Chronic inflammatory demyelinating polyneuropathy; This literature-non-study case was reported in a literature article and describes the occurrence of CHRONIC INFLAMMATORY DEMYELINATING POLYRADICULONEUROPATHY (Chronic inflammatory demyelinating polyneuropathy) in a 66-year-old female patient who received mRNA-1273 (Spikevax) for COVID-19 vaccination.       No Medical History information was reported.    On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced CHRONIC INFLAMMATORY DEMYELINATING POLYRADICULONEUROPATHY (Chronic inflammatory demyelinating polyneuropathy) (seriousness criterion medically significant). At the time of the report, CHRONIC INFLAMMATORY DEMYELINATING POLYRADICULONEUROPATHY (Chronic inflammatory demyelinating polyneuropathy) outcome was unknown. Related      The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown.   For mRNA-1273 (Spikevax) (Unknown), the reporter considered CHRONIC INFLAMMATORY DEMYELINATING POLYRADICULONEUROPATHY (Chronic inflammatory demyelinating polyneuropathy) to be related.    No concomitant and treatment medications reported.  Company Comment:  This literature non-study case concerns a 66-year-old female with relevant medical history of type 2 diabetes mellitus with neuropathy, hypertension, and hyperlipidemia, who experienced unexpected, serious (medically significant) adverse event of special interest Chronic inflammatory demyelinating polyradiculoneuropathy which occurred at an unknown time with regards to the mRNA-1273 vaccination. Eight months prior to admission, the patient had received mRNA-1273 two vaccine series. She experienced mild fever and malaise after the second dose, fatigue which lasted for several weeks. Three months after that, she woke up with no feeling in both her legs and right arm weakness. She was admitted to the hospital for a stroke workup which was negative and brain imaging was unremarkable. She was diagnosed with transient ischemic attack and urinary tract infection and was discharged on aspirin, atorvastatin and appropriate antibiotics. Her leg weakness kept on gradually worsening over the next two months and she also started having electric, shooting pain moving upwards from toes to hips and both legs. She also started noticing more bilateral arm weakness. Further, over the course of the next three months, she had a faster progression of her symptoms. She started using a wheelchair, as she could not get up from the couch. Her frequency of falls gradually increased to one to two daily falls on average. Symptoms were now associated with numbness and tingling in bilateral upper extremities, poor oral intake, and unintentional weight loss of 40 pounds over eight months. Bilateral leg weakness followed a waxing and waning pattern with an overall gradual decline in her strength. She tried as-needed ibuprofen for her extremity pain. She was evaluated by neurology service and was found to have hyporeflexia on the exam. She was subsequently hospitalized for further evaluation and underwent extensive workup. Physical examination revealed decreased motor strength in all extremities involving proximal and distal muscles, more in the legs than arms. Decreased sensations of light touch were noted in all extremities. She had absent deep tendon reflexes in both lower extremities. Muscle tone and bulk were normal. Serum protein electrophoresis showed a questionable protein band that was suspicious for being a monoclonal protein in the gamma globulin region. Serum immunofixation revealed IgG kappa monoclonal protein and a slightly abnormal IgG lambda monoclonal protein, which was not apparent in the less sensitive serum electrophoresis study. Urine protein electrophoresis showed predominantly glomerular proteinuria with an additional protein band that could potentially be a monoclonal protein. Urine immunofixation revealed IgG kappa monoclonal protein. Vitamin B1, folate, vitamin D, copper, and vitamin B12 levels were within the normal range. Lumbar puncture revealed clear CSF and albuminocytological dissociation with the folwoing results: CSF protein was 237 mg/dL, glucose was 56 mg/dL, and total nucleated cell (TNC) count was 2. Nerve conduction studies demonstrated an absent sural sensory nerve response. The peroneal motor nerve response distal latencies were prolonged with significantly reduced amplitudes and significantly slowed proximal conduction velocities. The tibial motor nerve response distal latencies were significantly prolonged with reduced amplitudes. The F response was absent on the right and prolonged on the left. The nerve conduction results were consistent with prolonged distal latencies and decreased amplitudes in the bilateral peroneal and tibial motor nerve conductions, absent right sural sensory potential, and widespread active and chronic denervation in all muscles tested in both lower extremities. This pattern supported the diagnosis of Chronic inflammatory demyelinating polyradiculoneuropathy with both axonal and demyelinating features. Concentric needle electromyography of the lower extremities demonstrated diffusely abnormal insertional activity with both fibrillations and positive sharp waves in all the tested muscles. The activated motor units of the lower extremities demonstrated increased motor unit complexities, increased amplitudes, and reduced recruitment patterns. These electrodiagnostic findings were consistent with severe bilateral neuropathy with acute and chronic denervation changes consistent with chronic inflammatory demyelinating polyradiculoneuropathy. She was treated with a 2 gm/kg dosing regimen of intravenous immunoglobulin therapy and was discharged to a rehabilitation facility. At the three-month follow-up, significant improvement in her symptoms was noted. She was continued on IVIG treatment with a 0.6 gm/kg x two days every four weeks regimen. The relevant medical history of type 2 diabetes mellitus with neuropathy, hypertension, and hyperlipidemia are confounders for the events. