A tourist with dengue fever and visual loss

Dengue fever is a viral disease transmitted by Aedes aegypti mosquitos. It is endemic in the Americas, southeast Asia, western Pacific, Africa, and the eastern Mediterranean. The disease is divided into four stages: stage 1 dengue fever is characterised by high fever, headache, vomiting, myalgia, arthralgia, retro-orbital pain, maculopapular rash, and thrombocytopenia; bleeding complications such as epistaxis, gingival bleeding, gastrointestinal bleeding, and haematuria can develop in stages 2 to 3.1 Patients who have stage 4 dengue fever, (also known as dengue shock syndrome) present with a rapid and weak pulse, narrow pulse pressure or hypotension, cold clammy skin, and altered mental status.1 Tourists are seldom effected by dengue fever,2,3 although it is a major endemic disease, affecting millions of people worldwide. Ocular manifestations of dengue fever in tourists have been described.4,5 The opthalmological findings mainly included retinal haemorrhages as a sign of increased vascular permeability and breakdown of the inner blood retinal barrier and cotton-wool spots representing microinfarctions of the nerve fibre layer due to occlusion of precapillary arterioles. Hypoperfusion is also confirmed by delayed choroidal filling during fluorescein angiography. In our patient, the results of the electrophysiological evaluation as well as colour vision impairment are consistent with optic neuritis as a symptom of central nervous system involvement. There is no specific antiviral treatment or commercially available vaccine.