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An Elderly Woman with Foot Drop and Hand Weakness
Case 61
An Elderly Woman with Foot Drop and Hand Weakness
A 76-year-old woman presented several days after a sudden onset of left foot drop that occurred immediately after a fall. She also complained of anorexia, weight loss, malaise, and numbness in both lower extremities for several weeks. Past medical history was positive for coronary artery disease, carotid endarterectomy, aortic valve stenosis with valve replacement, hypertension, and hyperlipidemia. Medications included atenolol, hydrochlorothiazide, amlodipine, thyroid supplement, and aspirin. She was referred for an EMG. General physical examination was normal. On neurologic examination, strength was intact except for mild weakness in both hands and toe dorsiflexors on the right, and she could not dorsiflex the left foot and toes or evert the left foot. Reflexes were absent in the ankles, trace at the knees, and normal in the arms. She had absent vibration sense in the toes and ankles and decreased pinprick,
temperature, and touch sensations in both lower extremities in a stocking distribution up to the calf. There was mildly decreased vibration sense and two-point discrimination in the fingers. The rest of the examination was normal.
WHAT IS THE DIFFERENTIAL DIAGNOSIS? Clinically, this patient had a polyneuropathy with a superimposed left peroneal neuropathy. It was not completely clear if peroneal palsy was caused by stretch trauma from the fall or was spontaneous and caused the fall. The differential diagnosis included a diabetic polyneuropathy. Other causes of neuropathy were also considered, including a polyneuropathy from a microangiopathic vasculitis. She could also have had a polyneuropathy with an L5 radiculopathy, plexopathy, or a sciatic nerve lesion.
AN EMG TEST WAS PERFORMED Motor Nerve Studies
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve L.
Normal £ 5.7
Normal ≥3
NR NR NR
Ankle Fibular head Knee Peroneal Nerve L.* Fibular head Knee
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Normal ≥ 40
Tibial Nerve L.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
NR NR NR
— NR NR
Ankle Pop. fossa
NR NR
NR NR
— NR
Normal £ 5.2
Normal ≥3
Normal ≥ 40
Peroneal Nerve R.
Normal £ 5.7
Normal ≥3
Normal ≥ 40
3.3 6.0
0.8 0.7
— 37
6.6 15.2 18.3
0.3 0.2 0.2
— 31 32
Ankle Fibular head Knee
*Recorded at the tibialis anterior muscle with needle electrode.
393
394
Case 61
Motor Nerve Studies—cont’d
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve R.*
Normal £ 5.2
Normal ≥3
Normal ≥ 40
3.1 5.3
7 6
— 45
Tibial Nerve R.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
Ankle Pop. fossa
4.6 14.4
1.1 0.3
— 36
Median Nerve R.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.2 9.0
2 1
— 44
Normal £ 3.6
Normal ≥8
Normal ≥ 50
3.2 6.7 9.1
2 1 1
— 44 50
Fibular head Knee
Wrist Elbow Ulnar Nerve R. Wrist Below elbow Above elbow
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Median Nerve L.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.0 8.4
16 15
— 45
Wrist Elbow
F-wave and Tibial H-reflex Studies Nerve Peroneal nerve L. Tibial nerve L. Peroneal nerve R. Tibial nerve R. Median nerve R. Ulnar nerve R. Median nerve L. H-reflex L. H-reflex R.
Latency (ms)
Normal Latency £ (ms)
NR NR NR NR 28.3 29.3 28.0 NR NR
54 54 54 54 30 30 30 34 34
Sensory Nerve Studies
*Recorded at tibialis anterior muscle.
Superficial peroneal nerve R. — Absent Sural nerve R. — Absent
EMG Data Muscle
Insrt Activity
Fibs
Pos Waves
Fasc
Amp
Dur
Poly
Pattern
Biceps brachii R. Triceps R. Brachioradialis R. 1st dorsal interosseous R. Abductor pollicis brevis R. Tibialis anterior R. Gastrocnemius R. Vastus lateralis R. Rectus femoris R. Lumbar paraspinals L. Gluteus medius L. Tensor fasciae latae L. Biceps femoris (long head) Biceps femoris (short head) Vastus lateralis L. Tibialis anterior L. Peroneus longus L. Gastrocnemius L.
