CC May 2017 Radial nerve mononeuropathy

echoecho's version from 2017-07-04 19:23


Question Answer
***What is the most common form of nerve injury resulting from fracture of a long bone?radial nerve palsy, or mononeuropathy
Because the radial nerve travels through the radial groove on the lateral aspect of the distal humerus, what could happen?1) making the radial nerve subject to partial or complete transection 2) contusion or entrapment in association with a distal humeral fracture
Radial nerve palsy occurs in 2-17% of humeral fracture and may be ____ or _____ in nature?1) primary 2) secondary
Give an example of primary injury?occurs at the time of injury
Give an example of secondary injury?results from surgical repair / stabilization or as a result of healing (i.e. entrapment in a bony callus)
When should primary radial nerve injury be suspected?both with a hx of distal humeral fractural and on clinical grounds
Why is radial nerve injury difficult to differentiate from a C7 root injury?because both may present with wrist and hand weakness
How can one differentiate between a radial nerve injury and a C7 root injury?on clinical grounds (C7 root injury causes radiculopathy that leads to weakness of the shoulder and hand muscles) (radial nerve injury does not lead to weakness of shoulder and hand muscles)
Which injury (radial nerve injury vs. C7 root injury) leads to numbness of the dorsum of the hand between the thumb and first finger? leads to numbness of the 3rd finger?1) radial nerve injury 2) C7 radiculopathy
Which injury (radial nerve injury vs. C7 root injury) leads to brachioradialis hypoflexia?radial nerve injury
*** If an acute radial nerve injury is suspected in the context of a fractured distal humerus, what should be considered? why?1) surgical exploration 2) to help identify the extent of nerve injury and allow surgical repair if indicated
What is a result of failure to repair a transected nerve?led to long-term nerve dysfunction
In the absence of clinical signs of C7 radiculopathy / spinal cord injury, what imaging is not indicated in the acute evaluation?MRI
List the imaging studies that may be considered in secondary cases of suspected radial nerve palsy that develop after the initial injury?1) ultrasound 2) EMG/NCV 3) peripheral nerve MRI
What should diagnostic testing be based on? What should diagnostic testing focus on?1) clinical exam 2) focus on nerve, plexus, suspected nerve root injury
Although EMG/NCV testing is often considered the gold standard for nerve evaluation, findings may NOT become positive for 3-4 weeks due to what?Wallerian degeneration (due to gradual degeneration of nerve along the axon that progresses from the site of injury away from the cell body
What is the cause of isolated radial nerve palsies in the newborn?intrauterine pressure on the radial nerve
Compared to neonatal cervical nerve root injuries, prognosis for newborn radial nerve injuries is often favorable with _______ _______ common?complete resolution
*** SUMMARY = What may result in radial nerve injury?distal fracture of the humerus
*** SUMMARY = Radial nerve injury must be distinguished from _____ weakness due to cervical spine (C7 root) injury?hand
*** SUMMARY = Prompt surgical evaluation can prevent what?chronic neurological deficits