What could be causing tingling sensations in my lower legs and feet, along with weird deep sensations in both arms, fingers, and wrists, and how should I proceed with diagnosis and treatment as an adult with potential underlying medical conditions?

Evaluation of Bilateral Tingling and Deep Sensations in Extremities

You need an urgent comprehensive neurological examination with specific testing for diabetic peripheral neuropathy, including 10-g monofilament testing, vibration sensation with 128-Hz tuning fork, and pinprick/temperature testing, along with immediate assessment of vascular status via ankle-brachial index to exclude peripheral arterial disease. 1, 2

Immediate Diagnostic Priorities

Your symptoms of bilateral tingling in lower legs/feet combined with deep sensations in arms, fingers, and wrists suggest a symmetric polyneuropathy that requires systematic evaluation to identify the underlying cause and prevent progression. 1

Critical First Steps

Perform targeted neurological examination including:

• Small-fiber function testing: Pinprick and temperature sensation in distal extremities 1
• Large-fiber function testing: Vibration perception using 128-Hz tuning fork, assessment of ankle reflexes, and 10-g monofilament testing on feet 1, 2
• Vascular assessment: Bilateral palpation of dorsalis pedis and posterior tibial pulses, capillary refill time, checking for rubor on dependency and pallor on elevation 2
• Ankle-brachial index (ABI): Essential to exclude peripheral arterial disease, as vascular claudication can mimic neuropathy but requires entirely different management 2

Most Likely Diagnoses to Rule Out

Diabetic Peripheral Neuropathy (Most Common)

If you have diabetes or prediabetes, this is the leading diagnosis. The bilateral, symmetric distribution affecting both upper and lower extremities is classic for diabetic neuropathy. 1

• Symptoms typically start distally and progress proximally 1
• Often worse at night, causing sleep disruption 2
• May present with burning, tingling, or "deep" uncomfortable sensations 1
• Check HbA1c, fasting glucose, and serum ferritin immediately 2

Peripheral Neuropathy from Other Causes

Exclude these systematically:

• Vitamin B12 deficiency: Check serum B12 and methylmalonic acid levels 1
• Thyroid dysfunction: Obtain TSH 1
• Alcohol use: Take careful history of alcohol consumption 1
• Medication-induced: Review all current medications, particularly chemotherapy agents, statins, or antiretrovirals 1
• Fabry disease: Consider if you have family history, early stroke, cardiac issues, or kidney disease—this rare genetic condition causes acroparesthesias (burning pain and tingling in hands and feet) 1

Lumbar Spinal Stenosis with Cervical Involvement

Less likely given bilateral upper extremity involvement, but consider if:

• Pain worsens with standing or spinal extension 3
• Relief occurs with sitting or spinal flexion 3
• Difficulty rising from sitting or lying positions 3

Critical Laboratory and Diagnostic Testing

Order immediately:

• Complete metabolic panel, HbA1c, fasting glucose 2
• Serum B12, methylmalonic acid, folate 1
• TSH, free T4 1
• Serum ferritin (if <50 ng/mL, indicates need for iron supplementation) 4
• Ankle-brachial index bilaterally 2
• Consider nerve conduction studies if diagnosis remains unclear after initial workup 1

Treatment Algorithm Based on Findings

If Diabetic Neuropathy Confirmed:

Immediate actions:

1. Optimize glycemic control aggressively—this is the only intervention that prevents progression 2
2. Start FDA-approved neuropathic pain medication:
   • Duloxetine 30-60 mg daily, OR 2
   • Gabapentin titrated to 900-3600 mg/day divided, OR 1, 2
   • Pregabalin 2
3. Comprehensive foot care protocol: Daily self-examination, podiatry referral, intensified surveillance 2
4. Screen for depression and anxiety—present in over two-thirds of patients with painful neuropathy 2

If Non-Diabetic Neuropathy:

• Treat underlying cause (B12 supplementation, thyroid replacement, discontinue offending medication) 1
• Symptomatic management: Phenytoin, carbamazepine, oxcarbazepine, gabapentin, or topiramate for painful symptoms 1
• Physical activity: Shown to improve neuropathic pain 1

If Fabry Disease Suspected:

• Refer to genetics/metabolic specialist immediately for enzyme testing 1
• Symptomatic treatment with gabapentin or carbamazepine while awaiting workup 1
• Consider aspirin for stroke prevention if diagnosis confirmed 1

Common Pitfalls to Avoid

Do not assume this is benign or self-limited. Bilateral symmetric neuropathy indicates systemic pathology requiring investigation. 1

Do not skip vascular assessment. Up to 24% of diabetic patients aged 55-74 have diminished pedal pulses, and peripheral arterial disease requires different management than neuropathy. 2

Do not overlook medication causes. Chemotherapy-induced peripheral neuropathy affects 30-40% of patients receiving taxane or platinum-based regimens and may require duloxetine for management. 1

Do not diagnose without objective testing. Clinical examination must include quantifiable assessments (10-g monofilament, 128-Hz tuning fork) rather than subjective symptom reporting alone. 1

Do not delay treatment while awaiting specialist evaluation. If diabetic neuropathy is suspected, start glycemic optimization and neuropathic pain medication immediately—over 95% of patients with painful diabetic neuropathy have sleep disturbances requiring prompt intervention. 2