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This literature non-study case concerns a 66-year-old female with relevant medical history of type 2 diabetes mellitus with neuropathy, hypertension, and hyperlipidemia, who experienced unexpected, serious (medically significant) adverse event of special interest Chronic inflammatory demyelinating polyradiculoneuropathy which occurred at an unknown time with regards to the mRNA-1273 vaccination. Eight months prior to admission, the patient had received mRNA-1273 two vaccine series. She experienced mild fever and malaise after the second dose, fatigue which lasted for several weeks. Three months after that, she woke up with no feeling in both her legs and right arm weakness. She was admitted to the hospital for a stroke workup which was negative and brain imaging was unremarkable. She was diagnosed with transient ischemic attack and urinary tract infection and was discharged on aspirin, atorvastatin and appropriate antibiotics. Her leg weakness kept on gradually worsening over the next two months and she also started having electric, shooting pain moving upwards from toes to hips and both legs. She also started noticing more bilateral arm weakness. Further, over the course of the next three months, she had a faster progression of her symptoms. She started using a wheelchair, as she could not get up from the couch. Her frequency of falls gradually increased to one to two daily falls on average. Symptoms were now associated with numbness and tingling in bilateral upper extremities, poor oral intake, and unintentional weight loss of 40 pounds over eight months. Bilateral leg weakness followed a waxing and waning pattern with an overall gradual decline in her strength. She tried as-needed ibuprofen for her extremity pain. She was evaluated by neurology service and was found to have hyporeflexia on the exam. She was subsequently hospitalized for further evaluation and underwent extensive workup. Physical examination revealed decreased motor strength in all extremities involving proximal and distal muscles, more in the legs than arms. Decreased sensations of light touch were noted in all extremities. She had absent deep tendon reflexes in both lower extremities. Muscle tone and bulk were normal. Serum protein electrophoresis showed a questionable protein band that was suspicious for being a monoclonal protein in the gamma globulin region. Serum immunofixation revealed IgG kappa monoclonal protein and a slightly abnormal IgG lambda monoclonal protein, which was not apparent in the less sensitive serum electrophoresis study. Urine protein electrophoresis showed predominantly glomerular proteinuria with an additional protein band that could potentially be a monoclonal protein. Urine immunofixation revealed IgG kappa monoclonal protein. Vitamin B1, folate, vitamin D, copper, and vitamin B12 levels were within the normal range. Lumbar puncture revealed clear CSF and albuminocytological dissociation with the folwoing results: CSF protein was 237 mg/dL, glucose was 56 mg/dL, and total nucleated cell (TNC) count was 2. Nerve conduction studies demonstrated an absent sural sensory nerve response. The peroneal motor nerve response distal latencies were prolonged with significantly reduced amplitudes and significantly slowed proximal conduction velocities. The tibial motor nerve response distal latencies were significantly prolonged with reduced amplitudes. The F response was absent on the right and prolonged on the left. The nerve conduction results were consistent with prolonged distal latencies and decreased amplitudes in the bilateral peroneal and tibial motor nerve conductions, absent right sural sensory potential, and widespread active and chronic denervation in all muscles tested in both lower extremities. This pattern supported the diagnosis of Chronic inflammatory demyelinating polyradiculoneuropathy with both axonal and demyelinating features. Concentric needle electromyography of the lower extremities demonstrated diffusely abnormal insertional activity with both fibrillations and positive sharp waves in all the tested muscles. The activated motor units of the lower extremities demonstrated increased motor unit complexities, increased amplitudes, and reduced recruitment patterns. These electrodiagnostic findings were consistent with severe bilateral neuropathy with acute and chronic denervation changes consistent with chronic inflammatory demyelinating polyradiculoneuropathy. She was treated with a 2 gm/kg dosing regimen of intravenous immunoglobulin therapy and was discharged to a rehabilitation facility. At the three-month follow-up, significant improvement in her symptoms was noted. She was continued on IVIG treatment with a 0.6 gm/kg x two days every four weeks regimen. The relevant medical history of type 2 diabetes mellitus with neuropathy, hypertension, and hyperlipidemia are confounders for the events. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.