Think dengue in the febrile returned traveller

As more and more Australians travel to Asia, it is vital clinicians can recognise and manage dengue

---

Fever in returned travellers should only be treated with NSAIDs after excluding dengue as a diagnosis, researchers advise.

An Australian study of more than 200 patients hospitalised for dengue over a three-year period found two in five had presented with signs of severe dengue, however most of these signs weren’t recognised as such.

“Even more worrying was that NSAIDs were prescribed to treat fever in 22% of cases, exposing patients to risks of further bleeding complications and renal impairment,” the authors said.

As more and more Australians travel to Asia, “it is vital for averting serious outcomes that clinicians can recognise and manage dengue”, the authors wrote.

According to the study, dengue’s commonest warning signs were fever, mucosal bleeding and abdominal pain. Headache also occurred in three quarters of those hospitalised.

Other commonly seen symptoms were retro-orbital pain, myalgia and arthralgia, which occurred in 33%, 67% and 43% of patients respectively.

More than one third reported diarrhoea and 20% reported abdominal pain, the study found.

The most common lab findings were leukopenia, thrombocytopenia and elevated liver enzyme levels.

Despite dengue commonly being thought to be more severe in those with exposure to multiple serotypes, some patients in this study developed haemorrhagic manifestations and severe disease on first exposure.

Previous exposure was no more likely to result in hospitalisation compared to those exposed for the first time, the authors found.

“Travellers without prior exposure to dengue can also develop severe dengue,” they said.

Dengue can manifest with symptoms that range from a mild febrile illness and a widespread rash, to shock or haemorrhage on the severe end of the spectrum.

In its three-phase course, dengue begins in the febrile phase between two and seven days, followed by the critical phase in which fever resolves and increased capillary permeability causes plasma leakage, and finally the recovery phase when patients may have a new rash that looks like “isles of white in a sea of red”, the authors explained.

This usually occurs on the palms and soles of the patients.

In an accompanying editorial, Adjunct Associate Professor David Lye, of Singapore’s Tan Tock Seng Hospital, said that Australian doctors need to think of dengue in returned travellers with fever.

“Referral for specialist opinion and confirmation of dengue virus infection by rapid diagnostic tests, such as non-structural antigen 1 assay, are appropriate when there is doubt about the diagnosis,” Professor Lye wrote.

Between 50 to 100 million people are estimated to be infected with dengue each year, and the number of Australians returning from overseas with the virus has increased over the last decade.

Since 2013, around 1800 cases of dengue were reported each year in Australia.

Almost half of those hospitalised in this study had contracted the virus in Indonesia.

Returned travellers who are suspected of having dengue can be managed by GPs with assistance from local infectious diseases services, or referred to hospital for further assessment, the study authors said.

“The main objectives of the referral would be to assess the patient for warning signs of severe dengue, and to decide whether admission for intravenous fluid therapy and biochemical monitoring is appropriate.”

One patient in the study had severe dengue, but no patients died.

MJA 2017; online 10 April