1. Non-Traumatic Brachial Plexopathy
All that radiates…..

2. I have NO RELEVANT financial disclosures.

3. Goals of lecture Review common brachial plexopathies
Discuss key history and physical examination issues which differentiate plexus from radiculopathy
Discuss positives and pitfalls of major diagnostic studies

4. Brachial Plexopathy
Brachial Plexus Neuropathy (Neuralgic amyotrophy ) (Parsonage-Turner)
True neurogenic thoracic outlet syndrome
Diabetic cervical radiculoplexus neuropathy
Malignancy
Primary tumor
Malignant invasion
Radiation

5. Brachial plexopathy Traumatic plexopathy Perioperative plexopathy
Stinger/burner
Hematoma/ false aneurysm
Perioperative
Stretch neck/ shoulder
Medial sternotomy
Regional anesthesia
Local shoulder surgery
Brachial plexus neuropathy

6. Neuralgic Amyotrophy: Parsonage and Turner Syndrome
History
Sudden onset of severe pain, often nocturnal, followed by weakness
Pain presents in cervical spine or shoulder blade and upper arm
Pain often diminishes or resolves after weakness develops
Often preceded by infection, trauma, vaccination, surgical intervention, stress

7. Neuralgic Amyotrophy: Parsonage and Turner Syndrome
Physical examination
Patchy findings which are not dermatomal; may be a combination of radiculopathy, brachial plexopathy and peripheral nerve abnormalities
Presentation (in order of frequency)
Upper and/or middle plexus
Frequently with long thoracic nerve involvement
Pan plexus > middle plexus/ posterior cord
Lower plexus
Anterior interosseus nerve predominant
Van Alfen, 2006

8. NA: Diagnostic studies
EMG: patchy findings of root/ plexus/ nerve
Confounding factors include comorbidites or asymptomatic electrical findings
MRI brachial plexus and shoulder
Most common abnormalities supra/infraspinatus
Acute: increase in T2 signal (muscular edema)
Subacute: T2 changes persist, atrophy may develop
Subacute to chronic: increased T1 signal due to fat infiltration
(Scalf, 2007)

9. Diagnostic studies Cervical MRI: watch for “TBU” (true but unrelated)
Major “abnormality” in 19% of asymptomatic patients
14% of patients < 40
28% of patients > 40
Milder disc narrowing or degeneration in 60% of patients > 40
(Boden, 1990)

10. Neuralgic Amyotrophy: Differential diagnosis
Cervical radiculopathy
Brachial Plexopathy
Peripheral nerve

11. True Neurologic TOS Most common cause: cervical rib/band
Elongated transverse process of C7, band arises from this C7 to upper first rib
Other etiologies include anterior scalene injury
T1 stretched >C8
Levin, 1998

12. True Neurologic TOS History Physical
Gradual onset of wasting and weakness of hand
Paresthesias of ulnar forearm and small finger
May have achiness in forearm
Physical
Thenar weakness/ atrophy> than hypothenar muscles
Flexor forearm muscles weak
Sensory loss varies, may not split ring finger

13. True Neurologic TOS: Differential diagnosis
Cervical radiculopathy (C8 or T1)
T1 results in more thenar weakness/ dermatomal findings (more T1 in APB)
C8 results in more hypothenar weakness/dermatomal findings
Peripheral nerve
Spinal cord injury
Other brachial plexopathies
Syrinx
Motor neuron disease

14. True Neurologic TOS: Studies
MRI/ Xray of cervical spine
MRI brachial plexus
Electrodiagnostic studies
Most sensitive findings: mabc snap often absent, ulnar snap low amplitude, median cmap low amplitude
mabc and median cmap share T1 innervation
Few small fibs in thenar > hypothenar musculature
*Vs median sternotomy plexopathy in which ulnar snap and ulnar cmap have lower amplitudes and and median cmap /mabc is less affected
Fibs in hypothenar>thenar musculature
Levin 1998
Not clear why median sternotomy affects C8/ulnar snap/cmap anatomically, may be from fracture of the 1st rib when ribs are spread because T1 is below the 1st rib at the level of the first rib articulation. And is less vulnerable. Good picture in levin Wilborn article.

15. Diabetic cervical radiculoplexus neuropathy (Massie, 2012)
Median age: 62 years old(32-83)
Pain initial symptom followed by subacute progression of weakness and numbness
Weakness is most common presenting complaint
Involves motor, sensory and autonomic fibres
Upper, middle and lower plexus equally involved
Greater than 50% of patients had at least one other body region affected (contralateral extremity, lumbosacral, thoracic)

16. Diabetic cervical radiculoplexus neuropathy
May precede or present simultaneously with lower extremity symptoms
Often improves over 2-9 months
May recur

17. Diabetic cervical radiculoplexus neuropathy: studies
Electrodiagnosis
Axonal neuropathy, paraspinal denervation
Snaps/cmaps decreased, ncv normal
Fibs, polys and large amplitude potentials in distribution of clinical complaints
Abnormal sensory and autonomic testing frequent
MRI reveals brachial plexus abnormality
Plexus>peripheral nerve increased T2 signal
Nerve hypertrophy>contrast enhancement
Muscle increased T2(edema) subacutely
increased T1 (fat) chronically
Blood sugars not terrible. Snaps, cmaps not terrible partly because cant check snaps and cmaps for upper trunk
Imaging and edx more widespread than clinical findings

