As we turn our attention to the modern world, we will see how it has changed everything about us, including our health and disease patterns. Since antibiotics were invented, most of us do not die from infectious diseases anymore. But new conditions arise or gain more popularity, such as diabetes and carpal tunnel syndrome. Diabetes is a metabolic disease caused by today’s pattern of eating and available foods. Carpal tunnel syndrome is an entrapment neuropathy commonly triggered by the misuse of electronic devices and repetitive movements in modern jobs.
This article will talk about carpal tunnel syndrome and give you a complete understanding of what it is about.
What is carpal tunnel syndrome?
A syndrome is a set of signs and symptoms that show up in patients with similar characteristics and a common trigger. Carpal tunnel syndrome is a set of signs and symptoms that show up in patients with entrapment neuropathy of the median nerve.
The median nerve runs through the wrists and into your hands. It is responsible for movement and sensory impulses sent to the brain. On its way into your hands, it goes through a structure called a carpal tunnel accompanied by different tendons. This is a very tight space, but it usually has enough room for them. Carpal tunnel syndrome develops when this structure becomes too tight. It reduces its size for different causes, and the nerve starts suffering compression.
What causes carpal tunnel syndrome?
Carpal tunnel syndrome is caused by compression of the median nerve as it goes through the carpal tunnel. As such, this syndrome has the usual signs and symptoms of nerve pinching, such as numbness and tingling. But much more happens in carpal tunnel syndrome that we don’t know about.
The disease goes beyond compression because the affected nerve is slowly damaged as the condition is sustained. It starts losing its myelin sheath, which works like the isolation sheath around cables. With a weakened myelin sheath, the nerve impulse can’t travel through the nerve as rapidly and effectively.
If the disease continues, it causes axonal degeneration. The long string of nerve cells that conducts the nerve impulses start to break down. As it happens, motor and sensory nerve fibers are affected. First, we start having sensory failure and sensory abnormalities. Then, we begin experiencing motor problems when trying to use our hands.
Each patient is different, and the disease develops differently in each one of them. However, in most people, there’s very high pressure in the carpal tunnel obstructing other structures. It is not only the median nerve that is involved. The venous outflow may also become damaged, causing liquid retention and edema in the hands. The nerves also receive insufficient blood flow and start undergoing ischemia.
But what triggers all of these changes? The exact cause is not entirely understood, and it appears to be a multifactorial disease. There are different risk factors, including genetic predisposition, medical risk factors, social and working situations that contribute to carpal tunnel syndrome development.
Risk factors
The main risk factors in carpal tunnel syndrome include:
- Female gender: Being a woman increases the chances of carpal tunnel syndrome because more women usually suffer from this health problem than men. There could be a genetic or morphologic predisposition in the size or the disposition of structures in their carpal tunnel.
- Increasing age: As we age, it becomes more likely to suffer from carpal tunnel syndrome. The disease is not common before age 30 years. On the contrary, the peak of diagnoses of carpal tunnel syndrome starts at age 40 years, and it is only reduced after 70 years old.
- Small bones forming the carpal tunnel: This is probably one of the most common genetic predispositions to carpal tunnel syndrome. These patients have smaller bones and a smaller carpal tunnel. Thus, a small change or accumulation of material around the area causes carpal tunnel syndrome. When carpal tunnel syndrome runs in families, this is a very likely cause.
- Repetitive movements of the wrist and hands: Work-related causes of carpal tunnel syndrome are prevalent, especially for people who need to use their hands to work for many hours every day and perform repetitive movements every time. For example, people with assembly-line jobs need to extend or flex their wrists for a long time. That includes people who work in electronic assembly, the fish and meat processing industry, hairdressers, and forestry work. Computer work is also related to a higher risk of carpal tunnel syndrome when an ergonomic position is not achieved.
- Frequent exposure to cold temperatures: Cold temperatures affect the body by reducing blood flow, causing constriction in vascular structures, and contributing to muscle tension. All of these aspects can independently increase the risk of carpal tunnel syndrome. For example, a reduction in the blood flow accelerates the process of ischemia of the median nerve described above, causing axonal degeneration and leading to carpal tunnel syndrome.
Frequent exposure to vibration
Vibration is also a significant risk factor, even if your hands are not moving. In most cases, hand-arm vibration at work comes from hand power tools used in heavy steel fabrication, construction sites, and similar workplaces. Vibration causes microtrauma and inflammation in the carpal tunnel, which thickens the tissues and reduces the carpal tunnel’s available space.
- Trauma and direct damage to the carpal tunnel: Direct trauma can also be a reason for a reduced space in the carpal tunnel, especially in people who endured fractures in the wrist area. Deformity in this structure can lead to the rapid development of carpal tunnel syndrome.
- Menopause and pregnancy: It is known that some women experience carpal tunnel syndrome during pregnancy. Others start experiencing the same problem after menopause. In each case, there is a hormonal factor involved, and it is hypothesized that estrogen levels protect the median nerve from compression. Lower levels of estrogen may speed up the development of carpal tunnel syndrome. Another cause can be a change in their blood circulation that favors liquid retention and edema in the wrist area during pregnancy. Under the proper environmental conditions, it may favor carpal tunnel syndrome and cause compression in the structures.
