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Advances in the Treatment of Autoimmune Neuromuscular Disease — From Diagnostic Challenges to Long-Term Management. Faculty. Chairperson Gil I. Wolfe, MD Professor and Chief of the Neuromuscular Section Department of Neurology University of Texas Southwestern Medical Center
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Advances in the Treatment of Autoimmune Neuromuscular Disease—From Diagnostic Challenges to Long-Term Management
Faculty Chairperson Gil I. Wolfe, MD Professor and Chief of the Neuromuscular Section Department of Neurology University of Texas Southwestern Medical Center University of Texas Southwestern Hospital Dallas, Texas Gregory T. Carter, MD, MS Clinical Professor of Physical Medicine and Rehabilitation and of Neuromuscular Medicine University of California Davis Sacramento, California Medical Director Regional Neuromuscular Center Providence St. Peter Hospital Olympia, Washington Erik R. Ensrud, MD Board certified in PM&R/EMG/Neurology/ Neuromuscular Disease Director, Neuromuscular Center and EMG Laboratory VA Boston Healthcare System Associate Neurologist Brigham and Women’s Hospital Boston, Massachusetts
Topics • Diagnostic criteria for autoimmune neuromuscular diseases (NMD) • Making treatment decisions—using experience, exploring the evidence • Role of rehabilitation in autoimmune NMD
Objectives On completion of this activity, participants should be able to: • Recognize the clinical presentations and key diagnostic features of autoimmune NMD • Select appropriate therapies and recognize potential treatment failures on the basis of patient history and available clinical evidence • Determine appropriate timing, dosage, and duration of therapies used in the treatment of autoimmune NMD • Recognize the long-term implications of NMD and become proficient in applying appropriate rehabilitative strategies
Dyck at Mayo Clinic, 1975 • Acquired neuropathy that shares a similar pathology and autoimmune etiology with GBS • Different from GBS • Usually, but not always, in the manner of presentation • Natural history of the disease • Rarely associated with antecedent infection • Responds to prednisone • Peak incidence at 40–60 yrs old Dyck PJ et al. Mayo Clin Proc. 1975;50:621-637; Burns T, Ensrud E. (Producers). (17 Aug 2007). “Chronic inflammatory polyradiculoneuropathy with Peter J. Dyck, MD” Available at: http://beta.aanem.org/Education/Products/PhyPodcasts.aspx?page=3&fileid=355.
Slow onset of progressive symmetric muscle weakness • Both proximal and distal weakness • Progresses for >2 months; may be relapsing-remitting • ~60% slowly progressive course • ~35% relapsing-remitting • Sensory loss less prominent than weakness; paresthesias and numbness, but rarely significant pain • Large-fiber sensory modalities are more affected • Diffuse decreased or absent reflexes • 3%–5% have evidence of CNS demyelination • Pathology • Multifocal demyelination • No vasculitic changes • Sural nerve biopsy is rarely necessary
Ensrud ER, Krivickas LS. Phys Med Rehabil Clin N Am. 2001:12:321-334.
AIDP • Prolonged distal motor and F-wave (early) latencies • Absent or impersistent F-waves • Slowing of CV and/or conduction block • Reduction of CMAPs +/- temporal dispersion • Abnormal or absent median SNAP + normal sural SNAP (AMNS) 39% Alberti MA et al. J Peripher Nerv Syst. 2011;16:136-142.
Very Early EDX Findings in GBS (Within 4 Days of Clinical Onset) • Abnormally late responses in 77% • Prolonged distal motor latency in 55% • Cranial nerve study abnormality in 44% • Motor nerve conduction velocity slowing in 23% Alberti MA et al. J Peripher Nerv Syst. 2011;16:136-142.
Complex topic • Need to study multiple nerves, “MS of PNS” • Correct temperature (>32.00C) is crucial • NCS shows electrophysiologic evidence of demyelination • Distal motor latency >125% normal • Conduction velocity <70% normal (<80% if CMAP amp ≥80% normal) • Conduction block • Temporal dispersion • Needle EMG tends to show more prominent reinnervation changes than acute denervation changes, consistent with slow temporal nature of pathology • EMG may look axonal because of secondary axonal damage Barohn RJ, Saperstein DS.Semin Neurol .1998;18:49-61.
GBS—Early Recognitionof Poor Prognosis • A recent paper looked at 397 GBS patients • Which patients were unable to walk at 4 weeks, 3 months, and 6 months? • Three important factors • Older age (>60) • Preceding diarrhea • MRC scores averaged 3 or less when the following were tested: • Shoulder abd/elb flexion/wrist exthip flexion/knee ext/ankle dorsiflexion • MRC scores were most predictive at 7 days after admission Walgaard C et al. Neurology. 2011;76:968-975.
