Double Crush Syndrome- symptoms, diagnosis & treatment

What is double crush syndrome?

Double crush syndrome is a medical condition that can be difficult to diagnose and may be overlooked or misunderstood. It occurs when a nerve is compressed or irritated at two or more points along its pathway, leading to symptoms in areas where the same nerve innervates. 

This condition was first described in the 1970s and has since been recognized as a potential cause of pain, weakness, numbness, and tingling, among other symptoms. 

It is often seen in individuals who perform repetitive movements with their hands or other body parts and can be exacerbated by underlying conditions such as diabetes or arthritis.

Etiology & Pathophysiology

Double crush syndrome can potentially develop in any part of the body where a nerve pathway exists, but it is most frequently observed in the upper extremities, especially in the hands and arms. 

It is often seen in individuals who perform repetitive movements with their hands, such as musicians, computer users, or athletes. 

These activities can cause microtrauma or inflammation in the nerves, which can increase the likelihood of compression or irritation at a lower point in their pathway. This can lead to symptoms such as pain, weakness, numbness, and tingling in the affected area, and can impact an individual's ability to perform daily activities.

Theories;

Multiple theories have been proposed to explain how double crush syndrome arises. One hypothesis is that the nerves become sensitized or more easily irritated at a higher point in their pathway, which increases their susceptibility to compression or irritation at a lower point. 

Another theory suggests that the compression or irritation at the lower point in the pathway may cause a reduction in blood flow to the nerve, which can worsen the damage already present at the higher point. Ultimately, the precise mechanisms underlying double crush syndrome remain unclear, and additional research is needed to elucidate its underlying pathophysiology.

Symptoms of double crush syndrome

Symptoms of double crush syndrome can manifest in various ways, including pain, weakness, numbness, and tingling in the affected area. 

These symptoms can occur continuously or intermittently and may be intensified by certain activities, such as typing or playing an instrument. At times, these symptoms may be mistaken for other nerve entrapment syndromes, such as carpal tunnel syndrome. Hence, a thorough evaluation and examination by a medical professional are crucial for an accurate diagnosis and appropriate treatment.

Diagnosis

Diagnosing double crush syndrome can be difficult as it involves detecting two or more points of nerve compression or irritation along the nerve pathway. To make a correct diagnosis, a comprehensive physical examination and diagnostic tests, such as nerve conduction studies and electromyography, may be required to identify the precise location and intensity of the nerve compression.

Treatment

The treatment options for double crush syndrome may vary depending on the severity and location of the nerve compression. 

Physical therapy is a common treatment modality that involves exercises to strengthen the affected muscles, improve the range of motion, and reduce inflammation using modalities such as heat or cold therapy. 

Medications, including nonsteroidal anti-inflammatory drugs and nerve-pain medications, may be prescribed to alleviate pain and inflammation. In severe cases where conservative management fails, surgery may be necessary to release the compression on the nerve and restore proper nerve function.