What are the possible causes and recommended work‑up for a week‑long onset of numbness and tingling in my right hand without weakness or other red‑flag symptoms?

Unilateral Hand Numbness and Tingling: Diagnostic Approach

For a week of isolated right-hand numbness and tingling without weakness or red flags, carpal tunnel syndrome is the most likely diagnosis and should be evaluated with focused physical examination maneuvers (Phalen's, Tinel's, median nerve compression test) before considering imaging or electrodiagnostic studies. 1, 2

Most Likely Diagnosis: Carpal Tunnel Syndrome

Carpal tunnel syndrome is the most common peripheral nerve entrapment and presents with pain, numbness, and tingling in the median nerve distribution—specifically the palmar aspect of the thumb, index, middle fingers, and radial half of the ring finger. 1, 2, 3

Key Physical Examination Findings to Assess

• Flick sign: Ask if the patient shakes their hand to relieve symptoms (highly suggestive of CTS). 2
• Phalen maneuver: Reproduce symptoms by having the patient hold wrists in full flexion for 60 seconds. 2, 3
• Tinel's sign: Percuss over the median nerve at the wrist to elicit paresthesias. 2, 3
• Median nerve compression test: Direct pressure over the carpal tunnel for 30 seconds reproduces symptoms. 2
• Sensory testing: Decreased pain sensation specifically in the thumb, index, and middle fingers (not the little finger). 3

When Electrodiagnostic Studies Are Needed

Patients with typical symptoms and positive physical examination findings do not require electrodiagnostic testing for initial diagnosis. 2 However, obtain nerve conduction studies if:

• Symptoms are atypical or the diagnosis is uncertain. 2
• Surgical decompression is being considered (to determine severity and prognosis). 2
• Symptoms persist beyond 4-6 weeks despite conservative management. 4

Alternative Diagnoses to Consider

Cervical Radiculopathy (C6-C7)

C7 radiculopathy can affect the middle finger but typically involves multiple fingers and is accompanied by neck pain or radiating arm pain. 5, 6 The unilateral single-week duration without neck symptoms makes this less likely. 5

Digital Nerve Compression

Isolated compression of the radial digital nerve from repetitive activities, tight jewelry, or local trauma can cause single-digit numbness. 4 This is more likely if symptoms are truly limited to one or two fingers rather than the entire median nerve distribution. 4

Thoracic Outlet Syndrome

Consider TOS if symptoms occur with specific arm positions (overhead activities, sustained phone use with arm abduction) and involve the entire hand with associated neck or shoulder discomfort. 6 Test with Adson's, Wright's, or Roos maneuvers. 6

Initial Management Algorithm

Conservative Treatment (First-Line for Mild-to-Moderate CTS)

1. Wrist splinting in neutral position, especially at night, is the cornerstone of initial therapy. 7, 2
2. Activity modification: Identify and reduce repetitive wrist flexion/extension activities at work or home. 4, 7
3. Local corticosteroid injection provides relief for more than one month and can delay surgery at one year—particularly effective if there is no sensory loss, thenar atrophy, or constant symptoms. 7, 2

Ineffective Therapies to Avoid

• NSAIDs, diuretics, and vitamin B6 are not effective for CTS. 7, 2

When to Refer for Surgery

Offer surgical decompression if:

• Symptoms are severe at presentation (thenar atrophy, constant numbness, significant weakness). 2
• Conservative therapy fails after 4-6 months. 2
• Electrodiagnostic studies confirm severe median nerve compression. 2

Endoscopic and open carpal tunnel release are equally effective, though patients return to work approximately one week earlier with endoscopic repair. 2

Red Flags Requiring Urgent Evaluation

If any of the following are present, obtain urgent neurological consultation and imaging:

• Rapidly progressive bilateral weakness with paresthesias. 6
• Areflexia or hyporeflexia in affected limbs. 6
• Ascending pattern of symptoms from hands to arms. 6
• Respiratory symptoms or dysautonomia. 6
• Recent infection within 6 weeks (concern for Guillain-Barré syndrome). 6

Common Pitfalls

• Do not order MRI cervical spine or electrodiagnostic studies as first-line tests for typical CTS presentation—clinical diagnosis with physical examination is sufficient to initiate conservative treatment. 2
• Bilateral symptoms suggest systemic causes (diabetes, hypothyroidism, B12 deficiency) rather than isolated entrapment and require metabolic workup. 6, 3
• Symptoms involving the little finger suggest ulnar nerve pathology (cubital or ulnar tunnel syndrome), not CTS. 3