Neurology

Question 1

Seddon classification

Answer 1

Neurapraxia
Axonotmesis
Neurotmesis

Question 2

Neurapraxia

Answer 2

Bruised nerve, results in numbness that is reversible

Question 3

Axonotmesis

Answer 3

Injury to axon that results in Wallerian degeneration
Wallerian degeneration is degeneration of the axon and eventually myelin sheath
Will regenerate over several months as long as the gap is not too big

Question 4

Neurotmesis

Answer 4

Complete severance of the nerve resulting in irreversible numbness

Question 5

Sunderland’s classification

Answer 5

1st through 5th degree classification of nerve damage

Question 6

First degree

Answer 6

conduction deficit without axonal destruction

Question 7

Second degree

Answer 7

axon is severed without reaching the neural tube, Wallerian degeneration with regeneration regeneration is likely (axonotmesis)

Question 8

Third degree

Answer 8

degeneration of axon with destruction of fascicle with irregular regeneration

Question 9

Fourth degree

Answer 9

destruction of axon and fascicle and with no destruction of nerve trunk, but a neuroma-in-continuity exists

Question 10

Fifth degree

Answer 10

complete loss, neuroma is likely and spontaneous recovery is rare

Question 11

Ankle block

Answer 11

Tibial nerve
Saphenous nerve
Medial dorsal cutaneous nerve
Deep peroneal nerve
Intermediate dorsal cutaneous nerve
Sural nerve

Question 12

Hallux block

Answer 12

1st dorsal digital proper nerve
Deep peroneal nerve
1st plantar digital proper nerve
2nd plantar digital proper nerve

Question 13

Mayo block

Answer 13

Saphenous nerve
Deep peroneal nerve
Medial dorsal cutaneous nerve
Medial plantar nerve

Question 14

Popliteal block

Answer 14

Sciatic nerve (tibial nerve and common peroneal nerve
Injection given at posterior knee, 7 cm proximal and 1 cm lateral to the transverse popliteal crease
Common epineurial sheath with common peroneal and tibial nerve
Saphenous is also blocked, just distal and anterior to the medial condyle of the tibia

Question 15

Bier block

Answer 15

IV regional anesthesia
Veins, arteries and nerves run together so by injecting local anesthetic into a vein, it diffuses is to the surrounding nerves
A tourniquet is placed around the calf and in IV cannula is inserted as distal as possible
The leg is exsanguinated with elevation and an Esmarch bandage and tourniquet is inflated
Lidocaine plain is injected and the IV cannula is removed prior to operation
The block persists as long as the calf tourniquet is inflated, however effect of the block disappears shortly after deflation

Question 16

Dermatomes of the lower extremity

Answer 16

L3, L4, L5

S1, S2

Question 17

L3

Answer 17

Medial knee

Question 18

L4

Answer 18

Medial hallux
Medial ankle
Knee cap

Question 19

L5

Answer 19

Dorsal central foot
 Plantar central foot
 Anterior ankle
 Posterior heel
 Lateral calf

Question 20

S1

Answer 20

L lateral ankle and midfoot
Lateral 5th digit
Posterior lateral calf

Question 21

S2

Answer 21

Medial plantar foot
Medial heel
Posterior medial calf

Question 22

Sullivan’s sign

Answer 22

Toes adjacent to affected morton’s neuroma splay apart on weight bearing

Question 23

Mulder’s sign

Answer 23

Silent palpable click

Question 24

Joplin’s neuroma

Answer 24

A benign enlargement of the medial plantar digital nerve
Located on the plantar medial aspect of the first MPJ of the hallux
Signs and symptoms are similar to other distal focal neuropathies - parasthesias, burning pain at point of compression or entrapment
Cause is usually biomechanical (pronation, hallux limitus)

Question 25

Tarsal tunnel

Answer 25

Entrapment or compression neuropathy within tarsal tunnel beneath flexor retinaculum (laciniate ligament) Tibial nerve divides into three branches beneath the flexor retinaculum (medial plantar nerve, lateral plantar nerve, medial calcaneal nerve Tarsal tunnel syndrome is analogous to carpal tunnel syndrome in the wrist

Question 26

Borders of the tarsal tunnel

Answer 26

Medial and posterior: flexor retinaculum (laciniate ligament) Lateral: calcaneus and posterior talus Anterior: distal tibia and medial mal

