Mustafa Khan

Clinical predictors of EMG-confirmed cervical and lumbosacral radiculopathy

BACKGROUND Electromyography (EMG) for suspected cervical or lumbosacral root compression is often negative, producing expense and physical discomfort that could have been avoided. To improve patient selection for testing, we sought to identify clinical features that would accurately predict presence of radiculopathy on EMG. METHODS Adult patients consecutively evaluated for suspected cervical or lumbosacral root compression at an academic clinical neurophysiology laboratory were prospectively enrolled. Presence of clinical features suggesting root disease (neck or back pain, dermatomal pain or numbness, myotomal weakness, segmental reflex loss, and straight leg-raising) was recorded prior to testing. EMG examination to confirm root compression was conducted per standard protocols. Analysis was based on computation of sensitivity, specificity, predictive values, and accuracy. RESULTS A total of 200 patients (55% male; mean age 46.4 years; 38% suspected of cervical and 62% of lumbosacral disease) were included. EMG evidence of root disease was detected in 31% of cervical and 62% of lumbosacral referrals. Dermatomal pain was the most sensitive, and segmental reflex loss and myotomal weakness the most specific individual predictors of root disease. Combined presence of dermatomal pain or numbness with segmental reflex loss and myotomal weakness approached specificities of 78% (lumbosacral disease) and 99% (cervical disease). In all cases, myotomal weakness was the most accurate predictor of root disease. CONCLUSION The diverse symptoms and signs of cervical and lumbosacral root compression predict a positive electrodiagnosis of radiculopathy with varying degrees of accuracy, and may be used to guide patient selection for EMG testing.

Risk of multiple sclerosis after idiopathic optic neuritis in a Pakistani population.

BACKGROUND AND OBJECTIVE Optic neuritis (ON) is associated with a 38% ten-year risk of developing multiple sclerosis (MS) in Western populations, but the corresponding risk in non-Western populations is unclear. We conducted this study to estimate the risk of progression to MS after an episode of ON in a South Asian population. METHODS Two hundred and fifty-three patients with idiopathic ON were identified by reviewing records of visual evoked potentials and chart notes from a single academic center spanning the years 1990-2007. A structured telephone interview was then conducted to identify patients who had subsequently received a diagnosis of MS. The diagnosis was corroborated from chart notes, where possible. Cumulative probability of conversion to MS was calculated using Kaplan-Meier survival analysis. RESULTS The five-year risk of developing MS was 14.6% and the ten-year risk was 24%. Patients (N = 218) who had one or more typical demyelinating lesions on baseline brain magnetic resonance imaging (MRI) had a 68% 10-year risk; those with no lesions or non-typical lesions had a 14% risk (p < 0.001). Female gender, recurrent ON, and occurrence of ON in winter months were also associated with increased risk (p < or = 0.001). Severity of ON and likelihood of detecting cerebrospinal fluid (CSF) oligoclonal bands were higher in patients who developed MS. CONCLUSION Idiopathic ON in Pakistan carries a lower risk of progression to MS compared with Western data. As in Western populations, however, presence of abnormal baseline brain MRI and CSF oligoclonal bands correlate with increased MS risk.

123. Early denervation in patients with axonal variant of Guillan–Barré syndrome

response, and side effects were recorded. Results: Sixteen patients used methotrexate in MG. Nine were women. Age at onset for using methotrexate ranged from 21 to 78 years (mean 54.2). Time from diagnosis of MG until start of methotrexate ranged from 0 months to 24 years. Weekly dosing ranged from 5 to 25 mg. Three patients used no other immunosuppressants. Eleven patients used at least two other immunosuppressant agents since MG was diagnosed. Eight patients underwent thymectomy, (two after starting methotrexate). One patient each had the following: transient elevation of hepatic transaminases that corrected with a lower dose, nausea prompting discontinuation, and multiple myeloma. Two patients died while taking methotrexate, but both the deaths were not felt to be related to methotrexate or MG. Six patients showed clinical improvement, and ten showed no changes. Eight patients decreased their daily pyridostigmine while on methotrexate. Conclusions: Methotrexate is a safe, well tolerated, and affordable medication used in this cohort of MG patients. Future randomized, prospective trials should be undertaken to determine if methotrexate is as effective as other immunosuppressant agents currently used in MG. Dr. Rivner is a consultant to Allergan.

