Paediatric inflammatory multisystem syndrome temporally associated with COVID-19 (spring 2021 update)

Question 1

estimated incidence

Answer 1

approximately 1 to 2/1000 in SARS-CoV-2-positive paediatric patients in the United States

Question 2

Mechanism

Answer 2

this syndrome is not the result of acute infection, but rather of a dysregulated immune response to earlier infection or exposure.

Question 3

The hallmark feature of PIMS/MIS-C

Answer 3

presence of high and persistent fever (>38°C for ≥3 days), unexplained by other causes.

Question 4

Clinical phenotypes

Answer 4

1) fever with hyperinflammation; 2) KD-like features (Box A); and 3) shock or shock-like states.

Question 5

Features of TSS

Answer 5

Hypotension with ≥2 of the following clinical and laboratory abnormalities:

1. Fever >38.5°C
2. Rash (diffuse macular erythema with subsequent desquamation)
3. Renal impairment
4. Coagulopathy (platelets < 100 x 109/L or disseminated intravascular coagulation)
5. Liver enzyme abnormalities
6. Acute respiratory distress syndrome
7. Extensive tissue necrosis (including necrotizing fasciitis)
8. Gastrointestinal symptoms

Question 6

Features of complete KD

Answer 6

Fever ≥5 days with at least 4 of 5 clinical criteria:

1. Erythema and cracking of lips, strawberry tongue, and/or erythema of oral and pharyngeal mucosa
2. Bilateral bulbar conjunctival injection without exudate
3. Rash: maculopapular, diffuse erythroderma, or erythema multiforme-like
4. Erythema and edema of the hands and feet in acute phase and/or periungual desquamation in subacute phase
5. Cervical lymphadenopathy (≥1.5 cm in diameter), usually unilateral

Question 7

Features of incomplete KD

Answer 7

Fever ≥5 days with <4 clinical features of classic KD

And CRP ≥ 30 mg/L, ESR ≥40 mm/h

With positive echocardiography findings*

Or 3 or more of the following:

Anemia for age

Platelet count ≥450 x 109/L after 7 days of fever

Albumin ≤30 g/L

Elevated ALT level

WBC ≥15 x 109/L

Urine WBC ≥10/hpf