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Poster 71: Acute Myasthenia Gravis Misdiagnosed as Acute Guillain-Barre Syndrome in a 15-Year- Old Girl: A Case Report
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There were abnormalities in motor units of rhomboid major and trapezius without abnormality in serratus anterior. Discussion: Electrodiagnostic findings are indicative of right accessory neuropathy and dorsal scapular neuropathy with no evidence for long thoracic neuropathy. Literature search does not reveal presentation of medial winging of the scapula in combined lesions of accessory and dorsal scapular nerves. The etiology of the neuropathies may be that of idiopathic brachial plexopathy, perhaps as a result of the viral respiratory illness. Conclusions: Medial winging of the scapula can result from dorsal scapular and spinal accessory neuropathy, though it is not clear if they must be in conjunction. Electromyography and nerve conduction studies are a reasonable way to evaluate the etiology of winging of the scapula. Keywords: Winging scapula, Dorsal scapular neuropathy, Spinal accessory neuropathy.
Poster 70 Accuracy of Diagnoses Delivered by an Automated Hand Held Nerve Conduction Study Device in Comparison to Standard Electrophysiologic Testing in Patients with Unilateral Leg Symptoms. Kevin Schmidt, MD (Mayo Clinic, Rochester, MN); Andrea J. Boon, MD. Disclosures: K. Schmidt, None. Objective: To evaluate the accuracy of the NC-Stat device compared with standard electrodiagnostic techniques (EDX) in patients experiencing unilateral leg symptoms. Design: 50 patients referred to a tertiary referral EMG laboratory for evaluation of unilateral leg symptoms were recruited. 25 patients with leg symptoms but no evidence of lumbosacral radiculopathy (LSR) on standard EDX were enrolled into group 1. Group 2 consisted of 25 patients with unilateral leg symptoms and evidence of LSR on standard EDX. After completing standard EDX, all 50 patients underwent automated nerve conduction studies utilizing the protocol recommended by the manufacturer. The computer generated reports were compared to the diagnoses generated by standard EDX. Setting: Tertiary referral EMG laboratory. Results: Preliminary data showed that in group 1 (patients with leg symptoms, but without evidence of L4, L5 or S1 radiculopathy on standard EDX testing), greater than 93% of patients were suggested to have LSR on automated testing. Five of these patients were found to have alternative diagnoses on standard EDX testing (including peripheral neuropathy, lumbosacral plexopathy, motor neuron disease and thoracic radiculopathy) and all 5 were suggested to have LSR on automated testing. In group 2 (patients with leg symptoms and standard EDX evidence of LSR), only 2 cases showed perfect concordance of findings on automated testing. Most frequently the automated testing identified 1 or more additional levels on either the symptomatic or contralateral leg that was either not tested or not corroborated with standard EDX. In 3 cases the automated device failed to identify a radiculopathy present on standard testing.
POSTER PRESENTATIONS
Conclusions: The NC-Stat device was found to have low specificity in the identification of lumbosacral radiculopathy in a population of 50 individuals with unilateral leg symptoms. The value of the device as a screening tool for lumbosacral radiculopathy appears limited, as nearly every patient evaluated with automated testing demonstrated abnormalities that would likely be secondarily referred for standard EDX evaluation. Keywords: Electrophysiology, Automated, Nerve conduction.
Poster 71 Acute Myasthenia Gravis Misdiagnosed as Acute Guillain-Barre Syndrome in a 15-YearOld Girl: A Case Report. Shu Q. Huang, MD (Metrohealth Medical Center, Cleveland, OH). Disclosures: S. Q. Huang, None. Patients or Programs: A 15-year-old girl. Program Description: Case presentation: A 15-year-old child had acute respiratory failure and was intubated. Prior she had rapid progressive difficulty in swallowing/speech. No numbness or weakness of extremities reported. Work up showed mild elevated CSF protein with no cells. Other work ups were noncontributory. No electrodiagnostic (EDX) study was done. Presumptive diagnosis was acute Guillain-Barre Syndrome (GBS) and IVIG was started. She had dramatic response to IVIG to her cranial and upper airway weakness; it raised the question of GBS as the diagnosis. Circulating acetylcholine receptor antibody was obtained and was positive. EDX then showed normal velocities and significant decrement in repetitive stimulation study to support myasthenia gravis. She responded and continues to do well with the use of medication. Setting: Tertiary medical center. Results: Even in a tertiary medical center where multiple specialties are involved in the care of patients such as this, one can miss acute myasthenia gravis especially in the pediatric population. Differential diagnosis for acute weakness in children is limited. The pediatric neurologist who made the decision to treat with IVIG with the clinical suspicion of GBS felt EDX study was not indicated before starting IVIG. I do not agree. EDX has such a high sensitivity and specificity in diagnosing GBS, polymyositis and neuromuscular disorder, one should at least attempt to get the EDX in dealing with patient with acute paralysis before initiating a regimen that has major risk. Fortunately, the patient did not have major reaction to IVIG. It is crucial to keep EDX as a key tool in mind when one faces weakness of unknown cause. Conclusions: In our facility, it is almost routine to ask for EDX consult when PICU has a patient with acute paralysis and no obvious CNS involvement. Initiating major treatmentwithout clear confirmation of the specific diagnisis is uncalled for especially if the study is available. It is absolutely crucial to include the EDX in working up acute paralysis. Keywords: Electrodiagnosis, Pediatric, Guillain-Barre, Myasthenia gravis.