Question 27

Causes of tarsal tunnel

Answer 27

``` Trauma (fracture, sprain, dislocation) Inflammatory conditions (RA, tendonitis, synovitis, diabetes) Space occupying lesions (ganglion, varicosities, lipoma, neurilemoma, edema) Biomechanical (excessive pronation - results in stretching of the tibial nerve ```

Question 28

Signs and symptoms of tarsal tunnel

Answer 28

Pins and needles, numbness, burning, shooting over entire plantar foot Symptoms are usually exacerbated by activity such as prolonged weight bearing, walking or running Intrinsic muscle atrophy with hammertoe formation is a late manifestation

Question 29

Signs and symptoms of tarsal tunnel

Answer 29

Pins and needles, numbness, burning, shooting over entire plantar foot Symptoms are usually exacerbated by activity such as prolonged weight bearing, walking or running Intrinsic muscle atrophy with hammertoe formation is a late manifestation

Question 30

Surgical treatment of tarsal tunnel

Answer 30

Longitudinal incision of flexor retinaculum Excise any space occupying lesions Do not damage medial calcaneal branch of tibial nerve Flexor retinaculum should not be sutured back after surgery

Question 31

Multiple sclerosis (MS)

Answer 31

Inflammatory disease Patchy demyelination of the CNS Diagnosis in teens to 35 Highly variable clinical course - relapsing and remitting Male to female 1:2 Motor, sensory, cerebellar or visual attacks that come on over 1-2 weeks and resolve over 4-8 weeks, sometimes do not resolve or only partially Diagnosis with MRI, spinal tap

Question 32

Amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease)

Answer 32

Progressive degenerative disease of upper motor neurons and lower motor neurons Diagnosis in 40’s Male to female 2:1 Fatal within 2-5 years Wasting, weakness, cramps, stiffness, slurred speech, symptoms begin in the hands, spread to the arms and legs Mental status is preserved

Question 33

Guillan Barre syndrome (Landry’s paralysis)

Answer 33

Acutely progressive self-limiting acquired inflammatory demyelinating polyneuropathy Rapid weakness and paralysis, can be life threatening due to breathing difficulty Ages 30-50 Spontaneous recover 1-3 weeks from onset, complete recovery takes months, can have residual foot drop Likely autoimmune cause, precipitating factors (viral infeciton, vaccination, recent surgery) Weakness begins in legs and progresses, sensory involvement may occur, muscle involvement always occurs

Question 34

Charcot-Marie-Tooth

Answer 34

Named after 3 physicians who first recognized the disease Hereditary demyelinating hypertrophic neuropathy of the PERIPHERAL nervous system Characterized by slow progressive distal muscle atrophy (especially the peroneals resulting in foot drop) Possibly sensory changes, less severe than muscle atrophy Autosomal recessive → 8 years of age When dominant → 30 years of age The earlier the onset, the poorer the prognosis

Question 35

Signs and symptoms of CMT

Answer 35

Weakness of peroneals Pes cavus ***Stork leg*** skinny legs due to peroneal atrophy Inverted champagne bottle legs Foot drop (slapping gait) Unsteady gait, tending to trip easily Stocking-glove sensory loss Decrease ankle DTR’s Hallux becomes fixed in plantarflexion late in disease state Hands may become involved Treatment is symptomatic with AFO for foot drop

Question 36

Charcot’s joint

Answer 36

Destructive arthropathy resulting from impaired pain perception and increased bone blood flow from reflex vasodilation Increased bone blood flow to bones, they become washed out and weak With impaired deep pain sensation and proprioception, small periarticular fractures go unnoticed until the entire joint is destroyed

Question 37

Friedreich’s ataxia

Answer 37

A spinal form of the hereditary sclerosis Onset in childhood or adolescence (5-15 yrs) Decreased DTRs, ataxia, pes cavus, scoliosis are common Life expectancy is limited

Question 38

EMG

Answer 38

Electromyography | Assesses the electrical activity generated by muscle fibers at rest and with activity

Question 39

Normal EMG

Answer 39

At rest, the electrical signal should be silent and with voluntary movement until potentials are roughly proportional to effort

Question 40

Denervation on EMG

Answer 40

In denervated muscles, there are fasciculations at rest With voluntary movement the number of motor units under voluntary control are decreased and the duration and amplitude of the individual potentials are increased The increase is due to collateral sprouting of axonal processes from surviving axons

Question 41

NCV

Answer 41

Nerve conduction velocity

Question 42

Purpose of NCV

Answer 42

Used to distinguish conditions involving the myelin sheath from those affecting the axon Helpful in determining the distribution of a nerve lesion, including areas of focal nerve compression (tarsal tunnel) NCVs measure the latency of motor nerve conduction, which is the time from stimulation of a nerve to the evoked muscle response

Question 43

How NCV is calculated

Answer 43

The test is performed by stimulating one point on a nerve and measuring the time taken before the muscle response The test is then repeated at a second site closer to the muscle By subtracting one time from the other, it is possible to determine the time taken for the impulse to cover the measurable distance between the two sites of stimulation The result is a rate of meters per second (mps)

Question 44

Normal NCV value

Answer 44

Normal values vary but are almost always greater than 40 mps