Nerve conduction velocity and circulating immunocomplexes in type 1 diabetic children

Subclinical pain and thermal sensory dysfunction in children and adolescents with Type 1 diabetes mellitus

AIMS

To assess cutaneous thermal and pain thresholds in upper and lower limbs in neurologically asymptomatic children and adolescents, and to study the relationships of clinical parameters and these sensory thresholds in subclinical diabetic neuropathy.

METHODS

Thirty-five neurologically asymptomatic patients, aged 8-16 years, diagnosed with Type 1 diabetes mellitus (DM), and a control group of 35 healthy age-matched subjects participated in the study. Warmth, cold, and heat-induced pain thresholds were measured in the dorsum of the right arm and foot, using quantitative sensory testing (QST). Relevant clinical parameters, retrieved from medical records or measured at the QST session, were obtained for each patient.

RESULTS

Compared with controls, diabetic patients had increased thresholds for warmth in the hand (P = 0.002), and cold and warmth in the foot (P = 0.015 and P = 0.004, respectively). Of the diabetic patients, 43% showed abnormality of at least one sensory threshold. A significant correlation was observed for duration of diabetes and heat-induced pain threshold in the hand (P = 0.045), but no correlation was found for age, height, weight, pre-test blood glucose, age of onset, current insulin dose, and mean of glycosylated haemoglobin determinations of the previous 18 months. No significant correlation was found for other sensory thresholds.

CONCLUSIONS

Using QST, abnormal cutaneous thermal perception is a common finding, in both upper and lower limbs, in neurologically asymptomatic young diabetic patients. Heat-induced pain threshold in the hand was correlated with the duration of the diabetes.

Subclinical neuropathy in type I diabetic children

OBJECTIVES

Small and large, somatic and autonomic nerve fibre functions were neurophysiologically evaluated in 33 asymptomatic neurologically free type I diabetic children and 69 age-matched healthy controls.

METHODS

The evaluation of large and small somatic nerve fibre function was performed by conventional nerve conduction studies, thermal specific and thermal pain sensitivity tests, as well as autonomic nerve fibre functions by sympathetic skin response and R-R interval variation assessment.

RESULTS

A significant difference was established between the healthy and the diabetic group. Neurophysiologically determined subclinical neuropathy was found in 87% of type I diabetic children. The majority of abnormal recordings were found on the lower limbs. The dysfunction of the somatic motor large nerve fibre type in the lower limbs was altered in 57% of patients, somatic sensory large in 39%, somatic sensory small in 45%, and sympathetic in 45%. The leading abnormal measure was a delayed sympathetic skin response on the foot (42% of diabetic children) followed by a reduced amplitude of sural nerve action potential (36%). The whole spectrum of recordings showed scattered involvement of nerve functions. There was no selective susceptibility of nerve fibre types exposed to a noxious factor.

CONCLUSION

A complex neurophysiological assessment, including standard nerve conduction studies as well as psychophysical examination and autonomic nerve function tests, evaluating the function of small and large nerve fibres, is recommended for evaluating the subclinical neuropathy in asymptomatic type I diabetic children.

Chronic inflammatory demyelinating polyneuropathy (CIDP) in diabetics

Seven diabetic patients developed a progressive, moderately severe, motor rather than sensory neuropathy predominantly affecting the legs. This met clinical and electrophysiological criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). Nerve biopsies showed a variety of abnormalities, none of which clearly distinguished between diabetic polyneuropathy and CIDP. The patients were treated with combinations of corticosteroids, azathioprine, plasmapheresis and intravenous immune globulin; all improved substantially. We believe that CIDP may masquerade as unusually severe and progressive diabetic distal symmetric polyneuropathy. It is important to recognize CIDP in diabetics because, unlike diabetic polyneuropathy, CIDP is treatable.

Long-term complications of diabetes mellitus, Part I: Retinopathy, nephropathy, neuropathy

Diabetic retinopathy, nephropathy, and neuropathy occur infrequently in small animals, but are capable of causing significant disease. The clinical and histopathologic findings seen with these late complications of diabetes are discussed. The pathogenesis of these disorders is most likely multifactorial; metabolic alterations secondary to the hyperglycemic state, and microvascular changes seen with diabetes have both been implicated. Current treatment consists of aggressive control of the hyperglycemia, as research continues into the pathology of the late complications in attempts to find a definitive therapy.