18. Diabetic cervical radiculoplexus neuropathy: studies
CSF protein elevated
Pathology: ischemic injury secondary to microvasculitis

19. Diabetic cervical radiculoplexus neuropathy: Differential Diagnosis
Radiculopathy
Neuralgic amyotrophy
Peripheral nerve
CIDP
Myelopathy

20. Brachial plexus and Malignancy
Primary tumor
Malignant invasion
Radiation (22%)
Kori, 1981

21. Brachial plexus and tumors
Primary tumors (rarely malignant)
Primarily benign: peripheral nerve sheath tumors
Neurofibroma: Upper trunk, lateral cord
Present with pain, supraclavicular mass
Occasionally mild neurologic deficit
Schwannoma
Often arise in spinal nerves
Rare neurologic deficit
Intraneural perineurioma (rare)
Slow progressive neurologic deficit

22. Brachial Plexopathy: malignant invasion
Breast and lung (70%), followed by lymphoma
Multiple others metastasize to upper lung before spreading to plexus (sarcoma, larynx, melanoma, bladder, etc)
(Kori et al, 1981)
Initial pain in shoulder to medial forearm/ulnar 2 fingers, can be severe in metastatic disease
Followed by weakness, sensory deficit in C7,8 and T1 distribution and medial cord distribution
Most tumors drain to lateral lymph nodes that are near the divisions of the lower trunk, thus c8-t1 symptoms

23. Brachial plexopathy: Malignant invasion
Primary tumors from head and neck may invade superior plexus
Metastasis to lymph nodes may result in patch involvement of plexus, but frequently involve lower trunk due to proximity of lateral axillary lymph nodes
Significant number of patients have epidural extension of disease
(Jaeckle, 2010)

24. Pancoast syndrome Superior pulmonary sulcus tumor
Tumor at apex of lung invades lower trunk/ medial cord
Pain along medial arm
Horner’s syndrome (2/3 of patients)
Paravertebral tumor near T1, involves the sympathetic trunk or ganglia

25. Brachial Plexopathy post radiation treatment
Most commonly delayed after radiation; risk is for the patient’s entire lifetime (3months – 26 years)
Risk factors include radiation dose (>6000 rads), treatment technique and concomitant use of chemotherapy
Rare complication of a radiation-induced nerve sheath tumor of the brachial plexus (can be delayed for many years)
Radiation-induced arteritis can result in ischemia in arm and hand
(Kori et al, 1981)(Stewart, 2010)(Jaeckle, 2010)

26. Brachial plexopathy post radiation
Most patients have sensory and motor abnormalities
Edema in arm possible, but also seen with metastasis
Presents with pain less commonly(18%) but can be severe and can develop later (65%) (Kori, 1981)
Distribution is most commonly in upper trunk and less common “pan plexus”
Horner’s syndrome less common than in direct metastatic spread
14% with radiation vs 56% with metastasis (Kori, 1981)
Can be progressive

27. Studies Radiation plexopathy:
Emg reveals fasciculations, myokymia, axonal damage
MRI/ CT scan chest and brachial plexus may need to repeated in 4-6 weeks if mass not seen
MRI cervical and thoracic spine if epidural spread a consideration
PET scan

28. Case 1 53 year old female 1-2 years of numbness in right arm
6 weeks ago patient wakes up with severe pain in the right upper extremity
Like a blood pressure cuff in upper arm radiating to the shoulder blade, no change in numbness

29. Case 1 3 days later patient receives cervical epidural.
3 days later patient notes weakness in right hand
1 week later patient has pronator teres injection and pain improves although no change in weakness or numbness

30. Case 1
At time of evaluation (6 weeks after onset of symptoms), no pain in cervical spine or upper extremity
Arm is stiff from elbow to hand
No change in numbness in right hand

31. Physical examination Cervical and shoulder mobility full
4/5 shoulder abductors, external rotators
4/5 abductor pollicis brevis
0/5 flexor digitorum profundus (median distribution) flexor pollicis longus
DTR biceps 1/ 4 bilaterally
Sensation decreased over distal volar thumb

32. Studies
Cervical MRI: small noncompressive central disc herniation at C56
Ultrasound : pronator teres entrapment and median nerve entrapment at wrist

33. EMG/NCV 6 weeks post flare
Median FDP and FPL spontaneous activity
FDP repetitive fire
FPL no voluntary potentials
APB normal, as is rest of screen
NCV
Decreased amplitude right LAC
Right Median mixed motor sensory prolonged

34. Actual treatment 1 month later: What do you think now?
Median nerve decompression at wrist
Median and anterior interosseus neurolysis
5 months later “good” recovery of FDP, FPL
What do you think now?

35. Original case Disputed
Surgeon says pronator syndrome/anterior interrosseus syndrome
Median nerve released at the pronator teres and carpal tunnel and patient ultimately improved
I say Neuralgic Amyotrophy
Patient would have improved with or without surgery
Acute, proximal pain
Patchy exam
LAC involvement in addition to anterior interosseus

36. Conclusions History and physical is critical
MRI/EDX may help to confirm diagnosis or be a trap
Diagnosis can not be made in isolation of the history and physical