Redistribution of Sudomotor Responses Is an Early Sign of Sympathetic Dysfunction in Type 1 Diabetes

Abstract

Patients with diabetic neuropathy typically have decreased sweating in the feet but excessive sweating in the upper body. Previous studies of sudomotor function in diabetes have included patients with longstanding disease. The present study was designed to test for the early presence of sudomotor dysfunction and to characterize its relation to glycemic control and other aspects of peripheral nerve function. A total of 37 patients (10 males, 27 females) enrolled in a longitudinal study, in which autonomic function was evaluated annually for 3 years. Patients enrolled 2-22 months after the diagnosis of type 1 diabetes. Forty-one ageand sex-matched healthy control subjects were also studied. Sweat production in response to acetylcholine stimulation was dramatically increased in the forearm at the time of the first evaluation (1.67 ± 0.24 µl/cm 2 in the diabetic patients vs. 1.04 ± 0.14 µl/cm 2 in the control subjects, P < 0.05). Likewise, the ratio of sweating in the forearm to sweating below the waist was higher in the diabetic patients (0.553 ± 0.07 µl/cm 2 ) than in the control subjects (0.385 ± 0.04 µl/cm 2 , P < 0.05). Forearm sweat was negatively associated with the renin-toprorenin ratio and vanillylmandelic acid (VMA) excretion (P < 0.025), tests of sympathetic nerve function. The ratio of sweating in the forearm to sweating in the foot was likewise increased in diabetic patients with poor glycemic control. We interpret this redistribution of sudomotor responses to be indicative of sympathetic nerve injury and conclude 1) that the sympathetic nervous system is especially vulnerable to the adverse effects of chronic hyperglycemia and 2) that sympathetic dysfunction can be detected very early in type 1 diabetes. Diabetes 50: [436][437][438][439][440][441][442][443] 2001

Autonomic thermoregulatory dysfunction in neurofibromatosis type 1

“…Impairments in the SR to local and/or central stimuli has already been reported in other diseases affecting the neural tissues, such as diabetes 11,12,16 , tuberous sclerosis 17,18 , multiple sclerosis The present results showed reduction of 35% to 65% in sweat secretion (induced by PILO and HEAT protocols) among NF1 volunteers compared to non-NF1 individuals. In the PILO tests, the reduction was associated with a decrease in sweating production (SGO = -39%) shown by NF1 males, and with a decrease in both SGO (-47%) and number of active sweat glands (ASG = -34%) presented by NF1 females.…”

“…As a result, most multiple sclerosis patients experience transient and temporary worsening of clinical signs and neurological symptoms during exposure to higher environmental temperatures and exercise 10 . Additionally, exercise intolerance and sweating dysfunction are considered common manifestations of diabetic autonomic neuropathy, even in the early stages of this disease, once the sweating response is diminished or completely suppressed, especially in lower limbs 11,12 . Neuropathy in NF1 patients has been related to nerve compression and/or loss of function by the growth of neurofibromas, or to inappropriate genetic signaling between neural cells, and it is considered to be a benign condition.…”

Diabetes mellitus tipo 1 na ausência de neuropatia autonômica não altera a taxa de sudorese no exercício

“…Hoeldtke et al (13) realizaram um estudo longitudinal com diabéticos comparados com não diabéticos, para caracterizar a presença de disfunção sudorípara como um sinal precoce da disfunção neural periférica e da qualidade do controle habitual do nível glicêmico. Os autores observaram aumento relativo na TS do antebraço e diminuição nos membros inferiores, o que resultava em alteração importante na relação TS braços/pés dos diabéticos que apresentavam controle inadequado da glicemia.…”

Sympathetic and Parasympathetic Neuropathy Are Frequent in Both Type 1 and Type 2 Diabetic Patients

“…Signs of sympathetic neuropathy have been described in diabetic patients without parasympathetic neuropathy (24). Indeed, Hoeldtke et al (25) report that sympathetic neuropathy as found from abnormal sudomotor response might be an early complication developing soon after the diagnosis of type 1 diabetes. Our study confirms that sympathetic neuropathy is frequent in type 1 diabetic patients.…”