A 34-year-old woman was admitted to the hospital with nausea, vomiting, abdominal pain, and a weight loss of 3 weeks’ duration. She developed weakness of the lower extremities associated with tingling at the tips of her toes 2 days prior to evaluation. She lost all feeling in the lower extremities on the day of admission, and this gradually progressed upward to the chest. She did not have incontinence of urine or stools.
Past medical history was remarkable for a traumatic brain injury with resultant bifrontal partial lobectomy, which left her with a severe craniofacial deformity and a left eye prosthesis.
Review of systems was negative for headache, neck pain, and problems swallowing or speaking. She had no fever, chills, cough, chest pain, or shortness of breath but had abdominal pain, nausea, and vomiting a few minutes after eating for the last week. Family history was noncontributory.
She was alert, awake, and oriented. There were frontal cranial deformities. Cranial nerve examination revealed the right pupil to be normal and reactive to light and accommodation; there was a left-side eye prosthesis; extraocular movements were intact on the right; there was no facial, palate, or tongue weakness. Strength in the upper extremities was 4/5 proximally and 4−/5 distally bilaterally, and both lower extremities were 0/5. Reflexes were absent all over. There were no Babinski signs. Sensory examination revealed loss of pinprick sensation to the waist and loss of vibration and position senses in both legs in the feet and ankles.
Cervical and thoracic MRI were normal. In the hospital, she received IV fluids and metoclopramide HCl. Five days after admission her arms weakened, and she became quadriparetic, reportedly became confused and disoriented, and developed respiratory failure. She was intubated and transferred to the ICU.
What is the Differential Diagnosis?
The differential diagnosis of a patient with acute paralysis includes myelopathy, which could be suggested in this patient because of the confusing sensory findings, but there were no Babinski signs or incontinence, and her spinal MRI was negative. The sensory findings are against a motor neuron disease such as polio or amyotrophic lateral sclerosis.
Disturbance of a neuromuscular transmission, particularly botulism, could present acutely but usually causes large pupils. This patient’s pupil was normal. The sensory findings, areflexia, and lack of extraocular involvement were all against myasthenia gravis. There were no cholinergic signs to suggest organophosphate poisoning. Myopathies, such as those that cause rhabdomyolysis, like metabolic disorders or from toxins, as well as polymyositis and infectious myositis, are also unlikely because of the areflexia and the sensory findings. In summary, this patient appeared to have a rapidly progressive acute polyneuropathy, such as Guillain–Barré syndrome (GBS), and the differential diagnosis also includes porphyria, as well as arsenic intoxication ( Fig. 43-1 ).
Fig. 43-1
Diagram of workup of patients who develop weakness in the intensive care unit. Ab , Antibody; AChR , acetylcholine receptor; ALS , amyotrophic lateral sclerosis; Ca , calcium; CK , creatine kinase; ELS , Eaton–Lambert syndrome; FANA , fluorescent antinuclear antibody; GBS , Guillain–Barré syndrome; ICU , intensive care unit; LP , lumbar puncture; Mg , magnesium; MuSK , muscle-specific kinase; NCV , nerve conduction velocity; NTE , neurotoxic esterase; PO 4 , phosphate; R/O , rule out; SF , spinal fluid; TFT , thyroid function test.
What Tests Should Be Done?
Laboratory studies revealed a white blood count of 18.7 thou/mm 3 (normal, 5–10 thou/mm 3 ), hematocrit 30.3% (normal, 40%–54%), mean corpuscular volume 73 fL (normal, 80–95 fL), hemoglobin 9.5 g/dL (normal, 14–18 g/dL); chemistries were within normal limits. Serum creatine kinase was 50 IU/L; l -lactate dehydrogenase, 810 IU/L; liver function tests were normal except for mildly elevated alkaline phosphatase at 196 IU/L (normal, 39–117 IU/L); erythrocyte sedimentation rate was 28 (normal, <30). No infectious process was found. HIV antibody and hepatitis screenings were negative. Serum immunofixation electrophoresis revealed increased polyclonal IgG. Quantitative immunoglobulins were within normal limits. She received IgG infusions 2 g/kg over 4 days.
An EMG Test was Performed
Motor Nerve Studies
Nerve and Site
Latency(ms)
Amplitude (mV)
Conduction Velocity (m/s)
Peroneal Nerve L.
Normal ≤ 5.7
Normal ≥ 3
Normal ≥ 40
Ankle
4.1
2
–
Fibular head
10.9
2
41
Knee
13.0
2
50
Tibial Nerve L.
Normal ≤ 5.3
Normal ≥ 4
Normal ≥ 40
Ankle
4.1
6
–
Pop. fossa
13.4
6
40
Median Nerve L.
Normal ≤ 4.2
Normal ≥ 6
Normal ≥ 50
Wrist
3.5
6
–
Elbow
6.9
6
53
Ulnar Nerve L.
Normal ≤ 3.6
Normal ≥ 8
Normal ≥ 50
Wrist
2.6
10
–
Below elbow
5.6
10
60
Above elbow
7.5
10
63
Axilla
9.6
10
67
Median Nerve R.
Normal ≤ 4.2
Normal ≥ 6
Normal ≥ 50
Wrist
3.7
5
–
Elbow
7.4
5
50
Nerve and Site
Latency (ms)
Amplitude (mV)
Conduction Velocity (m/s)
Ulnar Nerve R.
Normal ≤ 3.6
Normal ≥ 8
Normal ≥ 50
Wrist
2.7
6
–
Below elbow
5.7
6
60
Above elbow
7.5
6
67
Peroneal Nerve R.
Normal ≤ 5.7
Normal ≥ 3
Normal ≥ 40
Ankle
4.0
3
–
Fibular head
11.0
2
41
Knee
13.2
2
45
F-Wave and Tibial H-Reflex Studies
NR, No response.
Nerve
Latency (ms)
Normal Latency ≤ (ms)
Peroneal nerve L.
NR
54
Tibial nerve L.
51.1
54
Median nerve L.
24.3
30
Ulnar nerve L.
25.5
30
Median nerve R.
25.4
30
Ulnar nerve R.
25.5
30
Peroneal nerve R.
46.6
54
H-reflex L.
NR
34
H-reflex R.
NR
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)
Sural nerve L.
3.7
3.5
4.2
4.0
3
11
38
40
Ulnar nerve L.
2.2
2.6
2.7
3.1
14
13
55
50
Median nerve L.
2.6
2.6
3.1
3.1
21
20
50
50
Median palmar L.
0.8
1.0
1.3
1.5
40
30
86
50
Ulnar nerve R.
1.9
2.6
2.4
3.1
8
13
63
50
Median nerve R.
2.4
2.6
2.9
3.1
15
20
54
50
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