Children with coronavirus may have neurological symptoms in the absence of the respiratory ones typically associated with Covid-19, researchers have said.

A new study indicates that experts should consider Covid-19 when children present with these signs.

This is because respiratory symptoms are uncommon in children, or, when present, are mild and easily missed, scientists suggest.

It is also because data indicates that children carry the disease without symptoms.

The findings come after experts previously identified links to Covid-19 in a new and distinct condition in children.

The illness, named Paediatric Inflammatory Multisystem Syndrome Temporally associated with Sars-CoV-2 (PIMS-TS), was first recognised in April and up to 300 cases have been identified in the UK.

Writing in a paper published in JAMA Neurology, the authors of the new research said: “Children with Covid-19 may present with new neurological symptoms involving both the central and peripheral nervous system and splenial changes on imaging, in the absence of respiratory symptoms.

“This diagnosis should be considered within the differential diagnosis of splenial lesion.”

The study looked at patients younger than 18 years with Sars-CoV-2 infection and neurological symptoms admitted to Great Ormond Street Hospital for Children between March 1 and May 8 2020.

Of the 27 children with Covid-19 Paediatric Inflammatory Multisystem Syndrome, four who were previously healthy had new-onset neurological symptoms.

Symptoms included encephalopathy – damage or disease to the brain, headaches, brainstem and cerebellar signs – critical abnormalities of neurological activity in the control of automatic function to survive like breathing and heartbeat, muscle weakness, and reduced reflexes.

All four patients required intensive care unit admission for the treatment of Covid-19 Paediatric Inflammatory Multisystem Syndrome.

Changes were seen in all of the children on magnetic resonance imaging of the brain, the scientists from University College London reported.

Neurological improvement was seen in all patients, with two making a complete recovery by the end of the study.

Dr Ming Lim, reader in paediatric neurology at King’s College London, and consultant paediatric neurologist at the Children’s Neurosciences Centre, Evelina London Children’s Hospital, said: “In recent months, a novel post-infection hyper-inflammatory syndrome now termed PIMS-TS has been identified in children.

“This group of children, now in excess of 150 cases seen in London and up to 300 in the UK, initially present with a high fever, rash, conjunctivitis and abdominal pain, progress to have multi-organ failure often requiring prolonged high-level intensive care support.

“PIMS-TS is distinct from the manifestations of Covid infections in adults and the prior reports of childhood Covid infection.”

Dr Lim added: “This case series is the first to report the neurological features affecting children with PIMS-TS that are only starting to be recognised, either at outset or through the course of acute disease.

“Importantly, the longer-term neurological course and subsequent sequelae of this condition now requires urgent evaluation.

“Furthermore, the long-term multisystem, particularly cardiac outcomes of PIMS-TS, including the potential for future relapse, and how these impact on health and neurological, psychological and cognitive outcome, are also unknown.”