Norm Norm Norm Inc Norm Inc Inc Norm Norm Norm Norm Norm Norm Norm Norm Inc Inc Inc
None None None None None 2+ None None None None None None None None None 4+ 4+ None
None None None 1+ None 2+ 2+ None None None None None None None None 4+ 4+ 1+
None None None None None None None None None None None None None None None None None None
Norm Norm Norm Lg Lg Lg Lg Norm Norm Norm Norm Norm Norm Norm Norm Lg Lg Lg
Norm Norm Norm Inc Inc Inc Inc Norm Norm Norm Norm Norm Norm Norm Norm Inc Inc Inc
None None None None None None None None None None None None None None None None None None
Full Full Full Red Full Red Red Full Full Full Full Full Full Full Full Red Red Red
395
An Elderly Woman with Foot Drop and Hand Weakness
WHAT WERE THE EMG FINDINGS? This test demonstrated an absent left tibial CMAP and peroneal CMAP when recording at the extensor digitorum brevis muscle, and low-amplitude CMAP when recording at the tibialis anterior muscle. The nerve conduction velocity was mildly slow across the fibular head. The right peroneal and tibial nerves had low-amplitude CMAPs and decreased conduction velocities. The median and tibial nerves had decreased CMAP amplitudes and velocities. F-responses were prolonged, except for the left peroneal and tibial nerves in which they were absent. SNAPs were absent in both sural and superficial peroneal nerves. The right median SNAP was normal, while the left had a prolonged latency and low amplitude. Needle EMG showed denervation potentials in the left tibialis anterior and peroneus longus with reduced motor unit recruitment. There was also mild denervation on the right tibialis anterior and both gastrocnemius and first dorsal interosseous; other muscles were normal. It was concluded that the patient had a predominantly axonal sensory and motor polyneuropathy with secondary demyelination affecting mainly the lower extremities with more severe involvement of the left peroneal nerve. The lack of denervation in the other L5, or paraspinal muscles argued against a radiculopathy. The normal hamstring muscles, particularly the short head of the biceps, was against a sciatic neuropathy.
THE FOLLOWING LABORATORY STUDIES WERE DONE
hormone was elevated at 47.4 µV/mL (normal, 0.35–5.50 µV/mL) and glucose was 200 mg/dL. Lipid profile showed mild hyperlipidemia. Erythrocyte sedimentation rate (ESR) was 85 mm/hour; fluorescent antinuclear antibody was negative. CT scans of the chest and abdomen were normal. Her symptoms improved with physical therapy and fluid restriction. Her thyroid supplement was adjusted. She was diagnosed with diabetic neuropathy, with hypothyroidism as a possible contributing factor, and a peroneal palsy.
FOLLOW-UP She was referred for neurologic evaluation 2 months later because of acute onset of hand weakness in the right, more than the left. General physical examination was unremarkable except for mottling bluish discoloration of fingers and feet. Strength was 2/5 in the right wrist and finger extensors, 3/5 in the left hand; hand flexion was 4/5, finger flexion was 4/5, and hand muscles were 4−/5. In addition there was a left foot drop (Fig. 61-1). She had mild right foot dorsiflexion weakness. Motor examination was otherwise normal. Reflexes were 1 to 2+ in the left upper extremity, 0 in the right brachioradialis and biceps, and 1+ in the triceps. Knee and ankle reflexes were absent. She had absent vibration sense in feet, ankles, and fingers. Pinprick, touch, and temperature sensations were decreased to the mid-calf, left forearm, and right elbow. The rest of the examination was normal.
Electrolytes were normal except for a sodium of 126 mg/dL (normal, 135–155 mg/dL). Thyroid-stimulating
A SECOND EMG TEST WAS PERFORMED Motor Nerve Studies
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve L.
