What is the workup for a patient presenting with fingertip numbness?

Workup for Fingertip Numbness

For a patient presenting with fingertip numbness, begin with a focused history to determine if this represents peripheral neuropathy in a stocking-glove distribution (suggesting systemic disease) versus isolated hand symptoms (suggesting focal pathology), then proceed with targeted laboratory testing and consider electrodiagnostic studies if the diagnosis remains unclear. 1, 2

Initial Clinical Assessment

History Components

• Symptom characterization: Document whether numbness is bilateral or unilateral, symmetric or asymmetric, and whether it follows a stocking-glove pattern (fingers AND toes affected) versus isolated hand involvement 2, 3
• Associated symptoms: Ask specifically about tingling, burning sensations, pain (rated 0-10), weakness, and whether symptoms worsen at night 1, 2
• Progression pattern: Determine if symptoms started in toes first (typical of peripheral neuropathy) or began in fingers, and whether they are progressing proximally 4
• Red flag symptoms: Screen for autonomic dysfunction (orthostatic dizziness, constipation/diarrhea, urinary retention, erectile dysfunction, abnormal sweating), which suggests systemic neuropathy 2, 4
• Risk factors: Diabetes duration and control, alcohol use, chemotherapy exposure (particularly platinum agents or taxanes), family history of neuropathy, vitamin deficiencies, thyroid disease 1, 2, 4

Physical Examination

• Sensory testing: Perform pinprick sensation (small fiber function), temperature perception, vibration testing with 128-Hz tuning fork (large fiber function), and 10-g monofilament testing on fingertips and feet 2, 4
• Motor examination: Assess for distal weakness, particularly in toe/ankle dorsiflexors if lower extremities are involved, and check for muscle atrophy 4
• Reflexes: Test ankle reflexes and upper extremity reflexes; reduced or absent reflexes suggest peripheral neuropathy 4, 2
• Gait assessment: Observe for wide-based unsteady gait, which indicates proprioceptive loss 4

Critical pitfall: Asymmetric symptoms should prompt immediate consideration of alternative diagnoses such as cervical cord pathology, nerve entrapment, or stroke rather than typical peripheral neuropathy 2, 3

Laboratory Evaluation

Initial Testing Panel (Order for All Patients)

• Glucose metabolism: Fasting blood glucose and hemoglobin A1c 1, 2, 5
• Hematology: Complete blood count 2, 5
• Metabolic: Comprehensive metabolic profile including renal function 5
• Vitamin B12 level: Common treatable cause of neuropathy 1, 2, 5
• Thyroid function: TSH and free T4 1, 2, 5
• Protein studies: Serum protein electrophoresis with immunofixation to evaluate for paraproteinemia 5

Additional Testing (When Clinically Indicated)

• Infectious workup: Hepatitis B, C, and HIV testing if risk factors present 1, 2
• Autoimmune markers: Anti-ganglioside antibodies if Guillain-Barré syndrome suspected, anti-MAG antibodies if demyelinating neuropathy suspected 1

Electrodiagnostic Studies

Nerve conduction studies and electromyography should be ordered when: 2, 5

• Clinical features are atypical (asymmetric distribution, rapid progression, predominant motor involvement)
• The diagnosis remains unclear after initial evaluation
• Differentiation between axonal versus demyelinating neuropathy is needed
• Distinguishing focal entrapment (carpal tunnel syndrome) from generalized neuropathy is necessary

Note: These studies are NOT routinely needed for typical diabetic neuropathy presenting with symmetric distal sensory symptoms 2

Urgent Considerations

When to Consider Cervical Spine Imaging

Order urgent cervical spine MRI if: 3

• Bilateral hand numbness is accompanied by burning dysesthesias in forearms
• Any lower extremity symptoms are present (weakness, numbness, gait disturbance)
• Upper extremity weakness is greater than lower extremity involvement (central cord syndrome pattern)
• History of neck trauma or known cervical stenosis

When to Consider Stroke Evaluation

Refer for same-day stroke assessment if: 4

• Acute onset (within 48 hours) of hemibody sensory loss
• Symptoms include unilateral face, arm, or leg involvement
• Associated speech disturbance, visual changes, or coordination problems

Important distinction: Atypical sensory symptoms such as patchy numbness and tingling are generally less urgent and may be evaluated by a neurologist as required 4

Special Clinical Scenarios

Diabetic Patients

• All type 2 diabetes patients should be screened for neuropathy at diagnosis; type 1 diabetes patients after 5 years, then annually 2
• Loss of protective sensation (absent 10-g monofilament plus one other abnormal test) identifies high-risk feet requiring foot care specialist referral 2, 4
• Up to 50% of diabetic peripheral neuropathy is asymptomatic, so screening should not rely on symptoms alone 2

Chemotherapy-Exposed Patients

• Oxaliplatin causes acute cold-triggered symptoms plus chronic neuropathy that may worsen for 2-3 months after treatment cessation (coasting phenomenon) 4
• Paclitaxel-induced neuropathy is more prominent in lower extremities during treatment and typically improves over months after completion 4
• Diagnosis is clinical; EMG is not usually necessary if typical presentation 4

Dialysis Patients with Vascular Access

• Fingertip numbness with coldness, pallor, or pain during dialysis suggests steal syndrome 4
• Differentiate from carpal tunnel syndrome, which is also common in dialysis patients 4
• Fingertip necrosis is an alarming symptom requiring urgent vascular surgery referral 4