- Obesity: According to research, people with obesity are twice as likely to suffer from carpal tunnel syndrome as the rest of the population. One of the reasons is that obesity leads to systemic inflammation because fat cells create inflammatory substances called cytokines. Such higher inflammation levels affect small structures throughout the body, especially the carpal tunnel, reducing the space and causing edema. With a narrow carpal tunnel, the risk of suffering from this disease goes up.
- Rheumatic diseases such as rheumatoid arthritis and lupus: Rheumatic diseases are very complex, and they are not only joint problems. They also involve the nerves and blood vessels. These diseases have in common circulatory issues, joint problems, and nerve problems. Thus, even if there is no mechanical reduction of the carpal tunnel, the same signs and symptoms start to appear in these patients.
- Metabolic diseases such as hypothyroidism and diabetes: Different metabolic diseases may also become a risk factor of carpal tunnel syndrome, especially hypothyroidism and diabetes. In hypothyroidism, there are circulatory problems, and they cause a predisposition to fluid retention and higher pressure in the carpal tunnel. In diabetes, the association is more elusive, but it appears that diabetic neuropathy has something to do. Their nerves are affected by the uncontrolled disease, and the risk of carpal tunnel syndrome is higher.
- Tumors in the wrist or near the carpal tunnel: There are many causes of external obstruction of the carpal tunnel, ultimately triggering the disease. If there’s a tumor in the carpal tunnel or near the wrist, it would likely give out the same signs and symptoms as carpal tunnel syndrome.
Signs and symptoms
How can you recognize carpal tunnel syndrome? Here’s a helpful list of signs and symptoms to suspect the diagnosis. If you think that you have this condition, talk to your doctor right away to find out the source of the problem.
- Numbness: This is one of the most common sensory symptoms. These patients often describe that their hands fall asleep or they stop feeling things in their hands. This is numbness, and it is a sensory problem of the median nerve. The symptom is intermittent and usually appears when using the patient’s grip.
- Tingling: Like numbness, tingling is a sensory alteration caused by nerve entrapment of the median nerve. It is an abnormal sensation of stings in the hand, also intermittent and often appearing when the patient is closing his grip.
- Pain: Pain is also commonly described, and it is found in the area where the median nerve innervates the hand. In these cases, it is essential to rule out other joint pain causes and certain neurologic diseases.
- Cold hands: The median nerve also maintains the temperature of the hands because it has autonomic fibers. Thus, patients commonly feel their hands very cold or very hot.
- Sweating changes: Another autonomic function of the median nerve is sweating. Thus, patients can develop sweating changes in their hands, which can be either no sweating or profuse sweating.
Loss of grip
Besides autonomic function and sensory function, the median nerve also carries a few motor fibers and contributes to gripping and specific hand movements. These patients often feel weakness in their hands or lose their grip without realizing it.
- Sensory distribution: When evaluating these symptoms, it is essential to locate the pain’s sensory distribution. It is located in the palmar aspect of the hand and distributed in the first to the fourth fingers of the hand, usually the fifth finger and surrounding areas. This is where sensory and autonomic symptoms are mostly reported.
- More symptoms in the dominant hand: The dominant hand is more often affected by carpal tunnel syndrome than the other hand. The condition can be bilateral, too, but patients often describe more severe symptoms in their dominant hand, even in bilateral carpal tunnel syndrome.
- Worsening at night: The pain sensation, tingling, and numbness are usually exacerbated at night and when patients are actively using their grip or doing repetitive movements with their hands.
- Improvements by shaking the wrist: Many patients describe that shaking their wrists makes them feel an improvement in their symptoms.
- Hoffmann-Tinel sign: This sign is elicited in the physical exam by doctors. They locate the median nerve and tap on the skin where the median nerve is running. This prompts a sensation of tingling in the hands.
- Phalen sign: This is another sign used by doctors during their physical exam. They will ask the patient to flex or extend the wrist for 60 seconds. When they do, they start feeling tingling in the hands. The flexion or extension should be complete for the exam to be accurate.
- Square wrist sign: This exam is elementary and only requires measuring the wrist width and the wrist thickness. After that, doctors calculate the thickness to wrist ratio. When it is greater than 0.7, the diagnosis of carpal tunnel syndrome is more likely.
Treatment options
Treating carpal tunnel syndrome is a multi-step process and depends on the severity of the condition at the moment of diagnosis. We can use one of these treatment options depending on the patient:
- Aerobic fitness program: Instrumental in obese and overweight individuals or those with low levels of physical activity. They can benefit from an active fitness program with cycling, stationary bikes, and other exercises.
- Wrist splinting: Special splinting devices are used and put in place at nighttime. The usual treatment time is more than 3 weeks, and many patients respond very well to this treatment.
- Steroid injections: It is appropriate when wrist splinting does not work and provides long-term relief to the symptoms.
- Surgical release: The last step is using surgery to release the transverse ligament and reduce the tension in the carpal tunnel. The success rate of this surgery is very high without many complications.