Diabetic Peripheral Neuropathy

Peripheral neuropathy encompasses a broad range of clinical pathologies potentially presenting with peripheral nervous system dysfunction. Patients with peripheral neuropathy often present with varying degrees of numbness, tingling, aching, burning sensation, weakness of limbs, hyperalgesia, allodynia, and pain. This pain has been characterized as superficial, deep-seated, or severe, unremitting pain with exacerbation at night. While metabolic disorders represent the predominant etiology of extremity pain caused by an underlying peripheral neuropathy clinical pathology, broad clinical consideration is given to many clinical conditions. Although there are many possible causes of peripheral neuropathy, the most prevalent subtype, diabetic peripheral neuropathy (DPN), can lead to significant complications ranging from paresthesia to loss of limb and life. Early assessment of symptoms of peripheral polyneuropathy helps avoid neuropathic foot ulcers to combat potential morbidity and mortality resulting from the pathophysiologic poor wound healing potential, which can lead to limb compromise, local to systemic infection, septicemia, and even death. DPN is primarily diagnosed clinically through history and neurological assessment of small fiber sensation with temperature changes or pinpricks, large fiber sensation with vibrations, and ulceration risk with pressure testing using a 10 g monofilament. Neurology consultation and specialized testing, including nerve conduction studies and intraepidermal nerve fiber density testing, are only indicated for patients with atypical clinical features (eg, rapid symptom onset, severe neuromotor impairment, and asymmetrically abnormal sensation). The exact cause of DPN is not known. Proposed theories include metabolic, neurovascular, and autoimmune pathways have been proposed. Mechanical compression (eg, carpal tunnel), genetics, and social and lifestyle factors such as chronic alcohol consumption and smoking have all been implicated. Perpetually high blood serum glucose leads to insulin resistance, promoting oxidative stress, inflammation, and cell damage. First, the distal sensory and autonomic nerve fibers are damaged; the damage continues with proximal progression, leading to a gradual loss of protective sensation in the skin and foot joints. DPN management consists of several strategies, including preventative measures (eg, patient education, proper foot care, correct shoe wear, and annual foot exam), glucose control, dietary modifications, weight loss, and pain control. Half of the diabetic peripheral neuropathies may be asymmetric. If not recognized and preventative foot care is not implemented, patients have an increased risk of injury due to their insensate feet.