Brachial neuritis is a condition in which at least part of the brachial plexus—a group of nerves that run from the neck and upper back through the shoulder—becomes inflamed and typically causes severe shoulder pain. While the intense pain usually subsides within a few days, it is commonly followed by some numbness and weakness in the arm and/or shoulder that may take many months or longer before significantly recovering.
Other names for brachial neuritis include Parsonage-Turner syndrome and neuralgic amyotrophy. This article reviews what is known about brachial neuritis’s symptoms, diagnosis, and recovery process.
Initial Pain of Brachial Neuritis
When brachial neuritis pain initially starts, it is typically characterized by the following:
- Sudden onset (usually not related to an injury)
- Begins in the shoulder and/or upper arm
- Piercing, sharp, and/or radiating down the arm (not a dull ache or throbbing)
- Only on one side of the body
While the initial pain of brachial neuritis can be intense and unrelenting, it usually subsides within a few days. The period of intense pain is commonly followed by numbness and/or weakness in the arm that lasts much longer than the initial pain.
The Brachial Plexus and Inflammation
The brachial plexus is an intricate network of nerves that mostly stem from the lower neck and run through the shoulder before going down the arm. Nerve roots C5, C6, C7, C8, and T1 branch from the spinal cord and feed into the brachial plexus. C5 eventually combines with C6 to form the upper trunk of the plexus, C7 continues as the middle trunk, and C8 and T1 combine to form the lower trunk.
These three trunks go on to divide into more nerves, which become bundled again (into cords) before finally branching in different directions. The numerous nerves of the brachial plexus are critical to providing sensation and movement to the shoulder, arm, hand, and fingers.
Brachial neuritis symptoms of pain, tingling, numbness, and weakness depend on the location and function of the nerves that have become inflamed, as well as the severity of the inflammation.
The Course of Brachial Neuritis
The intense pain initially associated with brachial neuritis can last anywhere from a few hours to a few weeks, or possibly longer in rare cases. A few days after brachial neuritis starts, symptoms of numbness and weakness commonly become noticeable in the arm as some muscles may look smaller due to atrophy. Strength and sensation tend to come back slowly over a period of anywhere from a few months to a few years, depending on the severity of the brachial neuritis.
The medical literature has traditionally reported that most people with brachial neuritis make a complete (or near-complete) recovery if given enough time.1 However, more recent studies suggest that about half of people who develop brachial neuritis have some weakness and/or altered sensations that continue to affect daily life.2,3
Treatment for brachial neuritis typically involves pain management in the early stages when pain is most severe. After the pain starts to subside, physical therapy may be recommended to help rehabilitate the arm’s strength and range of motion.
Brachial neuritis typically only presents once, but the condition can recur.
Causes and Risk Factors
Most estimates state that less than 3 in 100,000 people get brachial neuritis, but others suggest the actual number may be much higher due to low awareness of the condition and underreporting.4,5 Brachial neuritis most commonly occurs in people ages 20 to 60, and it tends to affect more men than women.5,6 However, the condition is poorly understood and has no known cause.
Current medical literature suggests that brachial neuritis may be caused by some type of immune or autoimmune response. Various potential triggers have been reported by brachial neuritis patients in the literature, including recent infection, recent immunization, reaction to a surgical procedure, and many other types of stresses to the body. More research is needed before the medical community can state with certainty what causes brachial neuritis.
It should also be noted that there is an extremely rare genetic form of brachial neuritis, called hereditary neuralgic amyotrophy, which has a known cause (genetic inheritance) and typically recurs on a regular basis.
When Brachial Neuritis Is Serious
While uncommon, brachial neuritis can sometimes lead to a medical emergency, such as partial or full paralysis of the arm. If a patient has severe symptoms of arm weakness and is not showing progress toward recovery after several months, sometimes surgery, such as a nerve graft or tendon transfer, is considered to help restore muscle function.