What is the cause of nerve damage caused by intramuscular injection

Many people don’t understand what causes nerve damage after intramuscular injection? This situation often occurs when treating certain diseases that require intramuscular injection of drugs. Nerve damage occurs, and many people worry about whether their health will be seriously damaged as a result. In fact, many of these nerve damages caused by intramuscular injections have a negative impact on the body. So, what about nerve damage caused by intramuscular injection?

First, what is the matter with nerve damage caused by intramuscular injection? MTrP injection (Trigger point injection, TPI) is widely used in clinical practice, such as for the treatment of fibromyalgia, tension headache and myofascial pain syndrome. However, needle sticks occasionally occur during trigger point injections or nerve damage occurs during intraneural injections. Here we report a case of dorsal scapular nerve injury following injection into the rhomboid muscle trigger points. We use nerve conduction studies (NCS) and electromyography (EMG) to diagnose dorsal scapular nerve injuries.

Second, myofascial pain syndrome is characterized by the presence of MTrp in skeletal muscle, and palpation of MTrp can induce muscle tension, allodynia, and autonomic phenomena. Myofascial pain syndrome often occurs in the rhomboids and trapezius muscles. Trigger points in these areas can cause pain in the neck, interscapular area, scapula, and shoulder. Treatment with MTrP using local anesthetic injections is very effective. The patient complained of poor shoulder mobility after MTrP injection. NCS/EMG examination showed decreased amplitude and prolonged latency of the right dorsal scapular nerve compound muscle action potential, and positive sharp waves and decreased recruitment of the rhomboid major muscle. These results suggest a lesion in the right dorsal scapular nerve. In addition, the prolonged latency of compound muscle action potential was related to the damage of neurophospholipids, and the positive sharp waves in the right rhomboid major muscle clearly indicated axonal damage. Therefore the neuropathy exists in both phospholipids and axons.

What happens when an intramuscular injection causes nerve damage? Most dorsal scapular nerve injuries result from compression of the middle scalene muscle. The patient then developed right shoulder weakness after MTrP injection. In addition, positive sharp waves were found in the rhomboid major muscle, but not in the levator scapulae and rhomboid minor muscles, indicating that the nerve damage occurred in the rhomboid major muscle or nearby. The patient's history and EMG findings supported our hypothesis that the dorsal scapular nerve was injured by the MTrP injection into the rhomboids major muscle. The dorsal scapular nerve runs along the inner side of the scapula about one finger width away to the inferior angle of the scapula. Therefore, when performing MTrP injections in the rhomboid muscle near the scapula, special attention should be paid to the possible damage to the dorsal scapular nerve.