CIDP With Acute Onset(A-CIDP) • 170 patients with GBS • 1-year follow-up • Treatment–related fluctuation (TRF) in GBS always occurred within 8 weeks of symptom onset • Always 1 or at the most 2 TRFs • Consider A-CIDP when a patient thought to have AIDP/GBS deteriorates 8 weeks from onset or has 3 or more TRFs • Start maintenance therapy for CIDP when A-CIDP is recognized Ruts L et al. Neurology. 2010;74:1680-1696; Ensrud E. (Producer). (25 May 2010). “Distinguishing acute-onset CIDP from fluctuating Guillain-Barré syndrome : a prospective study “ with Dr. Pieter van Doorn. Available at: http://www.aan.com/rss/?event=feed&channel=1.
GBS—Rehabilitative Strategies • ICU setting • Passive ROM, prevent joint contracture • Active assisted ROM as tolerated • Close monitoring • Medical-surgical setting • Increase intervention • Isometric exercises while the patient is nonambulatory (Delorme technique) • Physical therapy
CIDP Evidence-based treatments Prednisone: 60–100 mg per day, followed by taper IVIG: 2 g/kg as induction therapy Plasma exchange 5–6 treatments Hughes RA et al. Cochrane Database Syst Rev. 2004;(4):CD003280. Mehndiratta MM et al. Cochrane Database Syst Rev. 2004;(3):CD003906. van Schaik IN et al. Cochrane Database Syst Rev. 2002;(2):CD001797.
MG—Routine Diagnostic Work-up Repetitive nerve testing (3 Hz) U-shaped decrement Reproducible Partially repairable Anti-acetylcholine receptor antibodies (IgG) Anti–muscle-specific tyrosine kinase (anti-MUSK) antibodies Chest CT to look for thymoma
Autoimmune NMD—Rehabilitative Strategies MG patients who are adequately medicated may have minimal rehabilitative needs During an acute crisis, passive limb exercises lower the risk of deep vein thrombosis (DVT) DVT prophylaxis is recommended Bulbar dysfunction increases the risk of aspiration
Anticholinesterase agents (pyridostigmine) for symptomatic relief • Corticosteroids • Immunosuppressants for steroid-sparing effect (azathioprine, mycophenolatemofetil, cyclosporine, tacrolimus, rituximab) • Plasma exchange or IVIG for a crisis; before thymectomy; for severe exacerbations; or in refractory patients • IVIG is more accessible • Plasma exchange may work faster • Thymectomy • Removal of thymoma • Thymectomy is a treatment option in nonthymomatous MG1
MG—Selection of Steroid–Sparing Agents • Azathioprine (may be used in conjunction with prednisone) • At least 1 year to see a full effect • Often seen—an increase of at least 10 from baseline MCV in CBC in responders • Mycophenolate • Tacrolimus
GBS—Treatment of Pain • Almost 90% of GBS patients experience pain • 66% have very severe pain • Gabapentin or pregabalin • Tricyclic antidepressants • Opioid analgesics
GBS—BiPAP for Respiratory Support • Respiratory failure is a significant cause of morbidity and mortality in GBS • 33% of GBS patients require intubation • Average time to intubation is 7 days after symptom onset • Little clinical experience with BiPAP in GBS (used more commonly in MG)
GBS—Rehabilitative Approachto Pain Management • Topical agents (capsaicin, lidocaine gel) • Desensitization techniques (pressure garment) • Transcutaneous electrical nerve stimulation (TENS)
NMD—Rehabilitative Strategies • Isotonic exercise • Isokinetic exercise • Occupational therapy—address activities of daily living (ADLs), functional concerns • Speech therapy if necessary • Assistive devices (walker, canes, etc)
NMD—Exercise as a Precautionary Step • Watch for weakness as a sign of overwork • Exercise level should be submaximal • Higher repetition, lower weight • Endurance training—water exercise for uniform resistance • Monitor serum creatine kinase; monitor for myoglobinurea; watch for delayed-onset muscle soreness or pain
Key Points—Summary • Autoimmune NMD • Diagnostic criteria • Treatment decisions • Role of rehabilitation • Diagnostic approach—typical presentations of GBS and CIDP • Acute presentation of CIDP with treatment–related fluctuations; timing could lead to diagnosis of acute-onset CIDP • Diagnostic elements of MG; long-term management and outcomes • Role of physical medicine and rehabilitative strategies in autoimmune NMD in the acute and chronic setting
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