History of Present Illness (from Admission H&P): Patient is a 18 Y female with a history of well controlled T1DM (HbA1c 8) who presents with a chief complaint of 1 day of muscle pain, muscle spasm, and fever. She went to her PCP on Monday (2 days prior) for a checkup as well as vaccines. She received both meningococcal vaccines (4B and B) in her right arm and DTAP and PPV 23 in her right leg. She was slightly fatigued that day after her vaccines. The following morning, she started feeling nauseated and then had an episode at school of near-syncope upon standing so went to the nurse and then mom brought her to PCP. She describes this as feeling a combination of vertigo and lightheadedness and her vision going dark. She was orthostatic but otherwise fine so PCP sent them home and told them to drink lots of fluids. Last night, she developed significant redness and swelling of the right leg, around the area of her vaccine and then also developed severe muscle pains in bilateral legs, back, and neck, which were worst in her lower back. She started having muscle twitching of bilateral upper extremities, which were not suppressible with tactile pressure. These movements were distressing for her in that they were uncomfortable and made her more sore. Mom tried ibuprofen at home which did not help, so they brought her to ER. While in the ER, she developed a scratchy throat and dry cough as well as fever to 39.5. Of note, she has not had any vomiting or diarrhea, has not had any rash other than the reaction to the vaccine, has not had any somnolence or alteration in mental status. She has never had any reactions to vaccines in the past and has no known allergies. Her glucoses have not been running high or low. She has had very poor appetite for the past day. Patient was admitted for high fevers, myalgia, and cellulitis of right thigh at site of previous vaccine. Initially, we checked for flu and other viral etiologies to explain the fever and myalgia, but these were all negative. She was started on clindamycin to cover staph and strep organisms for cellulitis. Neurology saw her with the initial concern for myoclonic jerks and felt these to be purely musculoskeletal. Over the course of her first day in the hospital, her cellulitis rapidly worsened with doubling in the size of the area of erythema and pain, and she continued to be febrile to 40 and did not defervesce with toradol or acetaminophen. During this time, she also was tachycardia and tachypnea with concern for clinical compensated sepsis. Blood cultures were repeated and she was given a NS bolus and broadened to vancomycin for staph bactericidal coverage and ceftriaxone for gram negative coverage with some concern for necrotizing fasciitis. She clinically stabilized from a hemodynamic standpoint at that point and fevers never returned. Ultrasound at that point did not show an abscess or DVT. She had an MRI the next morning which showed extensive cellulitis down to the fascia but no abscess, no significant myositis, no crepitus. The following day, her pain continued to be severe and the area of erythema continued to spread. ID was consulted and then ceftriaxone was switched to ceftazidime for pseudomonal coverage. Her cellulitis then clinically improved with clearing of the erythema, so the vancomycin was stopped. With continued improvement, she was switched to oral clindamycin and ciprofloxacin and observed for 1 more day. Her pain was initially controlled with toradol, morphine, oxycodone, acetaminophen. With clinical improvement on antibiotics, her pain management was switched to orals and she only required ibuprofen and 1 dose of oxycodone in the 24 hours prior to discharge. Endocrinology followed her during hospitalization and her blood sugars were well controlled except for a few episodes of hypoglycemia related to poor PO intake and possibly switching from home NOVOLOG to hospital HUMALOG.