Widespread pylephlebitis and infective thromboembolism due to Streptococcus anginosus-related appendiceal rupture: A case report

<i>Streptococcus anginosus</i> group is increasingly being recognised as a cause of invasive infections with a propensity to cause pyogenic abscesses. The most common sites of infection described include intra-abdominal, skin and soft tissues and bloodstream. Prompt identification of this bacteria as a cause of pyogenic disease is needed to appropriately commence antibiotic therapy, usually with beta-lactams. We describe an atypical case of <i>Streptococcus anginosus</i> infection with pylephlebitis, widespread infective thromboembolism and presumed mycotic pseudoaneurysm related to an appendiceal rupture. In this case, a blood culture was requested for investigation due to suspicion of sepsis which confirmed <i>Streptococcus anginosus</i> bacteremia. There was evidence of a distended cystic structure within the right iliac fossa, with extensive expansive portal mesenteric occlusive thrombi and mucinous deposits in the mesorectum and liver concerning for pseudomyxoma peritonei (PMP) with hepatic metastases on computed tomography scan of the abdomen and pelvis, and on magnetic resonance imaging of the liver. Further attempts of obtaining histopathology to investigate the concerns of malignancy were undertaken including a diagnostic laparoscopy, and various endoscopic interventions, however this was negative for malignancy. After receiving two weeks of intravenous antibiotics, the patient showed marked clinical, biochemical and radiological improvement. This case highlights the need to consider sepsis as a rare but significant cause of widespread thrombotic disease.