Normal £ 5.7
Normal ≥3
NR NR
Ankle Fibular head Peroneal Nerve L.* Fibular head Knee
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Normal ≥ 40
Tibial Nerve L.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
NR NR
— NR
Ankle Pop. fossa
5.3 14.9
2 1
— 37
Normal £ 5.2
Normal ≥3
Normal ≥ 40
Peroneal Nerve R.
Normal £ 5.7
Normal ≥3
Normal ≥ 40
13.1 16.5
1 1
— 36
5.7 12.8
1 1
— 36
*Recorded at tibialis anterior muscle.
Ankle Fibular head
396
Case 61
Motor Nerve Studies—cont’d
F-wave and Tibial H-reflex Studies
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Median Nerve R.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
6.3 13.0
0.1 0.0
— 33
Normal £ 3.6
Normal ≥8
Normal ≥ 50
8.1 NR
0.0 NR
— —
Wrist Elbow Ulnar Nerve R. Wrist Below elbow Radial Nerve R.
NR
NR
NR
Median Nerve L.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.2 13.1
2.4 0.1
— 23
Normal £ 3.6
Normal ≥8
Normal ≥ 50
Wrist Below elbow Above elbow Axilla
3.8 8.8 12.9 14.8
2.8 2.2 0.0 0.0
— 42 29 47
Radial Nerve L.
NR
NR
NR
Wrist Elbow Ulnar Nerve L.
Nerve
Latency (ms)
Normal Latency £ (ms)
NR NR NR NR NR NR
54 30 30 30 30 34
Peroneal nerve R. Median nerve R. Ulnar nerve R. Median nerve L. Ulnar nerve L. H-reflex R.
Sensory Nerve Studies
Nerve Median nerve R. Ulnar nerve R. Radial nerve R.
Latency (ms)
Normal Latency £ (ms)
Amp (mV)
Normal Amp ≥ (mV)
NR NR NR
3.1 3.1 3.1
NR NR NR
20 13 30
EMG Data Muscle
Insrt Activity
Fibs
Pos Waves
Fasc
Amp
Dur
Poly
Pattern
Deltoid L. Biceps brachii L. Extensor digitorum com. L. 1st dorsal interosseous L. Extensor carpi radialis L. Extensor digitorum com. L. Tibialis anterior L. Gastrocnemius L. Deltoid R. Biceps brachii R. Extensor digitorum com. R. Flexor carpi radialis R. Flexor carpi ulnaris R. 1st dorsal interosseous R.
Norm Norm Norm Inc Norm Inc Inc Inc Norm Norm Inc Inc Inc Inc
None None None 3+ None 2+ 2+ 2+ None None 2+ 1+ 2+ 2+
None None None 3+ None 2+ 2+ 2+ None None 2+ 1+ 2+ 2+
None None None None None None None None None None None None None None
Lg Norm Lg Lg Lg Lg Absent Lg Lg Lg Lg Lg Lg Lg
Inc Norm Inc Inc Inc Inc — Inc Inc Inc Inc Inc Inc Inc
None None None None None None — None None None None None None None
Red Red Full Red Red Red Absent Red Red Red Red Red Red Red
WHAT WERE THE EMG FINDINGS? This test showed interval worsening of the neuropathy with conduction blocks, most prominent in the left ulnar and median nerves (Fig. 61-2), and absent bilateral peroneal CMAPs. There was also diffuse denervation in both legs, as well as in the right median, radial, and ulnar innervated muscles.
In summary, the test showed a severe asymmetric polyneuropathy with both axonal degeneration and demyelinating features with conduction blocks, consistent with mononeuritis multiplex. Laboratory studies revealed normal chemistries, except for sodium 133 mg/dL and albumin 3 mg/dL. ESR was 105 mm/hour (normal, <0–20 mm/hour); FANA and HIV were negative. circulating antineutrophil cytoplasmic anti-
397
An Elderly Woman with Foot Drop and Hand Weakness
10 ms
A
A 1
271V 500 uV
A 2
398V 500uV
FIGURE 61-2 Left median nerve CMAP obtained with wrist stimulation (above), and during elbow stimulation (below); notice conduction block (500 mV/10 ms).
