Background PIMS-TS has emerged as a novel disease entity. A recent systematic review reported on 662 patients diagnosed with PIMS-TS. Most of these previous studies have focused on children’s presentation at the time of admission to tertiary centres and the subsequent investigations and outcomes.

Objectives This case series aims to analyse the clinical features of PIMS-TS at initial presentation and admission to explore if there are any early features of disease, which could enable earlier identification of these patients.

Methods Retrospective data was analysed for all children (aged 0–16 years) seen in North Middlesex University Hospital Paediatric Emergency Department (PED) between March and May 2020 with an eventual discharge diagnosis of ‘PIMS-TS’ or who fulfilled the RCPCH case definition criteria for PIMS-TS. 11 patients met the criteria for inclusion. Data was collected based on the RCPCH guideline including patient demographics, presenting symptoms and laboratory findings.

Results The mean age at presentation was 7.8 years (Range 18 months -13 years). Six patients were ‘re-presentations’. The mean time interval between first presentation and eventual admission was 2.7 days (Range 0 - 5 days). The most common symptoms at first presentation were: fever (100%), vomiting (67%), headache (50%) and rash (50%). Two patients were ambulated on IV antibiotics whilst the remaining four patients were reassured and discharged from PED with no follow up. All three patients who had bloods tested on first presentation had a raised CRP and lymphopenia. Two patients had hyponatraemia (67%).

The most common presenting symptoms at admission were fever (100%), abdominal pain (73%), rash (55%), vomiting (55%) and difficulty in breathing (55%). Four patients (36%) were hypotensive on initial assessment. The pathology results showed that nearly all patients had a raised CRP (91%) and five patients were lymphopenic (45%). The mean CRP was markedly elevated (212 mg/L). ESR was measured in two patients and was raised in both. Eight patients were hyponatraemic (73%). Fibrinogen, D Dimer and fibrinogen results were elevated in all cases where these were measured. Swab results for SARS-COV-2 PCR were negative in all 11 cases. Five patients tested positive for SARS-COV-2 antibody tests. Kawasaki symptoms were underrepresented in this case series with no such symptoms at first presentation and only some such as conjunctivitis (27%) and mucous membrane involvement (9%) appearing in a small number at admission.

Conclusions The results of this case series suggest that children with early PIMS-TS can present to PED with a non-specific febrile illness a few days before they become unwell with the more severe later features. There is a suggestion that certain abnormal blood test results at this point may indicate early PIMS-TS. Further research is needed to ascertain the significance of these findings. The authors support routine nationalised data collection for all cases of PIMS-TS. In addition to exploring optimal treatment options, a review of early signs, symptoms and investigation results will assist in answering the question of whether current accepted practices for investigation and follow up for patients with fever and nonspecific symptoms are adequate to ensure timely diagnosis of PIMS-TS.