually mild, predominate. The symptomatology of the C shape (lateral deformity on both sides) and the D shape (flattened anterior surface) is bilateral, although not often symmetrical, and includes anterolateral and posterior column disturbances and root signs. Radiculopathy may, however, occur in the absence of cord deformity if the spondylotic lesion is close to or inside the intervertebral foramen. As there is some relationship between cord shapes and symptomatology, the decision as to whether a particular deformity is responsible for the clinical presentation may be made with more confidence. Moreover, the degree of cord deformity correlates well with the severity of symptomatology. Those with mild deformity had relatively few or mild cord signs, whereas in those with severe deformity cord signs were numerous and severe. Certain observations on cord deformity in vivo support the view that compression is an important pathogenetic mechanism in cervical spondylotic myelopathy. Most patients had anterior cord compression and the anterolateral signs were more frequent and marked. Severity of cord signs is associated with the degree of compression. Removal of the compression is followed by re-expansion of the cord and clinical improvement. In a small number of cases where cord compression by osteophytic protrusion was mild, and where clinical improvement followed the removal of the protrusion, the theory of cord traction and friction appears to apply. The contribution of other mechanical factors and of ischaemia to cord damage is also discussed.