B
FIGURE 61-3 Sural nerve biopsy showing a vessel with inflammatory infiltrates embedded in the vessel wall; there is also fibrinoid necrosis (H&E stain, ×200).
C FIGURE 61-1 A, Discoloration of the fingers and right thenar atrophy in this patient. B, Right wrist drop; notice atrophy of the first dorsal interosseous muscle. C, Left foot drop and also bluish mottling discoloration of the skin.
bodies (C-ANCA) IgG index titer was 0.20 (normal, <0.8). Anti-MPO perinuclear ANCA (P-ANCA) IgG index was 4.6 (normal, <0.8). C3 and C4 complement were normal. Anti-SS-A (RO) and SSB (LA) Sjögren’s antibodies were normal. Spinal fluid showed glucose of 96 mg/dL and protein of 31 mg/dL, and had no cells. The elevated ESR and P-ANCA with a normal C-ANCA supported the diagnosis of a vasculitis. Therefore, a sural nerve and quadriceps muscle biopsies were done.
398
Case 61
WHAT DID THE NERVE AND MUSCLE BIOPSY SHOW? The muscle biopsy showed neurogenic atrophy with atrophic angular fibers. The sural nerve biopsy showed a smallto mild-sized vasculitis with infiltration of the vessel wall having some fibrinoid necrosis (Fig. 61-3). The patient was treated with prednisone 60 mg each day with improvement. This therapy was used with some trepidation because of her diabetes, which was closely monitored. As her diabetes mellitus worsened and she developed significant cushingoid features, she was slowly switched to azathioprine with close monitoring of her ESR and ANCA titers.
SUMMARY This patient presented initially with a polyneuropathy and a mononeuritis of the left peroneal nerve during a fall. Her sedimentation rate was elevated, and when later workup revealed an elevated P-ANCA titer, a nerve biopsy showed vasculitis. She responded well to steroids and later to azathioprine. For further discussion, important points, and references, see Case 62.
An Elderly Woman with Foot Drop and Hand Weakness
A 76-year-old woman presented several days after a sudden onset of left foot drop that occurred immediately after a fall. She also complained of anorexia, weight loss, malaise, and numbness in both lower extremities for several weeks. Past medical history was positive for coronary artery disease, carotid endarterectomy, aortic valve stenosis with valve replacement, hypertension, and hyperlipidemia. Medications included atenolol, hydrochlorothiazide, amlodipine, thyroid supplement, and aspirin. She was referred for an EMG. General physical examination was normal. On neurologic examination, strength was intact except for mild weakness in both hands and toe dorsiflexors on the right, and she could not dorsiflex the left foot and toes or evert the left foot. Reflexes were absent in the ankles, trace at the knees, and normal in the arms. She had absent vibration sense in the toes and ankles and decreased pinprick,
temperature, and touch sensations in both lower extremities in a stocking distribution up to the calf. There was mildly decreased vibration sense and two-point discrimination in the fingers. The rest of the examination was normal.
WHAT IS THE DIFFERENTIAL DIAGNOSIS? Clinically, this patient had a polyneuropathy with a superimposed left peroneal neuropathy. It was not completely clear if peroneal palsy was caused by stretch trauma from the fall or was spontaneous and caused the fall. The differential diagnosis included a diabetic polyneuropathy. Other causes of neuropathy were also considered, including a polyneuropathy from a microangiopathic vasculitis. She could also have had a polyneuropathy with an L5 radiculopathy, plexopathy, or a sciatic nerve lesion.
AN EMG TEST WAS PERFORMED Motor Nerve Studies
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve L.
Normal £ 5.7
Normal ≥3
NR NR NR
Ankle Fibular head Knee Peroneal Nerve L.* Fibular head Knee
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Normal ≥ 40
Tibial Nerve L.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
NR NR NR
— NR NR
Ankle Pop. fossa
NR NR
NR NR
— NR
Normal £ 5.2
Normal ≥3
Normal ≥ 40
Peroneal Nerve R.
