Regulatory Dysfunction of Microvasculature and Catecholamine Metabolism in Spinal Cord Injury
Since 1917 when Head and Riddoch (4) first described autonomic hyperreflexia in spinal cord injury, its attending neurophysiological symptoms have been well documented by other investigators. It is well known that the triggering mechanism may well be any noxious stimuli but most often autonomic hyperreflexia is caused by hyperirritability of the bladder due to formation of stones of calcium salts or infection of the urinary bladder; the common denominator being distension of the vesicular wall leading to increased intracystic pressure. The major symptoms during the so-called hyperreflexia are: pallor of the skin below in contrast to a histamine-like flush above the level of the lesion, vasodilatation in the head and neck accompanied by engorging pulsating corotid arteries. Moreover, the peak of hyperreflexia coincides with the height of intracystic and brachial blood pressures, headache, and piloerection. Guttmann and Whitteridge (3) were the first to observe that the hypertensive crises could be produced only in those subjects with lesions above the sixth thoracic dermatome (T6). The purpose of this communication is to shed more light on the etiology of these hypertensive episodes which occur spontaneously in human subjects with high level spinal cord injury and which are frequently the cause of cerebrovascular accidents.
KeywordsSpinal Cord Injury Brachial Blood Pressure Venous Occlusion Plethysmography Fourth Finger Hypertensive Episode
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- 1.Anden, N.E., Haggendal, E., Magnussen, T. and Rosengren, E.: The time course of the disappearance of noreadrenaline and 5-hydroxytryptamine in spinal cord after transection. Acta Physiol. Scand. 62: 115–118, 1964.Google Scholar
- 6.Naftchi, N.E. and Mendlowitz, M.: Drug modification of digital vascular reactivity to vasoactive substances. Bibl. Anat. 10:133–144, 1969 ( S. Karger, Basel, Switzerland).Google Scholar
- 7.Naftchi, N.E., Lowman, E.W., Sell, G.H., Demeny, M. and Rusk, H.: Hypertensive crisis associated with increased urinary catecholamine catabolites in spinal man. Fed. Proc. 30: 678, 1971.Google Scholar
- 8.Naftchi, N.E., Demeny, M., Kertesz, A. and Lowman, E.W.: The CNS and adrenal tyrosine hydroxylase activity and norepinephrine, serotonin, and histamine in the spinal cord after transection. Fed. Proc. 31: 832, 1972.Google Scholar