Case Study of the Week: Carpal Tunnel Syndrome

I despise diagnosing cases of numbness and tingling.  Give me something I can X-Ray or visualize directly.  Numbness and tingling in the hands can be caused by many different medical issues making pinning down the patient's problem difficult.  These symptoms may signal anything from heart attack or anxiety to to cervical radiculopathy or even stroke.  Fortunately for nurse practitioners, carpal tunnel syndrome, also known as median nerve entrapment, presents with some classic symptoms helping NP's make an accurate diagnosis.

Although median nerve entrapment isn't one of the more urgent or emergent diagnoses nurse practitioners make in the clinic or hospital, it can be very debilitating to your patients.  If left untreated, carpal tunnel syndrome results in significant pain and can impede a patient's ability to perform daily activities.  This syndrome occurs as a result of increased pressure on the median nerve, the nerve in the wrist providing feeling and movement to the hand.  

Case Presentation

A 40 year old female presents to your clinic with a 4 week history of intermittent aching in her right wrist and forearm along with numbness and tingling in the thumb and index finger of her right hand.  She states that after prolonged use, her hand feels weak.  It also feels swollen although no visible swelling is present.  She states that her symptoms are most noticeable at night and are usually relieved by vigorously shaking her hand.  The patient denies injury.  Her vital signs are normal and she has no medical history aside from obesity.  

On exam, you note the patient has a positive Tinel's sign, pain shooting from the wrist to the hand when tapping over the median nerve at the wrist.  On performing Phalen's test, instructing the patient to bend the wrist forward completely for 60 seconds, numbness, tingling and weakness are reproduced.  Based on these simple diagnostic tests, you diagnose this patient with carpal tunnel syndrome. 

Management and Outcome

Symptoms and physical exam are typically sufficient for diagnosis of carpal tunnel syndrome.  Electrodiagnostic tests such as nerve conduction studies can be used to confirm diagnosis and determine extent of median nerve damage.  These tests however have a high rate of false-positive and false-negative results limiting their usefulness.

Typically, carpal tunnel syndrome improves with conservative therapy.  Patients should be advised to avoid using vibrating hand tools as well as repetitive movements.  Physical therapy stretching and strengthening exercises also improve outcomes.  Wrist splints can be worn to decrease pressure on the median nerve further improving outcomes.  It is recommended wrist splints be worn at night.  NSAIDS and corticosteroid injections may provide temporary pain relief. 

In cases of severe median nerve entrapment where symptoms do not improve with conservative therapy, surgery may be necessary.  Surgical treatment aims to decompress the median nerve.  Surgical recovery is relatively slow with most patients recovering fully somewhere between 3 and 9 months.

Discussion

Contrary to popular belief, it is unknown if carpal tunnel syndrome is caused by repetitive hand movements.  Multiple factors contribute to development of median nerve entrapment including genetic predisposition, fluid retention during pregnancy or menopause, rheumatoid arthritis and repetitive use of vibrating hand tools.  Carpal tunnel syndrome can significantly limit both personal and professional aspects of your patient's lives.  It is important that nurse practitioners properly diagnose and treat carpal tunnel syndrome allowing patients to regain comfort and function of their hands.