Normal £ 5.7
Normal ≥3
Normal ≥ 40
3.3 6.0
0.8 0.7
— 37
6.6 15.2 18.3
0.3 0.2 0.2
— 31 32
Ankle Fibular head Knee
*Recorded at the tibialis anterior muscle with needle electrode.
393
394
Case 61
Motor Nerve Studies—cont’d
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve R.*
Normal £ 5.2
Normal ≥3
Normal ≥ 40
3.1 5.3
7 6
— 45
Tibial Nerve R.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
Ankle Pop. fossa
4.6 14.4
1.1 0.3
— 36
Median Nerve R.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.2 9.0
2 1
— 44
Normal £ 3.6
Normal ≥8
Normal ≥ 50
3.2 6.7 9.1
2 1 1
— 44 50
Fibular head Knee
Wrist Elbow Ulnar Nerve R. Wrist Below elbow Above elbow
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Median Nerve L.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.0 8.4
16 15
— 45
Wrist Elbow
F-wave and Tibial H-reflex Studies Nerve Peroneal nerve L. Tibial nerve L. Peroneal nerve R. Tibial nerve R. Median nerve R. Ulnar nerve R. Median nerve L. H-reflex L. H-reflex R.
Latency (ms)
Normal Latency £ (ms)
NR NR NR NR 28.3 29.3 28.0 NR NR
54 54 54 54 30 30 30 34 34
Sensory Nerve Studies
*Recorded at tibialis anterior muscle.
Superficial peroneal nerve R. — Absent Sural nerve R. — Absent
EMG Data Muscle
Insrt Activity
Fibs
Pos Waves
Fasc
Amp
Dur
Poly
Pattern
Biceps brachii R. Triceps R. Brachioradialis R. 1st dorsal interosseous R. Abductor pollicis brevis R. Tibialis anterior R. Gastrocnemius R. Vastus lateralis R. Rectus femoris R. Lumbar paraspinals L. Gluteus medius L. Tensor fasciae latae L. Biceps femoris (long head) Biceps femoris (short head) Vastus lateralis L. Tibialis anterior L. Peroneus longus L. Gastrocnemius L.
Norm Norm Norm Inc Norm Inc Inc Norm Norm Norm Norm Norm Norm Norm Norm Inc Inc Inc
None None None None None 2+ None None None None None None None None None 4+ 4+ None
None None None 1+ None 2+ 2+ None None None None None None None None 4+ 4+ 1+
None None None None None None None None None None None None None None None None None None
Norm Norm Norm Lg Lg Lg Lg Norm Norm Norm Norm Norm Norm Norm Norm Lg Lg Lg
Norm Norm Norm Inc Inc Inc Inc Norm Norm Norm Norm Norm Norm Norm Norm Inc Inc Inc
None None None None None None None None None None None None None None None None None None
Full Full Full Red Full Red Red Full Full Full Full Full Full Full Full Red Red Red
395
An Elderly Woman with Foot Drop and Hand Weakness
WHAT WERE THE EMG FINDINGS? This test demonstrated an absent left tibial CMAP and peroneal CMAP when recording at the extensor digitorum brevis muscle, and low-amplitude CMAP when recording at the tibialis anterior muscle. The nerve conduction velocity was mildly slow across the fibular head. The right peroneal and tibial nerves had low-amplitude CMAPs and decreased conduction velocities. The median and tibial nerves had decreased CMAP amplitudes and velocities. F-responses were prolonged, except for the left peroneal and tibial nerves in which they were absent. SNAPs were absent in both sural and superficial peroneal nerves. The right median SNAP was normal, while the left had a prolonged latency and low amplitude. Needle EMG showed denervation potentials in the left tibialis anterior and peroneus longus with reduced motor unit recruitment. There was also mild denervation on the right tibialis anterior and both gastrocnemius and first dorsal interosseous; other muscles were normal. It was concluded that the patient had a predominantly axonal sensory and motor polyneuropathy with secondary demyelination affecting mainly the lower extremities with more severe involvement of the left peroneal nerve. The lack of denervation in the other L5, or paraspinal muscles argued against a radiculopathy. The normal hamstring muscles, particularly the short head of the biceps, was against a sciatic neuropathy.
