What could be causing tingling in my feet that worsens at night, and how can it be treated, considering possible underlying conditions such as diabetes, vitamin deficiencies, or poor circulation?

Tingling in Feet Worse at Night

Your nighttime foot tingling is most likely diabetic peripheral neuropathy, and you need immediate screening for diabetes with HbA1c and fasting glucose, followed by a comprehensive foot examination to assess your risk for ulceration. 1, 2

Most Likely Diagnosis: Diabetic Peripheral Neuropathy

The pattern of tingling that worsens at night is a hallmark presentation of diabetic peripheral neuropathy (DPN), which affects up to 50% of diabetic patients. 1, 2 The American Diabetes Association specifically identifies "tingling or pain in the lower limb, especially at night" as a cardinal symptom requiring evaluation. 1

Key characteristics that confirm neuropathic pain include: 2

• Burning pain and "electrical shock" sensations
• Symptoms characteristically more severe at night, causing sleep disturbance
• Bilateral and symmetrical distribution starting in the feet
• May include feelings of "walking barefoot on marbles" or abnormal temperature perceptions

Immediate Diagnostic Workup Required

You must obtain these tests immediately: 1, 3

• HbA1c and fasting glucose (to screen for diabetes)
• Vitamin B12 level (deficiency causes identical symptoms)
• Serum electrolytes including calcium and magnesium
• Thyroid function tests
• Complete blood count

Physical examination must include: 1

• 10-g monofilament testing for loss of protective sensation
• Vibration testing with 128-Hz tuning fork
• Pinprick and temperature sensation assessment
• Ankle reflexes
• Palpation of pedal pulses to exclude peripheral artery disease
• Inspection for foot deformities and skin integrity

The American Diabetes Association emphasizes that up to 50% of DPN may be asymptomatic, making examination critical even when symptoms seem mild. 1

Alternative Diagnoses to Consider

Vitamin B12 deficiency presents identically to diabetic neuropathy with bilateral tingling feet. 1 This is particularly important because metformin (a common diabetes medication) causes B12 deficiency in approximately 7% of patients, creating a vicious cycle. 4 The FDA recommends measuring B12 at 2-3 year intervals in all metformin users. 4

Peripheral arterial disease (PAD) should be suspected if you have leg cramping consistently triggered by walking and relieved within 10 minutes of rest. 1, 3 However, PAD typically causes claudication rather than nighttime tingling. 1

Medication-induced neuropathy must be excluded through careful medication review, particularly diuretics, calcium channel blockers, lithium, and NSAIDs. 5

Treatment Algorithm

If Diabetes is Confirmed:

First-line pharmacologic treatment: 1, 2

• Pregabalin, duloxetine, OR gabapentin
• These achieve ≥50% pain reduction in 38% of patients at optimal dosing
• The American Diabetes Association recommends starting with any of these three agents

Aggressive glycemic control is mandatory - this is the only intervention proven to prevent DPN progression in type 1 diabetes and slow progression in type 2 diabetes. 1

Non-pharmacologic interventions: 1, 2

• Structured exercise programs (protective against neuropathy progression)
• Proper footwear if loss of protective sensation is present
• Daily foot self-examination
• Avoid prolonged cold water immersion or ice application (increases ulceration risk)

If Vitamin B12 Deficiency is Found:

The FDA recommends 100 mcg intramuscular or deep subcutaneous injection daily for 6-7 days, then alternate days for seven doses, then every 3-4 days for 2-3 weeks, followed by 100 mcg monthly for life. 6 Oral B12 is not dependable for severe deficiency. 6

Critical Risk Stratification

You must be assigned to an IWGDF risk category to determine follow-up frequency: 1

• Category 0 (no neuropathy): Annual foot exam
• Category 1 (neuropathy present): Every 6 months
• Category 2 (neuropathy + PAD or foot deformity): Every 3-6 months
• Category 3 (neuropathy + history of ulcer/amputation): Every 1-3 months

Addressing Quality of Life Impact

The presence of neuropathic pain profoundly impacts quality of life through severe sleep disturbance, fatigue, and reduced daily activities. 2 Over two-thirds of patients with painful diabetic neuropathy develop anxiety and/or depression. 2 Screening for and treating psychological comorbidities is essential - addressing depression and anxiety improves overall pain outcomes. 2

Common Pitfalls to Avoid

Do not assume diabetes is the only cause - always screen for B12 deficiency, thyroid disease, and other reversible causes, as diabetic neuropathy is a diagnosis of exclusion. 1

Do not delay foot examination - even without diabetes, loss of protective sensation dramatically increases ulceration and amputation risk. 1

Do not ignore asymmetric symptoms - peripheral neuropathic pain is invariably symmetrical; asymmetry demands investigation for other etiologies like nerve compression or radiculopathy. 2

When to Refer to Specialists

Immediate referral to foot care specialists is required if you have: 1

• Loss of protective sensation on monofilament testing
• Foot deformities or structural abnormalities
• History of foot ulceration or amputation
• Peripheral arterial disease
• Current smoking

A multidisciplinary approach including podiatry, endocrinology, and potentially pain management optimizes outcomes for high-risk patients. 1