Wahba Part 1 - Foot Drop + CIDP

Question 1

Differential for unilateral foot drop

Answer 1

Common peroneal neuropathy, L5 radiculopathy, lumbosacral plexopathy, sciatic n. lateral trunk

Question 2

Differential for chronic bilateral foot drop

Answer 2

Myotonia atrophica, Charcot Marie Tooth, polyneuropathy, ALS, distal myopathy (rare)

Question 3

What’s spared with peroneal mononeuropathy?

Answer 3

Ankle inversion, plantar flexion, and ankle jerk

Question 4

Presentation of CMT1

Answer 4

Distal weakness/wasting, pes cavus, arreflexia, mild sensory loss, thick peripheral nerves

Question 5

Presentation of CMT2

Answer 5

Later onset; nerve conduction velocity relatively normal - axonal>demyelinating pathology; Dx w/ slow nerve conduction, segmental demyelination, hypertrophy

Question 6

Anatomical course of common peroneal nerve

Answer 6

L5-S3 of sciatic nerve, travels w/ tibial division - motor branch to short head of biceps femoris, sensation to lateral knee. Separates in popliteal fossa, travels around fibular head, pass thru fibular tunnel, divides into superficial+deep peroneal nerves

Question 7

Presentation for compression at fibular head

Answer 7

Lose dorsiflexion, eversion; lose sensation to anterolateral leg+dorsum of foot. Pt would have tendency to invert foot and high stepping gait

Question 8

Presentation for entrapment of deep peroneal nerve in anterior tarsal tunnel

Answer 8

Weak toe dorsiflexion, sensory loss in 1st dorsal web space, spares eversion, foot drop, high stepping gait

Question 9

Presentation for entrapment of superficial peroneal nerve at fascial exit on anterolateral leg

Answer 9

Weak eversion, sensory loss to anterolateral leg/dorsum of foot, dorsiflexion spared

Question 10

Sensory loss for L5 Root

Answer 10

BIG TOE, MORE MEDIAL

Question 11

Etiology of L5 radiculopathy

Answer 11

L4-5 disc herniation, spinal canal stenosis, prolapsed disc

Question 12

Features of L5 radiculopathy

Answer 12

Lower back pain, pain radiating down leg (sciatica), weakness in extensor hallucis longus+ankle dorsiflexors+ peroneal muscles, ankle inversion+toe flexion weak, lose big toe sensation

Question 13

S1 radiculopathy

Answer 13

Weak gastrocnemius+soleus+no ankle jerk

Question 14

Innervation of gluteus muscles and tensor fascia lata

Answer 14

Gluts medius+maximus by L5-S1; TFL by L5

Question 15

Other causes of foot drop

Answer 15

Pushing something heavy (disc herniation?), pelvic surgery (retroperiotoneal hematoma of lumbosacral plexus), cancer of pelvis, tight cast,

Question 16

Muscles innervated by tibial nerve L5

Answer 16

Paraspinals, gluteus medius, TFL, flexor digitorum longus, tibialis posterior

Question 17

3 reasons to EMG a foot drop (instead of MRI)

Answer 17

1) asymptomatic discs (I’m assuming she meant the disc may not always cause the foot drop so MRI is less helpful) 2) MRI can miss lateral disc herniation 3) Pts in which MRI is xindicated

Question 18

Interpretation of Sensory Nerve Action Potential (SNAP)

Answer 18

Slow or absent across fibular head = common peroneal head entrapment; sural-saphenous SNAP absent = sciatic (higher); Normal SNAP = lesion in root only; SNAP gone = lesion in plexus or peripheral nerve

Question 19

Causes of peroneal nerve compression @ fibular head

Answer 19

Anesthesia/surgery, prolonged hospitalization, THA?, braces/cases, leg crossing, DM, polyneuropathy, Baker’s cysts

Question 20

What to do if you see a foot drop in first 12-24 hrs

Answer 20

Do stuff! Admit to hospital, consult neuro, imaging STAT, steroids

Question 21

Chronic Inflammatory Demyelinating Polyneuropathy -“GAINS” mnemonic

Answer 21

GRADUAL progressive weaknessARREFLEXIAINCREASED CSF w/o increase cell countNERVE demyelinationSTOCKING-glove pattern

Question 22

Stepwise progression in CIDP

Answer 22

Stepwise w/ periods of plateau - symmetric prox+distal weakness (esp hip flexors), mostly motor Sx, may start focal, spares breathing muscles

Question 23

Spinal tap findings for CIDP

Answer 23

Same as MS - increased protein >45, increased IgG, oligoclonal bands

Question 24

EMG findings

Answer 24

F WAVE

Question 25

Etiologies of CIDP

Answer 25

CTD, CMV, Hodgkin’s lymphoma, hepatitis, HIV, IBS, Lyme, MS, radiculoplexopathy

Question 26

Other issues w/ CIDP

Answer 26

Heme issues (M protein spike)