Diabetic peripheral neuropathy essentials: a narrative review

Background and Objective: Painful diabetic peripheral neuropathy (DPN) affects approximately 6–34% of all patients with diabetes. DPN-induced pain reduces the quality of life and makes daily activities difficult. Distal symmetric polyneuropathy (DSPN) is the most common type of DPN. Here we review the pathophysiology, diagnosis, and treatment of DPN. Methods: A MEDLINE database (PubMed) search was conducted for English-language articles dealing with the effect of DPN that were published until April 1, 2022. To identify potentially relevant articles, the following key search phrases were combined: ‘diabetes mellitus’, ‘diabetes’, ‘neuropathy’, ‘polyneuropathy’, ‘diabetic neuropathies’, ‘peripheral neuropathy’, ‘diabetic polyneuropathy’, ‘pathophysiology’, ‘diagnosis’, and ‘treatment’. Key Content and Findings: In a biopsy study of the sural nerve, damage to C and Aδ fibers were seen in patients who had recent onset of pain in their feet consisting of tingling, burning, and prickling, followed by initial demyelination/remyelination of large fibers. DPN is characterized by a pattern of distal-to-proximal axonal loss with symptoms. Hyperglycemia and dyslipidemia are the primary causes of DPN in patients with type 1 and 2 diabetes, respectively. The pattern of pain from DPN is described as “glove and stocking”. DPN-induced pain is described as burning, electric, sharp, and dull aching with various pain intensities. DPN is a diagnosis of exclusion; diagnosis is made with a thorough medical history, physical examination, and clinical testing to rule out other causes of pain. Anticonvulsants (pregabalin and gabapentin), antidepressants (duloxetine, venlafaxine, and amitriptyline), opioids (tramadol, tapentadol, and oxycodone), and topical capsaicin are commonly administered to treat DPN. The combination of two or three of these pharmacological agents better resolves pain at lower doses and with fewer side effects. Conclusions: Clinicians should have sufficient knowledge of DPN to ensure its accurate diagnosis and appropriate treatment. This review provides clinicians with the necessary knowledge of the pathophysiology, diagnosis, and treatment of painful DPN.