Acute Inflammatory Demyelinating Polyradiculoneuropathy (Guillain Barre Syndrome). Patient is a previously healthy 4 year old female who presented with intermittent migratory pain and difficulty with ambulation. Patient had her influenza vaccine on Feb 23. She at feeling well until Feb. 27 when she developed a fever and very minor rash on her trunk. This all resolved within the day. She was then well until March 3. Early in the day she went to her chiropractor where she had minor adjustments and massage. This was a normal routine for her. That evening she developed pain in there bilateral thighs, difficulty ambulating, and restlessness. This continued and on March 5 she was brought to ED for evaluation. She had a normal hip ultrasound and normal hip x-rays at that time. Laboratory records show unremarkable BMP, CRP <0.29, ESR 9, CPK 59, unremarkable CBC with WBC 12.4, Hgb 14.1, Plt 293, normal UA. She was discharged to home. On March 6 she was evaluated at her PCP and was diagnosed with transient synovitis. Over the next few days her symptoms continued to persist. She started to refuse walking up stairs but would instead crawl. She continued to complain of pain primarily in her legs, but also in her arms and abdomen. She had difficulty ambulating, sitting upright, flexing her hips, or flexing her spine. She was brought back to her PCP on 3/9 and had a spinal XR which was insignificant other than stool burden. Her symptoms persisted through the day so she was brought to ED that evening for evaluation. Labs were repeated and unremarkable other than WBC 20.5 with ANC 11.6 and platelets 658. LDH was normal at 179, UA 4.7, CPK 49, BMP unremarkable, CRP <0.29, B Burgdorferi 0.03, ESR 5. She was admitted for observation. She received a fleet enema with minimal results. She had ~5 caps of MIRALAX over the next 2 days with some stool output. On 3/11 she had a normal pelvis MRI and a lumbar spine MRI with contract which was normal with the exception of "lipoma on her filum terminale." She was discharged home at that time. Since that discharge she had continued difficulty with gait. 3/12 she attempted bowel clean out with MIRALAX without significant result. She had intermittent cramping abdominal pain that time. She could not lie flat on her back due to the pain. She resisted straightening of her legs or flexion at her hips. She could not sit on the toilet due to the pain, so is wearing pull-ups. She was still fully continent. Family again contacted her PCP who suggested they bring her to clinic for another evaluation. Since February 27 patient was afebrile and without further rash. She was been eating well and had no change in weight. She did not complain of any vision changes. Mother gave her TYLENOL and ibuprofen at home for the pain without significant relief. Patient was able to walk into the ED. She later couldn't bear weight, but after TORADAL was able to ambulate with difficulty (unsteady). Labs were obtained which were significant for normal ESR, normal CRP, elevated WBC to 19.6, ANC of 10.5. She was transferred from the ED to the med/surg ward for continued observation and work up. On admission patient was found to have an elevated WBC with normal CK, CRP, and ESR. Rheumatology was consulted and felt her presentation was not consistent with a rheumatologic process. Neurology was also consulted and plan was made for LP, labs, nerve conduction study and MRI of her thigh and brain while under sedation. LP and nerve conduction studies were consistent with GBS with normal labs and imaging. Her IgA level was obtained and was normal. She received IVIG on 3/15 and again on 3/16. She received a dose of BENADRYL following her second IVIG dose after which she had flushing, increased hyperactivity and irritability, and her SpO2 went down to 80% and she was started on blow by O2. She was only on blow by for a few minutes and her flushing and irritability resolved within an hour. Improvement in her strength was noticed following her first dose of IVIG and she continued to improve throughout her admission. Her respiratory status was monitored closely during her admission with NIF. PT and OT worked with patient during her admission. She was discharged to rehab as she continued to slowly improve her neuromusc exam.