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Clinical and electrophysiological features of phenytoin-induced polyneuropathy
imal w&mess, absent reflexes, aad sensory loss in tongue and in disrai extremities, pertkuhwly position sense. Laboratorystudies showed normal creatine kinase; cerebrospmaffluid (CSF) had normal protein and cells. Other caust% of acute paralysis were excluded. Electrophysiological studies revealed demyelinating/axonal radiculoneuropathy with absent H-reflexes, prolonged F-waves and diffise denervation. Serum phosphate normalized and she recovered in a period of 3 weeks with marked electrophysiologieal improvement. This patient bad a reversible acute paralysis resembling AIDP, which was excluded because of prominent sensory loss, normal CSF protein and a mixed demyelinating/axonal radiculoneuropathy, severe hypophosphatemia, and rapid recovery after repletion. Hypophosphatemia should be considered in patients with acute paralysis. M. Siddiqui, Junior Member Recognition Award.
lntroductiou: While phenytoin toxicity has been documented to cause neurophysiologi~al abnormalities in both clinical and ex~~rn~~ settings, whether long-term phenytoin treatment causes clinically significant neuropathy is controversial (J. Neurol. Neurosurg. Psychiat., 1982, 45: 620-626; Neurology, 1981.3 1: 826-831). We report 5 patients who developed polyneuropathy after long-term phenytoin treatment. Objectives: To describe clinical and electrophysiological features of phenytoin-induced peripheral neuropathy. Methods: All seizure patients with symptomatic polyneuropathy were evaluated clinically and electrophysiologically. Results: Five patients (mean 56 years) who had been on phenytoin for longer than 10 years were found to have a well-defmed neuropathy. No other etiology of neuropathy was present. All presented as insidious onset of distal, often disabling, paresthesias. Examination revealed distal sensory loss to pin and vibration; mild distal weakness, and reduced to absent deep tendon reflexes. Nerve conduction studies revealed reduced sensory nerve action potential ~ampiitudes in sural, ulnar, and median nerves, reduced compound muscle action potential amplitudes in deep peroneal and tibial nerves, and absent H-reflexes. The distal and F-wave latency and ~onducti~ velocity values were normal. Dj~~tinuat~on of endow, in 1 patient, has resulted in s~bili~ation of symptoms. Conclusion: We conclude mat phenytoin causes a lent-de~ndent~ axonal sensorimotor neuropatby that may be clinically significam in some patients.
195. Tremor in muttifocai motor neuropathy with conduction block. - T.N. Brunrmgan, HI, D.J. Lange and S.L. Pullman (Neurological institute, Columbia-Presbyterian Medlcrd Center, New York, NY)
Tremor is a frequent accompaniment of chronic inflammatory demyelinathtg polyneuropathy, but has not been reported in multifocal motor neuropatby with conduction block. We describe a (i&year-old woman with right leg weakness beginning at 35, followed several years later by left hand weakness. At 65, her weakness progressed and tremors developed. She denied sensory symptoms. Since a teenager, tremors occurred only when nervous. Alcohol had no effect. She had asymmetric weakness and atrophy in 4 limbs with a postural tremor, greatest in weak limbs. Sensation was normal, and triceps and leg reflexes am absent. Motor conduction blocks were found in multiple arm nerves, whereas sensory c~du~d~ studies were normal. Tremor analysis revealed a genemEzed low amp&ude kiietic tremor in the 7.5-8.5 Hz rauge, but aIs0 a 6 Hz tremor in the left hand and a 2-5 Hz tmmor in the extended rig& foot. hsertial foadhtg splits the postural hand tremor profiie into two peaks at 5.5 aad 7.5 Hz. The findings reveal a
neurogenic tremor, which is Z-10 times higher in amplitude in the weaker left hand and right foot, as well as a generahzed essential tremor, The neurogenic tremor appears due to exaggerated physiologic tremor with frequency modulation by peripheral mechanisms. T.H, Braunagan, III, Junior Member Recognition Award.