THE FOLLOWING LABORATORY STUDIES WERE DONE
hormone was elevated at 47.4 µV/mL (normal, 0.35–5.50 µV/mL) and glucose was 200 mg/dL. Lipid profile showed mild hyperlipidemia. Erythrocyte sedimentation rate (ESR) was 85 mm/hour; fluorescent antinuclear antibody was negative. CT scans of the chest and abdomen were normal. Her symptoms improved with physical therapy and fluid restriction. Her thyroid supplement was adjusted. She was diagnosed with diabetic neuropathy, with hypothyroidism as a possible contributing factor, and a peroneal palsy.
FOLLOW-UP She was referred for neurologic evaluation 2 months later because of acute onset of hand weakness in the right, more than the left. General physical examination was unremarkable except for mottling bluish discoloration of fingers and feet. Strength was 2/5 in the right wrist and finger extensors, 3/5 in the left hand; hand flexion was 4/5, finger flexion was 4/5, and hand muscles were 4−/5. In addition there was a left foot drop (Fig. 61-1). She had mild right foot dorsiflexion weakness. Motor examination was otherwise normal. Reflexes were 1 to 2+ in the left upper extremity, 0 in the right brachioradialis and biceps, and 1+ in the triceps. Knee and ankle reflexes were absent. She had absent vibration sense in feet, ankles, and fingers. Pinprick, touch, and temperature sensations were decreased to the mid-calf, left forearm, and right elbow. The rest of the examination was normal.
Electrolytes were normal except for a sodium of 126 mg/dL (normal, 135–155 mg/dL). Thyroid-stimulating
A SECOND EMG TEST WAS PERFORMED Motor Nerve Studies
Motor Nerve Studies—cont’d
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve L.
Normal £ 5.7
Normal ≥3
NR NR
Ankle Fibular head Peroneal Nerve L.* Fibular head Knee
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Normal ≥ 40
Tibial Nerve L.
Normal £ 5.3
Normal ≥4
Normal ≥ 40
NR NR
— NR
Ankle Pop. fossa
5.3 14.9
2 1
— 37
Normal £ 5.2
Normal ≥3
Normal ≥ 40
Peroneal Nerve R.
Normal £ 5.7
Normal ≥3
Normal ≥ 40
13.1 16.5
1 1
— 36
5.7 12.8
1 1
— 36
*Recorded at tibialis anterior muscle.
Ankle Fibular head
396
Case 61
Motor Nerve Studies—cont’d
F-wave and Tibial H-reflex Studies
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Median Nerve R.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
6.3 13.0
0.1 0.0
— 33
Normal £ 3.6
Normal ≥8
Normal ≥ 50
8.1 NR
0.0 NR
— —
Wrist Elbow Ulnar Nerve R. Wrist Below elbow Radial Nerve R.
NR
NR
NR
Median Nerve L.
Normal £ 4.2
Normal ≥6
Normal ≥ 50
4.2 13.1
2.4 0.1
— 23
Normal £ 3.6
Normal ≥8
Normal ≥ 50
Wrist Below elbow Above elbow Axilla
3.8 8.8 12.9 14.8
2.8 2.2 0.0 0.0
— 42 29 47
Radial Nerve L.
NR
NR
NR
Wrist Elbow Ulnar Nerve L.
Nerve
Latency (ms)
Normal Latency £ (ms)
NR NR NR NR NR NR
54 30 30 30 30 34
Peroneal nerve R. Median nerve R. Ulnar nerve R. Median nerve L. Ulnar nerve L. H-reflex R.
Sensory Nerve Studies
Nerve Median nerve R. Ulnar nerve R. Radial nerve R.
