Postoperative cauda syndrome caused by Staphylococcus aureus.

Toxic shock syndrome (TSS) is a well-defined clinical syndrome attributed to certain exotoxins produced by Staphylococcus aureus. The acute episode is often characterized by a toxic encephalopathy, possibly caused by direct neurotoxicity of these exotoxins, although this mechanism has never been proven. We describe a patient who developed TSS, meningitis and cauda equina syndrome simultaneously several days after lumbar laminectomy. A space-occupying lesion was excluded. Enterotoxin C-producing S. aureus was cultured from the surgical wound and the cerebrospinal fluid (CSF). The patient recovered from TSS but remained partially paralyzed. Presumably the cauda equina syndrome was caused by neurotoxic effects of the intrathecally produced S. aureus exotoxins. This case provides evidence for the neurotoxic effects of TSS-associated S. aureus exotoxins.

Changes in cerebral blood flow pattern after carotid endarterectomy.

A comparison was made between pre- and postoperative cerebral blood flow measurements in 20 patients who underwent endarterectomy. Most patients showed no difference between both studies. However in 4 of the series an increase in blood flow was observed while in another 4 patients a decrease occurred. Especially patients with a low preoperative flow seemed to have profited from the endarterectomy.

The possible significance of symmetry and asymmetry of the mean hemispheric CBF in patients with one-sided cerebral ischemia.

The difference in mean hemispheric CBF was compared in two groups of patients suffering from one-sided cerebral ischemia. One group without significant arteriographic abnormalities and a group with a one-sided internal carotid artery occlusion. The Xenon inhalation method (ISI) was used. It seems to be difficult to draw any conclusions from the differences between mean hemispheric ISI values, especially for patients with fairly severe clinical symptoms. In far the most patients without significant arteriographic abnormalities, no significant difference was found. A great difference (high ISI ratio) for patients with no or only slight symptoms may indicate a disturbed blood flow to the hemisphere with the lower ISI. Such high ratios were only found in patients suffering from a one-sided occlusion of the internal carotid artery. This rather simple and harmless method of blood flow measurement may prove to be a valuable contribution toward insight into the pathophysiology of blood flow in patients, especially those suffering from one-sided internal carotid artery occlusion.

ISI values and interhemispheric differences in patients with ischemic cerebrovascular disease; correlations with clinical and angiographic findings.

Xenon 133 inhalation CBF studies of one hundred patients with ischemic cerebrovascular disease in the territory of the carotid artery were compared in an attempt to gain more insight into the collateral capacity, especially in those with a stenosis or occlusion of one of the major arteries. Asymmetry of the ISI values for the two hemispheres was expressed as a ratio. High ratios (greater ISI asymmetries) were found for patients with an occlusion of the internal carotid or middle cerebral artery, especially--but not exclusively--those with the more severe clinical symptoms. It also appeared that even when the patient is in a good clinical condition, an elevated ratio reflects insufficiency of the collateral supply to the affected side. The ISI values for individual patients seem to be less useful, partly due to the variable age dependency of this flow parameter.

CBF measured by the Xenon-133 inhalation technique and quantified EGG (qEEG) investigations in patients with unilateral internal carotid artery occlusion.

The CBF measurements (Xenon-133, inhalation technique) and quantified EEG (qEEG) recordings of 20 patients with cerebrovascular disturbances due to an unilateral internal carotid artery occlusion were evaluated. One of the advantages of the inhalation method is the possibility of the simultaneous CBF measurement of both hemispheres. Special attention is paid to the difference in flow between the two hemispheres. The results of this investigation are compared with the findings of the qEEG studies. Furthermore the relationship between these results and the clinical state of the patient was studied. Although computer analysis revealed EEG abnormalities in 80% of the cases no correlation could be found between the grade of EEG abnormalities and the clinical data of the patient and/or the CBF parameters. A correlation was found between the asymmetry as well as the absolute values of the hemispheric flow and the clinical state. The question whether CBF measurements can provide a better insight into the pathophysiology of the blood flow pattern in patients with unilateral internal carotid artery occlusions was considered as well.

Doppler flow velocity measurements in patients with intracranial hypertension.

In patients with severe brain lesions monitoring of the intracranial pressure as well as monitoring of cerebral blood flow can be of clinical value. While at the moment there is no atraumatic method for measuring cerebral blood flow in man, it is recommended to measure blood flow velocity with the ultrasound Doppler technic in the common carotid artery. On theoretical grounds a positive correlation between cerebral blood flow and blood flow velocity can be expected and the observations presented show that such a correlation exists in normal controls and in neurological patients. In many neurological patients the flow velocity in the common carotid artery decreases with increasing intracranial pressure. This suggests that the autoregulation is disturbed. The demonstration of such a disturbance can have clinical implications.

Doppler haematotachography: problems in interpretation and new applications.

The Doppler-echographic examination (HTG) seems to be developing into a screening method for the detection of abnormalities of the large cerebropetal vessels. An appraisal is made of the possibilities and limitations of the HTG based on the literature, a group of 250 patients and several relevant case histories. In general an abnormal HTG curve seems to warrant further diagnostic investigations (angiography). A normal HTG curve not be considered sufficient reason to omit an angiographic examination. A number of new applications of the HTG examination are mentioned.