Biomedical subjects
C H Wriedt
Publications and source records attributed to C H Wriedt.
A severe, late reaction to radiological contrast media mimicking a sepsis syndrome.
An unusual, severe delayed reaction to non-ionic intravenous contrast media was observed. A 44-year-old man underwent a computed tomography scan with non-ionic contrast media. Four hours later the patient collapsed with hypotension and cardiovascular shock. Aggressive management (including inotropic support and fluid resuscitation) was instituted in the intensive care unit. Rigorous imaging and biochemical and microbiological investigation failed to identify a source of this man's circulatory collapse. A rapid recovery ensued and at 3 months follow-up the patient was suffering no residual effects from this event. To our knowledge, this is only the second report of a severe delayed reaction to radiological contrast media and the first that manifested as a prolonged hypotensive syndrome.
The electroencephalogram and acute ischemic stroke. Distinguishing cortical from lacunar infarction.
One hundred consecutive cases of clinically diagnosed, acute forebrain infarction were studied using computerized tomography (CT) and electroencephalography (EEG). Computed tomography confirmed brain infarction in 91 patients and was normal in the remaining nine. Each EEG was read independently by two experienced electroencephalographers without knowledge of CT or clinical details and their findings were compared with those of CT. Lateralized theta and/or delta activity predicted ipsilateral cortical infarction with a sensitivity of 76% and specificity of 82%. In contrast, cerebral hemisphere lacunae produced similar EEG abnormalities in only a few cases (9%). Electroencephalography is particularly useful following stroke if the initial CT excludes hemorrhage but does not detect infarction. In conjunction with clinical details, the EEG can then be used to indicate the likelihood of cortical involvement and thus suggest the likely pathophysiologic mechanism of infarction.
The diagnosis and management of post traumatic syringomyelia.
We have reviewed 21 cases with the clinical diagnosis of Post Traumatic Syringomyelia (P.T.S.). Fifteen of these cases had proven syrinx formation on Contrast Computed Tomography (C.C.T.) and the other 6 had obviously abnormal cords. A much earlier onset of P.T.C.M. was found in complete spinal injuries than in incomplete ones. We have discussed the technique of contrast computed tomography used at this hospital, its value in the diagnosis of this condition and its ability to define actual spinal cord structure. Most cases (91%) benefitted from surgery and several had marked sensory improvement, which previously has been described as unusual. Syringo-cisternal shunting, a new technique for the drainage of cervical and upper thoracic syrinxes is described. A theory is proposed to explain why, in some patients with classical presentations of P.T.S., no syrinx was found on C.C.T., although abnormal cords were found in all cases. It is felt that these abnormal areas of spinal cord are responsible for the presenting symptomatology and may be precursors of syrinxes.
Evaluation of three embolic agents in pig rete.
In ongoing research into potential embolic agents, three substances were evaluated for their effectiveness in occluding the pig rete. Selective injection of these agents produced varying degrees of occlusion, with the most effective a microfibrillar collagen hemostat in a 33% ethanol solution. Angiostat, a collagen particulate, did not produce rete occlusion, and all pigs injected with it developed adverse effects, including coma and apnea. Tisseel, a tissue sealant, produced partial rete occlusion, but was uniformly difficult to manage through long catheters, and its use was discontinued. Microfibrillar collagen hemostat with ethanol appears to have the greatest potential as an embolic agent in low-flow structures.
Improvement of cervicocranial i.v. digital subtraction angiography with pixel remasking and cardiac gating.
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The significance of internal carotid artery occlusion shown by i.v. digital subtraction angiography.
A retrospective review of 493 IV digital subtraction angiography examinations performed for cervicocerebral vascular disease revealed 27 apparent occlusions of the internal carotid artery. We identified 20 patients whose occlusions did not warrant further investigation. Fourteen occlusions were on the asymptomatic side, two were in patients who preferred medical treatment, two were in patients unsuitable for carotid endarterectomy, and two patients with bihemispheric transient ischemic attacks were treated for the contralateral carotid. Four very tight stenoses were found in the other seven patients, one of whom refused endarterectomy. As the signs of a very tight stenosis are subtle, and the number of such stenoses that are treatable is low (three in 493), cerebral angiography is justified in doubtful cases to avoid missing potentially treatable lesions.