Latency (ms)
Normal Latency £ (ms)
Amp (mV)
Normal Amp ≥ (mV)
NR NR NR
3.1 3.1 3.1
NR NR NR
20 13 30
EMG Data Muscle
Insrt Activity
Fibs
Pos Waves
Fasc
Amp
Dur
Poly
Pattern
Deltoid L. Biceps brachii L. Extensor digitorum com. L. 1st dorsal interosseous L. Extensor carpi radialis L. Extensor digitorum com. L. Tibialis anterior L. Gastrocnemius L. Deltoid R. Biceps brachii R. Extensor digitorum com. R. Flexor carpi radialis R. Flexor carpi ulnaris R. 1st dorsal interosseous R.
Norm Norm Norm Inc Norm Inc Inc Inc Norm Norm Inc Inc Inc Inc
None None None 3+ None 2+ 2+ 2+ None None 2+ 1+ 2+ 2+
None None None 3+ None 2+ 2+ 2+ None None 2+ 1+ 2+ 2+
None None None None None None None None None None None None None None
Lg Norm Lg Lg Lg Lg Absent Lg Lg Lg Lg Lg Lg Lg
Inc Norm Inc Inc Inc Inc — Inc Inc Inc Inc Inc Inc Inc
None None None None None None — None None None None None None None
Red Red Full Red Red Red Absent Red Red Red Red Red Red Red
WHAT WERE THE EMG FINDINGS? This test showed interval worsening of the neuropathy with conduction blocks, most prominent in the left ulnar and median nerves (Fig. 61-2), and absent bilateral peroneal CMAPs. There was also diffuse denervation in both legs, as well as in the right median, radial, and ulnar innervated muscles.
In summary, the test showed a severe asymmetric polyneuropathy with both axonal degeneration and demyelinating features with conduction blocks, consistent with mononeuritis multiplex. Laboratory studies revealed normal chemistries, except for sodium 133 mg/dL and albumin 3 mg/dL. ESR was 105 mm/hour (normal, <0–20 mm/hour); FANA and HIV were negative. circulating antineutrophil cytoplasmic anti-
397
An Elderly Woman with Foot Drop and Hand Weakness
10 ms
A
A 1
271V 500 uV
A 2
398V 500uV
FIGURE 61-2 Left median nerve CMAP obtained with wrist stimulation (above), and during elbow stimulation (below); notice conduction block (500 mV/10 ms).
B
FIGURE 61-3 Sural nerve biopsy showing a vessel with inflammatory infiltrates embedded in the vessel wall; there is also fibrinoid necrosis (H&E stain, ×200).
C FIGURE 61-1 A, Discoloration of the fingers and right thenar atrophy in this patient. B, Right wrist drop; notice atrophy of the first dorsal interosseous muscle. C, Left foot drop and also bluish mottling discoloration of the skin.
bodies (C-ANCA) IgG index titer was 0.20 (normal, <0.8). Anti-MPO perinuclear ANCA (P-ANCA) IgG index was 4.6 (normal, <0.8). C3 and C4 complement were normal. Anti-SS-A (RO) and SSB (LA) Sjögren’s antibodies were normal. Spinal fluid showed glucose of 96 mg/dL and protein of 31 mg/dL, and had no cells. The elevated ESR and P-ANCA with a normal C-ANCA supported the diagnosis of a vasculitis. Therefore, a sural nerve and quadriceps muscle biopsies were done.
398
Case 61
WHAT DID THE NERVE AND MUSCLE BIOPSY SHOW? The muscle biopsy showed neurogenic atrophy with atrophic angular fibers. The sural nerve biopsy showed a smallto mild-sized vasculitis with infiltration of the vessel wall having some fibrinoid necrosis (Fig. 61-3). The patient was treated with prednisone 60 mg each day with improvement. This therapy was used with some trepidation because of her diabetes, which was closely monitored. As her diabetes mellitus worsened and she developed significant cushingoid features, she was slowly switched to azathioprine with close monitoring of her ESR and ANCA titers.
SUMMARY This patient presented initially with a polyneuropathy and a mononeuritis of the left peroneal nerve during a fall. Her sedimentation rate was elevated, and when later workup revealed an elevated P-ANCA titer, a nerve biopsy showed vasculitis. She responded well to steroids and later to azathioprine. For further discussion, important points, and references, see Case 62.