Dengue fever is a common mosquito-borne viral infection in many tropical regions, including Sudan. Some patients develop severe forms of the disease, such as dengue hemorrhagic fever, which can lead to plasma leakage, bleeding, organ involvement, and life-threatening complications. Early identification of patients at risk of severe disease is essential for timely management and improved outcomes.

This study aims to describe the abdominal ultrasound findings in patients diagnosed with dengue fever and to examine how these findings relate to clinical features and blood test results, particularly low platelet counts (thrombocytopenia). Ultrasound is a non-invasive and widely available imaging method that may help detect complications early and guide clinical decision-making.

In this retrospective cross-sectional study, medical records and archived abdominal ultrasound images of 150 patients with laboratory-confirmed dengue infection were reviewed. The study evaluated the frequency of findings such as gallbladder wall thickening, fluid accumulation in the abdomen and chest, liver and spleen enlargement, and rare complications like internal bleeding. These imaging findings were then compared with patient demographics and laboratory results to determine their clinical significance.

By identifying the most common ultrasound features and their association with disease severity, this study seeks to support the use of abdominal ultrasound as a practical tool for risk assessment and monitoring in dengue-endemic settings. The results may help clinicians recognize severe dengue earlier and improve patient management in resource-limited environments.

Dengue fever is a major public health concern in endemic regions, with a wide clinical spectrum ranging from mild illness to severe dengue hemorrhagic fever characterized by plasma leakage, bleeding, and organ involvement. Early identification of patients at risk of progression to severe disease remains a clinical challenge, particularly in resource-limited settings where advanced diagnostic tools may not be readily available.

Abdominal ultrasonography has emerged as a useful, non-invasive imaging modality for detecting early signs of plasma leakage and organ involvement in dengue infection. Findings such as gallbladder wall thickening, ascites, pleural effusion, hepatomegaly, and splenomegaly have been reported to correlate with disease severity. However, data on the utility of these sonographic features in Sudanese populations remain limited.

This study was designed as a retrospective cross-sectional analysis conducted in Kassala, Sudan, covering the period from July 2024 to February 2025. It utilized archived abdominal ultrasound images and corresponding clinical and laboratory data of patients with NS1-confirmed dengue infection. The study focused on systematically evaluating predefined sonographic parameters and examining their relationship with hematological indicators, particularly platelet count as a marker of disease severity.

Statistical analysis was performed to determine the strength of associations between imaging findings and clinical severity indicators. Special attention was given to identifying imaging patterns that may serve as early predictors of severe disease, as well as documenting less common but clinically significant complications.

The findings of this study are intended to contribute to the existing body of evidence supporting the role of abdominal ultrasound in dengue management. By clarifying its prognostic value, the study aims to inform clinical practice and encourage the incorporation of ultrasound into routine assessment and risk stratification protocols in dengue-endemic and resource-constrained settings.

Inclusion Criteria:

• Patients with laboratory-confirmed dengue infection (NS1 positive)
• Patients who underwent abdominal ultrasonography during the course of illness
• Availability of complete clinical, laboratory (including platelet count), and ultrasound data
• Patients of all age groups and both sexes

Exclusion Criteria:

• Patients without confirmed dengue diagnosis
• Patients with incomplete or missing clinical, laboratory, or ultrasound records
• Patients with pre-existing hepatic, hematologic, or abdominal conditions that may affect ultrasound findings (e.g., chronic liver disease, malignancy)
• Poor-quality or non-interpretable ultrasound images

The study population consisted of patients with confirmed dengue infection who presented to healthcare facilities in Kassala, Sudan, between July 2024 and February 2025. All included patients had undergone abdominal ultrasonography as part of their clinical evaluation. Demographic, clinical, laboratory, and imaging data were retrospectively collected and analyzed to assess the relationship between ultrasound findings and disease severity.