Mononeuropathies: A Practical Approach to Diagnosis and Treatment

Dr. Simran Singh Basi MD, FRCPC, CSCN Diplomate (EMG) February 28, 2018 Faculty/Presenter Disclosure

• Faculty: Dr. Simran Singh Basi • Relationships with commercial interests: – Grants: Allergan Inc. – Consulting Agreement: Allergan Inc. Disclosure of Commercial Support

• Allergan Inc. (unrestricted educational grant) • Allergan Inc. (spasticity consulting agreement)

This presentation has not received financial support from Allergan Inc. nor will any of the treatments discussed deal with Allergan Inc. products. Mitigating Potential Bias

• The information in this presentation is based on recent information that is peer reviewed and all the recommendations involving clinical are based on evidence that is accepted within the profession; and all scientific research referred to, reported or used in the presentation in support or justification of patient care recommendations conforms to the generally accepted standards. Objectives

• Formulate a differential diagnosis for common mononeuropathies • Understand the basics of electrodiagnostic testing • Rationalize an approach to treatment Agenda

• General Approach to Neuromuscular Disorders • Median Mononeuropathy • Ulnar Mononeuropathy • Radial Mononeuropathy • Peroneal Mononeuropathy General DDx for Mononeuropathies

• UMN – Brain – Spinal Cord • LMN – Motor or Sensory Neuronopathy – – – – Mononeuropathy – NMJ – Myopathy Electrodiagnostic Testing

• Nerve Conduction Studies – Demyelination – Axonopathy • Needle – Muscle patterns • Neuropathic • NMJ • Myopathic

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• 30 yo M with 3 month history of right hand and mild weakness. Works as a mechanic. Difficulty sleeping at night time due to hand symptoms that awaken him from sleep. Otherwise healthy. Entrapment Points: • Ligament of Struthers (ligament connecting bone spur to medial epicondyle) • Lacertus Fibrosis (Bicipital aponeurosis thickening attaching biceps to radius bone) • Sublimis Ridge or Pronator Teres (FDS fascia or two heads of pronator teres) • AIN Syndrome • Carpal Tunnel Carpal Tunnel Contents: – FDS (4 tendons) – FDP (4 tendons) – FPL – Median Nerve Causes of CTS: (if non-dominant hand most involved, likely not idiopathic) – Idiopathic (repetitive activity, occupational) (female, dominant hand) – Tunnel Volume Changes: • Hypothyroid • DM2 • Renal Failure • Mass (Tumor, Hematoma) • Pregnancy • Bony Changes: Fracture (Colles), OA • RA tenosynovitis • CHF • Amyloidosis

CTS

Classification: • Mild CTS: Sensory abnormality • Moderate CTS: Sensory + Motor abnormality • Severe CTS: Sensory + Motor + Muscle Atrophy

DDx CTS

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – C6/C7 Radiculopathy • Neck pain, abnormal reflexes (biceps, brachioradialis, triceps) – Brachial Plexopathy (Upper/Middle Trunk, Lateral Cord) • Widespread Motor and Sensory abnormality – Proximal Median Nerve Lesion • Palmar Cutaneous Affected • Proximal median nerve muscles affected

EDx Role in CTS

• Assess DDx • Classify Severity of CTS – Mild: sensory nerves only – Moderate: motor + sensory nerves – Severe: EMG changes in median nerve palm muscles CTS Rx

1. Education: avoid wrist flexion/repetitive activities if possible 2. Modify work environment + proper ergonomics 3. Resting Wrist-Hand Orthosis qhs with 0-5 deg of wrist extension (MILD CTS) 4. Pharmacologic: - NSAIDs, diuretics, thyroid replacement - CSI into carpal tunnel (MODERATE CTS) + still use wrist splint 5. : Release of transverse carpal ligament (SEVERE CTS or failed non-surgical) Case 2

• 40 yo M with 3 month history of right hand weakness and numbness of digits 4&5. Dropping objects due to weakness.

Entrapment Points: (from proximal to distal) • Arcade of Struthers (fascial band connecting brachialis to triceps) • Ulnar Groove – proximal to medial epicondyle • Cubital Tunnel Syndrome – distal to medial epicondyle • Guyon’s Canal at the (UNE) a) Ulnar Groove (located just proximal to medial epicondyle) b) Cubital Tunnel Syndrome (bordered by medial epicondyle, olecranon and overlying FCU aponeurosis) ~ 3 cm distal to medial epicondyle

UNE

• Causes: • Chronic Mechanical Compression • Ganglion • Tumor • Excessive cubital valgus angulation • Accessory muscle (anconeous epitrochlearis)

DDx in UNE

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – Motor Neuron • No sensory symptoms – C8/T1 Radiculopathy • Neck pain with radicular features – Brachial Plexopathy (Lower Trunk, Medial Cord) • Weak hand muscles • Abnormal MABC (medial antebrachial cutaneous nerve) – Distal Ulnar Nerve Lesion (ulnar neuropathy at wrist) • Normal DUC and PUC

EDx Role in UNE

• Assess DDx • Localize entrapment site with inching studies • Characterize pathology – Demyelinating – Axonopathy Next Steps

• or MRI of elbow to look for causative pathology UNE Rx

1. Education: • Ulnar nerve hygiene practices • Avoid leaning on elbow • Avoid excessive elbow flexion for prolonged period • Cubital tunnel splint or pediatric zimmer splint or a towel around elbow qhs 2. Hand-Finger Orthosis if hand develops 3. Surgical Ulnar Nerve Transposition or Nerve Release/Decompression