146, Antibody panels in idiopathic polyneuropathy and motor neuron disease. - G.I. Wolfe, J.S. Katz, W.W. Bryan, F.H. Wians, Jr. and RJ. Barohn (University of Texas Southwestern Medical Center, Dallas, TX) latroduction: Antibody (Ab> panels against peripheral nerve antigens are commercially available. However, frequency of positive results and utility of these expensive panels are unknown. Gbjectives: To prospectively determine the frequency of positive Ab panels in patients with idiopathic sensorimotor pol~europa~y (PN) and motor neuron disease (MND). Methods: We obtained Ab panels {Geniea, Woreester, M& in consccutive patients with idiopathic PN and MND. PN patients received a “sensorimotor neuropathy profile” (SGPG/MAG, GM,, asiaio-GM,, GDlb, Hu, sulfatide). Multifocal motor neuropatby fMMN) or MND patients underwent a “motor neuropathy profile” @3PG/MAG, GM,, asialo-GM ,I. Results:Fifty-one patients were tested. Four of 27 patients (15%) with PN bad positive panels. SGPG/MAG was positive in 2, 1 with axonal PN and negative Western blot for anti-MAG Ab, and I with demyelinating PN, lgM pamprotein, and positive Western blot. Asialo-GM, was mildly positive in 2 PN patients, 1 with ataxic neuronopathy (negative anti-Hu Ab), and 1 with axonal PN. Of 7 patients with MMN, 6 were positive for anti-GM,. Two of 17 MND patients (12%) were mildly positive for SGPG/MAG with negative Western blots for anti-MAO Ab. Conclusions: Certain Ab tests are useful in select patients (GM, for MMN, MAC for IgM-associated neuropathyl. Ab panels are positive in IO-lS% of PN and MND patients, but do not correlate with clinical Endings and should not be ordered in these groups. 14’7. Are parasPinal muscle abnormalities really related to synqtom duration?, - T.R. ~~~~~ STLE. Pczzirt ’ and T.D. Lauder e ce The Johns Hopkll University, Baltimore, MIf; ’ Agency for Rerdtb Care Policy and Research, Roe&&~ Mn; ’ Mad&n Army Medll Center, Tacoma, WA1 Introduction: A long-held notion in the ei~~~iagn~~c literature is that pamspinal muscles (PSM) tend to show elec~myogmphic (EMG) abao~atid~ early on in a lumbosacral radiiuiopathy (LSR) and that more distal muscles become abnormal later in the disease process. Gbjectives: The purpose of this study was to determine whether PSM and other major proximal and distal muscle abnom-ralities are related to LSR symptom duration. Methods: A multivariate Probit analysis of 247 (retrospectively identified) electrodiagnostically confirmed LSRs was used to test these hypotheses. The dependent variable was a dichotomous indicator of whether a given muscle showed spontaneous activity (i.e., the muscle was abnormal). The probability of an abnormality was modeled as a function of the independent variables: age, sex, unilateral or bilateral symptoms, and symptom duration. Results: Maximum likelihood estimates showed no evidence of comlation between abnormal PSM and symptom duration. Symptom duration was also insignificant for the gastrocnemius, peroneus longus and vastus medialis. Conclusions: We conclude that the pr~b~l~ty of having EMG abnormalities in PSM is not related to symptom duration. A prospective study is needed to confirm these fiudiugs. Nonetheless, clinicians shoutd use caution when interpreting el~~~jagnosd~ findings in PSM based upon symptom duration.
lntroductiou: While phenytoin toxicity has been documented to cause neurophysiologi~al abnormalities in both clinical and ex~~rn~~ settings, whether long-term phenytoin treatment causes clinically significant neuropathy is controversial (J. Neurol. Neurosurg. Psychiat., 1982, 45: 620-626; Neurology, 1981.3 1: 826-831). We report 5 patients who developed polyneuropathy after long-term phenytoin treatment. Objectives: To describe clinical and electrophysiological features of phenytoin-induced peripheral neuropathy. Methods: All seizure patients with symptomatic polyneuropathy were evaluated clinically and electrophysiologically. Results: Five patients (mean 56 years) who had been on phenytoin for longer than 10 years were found to have a well-defmed neuropathy. No other etiology of neuropathy was present. All presented as insidious onset of distal, often disabling, paresthesias. Examination revealed distal sensory loss to pin and vibration; mild distal weakness, and reduced to absent deep tendon reflexes. Nerve conduction studies revealed reduced sensory nerve action potential ~ampiitudes in sural, ulnar, and median nerves, reduced compound muscle action potential amplitudes in deep peroneal and tibial nerves, and absent H-reflexes. The distal and F-wave latency and ~onducti~ velocity values were normal. Dj~~tinuat~on of endow, in 1 patient, has resulted in s~bili~ation of symptoms. Conclusion: We conclude mat phenytoin causes a lent-de~ndent~ axonal sensorimotor neuropatby that may be clinically significam in some patients.