12. Sensory nerve action potential ratios in acute inflammatory demyelinating polyneuropathies

Introduction: Poliomyelitis involves the anterior horn cells experiencing peripheral denervation, which alters the motor unit (MU) properties. The noninvasive motor unit number index (MUNIX) method and the invasive macro electromyography (EMG) method are the two techniques used to evaluate the MU involvement. Objective: To compare the two techniques in characterizing the MU properties in prior polio. Method: MUNIX and macro EMG were performed in 50 tibial anterior (TA) muscles in 34 patients with the diagnosis of prior polio. Clinical assessment of force and muscle atrophy was performed. Results: The MUNIX and the relative macro EMG parameters showed a moderate correlation. The MUNIX for the prior polio group was decreased, compared to the age-matched control subjects by 24% on average. The elevation of themacromotor unit action potential (MUAP)amplitude for thepatientgroupcompared toagematchedcontrol subjects (relative macro MUAP amplitude) was 5.1 corresponding to an estimated loss of 61% of the neurons. However, there was a great scatter of the individual results in both groups. MUNIX and macro MUAP amplitudewere correlatedwith both force andmuscle atrophy. Conclusion: The MUNIX describes the number of MUs, regardless of the effectiveness of the reinnervation process, in contrast to the macro EMG which is reflecting the mechanism of collateral reinnervation. Pros and cons for the two techniques in characterizing the MU properties in prior polio are discussed.

13. Frequency of blink reflex abnormality in chronic inflammatory demyelinating polyneuropathy

Introduction: Poliomyelitis involves the anterior horn cells experiencing peripheral denervation, which alters the motor unit (MU) properties. The noninvasive motor unit number index (MUNIX) method and the invasive macro electromyography (EMG) method are the two techniques used to evaluate the MU involvement. Objective: To compare the two techniques in characterizing the MU properties in prior polio. Method: MUNIX and macro EMG were performed in 50 tibial anterior (TA) muscles in 34 patients with the diagnosis of prior polio. Clinical assessment of force and muscle atrophy was performed. Results: The MUNIX and the relative macro EMG parameters showed a moderate correlation. The MUNIX for the prior polio group was decreased, compared to the age-matched control subjects by 24% on average. The elevation of the macro motor unit action potential (MUAP) amplitude for the patient group compared to age matched control subjects (relative macro MUAP amplitude) was 5.1 corresponding to an estimated loss of 61% of the neurons. However, there was a great scatter of the individual results in both groups. MUNIX and macro MUAP amplitude were correlated with both force and muscle atrophy. Conclusion: The MUNIX describes the number of MUs, regardless of the effectiveness of the reinnervation process, in contrast to the macro EMG which is reflecting the mechanism of collateral reinnervation. Pros and cons for the two techniques in characterizing the MU properties in prior polio are discussed.

PO2.3 Snap, Crackle & Pop – a Normal Variant of Increased Insertional Activity – May Be Misleading for Electromyographer: Case Series

Background: False positive findings are seen in a high percentage of imaging studies in prolapsed intervertebral discs (PIVD) necessitating electro-diagnosis as a confirmatory test in the diagnosis of radiculopathy induced low back pain. Methods: Aim was validation of paraspinal EMG (pEMG) in electrophysiological evaluation of radiculopathy. Detailed neurological examination was carried out in patients with L5/S1 radiculopathy due to PIVD. Peripheral electroneuromyographic studies and pEMG according to Haig’s technique (Muscle & Nerve 1993) were done; in the latter an increased score denoted increased abnormal EMG activity, and needle positions were classed as specific, medial and intermediate. Results: Twenty patients with a mean age of 40.2+10.1 years were studied. Spontaneous activity was analysed in lumbar paraspinal muscles. Mean symptom duration was 1.23+1.2 years. Nineteen (95%) had neurological deficits such as loss of tendon jerks, radicular sensory loss and muscle weakness. On MR, mean L5 and S1 spinal canal diameters were 10.15+2.0 mm and 10.1+2.2 mm, while mean lateral recess diameters were 3.55+1.5 and 5.15+1.35 mm, respectively. Mean spontaneous EMG scores (at L5/S1 levels in specific EMG position were 1.45+1.7 and 1.15+1.46 respectively. Statistical analysis using Chi-square test showed a highly significant difference in pEMG activity in S1 specific EMG position between subjects with normal and abnormal lateral recesses at the corresponding segment (p = 0.0012). No other statistically significant association was seen. Conclusions: In this study pEMG had a higher sensitivity for abnormalities than either peripheral EMG or imaging studies. The S1 specific pEMG insertion site correlated only for S1 lateral recess MRI abnormalities.

