Diabetic neuropathy

Case history #1

A middle-aged man with type 2 diabetes presents with shooting and burning pain in his feet and lower legs, most severe at night, associated with numbness and allodynia (pain from stimuli that are not normally painful). In the past 6 months, the pain has become much worse and disturbs his sleep. He has been told that his blood glucose is borderline elevated and has been advised to start diet and exercise. He also takes medication for hypertension and recalls that his cholesterol is elevated.

Case history #2

A 54-year-old woman with type 1 diabetes has developed an ulcer on her right foot. She cannot recall any particular injury and has been walking as normal with no pain. Physical examination of the foot reveals a painless ulcer over the metatarsal head. She also complains of feeling tired and has noticed she is particularly dizzy and unsteady on her feet when she stands up. Blood pressure (BP) measurements in the supine position, repeated after 2 minutes of standing, reveal an abnormal fall in systolic BP, from supine to standing position, of 32 mmHg.

Other presentations

Weakness is less common than pain and is usually minor. It occurs much later in the course of DN. If weakness is present, it follows a distal pattern, with wasting and weakness of the interossei of the hands and feet.

An acute onset of severe sensory neuropathy may occur rarely, but chronic sensorimotor neuropathy is more common.

In addition to symptoms associated with orthostatic hypotension, patients with autonomic neuropathy may present with nausea, vomiting, and early satiety (gastroparesis); difficulty in emptying the bladder (cystopathy); or erectile dysfunction.

Other rare types of neuropathy that may present include cranial neuropathies, mononeuropathies (e.g., carpal tunnel syndrome or foot drop [related to common peroneal neuropathy]), truncal radiculopathy (presenting with pain over the thoracic or abdominal wall), or diabetic amyotrophy. Diabetic amyotrophy is more common in older patients with type 2 diabetes and presents with severe pain, muscle weakness, and muscle atrophy in the thigh unilaterally or bilaterally.