PT  - JOURNAL ARTICLE
AU  - Zhang, Ling
AU  - Ferrante, Mark
AU  - Ly, Helen
AU  - Bertorini, Tulio
TI  - The Neuromuscular Features of Light Chain Deposition Disease (P5.056)
DP  - 2015 Apr 06
TA  - Neurology
PG  - P5.056
VI  - 84
IP  - 14 Supplement
4099  - http://n.neurology.org/content/84/14_Supplement/P5.056.short
4100  - http://n.neurology.org/content/84/14_Supplement/P5.056.full
SO  - Neurology2015 Apr 06; 84
AB  - OBJECTIVE: To discuss the clinicopathologic and electrodiagnostic features of myopathic LCDD. BACKGROUND: Monoclonal immunoglobulin deposition disease (MIDD) indicates an underlying plasma cell dyscrasia. Pathogenic tissue deposits are composed of light chains, heavy chains, or both. Light-chain deposition disease (LCDD) is most prevalent and is usually associated with multiple myeloma. When light chain deposits do not polymerize, they are do not have amyloidotic properties and, thus, are congophilic red (CR) negative. DESIGN/METHODS: METHODS: Over a 6-month period, a 62yo Caucasian female, with hypothyroidism and CTS, developed progressive fatigability, SOB, generalized weakness, dysphagia, and weight loss (22#). Examination showed hypophonia, mild macroglossia, tongue stiffness, submandibular and submental musculature stiffness, firm sternocleidomastoids, generalized 4-extremity weakness, and bilateral thenar atrophy. Extensive workup showed a faint gamma region band (SPEP); free kappa light chains (urine IFE); kappa level 4165 with kappa/lambda ratio 737.17 (serum free light chains); generalized myopathic MUAPs with fibrillations (EMG), and severe bilateral CTS (EMG). Tissue studies included fat pad biopsy (CR-negative), tongue biopsy (amorphous, pink, fibrotic, CR-negative material); muscle biopsy (kappa light chain positive, CR-negative). She was aggressively hydrated and chemotherapy started. Three weeks later, she developed worsening respiratory insufficiency, ARDS, sepsis, respiratory arrest, and cardiac arrest resulting in death. RESULTS: Microscopically, LCDD appears as an amorphous material (unpolymerized light chains) capable of infiltrating skeletal muscle that is congophilic red negative. CONCLUSIONS: Clinicians need to be aware of LCDD myopathy, especially when amyloidosis is suspected and tissue testing is CR-negative. The generalized fibrillations were nearly gone just one week later, suggesting reversible sarcolemmal disruption possibly related to enhanced light chain renal excretion following aggressive hydration. Study Supported by:Disclosure: Dr. Zhang has nothing to disclose. Dr. Ferrante has nothing to disclose. Dr. Ly has nothing to disclose. Dr. Bertorini has nothing to disclose.Wednesday, April 22 2015, 2:00 pm-6:30 pm