195. Tremor in muttifocai motor neuropathy with conduction block. - T.N. Brunrmgan, HI, D.J. Lange and S.L. Pullman (Neurological institute, Columbia-Presbyterian Medlcrd Center, New York, NY)
Tremor is a frequent accompaniment of chronic inflammatory demyelinathtg polyneuropathy, but has not been reported in multifocal motor neuropatby with conduction block. We describe a (i&year-old woman with right leg weakness beginning at 35, followed several years later by left hand weakness. At 65, her weakness progressed and tremors developed. She denied sensory symptoms. Since a teenager, tremors occurred only when nervous. Alcohol had no effect. She had asymmetric weakness and atrophy in 4 limbs with a postural tremor, greatest in weak limbs. Sensation was normal, and triceps and leg reflexes am absent. Motor conduction blocks were found in multiple arm nerves, whereas sensory c~du~d~ studies were normal. Tremor analysis revealed a genemEzed low amp&ude kiietic tremor in the 7.5-8.5 Hz rauge, but aIs0 a 6 Hz tremor in the left hand and a 2-5 Hz tmmor in the extended rig& foot. hsertial foadhtg splits the postural hand tremor profiie into two peaks at 5.5 aad 7.5 Hz. The findings reveal a
neurogenic tremor, which is Z-10 times higher in amplitude in the weaker left hand and right foot, as well as a generahzed essential tremor, The neurogenic tremor appears due to exaggerated physiologic tremor with frequency modulation by peripheral mechanisms. T.H, Braunagan, III, Junior Member Recognition Award.
146, Antibody panels in idiopathic polyneuropathy and motor neuron disease. - G.I. Wolfe, J.S. Katz, W.W. Bryan, F.H. Wians, Jr. and RJ. Barohn (University of Texas Southwestern Medical Center, Dallas, TX) latroduction: Antibody (Ab> panels against peripheral nerve antigens are commercially available. However, frequency of positive results and utility of these expensive panels are unknown. Gbjectives: To prospectively determine the frequency of positive Ab panels in patients with idiopathic sensorimotor pol~europa~y (PN) and motor neuron disease (MND). Methods: We obtained Ab panels {Geniea, Woreester, M& in consccutive patients with idiopathic PN and MND. PN patients received a “sensorimotor neuropathy profile” (SGPG/MAG, GM,, asiaio-GM,, GDlb, Hu, sulfatide). Multifocal motor neuropatby fMMN) or MND patients underwent a “motor neuropathy profile” @3PG/MAG, GM,, asialo-GM ,I. Results:Fifty-one patients were tested. Four of 27 patients (15%) with PN bad positive panels. SGPG/MAG was positive in 2, 1 with axonal PN and negative Western blot for anti-MAG Ab, and I with demyelinating PN, lgM pamprotein, and positive Western blot. Asialo-GM, was mildly positive in 2 PN patients, 1 with ataxic neuronopathy (negative anti-Hu Ab), and 1 with axonal PN. Of 7 patients with MMN, 6 were positive for anti-GM,. Two of 17 MND patients (12%) were mildly positive for SGPG/MAG with negative Western blots for anti-MAO Ab. Conclusions: Certain Ab tests are useful in select patients (GM, for MMN, MAC for IgM-associated neuropathyl. Ab panels are positive in IO-lS% of PN and MND patients, but do not correlate with clinical Endings and should not be ordered in these groups. 14’7. Are parasPinal muscle abnormalities really related to synqtom duration?, - T.R. ~~~~~ STLE. Pczzirt ’ and T.D. Lauder e ce The Johns Hopkll University, Baltimore, MIf; ’ Agency for Rerdtb Care Policy and Research, Roe&&~ Mn; ’ Mad&n Army Medll Center, Tacoma, WA1 Introduction: A long-held notion in the ei~~~iagn~~c literature is that pamspinal muscles (PSM) tend to show elec~myogmphic (EMG) abao~atid~ early on in a lumbosacral radiiuiopathy (LSR) and that more distal muscles become abnormal later in the disease process. Gbjectives: The purpose of this study was to determine whether PSM and other major proximal and distal muscle abnom-ralities are related to LSR symptom duration. Methods: A multivariate Probit analysis of 247 (retrospectively identified) electrodiagnostically confirmed LSRs was used to test these hypotheses. The dependent variable was a dichotomous indicator of whether a given muscle showed spontaneous activity (i.e., the muscle was abnormal). The probability of an abnormality was modeled as a function of the independent variables: age, sex, unilateral or bilateral symptoms, and symptom duration. Results: Maximum likelihood estimates showed no evidence of comlation between abnormal PSM and symptom duration. Symptom duration was also insignificant for the gastrocnemius, peroneus longus and vastus medialis. Conclusions: We conclude that the pr~b~l~ty of having EMG abnormalities in PSM is not related to symptom duration. A prospective study is needed to confirm these fiudiugs. Nonetheless, clinicians shoutd use caution when interpreting el~~~jagnosd~ findings in PSM based upon symptom duration.