There were abnormalities in motor units of rhomboid major and trapezius without abnormality in serratus anterior. Discussion: Electrodiagnostic findings are indicative of right accessory neuropathy and dorsal scapular neuropathy with no evidence for long thoracic neuropathy. Literature search does not reveal presentation of medial winging of the scapula in combined lesions of accessory and dorsal scapular nerves. The etiology of the neuropathies may be that of idiopathic brachial plexopathy, perhaps as a result of the viral respiratory illness. Conclusions: Medial winging of the scapula can result from dorsal scapular and spinal accessory neuropathy, though it is not clear if they must be in conjunction. Electromyography and nerve conduction studies are a reasonable way to evaluate the etiology of winging of the scapula. Keywords: Winging scapula, Dorsal scapular neuropathy, Spinal accessory neuropathy.
Poster 70 Accuracy of Diagnoses Delivered by an Automated Hand Held Nerve Conduction Study Device in Comparison to Standard Electrophysiologic Testing in Patients with Unilateral Leg Symptoms. Kevin Schmidt, MD (Mayo Clinic, Rochester, MN); Andrea J. Boon, MD. Disclosures: K. Schmidt, None. Objective: To evaluate the accuracy of the NC-Stat device compared with standard electrodiagnostic techniques (EDX) in patients experiencing unilateral leg symptoms. Design: 50 patients referred to a tertiary referral EMG laboratory for evaluation of unilateral leg symptoms were recruited. 25 patients with leg symptoms but no evidence of lumbosacral radiculopathy (LSR) on standard EDX were enrolled into group 1. Group 2 consisted of 25 patients with unilateral leg symptoms and evidence of LSR on standard EDX. After completing standard EDX, all 50 patients underwent automated nerve conduction studies utilizing the protocol recommended by the manufacturer. The computer generated reports were compared to the diagnoses generated by standard EDX. Setting: Tertiary referral EMG laboratory. Results: Preliminary data showed that in group 1 (patients with leg symptoms, but without evidence of L4, L5 or S1 radiculopathy on standard EDX testing), greater than 93% of patients were suggested to have LSR on automated testing. Five of these patients were found to have alternative diagnoses on standard EDX testing (including peripheral neuropathy, lumbosacral plexopathy, motor neuron disease and thoracic radiculopathy) and all 5 were suggested to have LSR on automated testing. In group 2 (patients with leg symptoms and standard EDX evidence of LSR), only 2 cases showed perfect concordance of findings on automated testing. Most frequently the automated testing identified 1 or more additional levels on either the symptomatic or contralateral leg that was either not tested or not corroborated with standard EDX. In 3 cases the automated device failed to identify a radiculopathy present on standard testing.
POSTER PRESENTATIONS
Conclusions: The NC-Stat device was found to have low specificity in the identification of lumbosacral radiculopathy in a population of 50 individuals with unilateral leg symptoms. The value of the device as a screening tool for lumbosacral radiculopathy appears limited, as nearly every patient evaluated with automated testing demonstrated abnormalities that would likely be secondarily referred for standard EDX evaluation. Keywords: Electrophysiology, Automated, Nerve conduction.
Poster 71 Acute Myasthenia Gravis Misdiagnosed as Acute Guillain-Barre Syndrome in a 15-YearOld Girl: A Case Report. Shu Q. Huang, MD (Metrohealth Medical Center, Cleveland, OH). Disclosures: S. Q. Huang, None. Patients or Programs: A 15-year-old girl. Program Description: Case presentation: A 15-year-old child had acute respiratory failure and was intubated. Prior she had rapid progressive difficulty in swallowing/speech. No numbness or weakness of extremities reported. Work up showed mild elevated CSF protein with no cells. Other work ups were noncontributory. No electrodiagnostic (EDX) study was done. Presumptive diagnosis was acute Guillain-Barre Syndrome (GBS) and IVIG was started. She had dramatic response to IVIG to her cranial and upper airway weakness; it raised the question of GBS as the diagnosis. Circulating acetylcholine receptor antibody was obtained and was positive. EDX then showed normal velocities and significant decrement in repetitive stimulation study to support myasthenia gravis. She responded and continues to do well with the use of medication. Setting: Tertiary medical center. Results: Even in a tertiary medical center where multiple specialties are involved in the care of patients such as this, one can miss acute myasthenia gravis especially in the pediatric population. Differential diagnosis for acute weakness in children is limited. The pediatric neurologist who made the decision to treat with IVIG with the clinical suspicion of GBS felt EDX study was not indicated before starting IVIG. I do not agree. EDX has such a high sensitivity and specificity in diagnosing GBS, polymyositis and neuromuscular disorder, one should at least attempt to get the EDX in dealing with patient with acute paralysis before initiating a regimen that has major risk. Fortunately, the patient did not have major reaction to IVIG. It is crucial to keep EDX as a key tool in mind when one faces weakness of unknown cause. Conclusions: In our facility, it is almost routine to ask for EDX consult when PICU has a patient with acute paralysis and no obvious CNS involvement. Initiating major treatmentwithout clear confirmation of the specific diagnisis is uncalled for especially if the study is available. It is absolutely crucial to include the EDX in working up acute paralysis. Keywords: Electrodiagnosis, Pediatric, Guillain-Barre, Myasthenia gravis.