Cause of mysterious hepatitis illness in children still unknown

Three-quarters of the acute hepatitis cases of unknown origin have occurred in children less than five years of age. — AFP

Hundreds of infants and young children worldwide have been struck by acute hepatitis of unknown origin since March (2022).

This illness, which causes a sudden onset of liver inflammation (i.e. hepatitis), has been confirmed in one Malaysian child.

The previously-healthy four-year-old boy from Sabah rapidly deteriorated after his diagnosis in March (2022), and had to undergo a liver transplant at the end of that month.

He was subsequently discharged in good health in April (2022).

Says paediatrician Dr Connie Teo Kai Ru: “The clinical syndrome among identified cases is acute hepatitis with significantly elevated liver enzymes.

“Many of the symptoms that have been reported include gastrointestinal issues such as abdominal pain, diarrhoea and vomiting, as well as increased levels of liver enzymes and jaundice (yellowing of the whites of the eyes).

“Other symptoms of this acute hepatitis include dark urine, pale/grey-coloured faeces, itchy skin, and muscle or joint pain.

“In most cases, the patient did not present with a fever.

“Hence, the common viruses that cause acute viral hepatitis (i.e. hepatitis viruses A, B, C, D and E) have not been detected in any of these cases.”

She notes that due to the unknown source of infection, it is difficult to know what specific precautions to take in preventing the spread of the disease, especially for children who appear to be more susceptible and vulnerable to this disease.

Indeed, oftentimes, patients who have hepatitis do not even realise they are carrying a hepatitis virus.

She says: “Although most cases of hepatitis do not show obvious signs and symptoms, one should see a doctor if they develop a poor appetite, nausea, vomiting or start to get abdominal pain.

“Complications of hepatitis result in liver cirrhosis, which is severe liver damage that causes cell death, or the most harmful consequence is liver cancer.”

According to Dr Teo, studies in several countries, including the United Kingdom, which was the first to report such cases in March (2022), suggest that this acute hepatitis in children may be transmitted by a mutated adenovirus type 41F.

Based on research by the World Health Organization (WHO), the virus was found to start spreading during the Covid-19 pandemic.

“The adenovirus has been found in 75% of cases tested in the UK, with the majority of cases showing Type 41 adenovirus.

“However, many of the remaining cases did not have proper samples taken, highlighting the importance of appropriate sampling (whole blood) to further characterise the type of adenovirus detected.

“Additionally, type 41 adenovirus infection has not been previously linked to such a clinical presentation in otherwise healthy children,” she says.

More thorough research is still being conducted as an adenovirus infection does not explain the more severe cases observed.

Dr Teo adds that it is important to note that the current association identified with the adenovirus could be an incidental finding.

“Adenovirus usually does not cause hepatitis in children, but in such affected children, there may be a co-factor, such as a toxin or previous viral infection.

“The virus also comes in many genetic varieties and can occur at any age in children who will display symptoms typical of respiratory illnesses, such as fever, coughs, colds and sore throats.

“I also read some research from Japan where the adenovirus was found in respiratory droplets or secretions, or via direct contact with an infected person, stool or contaminated surface,” she says.

The mutated adenovirus type 41F can last on environmental surfaces for a long time, making its transmissibility much higher than other viruses, she adds.

“The standard hygiene recommendations, which include good hand hygiene, as well as cleaning and disinfecting surfaces in settings frequented by young children, should always be followed,” says Dr Teo.

Additionally, parents should ensure that their children’s vaccinations are up to date.

“Vaccination is still a necessity – it has been implemented for so long, especially in preventing hepatitis A and B among children and has proven to be effective.

“We do not deny that this virus can cause significant effects on a patient, but also bear in mind that there are various methods of treatment that can be done,” she says.

Parents should be alert and ready to bring their children for consultation or treatment if they show any symptoms.

And as the presentation of hepatitis may not be obvious in the early phase, it is always advisable to return to see the doctor if the child is not better 48 to 72 hours after the initial consultation.