A 38-year-old man with a 2-year history of kidney failure caused by progressive glomerulonephritis requiring peritoneal dialysis presented with a 1-year history of numbness, tingling, and shooting pains in both feet and legs, associated with mild leg weakness and cramps. Review of systems revealed mild, nonspecific neck pain.
The patient denies a history of diabetes or of tobacco or alcohol use. Family history was noncontributory.
Examination revealed normal mental function, cranial nerves, and strength without evidence of muscle wasting or weakness. Biceps and triceps reflexes were normal, but brachioradialis and ankle reflexes were absent; they were trace in the knees. He had decreased vibration sense in the toes and decreased pain sensation up to the mid-calves. There was a mildly decreased pain sensation in the right ulnar nerve distribution in the hand. The rest of the examination was normal.
What is the Most Likely Diagnosis?
This patient had a predominantly sensory neuropathy. The most likely diagnosis was a uremic polyneuropathy, although other common causes of neuropathy, such as diabetes, needed to be ruled out. Other possibilities included B 12 deficiency, paraneoplastic neuropathy, amyloidosis, toxic neuropathies, and microangiopathic neuropathy. Pyridoxine intoxication or other toxic neuropathies caused by medications could have a similar presentation, but he had not taken excessive amounts of vitamins nor had he been exposed to toxins or medications that could cause neuropathies. Myelin-associated glycoprotein–associated neuropathy was unlikely because of his age and prominent small fiber involvement.
There was a suggestion of a right ulnar neuropathy.
What Tests Should Be Done?
Fasting blood sugar, glycosylated hemoglobin, erythrocyte sedimentation rate, immunoelectrophoresis, complete serum chemistry profile, and liver function tests were normal, except for blood urea of 60 mg/dL (normal, 24–49 mg/dL). Creatinine was 7.2 mg/dL (normal, 0.6–1.2 mg/dL).
An EMG Test was Performed
Motor Nerve Studies
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Median Nerve R.
Normal ≤ 4.2
Normal ≥ 6
Normal ≥ 50
Wrist
4.2
8
–
Elbow
9.2
8
50
Ulnar Nerve R.
Normal ≤ 3.6
Normal ≥ 8
Normal ≥ 50
Wrist
3.4
14
–
Below elbow
8.5
12
50
Above elbow
11.9
8
35
Axilla
14.5
8
51
Erb’s point
18.1
3
69
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Ulnar Nerve L.
Normal ≤ 3.6
Normal ≥ 8
Normal ≥ 50
Wrist
3.2
16
–
Below elbow
7.4
16
50
Above elbow
9.7
16
52
Peroneal Nerve R.
Normal ≤ 5.7
Normal ≥ 3
Normal ≥ 40
Ankle
4.8
0.4
–
Fibular head
15.8
0.4
28
Knee
18.9
0.4
39
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Tibial Nerve R.
Normal ≤ 5.3
Normal ≥ 4
Normal ≥ 40
Ankle
5.0
3
–
Pop. fossa
16.6
2
36
F-Wave and Tibial H-Reflex Studies
Nerve
Latency (ms)
Normal Latency ≤ (ms)
Median nerve R.
31.1
30
Ulnar nerve R.
39.1
30
Ulnar nerve L.
32.0
30
Peroneal nerve R.
NR
54
Tibial nerve R.
NR
54
H-reflex R.
40
34
H-reflex L.
39.9
34
Sensory Nerve Studies
Nerve
Onset Latency (ms)
Normal Onset Latency ≤ (ms)
Peak Latency (ms)
Normal Peak Latency ≤ (ms)
Amp (μV)
Normal Amp ≥ (μV)
Conduction Velocity (m/s)
Normal Conduction Velocity ≥ (m/s)
Median nerve R.
2.6
2.6
3.1
3.1
23
20
50
50
Ulnar nerve R.
3.2
2.6
3.7
3.1
4
13
38
50
Sural nerve R.
NR
3.5
NR
4.0
NR
11
NR
40
Sural nerve L.
NR
3.5
NR
4.0
NR
11
NR
40
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