What Would You Do? EMG Cases - AANEM

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What Would You Do? EMG Cases

Benn E. Smith, M.D.

Department of Neurology

August 2015

DISCLOSURE

Relevant Financial Relationship(s)

Off Label Usage

• 57 yo. female with 2 weeks of arm soreness after collecting tickets at the US Open, holding the stubs in her hand for 8 hours, accompanied by tingling all the way down the arm and pain in the hand, wrist and elbow

• Meds: aspirin 81 mg QD, HCTZ 25 mg QD, loratadine 10 mg QD, simvastatin 10 mg QD

• PMH: migraine, HTN, hyperlipidemia,

• Exam: normal with the exception of possible weakness of the left thumb

• Labs: FBS 184 mg/dL, HbA1c 8.5, triglycerides 362 mg/dL, total cholesterol 282 mg/dL, LDL 164 mg/dL, sTSH 102.70 mIU/L

Case 1

What is your clinical impression?

6-772-578-8

The most likely diagnosis:

a. cervical radiculopathy

b. diabetic neuropathy

c. carpal tunnel syndrome

d. anterior interosseous neuropathy

e. musculoligamentous syndrome

Case 1

EMG/NCS

Case 1

Anterior Interosseous Neuropathy (and bilateral carpal tunnel syndrome)

Case 1

anterior interosseous nerve

Hickam’s Dictum

"Patients can have as many

diseases as they damn well please"

John Hickam MD Duke University 1950s

• 78 yo. male with right buttock pain getting off the table after a knee x-ray, followed a day later by easing of the buttock pain and the beginning of right leg pain and a day later right foot numbness.

• Meds: gabapentin, simvastatin, metoprolol, gemfibrozil, aspirin

• PMH: hypertension; hyperlipidemia; stroke with residual left homonymous hemianopsia; osteoarthritis; nephrolithiasis; stable pulmonary nodule since 2006

• Exam: moderately decreased light touch sensation and pinprick involving the sole of the right foot, normal strength, sensation and reflexes otherwise and flexor plantars

• Labs: glucose 116, HbA1c 6.1; Hb 12.3, with LFTs ,sTSH, SPEP: normal

Case 2

• 78 yo. male with right buttock pain getting off the table after a knee x-ray, followed a day later by easing of the buttock pain and the beginning of right leg pain and a day later right foot numbness.

• Meds: gabapentin, simvastatin, metoprolol, gemfibrozil, aspirin

• PMH: hypertension; hyperlipidemia; stroke with residual left homonymous hemianopsia; osteoarthritis; nephrolithiasis; stable pulmonary nodule since 2006

• Exam: moderately decreased light touch sensation and pinprick involving the sole of the right foot, normal strength, sensation and reflexes otherwise and flexor plantars

• Labs: glucose 116, HbA1c 6.1; Hb 12.3, with LFTs ,sTSH, SPEP: normal

Case 2

What do you think is going on?

EMG/NCS

a. lumbosacral radiculopathy

b. diabetic radiculoplexus neuropathy

c. tarsal tunnel syndrome

d. sciatic mononeuropathy

e. distal tibial mononeuropathy

EMG/NCS

Care to revise your diagnosis?

Case 2

Thoughts on localization?

EMG/NCS

Case 2

Thoughts on localization?

Case 2

Distal Tibial Mononeuropathy (associated with impaired carbohydrate metabolism)

Case 2

posterior tibial nerve

• 33-year-old RHWF always had weak ankles with frequent ankle sprains since junior high school; unable to tolerate high heels for at all, the feet hurt all the time; pins and needles sensations in the soles; on crossing her legs, there is transient numbness and tingling of the entire leg; similar symptoms happen in the upper limb when she carries her 17 month old daughter; frequent leg cramps.

• PMH: Hypertension, history of jaw surgery at age 22 for malocclusion and a receding jaw

• Meds: sertraline, nadolol

• Exam: BP normal, moderate distal symmetric quadriparesis, sensory examination normal in upper limbs. In the lower extremities there is a symmetrical distal stocking type impairment to light touch below the ankle, impairment to pinprick to the midforefoot, and absent vibratory sensation at the hallux, joint position sense is intact, 10 g filament not perceived on the dorsum of the big toe, total areflexia with reinforcement, plantar responses flexor, peripheral nerve trunks not palpably enlarged, gait normal, Romberg test negative, heel walking absent bilaterally, toe walking intact (Neuropathy Impairment Score 47)

• Labs: CBC, B12, fasting glucose, HbA1c, LFTs ,sTSH, SPEP: negative or normal

Case 3

The most likely diagnosis is:

a. familial amyloid neuropathy

b. chronic inflammatory demyelinating neuropathy

c. Charcot Marie Tooth neuropathy

d. sarcoid neuropathy

e. nitrofurantoin toxic neuropathy

Case 3

What is most likely from history and exam?

