Age: 9.0
Sex: F
Vaccine: COVID19
Symptoms: Lymphopenia, Metabolic function test, Multisystem inflammatory syndrome in children, Myocarditis, N-terminal prohormone brain natriuretic peptide
Clinical narrative: The patient presented to the hospital 11/20/21 with signs and symptoms consistent with MIS-C as detailed next, felt to be triggered by previous COVID-19 infection (SARS-COV-2 nucleocapsid antibody was positive). Symptoms began the same day sh received influenza and COVID-19 vaccinations and in the context of known exposure to siblings with cold-like symptoms 1.5 months prior to admission.    In detail, her symptoms began 11/15/21 with fevers of 102 -103 degF, occurring hours after receiving an influenza vaccine and her first COVID-19 vaccine (Pfizer) at a well child visit earlier in the day. On day 2 of illness, she developed abdominal pain, nausea, loose stools, and her fevers continued. On day 3-4 of illness, she developed a diffuse confluent sunburn-like rash on her abdomen, chest, and face, which spread to her  arms (no involvement of palms/soles). Conjunctival injection developed by day 4 of illness and the rash worsened. She was brought to the ED on day 5 of illness when she felt her vision was a little blurry, where she was found to be hypotensive requiring a fluid bolus and she was admitted to the PICU. She was found to have multisystem inflammation with acute kidney injury, coagulopathy, myocarditis with elevated serum troponins but no compromised function, and vasodilatory shock.  Studies were consistent with MISC with hepatomegaly, splenomegaly, increased echogenicity of the kidneys on ultrasound, acute kidney injury with Cr of 3.6, elevated CRP, pro-calcitonin, ESR, BNP, troponin, D-dimer, and fibrinogen, hypoalbuminemia, thrombocytopenia, as well as lymphopenia (normal WBC and low absolute lymphocyte count of 800 cells/uL). Her echocardiogram showed normal ventricular function, coronary arteries and anatomy. EKG was normal. CXR was normal. Initial differential diagnosis included MISC, shock KD, toxic shock syndrome, sepsis, less likely tick-born illness (no high risk exposures). Lower extremity dopplers were normal. Sepsis/ID workup was negative by blood cultures, respiratory viral multiplex nasopharyngeal PCR panel, COVID-19 nasopharyngeal PCR, ehrlichia and anaplasma serologies and PCRs, rickettsia rickettsii serologies, and a strep A PCR test from outside pediatrics clinic was negative 2 days prior to admission. COVID-19 serologies were positive for SARS-CoV-2 nucleocapsid antibody (qualitative) and spike antibody (titer of 182 U/mL; normal reference < 0.8 U/mL), indicating a past infection which was felt to be the trigger for her MIS-C.    She was treated for MIS-C with IVIG, steroids, lovenox, and high dose aspirin. Lisinopril was given for elevated blood pressures presumably secondary to steroids. Empirical antibiotics for possible sepsis or toxic shock syndrome (ceftriaxone, clindamycin, vancomycin) were discontinued 48 hours of blood culture negativity and with no evidence of focal infection. She had excellent clinical recovery on MIS-C treatments. Pressors with norepinephrine were weaned off within 12 hours of admission, and her rash and fevers quickly resolved along with her other presenting symptoms. Inflammatory markers eventually were all improving by the day of discharge 11/24/22. She was discharged to home on weaning oral steroids, lovenox, aspirin, lisinopril. Upon hematology and cardiology outpatient follow up over the next two months (visits on 12/1/21 and 1/12/22 with repeat labs 1/3/22), she was doing well without any cardiac symptoms of chest pain, shortness of breath, palpitations, or syncope. She was noted to have demonstrated full recovery and with no recurrence of symptoms or inflammation on repeat labs (1/3/22) after coming off the steroids (completed 12/27/21). Lovenox was stopped 12/1/21. Aspirin was stopped 1/12/22 after her vW and FVIII levels normalized indicating resolution of vasculitis. She received her second COVID-19 vaccine (Pfizer) on 1/13/22. A cardiac MRI was normal on 1/24/22.