Case 3

• 30 yo M with 1 week history of . Patient was recently out of the country with his wife for their honeymoon. Radial Nerve Entrapment Sites: (proximal to distal) • Palsy (can also affect axillary and ) • Spiral Groove • (intramuscular septum between Brachialis and BR) – NO weakness - just pain • PIN lesion/ Arcade of Frohse/ Supinator Syndrome (connective tissue of Supinator) • Wartenberg Syndrome (superficial radial nerve palsy) DDx in Wrist Drop

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – C6/C7 Radiculopathy • Neck pain, abnormal Triceps reflex – Brachial Plexopathy (Middle Trunk, Posterior Cord) • Weak muscles • Weak Thoracodorsal Nerve muscle (latissimus dorsi) – Radial Nerve Lesion • Spiral Groove • PIN lesion

EDx Role in Wrist Drop

• Assess DDx • Localize level of radial nerve lesion • Characterize Pathology – Demyelinating – Axonopathy

Radial Nerve at Spiral Groove

• Caused by: – Compression – #

• Clinical: – Weakness and paresthesias in radial nerve below spiral groove (Triceps, Anconeus, Posterior cutaneous nerve of arm OK) – Paresthesias in lateral arm, posterior and superficial radial sensory nerve to dorsal lateral hand Q:

• How does wrist drop differ if spiral groove lesion vs PIN lesion? A:

• In PIN lesion, ECRL/ECRB preserved so will get some wrist extension laterally whereas spiral groove lesion has no wrist extension at all. Next Steps

• U/S or MRI to look for compressive lesion at spiral groove Rx of at Spiral Groove • 1. Education • 2. Physiotherapy for wrist extensor strengthening • 3. Wrist-Hand-Finger Orthosis • 4. Pain medication • 5. Surgical Intervention Case 4

• 40 yo male gardener with 4 weeks history of right foot drop. He is otherwise well. Unremarkable past medical history, no medications, unremarkable family history. DDx Foot Drop

• UMN: – CNS lesion (seizure, migraine, TIA/stroke of lateral thalamus + internal capsule) • UMN signs • LMN – L5 Radiculopathy • Back pain, abnormal hamstring reflex • Weak foot inversion, weak abductors – Lumbosacral Plexopathy • Widespread motor and sensory abnormality – • Weak foot inversion, normal abductors – Common Peroneal Nerve • Lateral cutaneous nerve of the knee • Weak eversion – Deep Peroneal Nerve • Normal eversion – Polyneuropathy • ex. CMT – Tibialis Anterior Pathology • No sensory abnormality Peroneal Nerve Course: – Lateral Cutaneous Nerve of Knee (comes from common peroneal before it splits into superficial and deep) – provides sensation to lateral knee – Superficial Peroneal Branch – Deep Peroneal Branch EDx Role in Foot Drop

• Assess DDx • Localize Peroneal Nerve lesion • Characterize Pathology – Demyelinating – Axonal Loss Common Peroneal Neuropathy

• FIBULAR NECK most common site of nerve injury: – Trauma (fibular #) – Stretch (forcible ankle inversion) – Compression at fibular head: • 1. Cast • 2. Stockings • 3. Improper position during surgery – Occupational: • 1. Gardening • 2. Farmwork (squatting, kneeling) “Strawberry Picker’s Palsy” – Entrapment at Fibular Tunnel (between fibula and peroneus longus) – Mass Lesion (ganglia, tumors, Baker’s Cyst) – Miscellaneous (weight loss, habitual leg crossing, DM2)

Next Steps

• U/S or MRI to look for nerve irritation/mass lesion

Common Peroneal Neuropathy Rx

1. Education: avoid leg crossing, repetitive squatting 2. Lateral Knee padding 3. Ankle-Foot-Orthosis (posterior leaf spring) 4. Neuropathic Pain Medication 5. CSI 6. Surgical Intervention

Thank You!

http://www.bing.com/images/search?view=detailV2&ccid=Y3GeBXNG&id=CD876D79BB737136F1980FEE7A72455B8FB05928&q=carpal+tunnel+syndrome+humor&simid=608028797659712487&selectedIndex=11 References

• Baima, J and L. Krivickas. Evaluation and treatment of peroneal neuropathy. Curr Rev Musculoskeletal Med. 2008 Jun; 1(2): 147-153. • Braddam RL. Physical Medicine and Rehabilitation 4th Edition. Elsevier Saunders. 2011. p. 171-257. • Caliandro, P, La Torre G, Padua R, Giannini F and L. Padua. Treatment of ulnar neuropathy at the elbow (UNE). Cochrane Library. November 15, 2016. • Cuccurullo SJ. Physical Medicine and Rehabilitation Board Review 3rd Edition. Demos Medical Publishing. 2015. p. 341-471. • Kothari MJ. Treatment of carpal tunnel syndrome. http://www.uptodate.com/home. • Lifchez S, Dzwierzynski and J. Sanger. Compression neuropathy of the radial nerve due to ganglion cysts. Hand. 2008 Jun; 3(2): 152-154. • Preston D and B. Shapiro. Electromyography and Neuromuscular Disorders 3rd Edition. Elsevier Saunders. 2013. p. 267-357. • Russell SM. Examination of Peripheral Nerve . Thieme. 2006. p. 1-108.