PIMS-TS: An update on the COVID-related paediatric condition

Lung health
PIMS-TS: An update on the COVID-related paediatric condition

COVID-19 infection in children and adolescents is often mild or asymptomatic, but rarely can trigger a multi-system inflammation disorder that requires urgent care. We provide the latest findings on the aetiology of PIMS-TS from the world’s largest study on the condition led by our consultants.

A rare syndrome requiring urgent care

In the middle of the UK’s first lockdown in 2020, a number of teenagers were admitted to the paediatric intensive care unit at Evelina London Children’s Hospital requiring inotropic support in the absence of infection.

It would later emerge that these teenagers, like others across the world, were affected by a complication of COVID-19 resulting in multi-system inflammatory disease, often leading to multiorgan failure and shock that required urgent intensive care.

This condition was defined and named ‘paediatric inflammatory multi-system syndrome temporally associated with SARS-CoV-2’ (PIMS-TS) by the Royal College of Paediatrics and Child Health in the UK, and MIS-C (multisystem inflammatory syndrome in children) by the WHO and CDC in the US.

What increases the risk of developing PIMS-TS?

Although it was originally described as a Kawasaki-like syndrome, the age of presentation for PIMS-TS is generally older. Where Kawasaki syndrome mostly affects children under 5, PIMS-TS presents with greater frequency in those aged 8-15. However, exactly how the infection trigger this syndrome is still unknown and it remains a rare outcome of COVID-19 infection in children and adolescents.

What is known is that the syndrome tends to appear 4-6 weeks after COVID-19 infection. Also, the COVID-19 infection is usually mild or asymptomatic, in-line with what is normally expected for these age groups (patients do not experience a more severe form of the infection before presenting with PIMS).

In terms of a mechanism of disease, it is thought that the viral spike protein may resemble a superantigen that can drive the development of a cytokine storm, triggering the multi-system inflammation observed with PIMS. Viral sequencing studies have also revealed that different strains of the virus do not influence the likelihood of the syndrome developing. It is therefore more likely that factors such as host genetics that trigger it.

To further understand the syndrome and its aetiology, our consultant paediatric cardiologists, Professor Alain Fraissé and Dr Carles Bautista, recently led the world’s largest cohort study on PIMS-TS across 13 countries. Among other findings, it demonstrated that patients from a BAME background were most susceptible, with almost a third of patients with PIMS-TS in the study being from a black background (30.6%).

In addition, obesity was a common comorbidity associated with the development of the syndrome, with 26.2% of patients meeting this criterion. However, no other potential risk factors (including diabetes) were found to be associated. Interestingly, the study also revealed that a shorter period of symptoms before admission to hospital significantly increased the likelihood of a worse outcome and the requirement for extracorporeal membrane oxygen and/or death.

What should doctors look out for?

“What our study demonstrated is that it is essential to admit patients to an acute care centre as soon as possible with this condition, to ensure the best outcomes. It is hard to predict which patients will deteriorate most rapidly, but in the right setting they may be stabilised promptly to enable their recovery. Rapid accurate diagnosis is therefore key,” explains Dr Bautista. 

Clinical features of PIMS-TS:

  • Aged 18 or under
  • Recent history (previous 4 to 6 weeks of COVID-19 infection or contact with infected individual
  • Abdominal symptoms: diarrhoea, pain and vomiting
  • Conjunctivitis and/or widespread rash
  • Cracked lips and/or strawberry red tongue
  • Headache
  • Hypotension and/or dizziness
  • Lethargy and myalgia
  • Peeling on hands and feet
  • Prolonged high fever
  • Tachycardia +/- shock

Multi-disciplinary care is needed

“As PIMS-TS can be a multi-system condition, a multi-disciplinary approach is needed for its successful treatment. At Royal Brompton Hospital, we work in partnership with St.Mary’s Hospital to provide the best care,” explains Dr Bautista.

“With our expertise in heart and lung care, we can work quickly to diagnose the condition and stabilise the acute cardiac and respiratory problems associated with it. As the gastrointestinal system is also often involved as well as other systems, we tap into the expertise of our partner hospitals for a total body approach to care.”