MS or Carpal Tunnel Syndrome? How to Tell the Difference
Distinguishing between the symptoms of multiple sclerosis (MS) and those of other conditions can be difficult at times. One year after I was diagnosed with MS, I began to experience problems with both of my hands. They became clumsy, painful, stiff, tingly, and numb, while my forearms were painful. I initially suspected MS because symptoms that had led to my eventual MS diagnosis included weakness and numbness in my left arm, hand, and last two fingers.
But this presumed MS attack was somewhat different. It affected both hands and caused pain in my fingertips that made touching anything—like piano keys or a computer keyboard—excruciatingly painful. I was dropping things and couldn’t continue to do the things I loved and needed to do.
My neurologist examined me carefully. He checked my strength, coordination, and reflexes. He flicked my middle fingernails looking for the Hoffmann reflex. He tapped the area over my wrists (Tinel’s test) and had me hold my hands in a reverse prayer position (Phalen) to see if either maneuver elicited additional tingling or numbness in my fingers. None of these tests are definitive, but they can be helpful in diagnosing carpal tunnel syndrome (CTS).
My doctor suspected CTS, but I had doubts; this hurt so much! After conservative treatment with anti-inflammatory medication, wrist splints, and exercises did not improve symptoms, my neurologist ordered needle electromyography (EMG) and nerve conduction studies (NCS).
The pain had become so intense that I dreamed, more than once, that cutting my arms off would provide blessed relief.
Results from the EMG and NCS tests showed that my doctor and I were both correct and incorrect in our assessments. The tests indicated that I did have CTS, but the mild amount of nerve entrapment detected could not explain the level of pain I was experiencing. I was referred to a hand surgeon for consultation. The ending to this story involves steroid injections given directly into my wrists, more splinting, referral to a rheumatologist, and eventually diagnosis of rheumatoid arthritis, which was responsible for the pain and severe neurological symptoms that I had experienced for over six months.
Fortunately, my story resulted in an accurate diagnosis and allowed me to avoid unnecessary carpal tunnel release (CTR) surgery. Some patients have not been so fortunate. Research published in the journal Mayo Clinic Proceedings details the cases of 12 patients who had experienced unsuccessful results from CTR surgery. It turns out that most of them didn’t have CTS to begin with but rather other neurological conditions, including MS.
Potential symptoms of CTS: Numbness, paresthesia, pain, weakness, sensorimotor hand dysfunction
Potential symptoms of MS: Numbness, paresthesia, pain, weakness, sensorimotor hand dysfunction
In the study, patients referred to the Mayo Clinic following unsuccessful CTR surgery underwent EMG and clinical evaluation. Doctors discovered that these 12 patients had the following diagnoses: polyneuropathy (5 patients), motor neuron disease (4), cervical radiculopathy (3), multiple sclerosis (2), cervical spondylotic myelopathy (1), post-traumatic syringomyelia (1), severe CTS due to scarring (1), and asymptomatic median neuropathy of the wrist (1). Some patients were found to have more than one neurologic condition that may have been mistaken for CTS, and only the patient with scarring and the patient with asymptomatic median neuropathy of the wrist met electrodiagnostic criteria for CTS.
Researchers conclude that various neurologic disorders can mimic CTS, but that misdiagnosis is more commonly associated with atypical clinical or electrodiagnostic features. The wide variety of presenting symptoms in CTS may lead some doctors to be too "cavalier" in the use of CTR for atypical cases when electrodiagnostic findings are not clear for CTS. Authors emphasize that surgery may not be beneficial when CTS coexists with another neurologic disorder that is the primary cause of hand symptoms.
Witt JC, Stevens JC. Neurologic disorders masquerading as carpal tunnel syndrome: 12 cases of failed carpal tunnel release. Mayo Clin Proc. 2000;75(4):409-13.