Snapshot A 35-year-old man presents to the emergency department for difficulty with walking. His symptoms began approximately 1 week ago and has progressively worsened. He has noticed some lightheadedness with standing up from a seated position and some numbness in the bilateral lower extremities. Physical examination is notable for 4/5 power and decreased sensation to light touch and pinprick in the bilateral lower extremity and absent patellar and ankle reflexes. A lumbar puncture is performed, which demonstrates a cell count of 1/uL, protein is 135 mg/dL, and glucose is 65 mg/dL. He is admitted to the neurology floor for frequent negative inspiratory pressure and vital capacity measures and intravenous immunoglobulin. Introduction Definition an immune-mediated polyneuropathy that has many variant forms acute inflammatory demyelinating polyneuropathy chronic inflammatory demyelinating polyneuropathy Miller Fisher syndrome ophthalmoplegia ataxia areflexia Epidemiology risk factors recent infection Campylobacter jejuni most commonly identified Mycoplasma pneumoniae HIV Ebstein-Barr virus Zika virus Pathogenesis a previous infection triggers an immune response that cross-reacts with parts of the peripheral nerve via molecular mimicry damages the Schwann cells Prognosis improved outcomes with either plasmapheresis or intravenous immunoglobulin Presentation Symptoms/physical exam classic presentation typically ascending (and fairly symmetric) muscle weakness along depressed or absent reflexes other findings may include autonomic dysfunction peripheral cranial nerve palsies cranial nerve III-XII Miller Fisher variant ophthalmoplegia ataxia areflexia Imaging MRI indication typically used to rule out other causes of weakness findings in acute cases, may demonstrate enhancement and thickening of the intrathecal spinal nerve roots cauda equina Studies Spirometry to ensure adequate respiratory function intubate early if necessary Lumbar puncture albuminocytologic dissociation elevated protein normal white blood cell count Nerve conduction studies slowed conduction velocity reduced amplitude in compound muscle action potentials Differential Acute myelopathy differentiating factors spinal cord lesion on MRI Treatment Conservative acute supportive care indication to acutely manage complications of Guillain-Barre syndrome, such as respiratory failure managed with intubation hypotension managed with fluids or phenylephrine atrioventricular blocks and asystole managed with atropine or cardiac pacing Medical plasmapheresis indication hastens neurological recovery intravenous immunoglobulin (IVIG) indication hastens neurological recovery note that plasmapheresis and IVIG are equally effective Complications Respiratory failure Autonomic instability Complications from IVIG and plasmapheresis 35 year old banker presents to the ED after hitting his head when he tripped while climbing the subway stairs. He has noted his legs feeling heavy over the last 5 days and reported trouble pushing himself up afterthe fall. Rnausea, vomiting, and diarrhea 3 days ago (admits to eating discount sushi). Exam is remarkable for symetric 3/5 lower and upper extremity weakness, absent ankle and patellar reflexes and 1+ biceps reflex. He is only able to count to 10 in one breath. Routine labs, chest x-ray, and head CT are unrevealing.