Symptoms of Diabetic Peripheral Neuropathy
Diabetic peripheral neuropathy presents with distinct sensory symptoms that vary based on which nerve fiber types are affected, ranging from painful burning and tingling in early small-fiber involvement to numbness and loss of protective sensation with large-fiber damage. 1
Early Symptoms: Small-Fiber Involvement
The most common early symptoms result from small-fiber dysfunction and include: 1
- Burning pain - often described as unremitting burning sensations in the feet and legs 1, 2
- Dysesthesia - unpleasant tingling or "pins and needles" sensations 1, 3
- Electric shock-like pains - sharp, shooting pain sensations 2
- Aching pain - persistent discomfort in the lower extremities 2
These symptoms typically begin in the toes and progress proximally in a length-dependent, symmetric pattern. 4
Late Symptoms: Large-Fiber Involvement
As neuropathy progresses to involve large nerve fibers, patients develop: 1
- Numbness - loss of sensation starting distally in the feet 1, 3
- Loss of vibration sense - inability to detect vibration with tuning fork testing 1
- Loss of protective sensation (LOPS) - critical finding that indicates risk for foot ulceration 1
Critical Clinical Consideration
Up to 50% of diabetic peripheral neuropathy cases are completely asymptomatic, yet these patients remain at high risk for foot ulceration and amputation. 1, 3 This underscores why systematic screening with objective testing (10-g monofilament, vibration testing) is essential rather than relying on patient-reported symptoms alone. 1
Autonomic Symptoms
When autonomic nerves are affected, patients may experience: 1
- Orthostatic hypotension - dizziness upon standing 1
- Resting tachycardia - elevated heart rate at rest 1
- Gastroparesis - delayed gastric emptying 1
- Constipation or diarrhea - bowel dysfunction 1
- Erectile dysfunction - in male patients 1
- Sudomotor dysfunction - abnormal sweating patterns (increased or decreased) 1
- Hypoglycemia unawareness - loss of warning symptoms before low blood sugar 1
Pattern of Symptom Progression
The classic presentation follows a distal-to-proximal, symmetric pattern starting in the toes and gradually ascending the legs. 4 Later stages may involve the hands, creating a "stocking-glove" distribution. 3 Sensory symptoms predominate over motor symptoms in most cases. 4
Common Pitfall
A major diagnostic error is assuming that absence of pain means absence of neuropathy—asymptomatic patients require the same rigorous screening and foot protection strategies as symptomatic patients. 1, 3