Diabetic autonomic neuropathy

Abstract

This review attempts to outline the present understanding of diabetic autonomic neuropathy. The clinical features have been increasinly recognised but knowledge of the localization and morphology of the lesions and their pathogenesis remains fragmentary. A metabolic causation as postulated in somatic nerves accords best with clinical observations. Most bodily systems, particularly the cardiovascular, gastrointestinal and urogenital, are involved with added disturbances of thermoregulatory function and pupillary reflexes. Possible effects on neuroendocrine and peptidergic secretion and respiratory control await definition. Current interest centres around the development of a new generation of tests of autonomic nerve function that are simple, non-invasive, reproducible and allow precision in diagnosis and accurate quantitation. Most are based on cardiovascular reflexes and abnormality in them is assumed to reflect autonomic damage elsewhere. Probably no single test suffices and a battery of tests reflecting both parasympathetic and sympathetic function is preferable. Little is known of the natural history. The prevalence may be greater than previously suspected and although symptoms are mild in the majority, a few develop florid features. The relation of control and duration of diabetes to the onset and progression of autonomic neuropathy is not clearly established. Once tests of autonomic function become abnormal they usually remain abnormal. Symptomatic autonomic neuropathy carries a greatly increased mortality rate possibly due to indirect mechanisms such as renal failure and direct mechanisms such as cardio-resiratory arrest. Improved treatment of some of the more disabling symptoms has been possible in recent years.

Inhomogeneous Derangement of Cardiac Autonomic Nerve Control in Diabetic Rats.

“…Neuropathy is a well known and common complication of DM, manifesting as sensory dominant polyneuropathies including autonomic neuropathies such as orthostatic hypotension, atonic bladder, impotence, and so forth. 1 The present study used spontaneous DM Kob rats for the detection of possible neuropathies as functions of parameters in spectral analysis of HRV or frequency domain parameters. The spontaneously diabetic BB (Bio-Breeding) Kob rat is very similar to human insulin-dependent DM patients [16][17][18][19] in terms of hypoinsulinemia, hyperglycemia, glycosuria, hyperlipidemia without obesity, depressed activity of myosin ATPase, etc.…”

“…Thus it appears that the cardiac sympathetic nerves are less vulnerable to diabetic injury, a finding that partially confirms previous studies. 1,3,[22][23][24] Diabetic patients with autonomic neuropathy, either parasympathetic alone or combined parasympathetic and sympathetic, have an increased resting HR compared with normal subjects. 6,23 However, Bellavera et al reported that there was no significant difference in HR between healthy subjects and DM patients.…”

Quantitative study of the myenteric plexus of the stomach of rats with streptozotocin-induced diabetes

“…It has been commented that atony, distention and gastric emptying are generally asymptomatic because of a possible denervation of afferent sensory fibers 20 . Other authors argue that when the symptoms are present they include anorexia, nausea, vomiting and persistent fullness 1,5 .…”

Nitric oxide-mediated neurotransmission is attenuated in the anococcygeus muscle from diabetic rats

“…The results suggest that STZ-induced diabetes impairs smooth muscle reactivity to nitric oxide in the rat anococcygeus muscle. [Diabetologia (1994) 37: 232-237] Key words Anococcygeus muscle (rat), diabetes, nitrergic nerves, nitric oxide, NOLA, NANC transmission, nonvascular smooth muscle, sodium nitroprusside, streptozotocin.Neuropathy of the autonomic nervous system is a complication of diabetes mellitus which may contribute to alterations in cardiovascular, gastrointestinal and genitourinary function [1,2]. These alterations may be manifested through clinical problems including postural hypotension, diabetic diarrhoea, diabetic cystopathy and impotence.…”