Characteristics and outcome of patients with malaria presented to a Hong Kong emergency department—A retrospective cohort analysis

Abstract

Malaria remains a significant cause of illness for return travellers in Hong Kong. However, the lack of experience of local healthcare providers in tropical medicine and non‐specific presenting symptoms may lead to underdiagnosis or delayed diagnosis of the disease. We evaluate patients presenting with malaria to a local emergency department to understand the disease presentation and outcome.A retrospective review of all patients diagnosed with malaria presenting to the emergency department from January 2009 to December 2019 was conducted. Information about patient demographics, travel history, presenting vital signs and blood results, how the diagnosis is made, clinical features and outcomes were analysed. Subgroup analysis was also performed for comparison.Among the 70 patients diagnosed with malaria, most of them were imported cases (98.6%). Most were infected with Plasmodium Falciparum (50%) and Plasmodium vivax (45.7%). The common presenting symptoms included fever (100%), nausea or vomiting (42.9%) and headache (38.6%). 43 out of 70 cases had a diagnosis made in the emergency department, either by malarial blood smear (34.3%) or incidental haematological findings (27.1%). Most cases could be discharged uneventfully (90%), with six cases requiring Intensive Care Unit admission during the stay (8.6%). Patients with diagnoses not made in AED had a significantly lower mean arterial pressure (p = 0.009) and haemoglobin level (p = 0.004). Significantly lower platelet count (p = 0.002) and higher bilirubin level (p = 0.041) were found in patients who required ICU admission. For those who had AED reattendance before diagnosis was made, their creatinine levels were significantly higher (p = 0.022) and had a longer length of stay (p = 0.021).The clinical presentation of imported malaria cases is non‐specific, and high suspicion of malaria should be raised when diagnosing febrile patients with a travel history. The history of taking malarial chemoprophylaxis is essential and should have been included in most cases. Malarial‐specific treatments were rarely given in the emergency department despite diagnosis.