Clinical illness and outcomes in patients with Ebola in Sierra Leone

Abstract

Background: Limited clinical and laboratory data are available on patients with Ebola virus disease (EVD). The Kenema Government Hospital in Sierra Leone, which had an existing infrastructure for research regarding viral hemorrhagic fever, has received and cared for patients with EVD since the beginning of the outbreak in Sierra Leone in May 2014.

Methods: We reviewed available epidemiologic, clinical, and laboratory records of patients in whom EVD was diagnosed between May 25 and June 18, 2014. We used quantitative reverse-transcriptase-polymerase-chain-reaction assays to assess the load of Ebola virus (EBOV, Zaire species) in a subgroup of patients.

Results: Of 106 patients in whom EVD was diagnosed, 87 had a known outcome, and 44 had detailed clinical information available. The incubation period was estimated to be 6 to 12 days, and the case fatality rate was 74%. Common findings at presentation included fever (in 89% of the patients), headache (in 80%), weakness (in 66%), dizziness (in 60%), diarrhea (in 51%), abdominal pain (in 40%), and vomiting (in 34%). Clinical and laboratory factors at presentation that were associated with a fatal outcome included fever, weakness, dizziness, diarrhea, and elevated levels of blood urea nitrogen, aspartate aminotransferase, and creatinine. Exploratory analyses indicated that patients under the age of 21 years had a lower case fatality rate than those over the age of 45 years (57% vs. 94%, P=0.03), and patients presenting with fewer than 100,000 EBOV copies per milliliter had a lower case fatality rate than those with 10 million EBOV copies per milliliter or more (33% vs. 94%, P=0.003). Bleeding occurred in only 1 patient.

Conclusions: The incubation period and case fatality rate among patients with EVD in Sierra Leone are similar to those observed elsewhere in the 2014 outbreak and in previous outbreaks. Although bleeding was an infrequent finding, diarrhea and other gastrointestinal manifestations were common. (Funded by the National Institutes of Health and others.).

Figure 1. Case Fatality Rates among Patients with Ebola Virus Disease (EVD) in Sierra Leone

Shown are case fatality rates among patients with confirmed EVD, a known outcome, and available data, according to age and viral load.

Figure 2. Signs and Symptoms in Patients with Fatal and Nonfatal EVD

Shown are signs and symptoms at presentation among patients with confirmed EVD, which were assessed by a review of the charts of patients who had known outcomes. The only symptoms that were significantly associated with a fatal outcome were weakness, dizziness, and diarrhea. Any fever at presentation was not associated with a fatal outcome. However, a temperature above 38°C (100.4°F) had such an association.

Figure 3. Vital Signs in Patients with Fatal and Nonfatal EVD

Shown are findings for six vital signs at presentation in patients with confirmed EVD who had known clinical outcomes, according to a review of chart data. Blue shading indicates normal ranges for the measurements. The only vital sign at presentation that was significantly associated with a fatal outcome was increased body temperature (above 38°C [100.4°F]). The T bars indicate standard errors.

Figure 4. Comparison of Metabolic Measures in Patients with Fatal and Nonfatal EVD

Laboratory measurements at presentation that were associated with a fatal outcome included elevated levels of blood urea nitrogen, creatinine, and aspartate aminotransferase (AST). Blue shading indicates normal ranges for the various measures. Results for sodium, potassium, chloride, glucose, calcium, albumin, total protein, and total bilirubin are provided in Table S10 in the Supplementary Appendix. The T bars indicate standard errors. ALT denotes alanine aminotransferase. To convert the values for blood urea nitrogen to millimoles per liter, multiply by 0.357. To convert the values for creatinine to micromoles per liter, multiply by 88.4.