Painful diabetic neuropathy: clinical aspects

Painful diabetic neuropathy (PDN) is one of several clinical syndromes in patients with diabetic peripheral neuropathy (DPN) and presents a major challenge for optimal management. The epidemiology of PDN has not been extensively studied. On the basis of available data, the prevalence of pain ranges from 10% to 20% in patients with diabetes and from 40% to 50% in those with diabetic neuropathy. Neuropathic pain can be disabling and devastating, with a significant impact on the patient's quality of life and associated healthcare cost. Pathophysiologic mechanisms underlying PDN are similar to other neuropathic pain disorders and broadly invoke peripheral and central sensitization. The natural course of PDN is variable, with the majority of patients experiencing spontaneous improvement and resolution of pain. Quantifying neuropathic pain is difficult, especially in clinical practice, but has improved recently in clinical trials with the development of neuropathic pain-specific tools, such as the Neuropathic Pain Questionnaire and the Neuropathic Pain Symptom Inventory. Hyperglycemia-induced pathways result in nerve dysfunction and damage, which lead to hyperexcitable peripheral and central pathways of pain. Glycemic control may prevent or partially reverse DPN and modulate PDN.