A study has been published by a team from the Deutsches Hospital, Buenos Aires and the Hospital de Clínicas “José de San Martín”, University of Buenos Aires, Argentina, which validates the position that diabetic peripheral neuropathy, especially in the feet in an early, diagnosable condition of both type 1 and type 2 diabetes.
In a review “Early Diabetic Neuropathy: A Diagnostic Challenge” (Duarte, 2017) the author identifies that diabetic peripheral neuropathy is a major complication in type 1 and 2 diabetes and can occur early, even before hyperglycaemia. The review states:
“Regarding its diagnosis, the American Academy of Neurology considered that symptoms alone have a poor diagnostic accuracy in predicting the presence of neuropathy. Signs are better predictors than symptoms, and multiple signs, even better than single signs.”
The American Diabetes Association recommends that all patients should be assessed for peripheral neuropathy at diagnosis of type 2 diabetes or in the case of type 1 diabetes after 5 years following diagnosis and thereafter at least annually.
This DPN screening should include taking a careful history and assessment of either temperature or pinprick sensation, and vibration sensation using a 128-tuning fork; as well as annual 10-g monofilament testing. Electrophysiological testing is rarely needed.
However, the impairment of nerves starts early in glycemic dysregulation prior to over hyperglycaemia, included in patients with “near impaired glucose tolerance” : insulin resistance, and metabolic syndrome other than impaired glucose tolerance may represent independent risk factors for peripheral neuropathy.
The staging of diabetic neuropathy is crucial. The diagnosis of asymptomatic or preclinical neuropathy is essential in order to stop progression to advanced or irreversible stages, and to prevent further complications. Once symptoms appear, there are few effective therapeutic strategies.
Screening for neuropathy should include history, assessment of sensation, and monofilament testing annually. Standard nerve conduction studies assess large fibres, but other techniques are needed to assess small fibres.
Tests like cutaneous silent period, sympathetic skin responses and QSART, Neuropad®, confocal corneal microscopy and skin biopsy can evaluate small fibres to accurately diagnose autonomic neuropathy and allow early interventions.