Carpal Tunnel Syndrome, or CTS, is very common. Many neurologically normal people have occasional symptoms after unusual repetitive work like hammering. Others have nightly pain and numbness and eventually weakness. One invariable feature of the history is waking at night with numbness. My first "test" is to ask: "Are you waking up all night shaking your hand awake?" An affirmative is suggestive of carpal tunnel syndrome but a "Eureka" is almost diagnostic.

CARPAL TUNNEL

SYNDROME

 

 

 

 

Too much is sometimes made of "pinched nerves" but Carpal Tunnel is truly a pinched nerve. It is by far the most common of the so-called nerve entrapments ("pinch" lacks the gravitas we like in materia medica) and produces a stereotyped syndrome of pain and/or numbness seemingly in the entire hand although the numbness is never above the wrist. Eventually, the entire arm may ache, no position is comfortable and finally, ignored long enough, there is irreversible atrophy of a thumb muscle with grip weakness - - dropping things, inability to open jars.

At the arrow on the left we see the median nerve as it sinks below the transverse ligament of the wrist, the tight bony canal, illustrated by the late great Frank Netter.

 

 

 

 

 

 

The sensory distribution of the median nerve is well defined and consistent even "splitting the ring finger" reliably when tested, gently, with pinwheel. In general, the more distal the lesion (in this case repetitive motion/trauma at the wrist) the more localized the symptoms. In the case of Carpal Tunnel Syndrome, the sensory involvement is dependably limited to the sensory distribution of the nerve as shown in dark blue:

 

 

 

 

 

 

 

 

Wrist splints: an excellent low-tech solution for the diagnosis and treatment of episodic or mild Carpal Tunnel Syndrome. Wear them to bed every night and, if comfortable, while doing those activities such as hammering and bicycle riding which are well known to aggravate the condition. Wrist splints are cheap and easier to replace than wrists.

 

Cortisone injection: before going to surgery, consider a cortisone shot from someone with plenty of experience. It may temporarily stir up the pain, but if the diagnosis is correct, (and absent low thyroid or the rare case of acromegaly - both conditions ruled out with blood tests) then there is almost always improvement (allow 2-3 days) though not always permanent.

 

 

Cortisone injections probably should not be repeated in the same site more than 2-3X per year. Patients should know that a small area of depigmentaion, and sometimes scalloping of tissue and rarefaction, may develop at the site of injections, sometimes weeks later. The small white patch, when it occurs, usually fills in again over the ensuing months.

Surgery: this is the definitive treatment for nerve conduction documented moderate to severe CTS. Nerve conductions are the definitive test for this conduction and slowing across the wrist should be documented before undertaking an operation or it won't do any good.

Surgery works and is indicated when weakness (of grip) is present and the pain intolerable and cortisone hasn't been good enough. The surgery is quite safe, done under local, come and go, but the hand must be immobilized and then rehabilitated for weeks or months to assure recovery without adhesions or deficits.

 

 

 

 

 

 

NOT TO BE OVERLOOKED

In two important but fortunately rare conditions, Carpal Tunnel Syndrome may be the presentation. Both are SIGHT DIAGNOSES readily confirmed or ruled out with a blood test.

 

 

 

 

 

 

 

 

 

 

 

1. ACROMEGALY - enlargement of hands and jaw and feet, coarsening of features, atypical headache due to a benign but enlarging tumor (adenoma) of growth hormone secreting cells in the pituitary gland.

 

 

 

 

 

 

 

 

 

 

 

2. MYXEDEMA - an extreme and potentially terminal stage of hypothyroidism.