A 3 year old girl presented with a 4 week history of foot pain. The pain was initially thought to be intermittent and was particularly bothersome at bedtime. She became increasingly irritable. Her gait became abnormal 1–2 weeks prior to presentation, as she began to walk with both feet inverted which had been attributed to increasing foot pain. She also began falling more frequently. On the day of presentation and hospitalization, she refused to walk and appeared unable to bear weight on her legs. No bowel or bladder incontinence was noted. Her medical history was otherwise unremarkable. Birth history and neurodevelopmental history had been unremarkable.

Physical examination noted an alert but irritable girl. Height was 50th percentile and weight was 50th percentile. General medical examination was unremarkable. Cranial nerve examination was unremarkable. Muscle bulk was intact. Muscle strength testing revealed proximal and distal weakness of her upper and lower extremities. When placed in a standing position she could bear weight on her legs (with knees locked) but was unable to take any steps. She complained of back pain when standing. Deep tendon reflexes were reduced to absent in the upper and lower extremities. Plantar responses were flexor, bilaterally. Sensory testing showed decreased response to tickle and pin-prick. No sensory level was noted.

Serum CK was 48 U/L (normal <175 U/L).

Nerve conduction studies provided electrophysiological evidence for a sensorimotor polyneuropathy with demyelinating features (Table 25.2). The waveforms for the left median nerve and tibial nerve motor conduction studies revealed delayed distal onset latencies as well as temporal dispersion (Fig. 25.2). Late responses (F-responses, H-reflex) were not performed given low CMAP amplitudes observed. Left median and tibial motor CMAPs showed temporal dispersion (Fig. 25.2 above).

Additional testing included the following:

Lumbar puncture revealed CSF leukocytes 1/hpf (normal <5), CSF erythrocytes 0/hpf, CSF protein 1.07 g/L (normal 0.15–0.6 g/L) and CSF glucose 3.7 mmol/L (normal 2.0–4.4 mmol/L).

MRI of the spine revealed nerve root enhancement.

Given the clinical, electrophysiological and biochemical evidence she was diagnosed with Guillain-Barré syndrome (see Chap. 18). She was treated with intravenous immunoglobulin (IVIG) 1 g/kg for each of two consecutive days. She demonstrated signs of clinical recovery within days and was able to walk cautiously 7 days later. Her physical examination was entirely normal when re-examined 4 months later.

After undergoing cardiac surgery, a 10-year-old boy awoke complaining of numbness of the plantar and dorsal surfaces of his left foot. He also had weakness of his left lower extremity.

Physical exam of his left leg on post-operative day #1 noted: gluteus maximus 5, gluteus medius 5, hamstrings 5, tibialis anterior 1, peroneus longus 1, gastrocnemius 1, tibialis posterior 1, extensor halluces longus 1. Left patellar reflex 2+, left ankle reflex was absent. Sensation was reduced over the left tibial and peroneal distributions; however, sensation was intact over the left saphenous distribution. MRI brain was performed due to post-operative concern of potential ischemic brain injury. However, brain imaging was entirely normal.

He showed improvement in his symptoms during the 4 weeks between his cardiac surgery and his presentation for electrophysiological testing. He was now able to walk and bear weight on his left leg; however, he noted persistent weakness. He states that when he touches his left foot this sensation has improved. He notes markedly decreased sensation to the left plantar surface of the foot; however, he states that sensation over the left dorsal surface of the foot has improved.

On physical examination 1 month after the surgery, he was noted to be an alert and well-appearing boy. Height was 90%ile and weight 70%ile. Cranial nerves were intact. Muscle strength of his left leg was as follows (according to the Medical Research Council scale): gluteus maximus 5, gluteus medius 5, hip flexors 5, adductors 5, hamstrings 4, tibialis anterior 4+, tibialis posterior 4, peroneus longus 4+, gastrocnemius 3, EHL 4, toe flexors 4-. Mild atrophy was noted to his left EDB and left gastrocnemius. Strength testing of right leg was normal. Deep tendon reflexes were graded as 2+ at the patellae bilaterally, 2+ at the right ankle, and 0 at the left ankle. Sensation was decreased over the sole of the left foot in the tibial nerve distribution. However, sensation appeared intact over the saphenous and common peroneal distributions. He was able to walk with no discernable foot drop. He could not rise up on his heels on the left side. He also was unable to do a toe raise when standing on his left foot alone. Neurophysiological testing 1 month after surgery revealed the following (Table 25.3).

Neurophysiological testing, specifically the pattern of abnormality on needle EMG, provided evidence for a left sciatic neuropathy. Given his clinical improvement, a large proportion of the injury was attributed to neurapraxia; however, his mild persistent weakness and evidence of denervation in sciatic-innervated muscles also indicated some degree of axontnesis. The intact superficial peroneal and sural SNAP amplitudes as well as the intact common peroneal nerve (EDB) and tibial (AH) CMAP amplitudes also suggest that axontmesis was a relatively minor component of the overall injury.

The lack of clinical or electrographic changes in the left gluteus medius (L5-root, superior gluteal nerve innervated muscles) or left paraspinal muscles (L5-root) were helpful for excluding the possibility of a left lumbosacral or nerve root injury.

Clinical re-examination 6 months post-operatively demonstrated full recovery.

A 9-year-old boy was evaluated for coordination problems and frequent falling. His parent noted him to have ‘always been clumsy’. However, over the past 1–2 years it has become more evident. Over the past few months he had fallen three times in the shower, bringing the curtain down with him when he fell. He has done well academically. He has had increasing problems keeping up with his peers in sports, particularly skating. He reports no paresthesiae or pain. No weakness was reported; he can run up a set of stairs or climb up one foot per step. His parents had noted subtle voice changes; he has been noted to speak more slowly and hesitantly. Past medical history was otherwise unremarkable. His neurodevelopment was appropriate. He was on no regular medication. Family history was unremarkable.

Physical examination noted a boy with height at 25th percentile and weight at 50th percentile. General medical exam was notable for slight pes cavus and early hammertoeing. Cranial nerve examination was notable only for mild dysarthria. Muscle strength testing was entirely normal. Complete areflexia was evident. Plantar responses were extensor, bilaterally. Heel contractures were noted; with his knees straight his ankles could be passively dorsiflexed to neutral position only. Sensory testing confirmed decreased vibration sense at both toes. Proprioception was diminished. Cold and fine touch was intact. He demonstrated sensory ataxia, with difficulty touching his nose with his eyes closed. The Romberg test was positive; he swayed considerably. He could not perform a tandem gait. He could not stand on one leg (either side).

Nerve conduction studies demonstrated electrophysiological evidence for a severe sensory neuropathy or ganglionopathy (Table 25.4).