Why Does It Happen at Night?

The answer is elegant and entirely explainable once you understand the anatomy. The median nerve travels from the neck, down the arm, through the wrist inside a narrow passage called the carpal tunnel — a rigid channel formed by the wrist bones on three sides and the transverse carpal ligament on the fourth. There is very little room to spare.

During the day, the wrist is mostly in a neutral or slightly extended position — which keeps the carpal tunnel at its maximum width. When you sleep, the wrist naturally falls into flexion — bending toward the palm. Wrist flexion reduces the carpal tunnel volume significantly, further compressing the already-irritated median nerve. The nerve, which has been under pressure all day from repetitive activities, reaches a threshold that triggers the characteristic tingling.

This is why the classic carpal tunnel behavior is waking up to shake the hand — shaking moves the wrist and fluid around, temporarily reducing pressure and restoring circulation to the nerve. Most patients describe this as instinctive — they wake up doing it without fully realizing why.

The Full Symptom Picture

Carpal tunnel syndrome (CTS) is more than just nighttime numbness. The complete symptom spectrum, from early to advanced:

Early Symptoms (Mild CTS)

• Intermittent nighttime numbness and tingling in thumb, index, and middle fingers
• Symptoms improve after shaking the hand
• Occasionally numb when holding a phone, book, or steering wheel for extended periods
• Symptoms come and go — not constant
• Normal grip strength and hand function

Moderate Symptoms

• Nighttime symptoms more frequent and harder to relieve by shaking
• Daytime numbness appearing — particularly during prolonged gripping
• Occasional dropping of objects or difficulty with fine motor tasks (buttons, keys)
• Forearm aching or wrist pain in addition to finger numbness
• Symptoms present multiple nights per week

Advanced Symptoms (Severe CTS)

• Constant numbness — not just at night
• Visible wasting of the thenar muscle (the muscle at the base of the thumb — it looks flattened)
• Significant grip and pinch weakness — unable to hold objects securely
• Poor dexterity and coordination in the affected hand
• Numbness that doesn't improve with shaking

How Severe Is Your Carpal Tunnel?

Severity guides treatment — mild CTS often responds beautifully to a splint and injection, while moderate-severe CTS typically needs surgery. Here's a simple framework:

What Causes Carpal Tunnel Syndrome?

The underlying cause is anything that either narrows the carpal tunnel or increases the volume of its contents — reducing the space for the median nerve:

• Repetitive wrist use — assembly line work, keyboard and mouse use, vibrating tools. The most common occupational cause.
• Pregnancy and hormonal changes — fluid retention increases carpal tunnel pressure. CTS affects up to 50% of pregnant women, usually resolving after delivery.
• Wrist anatomy — some people simply have a smaller carpal tunnel. Women are 3× more likely to develop CTS partly for this reason.
• Diabetes — metabolic nerve disease makes the median nerve more vulnerable to compression. Diabetics have a 3–5× higher CTS rate.
• Hypothyroidism — fluid retention and metabolic nerve changes increase CTS risk significantly.
• Prior wrist fracture — even well-healed distal radius fractures can narrow the carpal tunnel.
• Inflammatory arthritis — synovitis of the wrist tendons within the carpal tunnel increases pressure.

Your Treatment Options — From Splint to Surgery

The right treatment depends on severity. Here's the evidence-based progression:

Do I Need a Nerve Test (NCS/EMG)?

Nerve conduction studies (NCS) and electromyography (EMG) measure how fast electrical signals travel through the median nerve — confirming the diagnosis and grading severity. Dr. Chambers can order these at your first visit.

NCS are used to:

• Confirm the diagnosis — particularly when symptoms are atypical or bilateral
• Grade severity — mild, moderate, or severe slowing guides treatment urgency
• Rule out other causes — cervical radiculopathy (neck nerve) can mimic CTS and shows up differently on NCS
• Document baseline before surgery

For classic presentation — nighttime thumb/index/middle numbness, positive Phalen test, positive Tinel sign at the wrist — the diagnosis is often clear without NCS. Dr. Chambers will determine at your visit whether nerve studies are needed for your situation.

Special Situations

Carpal Tunnel Syndrome During Pregnancy

CTS is extremely common during pregnancy, particularly in the third trimester, due to fluid retention increasing carpal tunnel pressure. The good news: it resolves in the majority of women within weeks to months of delivery. Treatment during pregnancy focuses on wrist splinting and activity modification. Cortisone injection is safe with appropriate timing relative to breastfeeding. Surgery is rarely needed during pregnancy but can be performed safely when symptoms are severe.

Bilateral Carpal Tunnel Syndrome

Both hands are affected in up to 50% of CTS patients. When both sides need surgery, Dr. Chambers typically stages them — operating on the dominant (more symptomatic) hand first, then the other side 3–6 weeks later once the first hand is functional. Having surgery on both hands simultaneously would leave the patient without a functioning hand for activities of daily living.

Carpal Tunnel Syndrome in Diabetics

Diabetics have a higher rate of CTS and also slower nerve recovery after surgery. Blood sugar control before surgery significantly improves outcomes. Surgery is still very effective in diabetics — but blood glucose should be well-managed, ideally with HbA1c under 7.5, before elective carpal tunnel release.

Frequently Asked Questions