Patient is an 18 year old previously healthy young lady who on 3/11/2021 and 4/1/2021 received the first and second immunizations of the COVID-19 vaccine; Lots# EN6199 & #EP7534; respectively. Subsequently, on 4/18/2021 she began to have symptoms of muscle aches and then by 4/25/2021 muscle pain and weakness. Her mom who is a doctor ordered labwork on 5/25 testing including CBC, BMP, ESR/CRP, ANA, Iron panel, TFTs around May, which was all normal except AST/ALT elevation. Mono was negative at the time. Went to pediatrician, repeated the labs around 6/3 and performed EBV titer testing.  Notable for transaminitis and EBV IgG/IGM + and elevated CK around 1700 back in May. Was diagnosed with Mono by pediatrician. Then symptoms worsen in mid-June around 6/14. At the end of June on 6/30 had additional labs performed including CBC, CMP normalized except for LFTs which were still high: AST 128, ALT 52. CK 1709. Imaging workup on 7/1/21 included Ultrasound Abdomen which showed borderline hepatomegaly, otherwise unremarkable & Ultrasound Pelvis w/o TV which showed Limited exam due to extensive bowel gas, colonic stool, inadequate bladder filling. Uterus/ovaries not visualized. Appendix not visualized. No free fluid. She also had a X-ray Chest 7/6/21 with no acute cardiopulmonary disease. Seen by Dr. on 7/9 who referred to ID & Rheum for further evaluation. Unfortunately, patient missed the 7/12 ID appointment and I do not have records of the Rheumatology appointment available for review.  She was diagnosed with polymyotitis after seeing a neurologist and rheumatologist. Reportedly had anti MDA and anti NXP antibodies present suggestive of dermatomyositis. Rheumatologist thought dermatomyositis very unlikely without skin manifestations, while neurologist felt that the diagnosis of dermatomyositis was warranted. The patient was placed on prednisone 60mg daily and was tapered down over several weeks. During that time, the symptoms initially improved 20-40%. She did have diarrhea, but stool testing for Ecoli and salmonella were negative. Neurologist recommended 5 day course IVIG, which patient started 8/11, but stopped after 3 days when patient had an ER visit on 8/13 and had US Abdomen and CT Abdomen/Pelvis which showed 1. Findings are reflective of an mild enterocolitis, 2. The appendix is within normal limits, & 3. Mild free fluid present throughout the abdomen and pelvis. 10 days later, patient was given 4th dose of IVIG, but patient got abdominal pain and the 5th dose was delayed 10 days again.  Subsequently, MRI: 09/08/21Diffuse edema in the skeletal muscles including the intercostal space, paraspinal muscles and pelvic muscles presenting polymyositis.  She was then taken to ER on 9/12 and admitted. Labs during recent admission:    09/12/21 WBC 16.6*  HGB 10.2*  HCT 32.4*  PLT 606*  On admission, her C-reactive protein was high at 8.2 mg/dL (ref 0.5-0.9) and her ESR was high at 110 mm/hr (ref 1-20). Abdominal xray with findings suggestive of a small bowel obstruction. Admission CT showed large 20cm pelvic abscess, s/p percutaneous drain.  Repeat CT showed improvement of pelvic abscess. She spent 11 days in the hospital and was discharged on 9/22. The intra-abdominal abscess was suspected to have a GI source (cultures grew E. coli and alpha hemolytic strep). Discharge diagnoses were: Pelvic abscess in female  Sinus tachycardia Polymyositis Acute abdominal pain Mild protein-calorie malnutrition   Leukocytosis  SIRS (systemic inflammatory response syndrome)  UTI (urinary tract infection)  Normocytic anemia  Thrombocytosis  Acute colitis  Associated symptoms include 15 lb weight loss since the start of her symptoms.