EMG/NCS

EMG/NCS uniform demyelination

Fibular/EDB motor response

Ulnar/ADM motor response

Median/APB motor response

EMG/NCS

F wave

latency

61.8 ms

F wave

latency

58.3 ms

Blink reflex

R1 latency

EMG/NCS

Case 3

Diagnosis from all information we now have?

Case 3

Charcot Marie Type 1A (with PMP22 duplication at allele 2)

• 48 yo female known to have multiple hereditary exostoses now reporting several weeks of pain and tingling on the lateral aspect of the right hand and forearm

• PMH: unremarkable

• Meds: none

• Exam: subjective decreased sensation over the right hand laterally, moderate weakness of ADM and FDI on the right side

• Labs: none performed (patient seen in Orthopedic Surgery)

Case 4

3D Reconstruction of CT Images

humeral

exostosis

a. ulnar neuropathy at the elbow

b. lower trunk brachial plexopathy

c. atypical carpal tunnel syndrome

d. radiculopathy at the C8 level

e. exostosis compressing ulnar nerve

Case 4

Diagnosis based on the clinical presentation?

EMG/NCS

d. C8 radiculopathy

e. exostosis compressing ulnar nerve

Case 4

Do the NCS and EMG help with the differential?

EMG/NCS

EMG/NCS (short segment stimulation or “inching”)

“Inching” Study (short segment stimulation)

• Perform when routine ulnar motor studies reveal an abnormality in the elbow region

• Begin at below elbow stimulation site and stimulate across elbow at 2 cm intervals

• Measure distance of each stimulation site in relation to G1 and medial epicondyle

• Graph individual traces and assess for amplitude (conduction block) or latency changes (focal slowing)

EMG/NCS (short segment stimulation or “inching”)

amplitude

reduction (partial focal motor

conduction block)

1.2 and 1.3 ms

focal slowing

d. C8 radiculopathy

e. C8 anterior primary ramus lesion

Case 4

Does that help decide what this is?

Ulnar Neuropathy at the Elbow

• Most common site of ulnar neuropathy

• Two major areas of abnormality:

• condylar groove

• cubital tunnel

• EDX studies can help with localization

Elbow Anatomy

Condylar Groove

• Ulnar nerve passes behind medial epicondyle

• Ulnar nerve vulnerable to stretch or external compression

• Felt to be more common site of injury than cubital tunnel

Cubital Tunnel Anatomy

• Aponeurosis between heads of FCU muscle form the roof

• Medial ligaments of elbow and flexor digitorum profundus muscle form floor

d. C8 radiculopathy

e. C8 anterior primary ramus lesion

Case 4

Ulnar neuropathy at the elbow (at the level of the medial epicondyle)

• 19 yo male with gradual onset of painless weakness in the right arm, followed a few weeks later by left arm weakness, trouble focusing but no diplopia or ptosis, and the head drop. At the same time he began to lose weight, dropping from 115 to 99 pounds, having to eat slowly because of arm weakness. Within a few weeks swallowing became labored. The legs then became involved. Within several weeks he could not longer shower nor brush his teeth, nor make a sandwich unassisted.

• PMH: none

• Exam: marked atrophic and flaccid bulbar, neck flexor and extensor as well as upper extremity weakness with mild to moderate scattered lower extremity weakness (Neuropathy Impairment Score 87)

• Labs: CBC, B12, fasting glucose, HbA1c, LFTs , sTSH, CK, ENA antibodies: normal; SPEP/IEP: IgM kappa MGUS; antiMAG 1:20,000; CSF protein 70 mg/dL

Case 5

a. limb girdle muscular dystrophy

b. inflammatory myopathy

c. myasthenia gravis

d. amyotrophic lateral sclerosis

e. West Nile virus poliomyelitis

Case 5

What is your clinical impression?

EMG/NCS

Case 5

How about now?

Case 5

FUS* Familial ALS RNA binding protein on 16p11

*Fused in Sarcoma

• 86 yo male with >1 year of painless difficulty with balance and walking, using a cane for 6 months, 2 falls in the last year, knocks over water glasses, some difficulty turning in bed, a little nocturnal sialorrhea

• PMH: hypertension, hypercholesterolemia

• Exam: normal mental status, severe bilateral hearing loss, normal strength, hypoesthesia of forefoot bilaterally, lower limb hyperreflexia, bilateral extensor plantars (Neuropathy Impairment Score 4), gait with slight right leg dragging, and 3-4 Hz tremor of left hand

• Labs: fasting glucose 96 mg/dL, HbA1c 6.0%, 2 hour OGTT 105 mg/dL

Case 6

Why the problems with balance?

a. peripheral polyneuropathy

b. cervical spondylotic myelopathy

c. multiple lumbosacral radiculopathies

d. extrapyramidal movement disorder

e. peripheral vestibular dysfunction

Case 6

EMG/NCS

could be peripheral

could be peripheral must be central

Vestibular Testing

Computerized Dynamic Posturography

Testing was abnormal,

results consistent with

vestibular system

dysfunction with visual

preference

Case 6

Now that we have more information…

Case 6

Sometimes it isn’t so simple!

What Would You Do? EMG Cases - AANEM

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