How should I examine a patient presenting with a burning sensation in their feet to confirm the diagnosis?

Examination Approach for Patients with Burning Sensation in the Feet

A comprehensive neurological assessment with 10-g monofilament testing plus at least one other sensory test (pinprick, temperature, or vibration) is essential to confirm burning sensation in the feet, particularly to identify loss of protective sensation (LOPS). 1

Initial Assessment

History Taking

• Obtain detailed symptom characteristics:
  • Distribution pattern (stocking-glove distribution suggests peripheral neuropathy)
  • Quality (burning, tingling, electric shock-like)
  • Timing (worse at night suggests neuropathy)
  • Aggravating/relieving factors
• Assess for risk factors:
  • Diabetes history and glycemic control 1
  • Prior ulceration or amputation 1
  • Smoking history 1
  • History of peripheral vascular disease 1
  • Alcohol use, toxin exposure, nutritional deficiencies 2

Physical Examination Components

1. Neurological Assessment

• 10-g monofilament testing (most useful test for LOPS) 1
• Plus at least one additional sensory test:
  • Pinprick sensation
  • Temperature sensation
  • Vibration testing using 128-Hz tuning fork
  • Ankle reflexes 1

Note: Absent monofilament sensation suggests LOPS, while at least two normal tests (and no abnormal test) rules out LOPS 1

2. Vascular Assessment

• Inspection of skin (color, temperature, integrity)
• Palpation of pedal pulses (dorsalis pedis, posterior tibial)
• Assessment for:
  • Rubor on dependency
  • Pallor on elevation
  • Capillary refill time 1, 3

3. Skin and Musculoskeletal Assessment

• Inspect for:
  • Foot deformities
  • Preulcerative callus or corn
  • Skin integrity
  • Signs of infection
  • Hair loss (suggests vascular insufficiency)
  • Nail changes 1

Diagnostic Algorithm

1. First-line assessment:

   • Complete neurological examination with 10-g monofilament plus at least one other sensory test
   • Vascular assessment including pedal pulses

2. If abnormal neurological findings:

   • Assess for diabetes with fasting blood glucose/HbA1c
   • Consider vitamin B12 levels, thyroid function tests
   • Consider referral for electrodiagnostic studies if etiology unclear 2

3. If abnormal vascular findings:

   • Perform ankle-brachial index (ABI)
   • Consider referral for vascular assessment if ABI abnormal or symptoms of claudication present 1

4. If normal neurological and vascular findings:

   • Consider other causes: medication side effects, inflammatory conditions
   • Consider referral to neurology for further assessment 2

Common Pitfalls and Caveats

• Relying solely on patient's subjective description without objective testing can lead to misdiagnosis
• Failing to perform both neurological and vascular assessments may miss mixed pathology
• Not recognizing that burning feet can be an early sign of diabetic neuropathy before other clinical manifestations 1, 2
• Overlooking non-diabetic causes of burning feet, such as vitamin B deficiencies, alcohol use, or medication side effects 2, 4

Follow-up Recommendations

• Patients with evidence of sensory loss should have their feet inspected at every visit 1
• Patients with symptoms of claudication or decreased/absent pedal pulses should be referred for ankle-brachial index and further vascular assessment 1
• Patients with confirmed neuropathy should receive education on foot self-care and prevention of complications 1

By following this structured approach to examination, clinicians can effectively confirm the presence of burning sensation in the feet, identify its underlying cause, and implement appropriate management strategies to reduce morbidity and mortality associated with conditions like diabetic neuropathy and peripheral arterial disease.