Brachial plexus

The brachial plexus is a complex network of nerves that conducts signals from the spine to the shoulder, arm, and hand. Damage to these nerves causes brachial plexus injury. The site and type of damage determine the outlook or prognosis of the condition. ^[1]

Types

There are four general types of neuronal injury: Avulsion is the worst wherein the nerve is torn out of the spinal cord, often injuring the cord itself thus recovery is poor. Neurotmesis is the second worst but equally poor in prognosis. There is axonal rupture with disruption of nerve sheath. Axonotmesis is axonal rupture but the nerve sheath remains intact. Here, outcome is improved. The most common form and with the best prognosis is called neuropraxia  wherein the damage is to the nerve sheath alone causing temporary conduction block. The nerves will often regain complete function spontaneously. ^[2]

Causes

The etiology of brachial plexus is multifactorial. Brachial plexus injury of newborn is due to traction or stretch injury to the shoulder during delivery. Non-birth related injuries are often caused by traumatic falls during accidents or from playing football, wrestling, or other “contact” sports.^[2]

Risk factors

For brachial plexus injury of newborn, the following are risk factors: Maternal uterine abnormalities such as bicornate uterus, maternal diabetes, macrosomia (baby is abnormally large), fetus in tranverse lie, poor fetal tone, neonatal depression, abnormal presentation during parturition, dysfunctional labor and the use of mechanical forces during labor.^[2]

Symptoms

Symptoms include loss of sensation, muscle weakness, numbness or tingling, redness, warmth or swelling, pain in the shoulder, arm, hand or finger and soreness. In serious conditions, there may be changes in consciousness level, slurred speech, paralysis, sudden and severe pain in shoulder, arm, hand or finger, visual disturbances, sudden severe headache and sudden weakness, numbness, or tingling on one side of the body.^[3]

Diagnosis

After getting history and doing a physical examination focused at large on sensory and motor functions, the patient may undergo laboratory exams such as electromyography, nerve conduction studies, Magnetic Resonance Imaging (MRI) and Computerized Tomography (CT) myelography.^[4]

Treatment

Some brachial plexus injuries heal spontaneously. Injury at birth tends to improve or recover by 3 to 4 months of age. Treatment for brachial plexus injuries includes physical therapy and, in some cases, surgery.^[5]

References:

1. http://www.ninds.nih.gov/disorders/brachial_plexus/brachial_plexus.htm
2. http://pedclerk.bsd.uchicago.edu/brachialPlexus.html
3. http://www.localhealth.com/article/brachial-plexus-injury/symptoms
4. http://www.mayoclinic.com/health/brachial-plexus-injury/DS00897/DSECTION=tests-and-diagnosis
5. http://www.ninds.nih.gov/disorders/brachial_plexus/brachial_plexus.htm