Renal Involvement in Dengue Fever; A baseline study

Abstract

Dengue fever is considered as the major mosquito-borne disease in Sri Lanka. According to the World Health Organization, Dengue cases have been reported since the 1960s and dramatically increased in Sri Lanka. There have been 35,054 cases reported in 2021 from all health regions of the country. Currently, it has become a major public health problem with a significant morbidity, high bed occupancy and a case fatality rate of 0.08%. Dengue virus infected individuals develop a febrile illness after an incubation period of 4-7 days, manifesting as undifferentiated fever, dengue fever, dengue haemorrhagic fever and expanded dengue syndrome. The conventional signs and symptoms of dengue fever include high-grade fever, headache, retro-orbital pain, arthralgia and myalgia, vomiting, sore throat, and maculopapular rash. The main clinical features observed during plasma extravasation are haemoconcentration, an fall in platelet count, and decreased urine output. Since haemoconcentration is controversial in patients with concealed bleeding, the actual clinical sign of leakage is a sharp drop in platelet count and urine output. Renal involvement in dengue fever is one of the identified complications. It can range from mild proteinuria to severe dengue hemorrhagic fever with acute kidney injury. This study aims to identify the phase at which renal function is compromised in dengue fever by detecting changes in urine and serum. A descriptive cross-sectional study was conducted in the three internal medicine units of Teaching Hospital, Kurunegala. All the patients diagnosed with dengue fever were recruited in the sample over a period of 12 months. Patients who are in febrile phase of dengue fever were included and patients who have entered into the critical phase at the admission and the patients with comorbidities were excluded. Demographic data of the patients, history of the illness, presenting symptoms, co-morbid conditions, and dengue contact history were recorded using interviewer administered questionnaire. Physical examination findings and other routine investigation data were obtained from the clinical records (bed head tickets) of the patients. On admission, all the patients with dengue fever were investigated for baseline tests of serum creatinine, urine osmolality, urine protein, and urine glucose after confirmation of diagnosis with serological testing. Six hourly urine samples were obtained to investigate for urine osmolality and proteins. A sample was obtained for serum creatinine at the onset of leaking from the patients who enter into leaking phase. On discharge, a urine sample and a serum sample were obtained for follow up tests. Ethical clearance for the study was obtained from Ethical Committees of Teaching Hospital, Kurunegala and the Faculty of Medicine, University of Kelaniya. Total of 135 diagnosed dengue patients were recruited and, among them were 27 patients in leaking phase. Majority of the leaking patients (66.7%, n = 18) were in adult category (25 years – 64 years) and were males (66.7%). There was a significant increment in the serum creatinine value at the time of admission and at the beginning of leaking phase (Mean difference – 0.071mg/dl SD – 0.148 with a p = 0.035). It had been settled by the time of discharge (Mean difference – 0.103mg/dl SD – 0.151 with a p = 0.005). At the same time there had been a transient proteinuria in 65% (15) patients who had fluid leak. The behaviour of urinary osmolality is exemplified in the osmolality against urine output chart of patient 5.Renal concentration ability had also been affected in the initial stage of the leaking phase, as 17 leakers out of 27 patients who entered into leaking phase showed deranged physiology with the input output and osmolality relationship. It can be concluded that the kidneys are affected in the initial stage of leaking phase of the dengue infection. and further studies needed to confirm this finding. We would like to thank Wayamba University of Sri Lanka for providing financial support for this study and all the staff members of the faculty of Medicine, Wayamba University of Sri Lanka for supporting in everyway to complete this study successfully.