Kawasaki disease is a rare but serious disorder that affects the blood vessels, and it can be hard to diagnose, especially when it is complicated by another infection. US researchers have found that qPCR (quantitative polymerase chain reaction) may be able to help solve these diagnostic puzzles.

Kawasaki symptoms - strawberry tongue

Source: Dong Soo Kim (derivative work – Natr – talk)

Symptoms of Kawasaki disease include red cracked lips, a red swollen tongue (‘strawberry tongue’), red eyes, swollen hands and feet, swelling in the lymph nodes in the neck, and a high fever. Diagnosis of Kawasaki disease is through a clinical assessment, as there are no laboratory tests available.

The symptoms of Kawasaki disease can be frightening but for most children there is no long-term damage. However, in some, it can lead to heart problems, including heart attacks at a young age, and Kawasaki disease is the leading cause of paediatric-acquired heart disease in the developed world. Quick diagnosis is important to try to prevent long-term heart problems, but there is no laboratory test, and other disorders can show similar symptoms, including mercury poisoning, juvenile arthritis, scarlet fever, and adenovirus infections.

Even after testing for an adenovirus, the diagnosis is still not simple, as finding evidence of infection doesn’t mean that Kawasaki disease can be ruled out. According to recent research at the Nationwide Children’s Hospital that used PCR to detect the viruses, it’s not uncommon for a child with Kawasaki disease to have an adenovirus infection as well.

The research, which was published in Clinical Infectious Diseases, aimed to see whether there were any differences in the levels of adenovirus in the upper airway in children with human adenovirus infection compared with those diagnosed with Kawasaki disease. Quantitative PCR can detect adenoviruses that persist quietly in the adenoids and tonsils, as well as viruses that are actively replicate. The researchers carried out qPCR on 77 patients with Kawasaki disease, and found that almost 13% were infected with adenoviruses.

These results confirm that simply finding evidence of an adenovirus infection should not rule out Kawasaki disease. According to Preeti Jaggi, lead study author, quantitative PCR, culture and human adenovirus typing methods may help distinguish human adenovirus disease mimicking Kawasaki disease from Kawasaki disease with accompanying human adenovirus detection.

Suzanne Elvidge is a freelance science, biopharma, business and health writer with more than 20 years of experience. She is editor of Genome Engineering, a blog that monitors the latest developments in genome engineering and that aims to educate (and sometimes to entertain!) and has written for a range of online and print publications including FierceBiomarkers, FierceDrugDelivery, European Life Science, the Journal of Life Sciences (now the Burrill Report), In Vivo, Life Science Leader, Nature Biotechnology, PR Week and Start-Up. She specialises in writing on pharmaceuticals, biotechnology, healthcare, science, lifestyle and green living, but can write on any topic given enough tea and chocolate biscuits. She lives just beyond the neck end of nowhere in the Peak District with her second-hand bookseller husband and two second-hand cats.