Non-Traumatic Brachial Plexopathy

All that radiates…..

Disclosure

I have NO RELEVANT financial disclosures.

What’s on the menu today?

• Review common brachial plexopathies

• Discuss key history and physical examination issues which differentiate plexus from radiculopathy

• Discuss positives and pitfalls of major diagnostic studies

Brachial Plexopathy

• Brachial Plexus Neuropathy (Neuralgic amyotrophy ) (Parsonage-Turner)

• True neurogenic thoracic outlet syndrome• Diabetic cervical radiculoplexus neuropathy• Malignancy– Primary tumor– Malignant invasion– Radiation

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

Neuralgic Amyotrophy: Parsonage and Turner Syndrome

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

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

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)

Neuralgic Amyotrophy: Differential diagnosis

• Cervical radiculopathy• Brachial Plexopathy• Peripheral nerve

True Neurologic Thoracic Outlet Syndrome

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

True Neurologic TOS

• History– 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

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

• Levin 1998

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

Diabetic cervical radiculoplexus neuropathy

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

Diabetic cervical radiculoplexus neuropathy

• May precede or present simultaneously with lower extremity symptoms– Greater than 50% of patients had at least one

other body region affected (contralateral extremity, lumbosacral, thoracic)

• Often improves over 2-9 months• May recur

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

Diabetic cervical radiculoplexus neuropathy: studies

• CSF protein elevated• Pathology: ischemic injury secondary to

microvasculitis

Diabetic cervical radiculoplexus neuropathy: Differential Diagnosis

• Radiculopathy• Neuralgic amyotrophy• Peripheral nerve• CIDP• Myelopathy

Brachial Plexus and tumors

Brachial plexus and Malignancy

• Malignancy (78%)– Primary tumor– Malignant invasion

• Radiation (22%)• Kori, 1981

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

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)

• Initial pain in shoulder to medial forearm/ulnar 2 fingers, can be severe in metastatic disease

• Weakness generally follows pain • Sensory deficit in C7,C8 and T1 /medial cord

distribution

Brachial plexopathy: Malignant invasion

• Primary tumors from head and neck may invade superior plexus

• Metastasis to lymph nodes may result in patchy 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)

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

Brachial Plexopathy post radiation treatment

• Most commonly delayed after radiation; risk is for the patient’s entire lifetime (3months – 26 years)

• Risk factors include– Technique– Total dose (>6000 rads, 50-74 Gy)– Dose/fraction– Radiation volume– Time from radiation– Radiation type– Concomitant use of chemotherapy

– (Kori et al, 1981)(Stewart, 2010)(Jaeckle, 2010), (Stubblefield, MD, 2015)

Brachial Plexopathy post radiation treatment

• Rare complication: 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)

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

Case One

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

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

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

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

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

Studies

• Cervical MRI: small noncompressive central disc herniation at C56

• Ultrasound : pronator teres entrapment and median nerve entrapment at wrist

EMG/NCV 6 weeks post flare

• EMG– 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 (borderline)– Right Median mixed motor sensory prolonged

Differential Diagnosis

• Cervical Radiculopathy• Brachial Plexopathy: Neuralgic amyotrophy• Peripheral nerve lesion: anterior interrosseus

syndrome, carpal tunnel, pronator syndrome

Actual treatment

• 1 month later:– Median nerve

decompression at wrist– Median and anterior

interosseus neurolysis– 5 months later “good”

recovery of FDP, FPL

• What do you think now?

Controversy at the Rothman Institute!

• Disputed– Surgeon: pronator syndrome/anterior

interrosseus syndrome• Median nerve released at the pronator teres and carpal

tunnel and patient ultimately recovered strength

– Freedman: Neuralgic Amyotrophy• Patient would have improved with or without surgery

Acute, proximal pain, followed by weaknessPatchy examLAC involvement in addition to anterior interosseus

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