Unusual presentation of complicated relapsing fever with spontaneous hemoperitoneum mimicking surgical acute abdomen: a case report.

BACKGROUND: Louse-borne relapsing fever (LBRF) is a prevalent disease in Ethiopia, affecting malnourished and impoverished populations. Historically fatal, mortality has decreased to less than 5% with antibiotics. Symptoms include high fever, rigors, myalgia, hepatosplenomegaly, jaundice, and petechial rash. Diagnosis is challenging due to Giemsa-stained blood films and PCR in resource-limited settings. CASE PRESENTATION: A 29-year-old Ethiopian patient experienced abdominal pain, vomiting, diarrhea, and high fever for 3 days. Physical examination revealed low blood pressure, oxygen saturation, tachycardia, decreased air entry, and a tender abdomen. A bedside ultrasound revealed bilateral pleural collection, dense B lines, an air bronchogram, and abdominal collection. The patient had thrombocytopenia, leukocytosis, acute kidney injury, elevated transaminase levels, and Borrelia spirochetes in her blood. The patient recovered fully within 8 days after respiratory failure. DISCUSSION: This case highlights the importance of recognizing relapsing fever (RF) as a critical mimic of surgical abdomen, preventing unnecessary surgical interventions in hemorrhagic abdominal emergencies. CONCLUSION: A life-threatening Borrelia-induced hemoperitoneum in Ethiopia was successfully managed, despite complications of surgical acute abdomen with hemoperitoneum, severe thrombocytopenia, and multiorgan involvement, highlighting the importance of infectious consideration in acute abdomen.