PO10.19 clinical spectrum of pseudo seizures at a tertiary care hospital Karachi: a video EEG based study

Background: Cyclic vomiting syndrome (CVS) is characterized by recurrent, stereotypic episodes of incapacitating nausea, vomiting, and other symptoms, separated by intervals of comparative wellness. The second edition of the International Headache Classification classifies CVS as the subgroup of childhood periodic syndromes, which are common precursors of migraine. CVS may respond to migrainedirected prophylactic agents such as beta-blockers, amitriptyline, and cyproheptadine. Since 1988, valproate has been prescribed for migraine prophylaxis. The aim of this therapeutic trial was to evaluate the use of valproate, an antimigraine prophylactic drug, for the prophylactic management of CVS in children. We used prophylactic therapy in patients in whom the episodes of CVS occurred more-than-once a month and/or who particularly has severe and disabling episodes. Methods: The nature of the trial and the possible side effects of the drug were explained to the prospective participants, i.e., parents as well as patients. After receiving an informed consent, 13 children diagnosed with severe CVS were enrolled in the study. Prophylactic therapy consisted of valproate administered at a dose of 10 40 mg. All patients underwent diagnostic tests to rule out organic causes of their symptoms. Vomiting was severe enough in all patients to cause dehydration requiring hospitalization for intravenous rehydration. Electroencephalogram (EEG) showed spikes or spike-wave complexes in two patients, and normal EEG in the remaining patients. Nine of the 13 patients did not respond to medical therapies such as propranolol, amitriptyline, cyproheptadine, phenobarbital, phenytoin, and carbamazepine. Three patients required combination therapy with valproate and phenobarbital. Results: Of the 13 patients, two showed complete resolution of their symptoms; nine showed marked improvement, which was evidenced by a low number of attacks with reduced severity; and two failed to respond to valproate therapy. Four patients experienced relapse with a decreased dosage of valproate. Side effects associated with long-term valproate administration were not observed, with the exception of mild liver dysfunction. Conclusions: Valproate appears to be effective for the prophylactic management of severe CVS, with 85% of all patients achieving a reduction in the frequency of attacks.

PO5.53 critical illness polyneuropathy and myopathy: experience at a tertiary care center in Pakistan

Background: CIDP is a progressive or relapsing immune mediated disorder often responsive to corticosetereroids, IV immunoglobulin & plasma exchange. Hepatitis C is common cause of death in patient having chronic hepatic disorder & affecting approx. 1 out of 10 20 population of Pakistan. Hepatitis C may be associated with peripheral neuropathies mainly axonal, chronic as well as acute cryoglobulinemia, and association with CIDP is less commonly explained. To date the optimal antiviral treatment of Hepatitis C viral infection is the combination of peg interferon-a with ribavarin. Case report: 44 years old, male with hepatitis C associated CIDP improved with combination of antiviral therapy like interferon-a and Ribavarin. Five weeks after starting therapy he felt 80% improvement in symptoms (muscle power & numbness). Viral eradication was confirmed (HCV PCR negative) after treatment patient became symptoms free. Repeat NCS/EMG turned to be normal except absent bilateral H-reflex (possibly secondary to underlying diabetes mellitus. Conclusions: We described a patient with hepatitis C associated CIDP that markedly improved with the antiviral therapy. The current case report may be an initiative to do more studies in the different canters, particularly in countries where HCV-infection is more common, like in our country Pakistan.