Most Common Cause of Bilateral Neuropathic Foot Pain
Diabetes mellitus is the most common cause of bilateral neuropathic pain in both feet, presenting as distal symmetric polyneuropathy. 1, 2
Epidemiology and Clinical Significance
- Diabetes is the leading cause of peripheral neuropathy in the Western world, with prevalence estimates around 28.5% among diabetic patients 1, 2
- Painful diabetic peripheral neuropathy (DPN) specifically affects 10-26% of diabetic patients, with one population-based study showing a prevalence of 16% 3
- Alarmingly, 12.5% of patients with painful DPN never report symptoms to their physician, and 39% never receive treatment for their pain 3
Characteristic Clinical Presentation
The diagnosis is primarily clinical and follows a distinctive pattern:
Symptom Pattern
- Pain is invariably bilateral and symmetrical - asymmetrical symptoms should prompt investigation for alternative etiologies 3, 4
- Symptoms begin distally in the feet and may progress proximally up the limbs in a length-dependent fashion 4, 5
- Nocturnal exacerbation is characteristic, often causing severe sleep disturbance 3, 5
Pain Descriptors
- Burning pain, "electrical shock" sensations, stabbing or knife-like pains 4
- Uncomfortable tingling (paresthesia) and allodynia (pain from normally non-painful stimuli like clothing) 4
- Patients may describe walking as "barefoot on marbles" or "barefoot on hot sand" 4
- Altered temperature perceptions with feet feeling abnormally warm or cold 4
Physical Examination Findings
- Blunting of sensation on clinical examination of the feet, including pinprick, vibration, light touch, and reduced ankle reflexes 3, 5
- Occasionally in acute painful DPN, symptoms may be present without objective signs 3
Important Clinical Pitfall
Diabetic neuropathy is a diagnosis of exclusion. You must carefully exclude other causes of bilateral neuropathic foot pain including: 3
- Peripheral vascular disease
- Alcohol abuse (another common cause of symmetric neuropathy)
- Vitamin B12 deficiency
- Renal disease
- Neurotoxic medications
- Heavy metal poisoning
- Chronic inflammatory demyelinating polyneuropathy
- Inherited neuropathies
- Spinal canal stenosis
Diagnostic Approach
- The diagnosis relies on patient description of distal, symmetrical pain with nocturnal exacerbation 3
- Clinical examination should demonstrate abnormalities in at least one of: temperature sensation, pinprick sensation, vibration perception, pressure sensation, or ankle reflexes 5
- Nerve conduction studies are particularly important to exclude entrapment syndromes and other focal causes 3
Impact on Quality of Life
The presence of neuropathic pain significantly affects patient outcomes: