Fever and increased gastrointestinal uptake on positron emission tomography after anti-tumour necrosis factor therapy: a case report of Whipple's disease

Introduction: Whipple's disease is a rare condition that can present with atypical and non-specific features requiring a high index of suspicion for diagnosis. Case Presentation: We present a case of a man in his 40s with peripheral arthritis and bilateral sacro-ileitis for 4-5 years that was treated with an anti-tumour necrosis factor therapy, which led to worsening of his symptoms, elevation of the inflammatory markers, and the development of fever, night sweats, anorexia, and a significant weight loss. The patient had no abdominal pain, diarrhoea, or other gastrointestinal symptoms. An FDG-PET scan showed increased uptake in the stomach and caecum. Endoscopic examination showed inflammatory changes in the stomach and normal mucosa of the duodenum, jejunum, terminal ileum, caecum, and colon. Histopathology was inconclusive, but the diagnosis was confirmed with Tropheryma whipplei PCR testing. He had no neurological symptoms, but cerebrospinal fluid Tropheryma whipplei PCR was positive. He was treated with intravenous ceftriaxone 2 g daily for 4 weeks, followed by trimethoprim/sulfamethoxazole 160/800 mg twice daily for 1 year with close monitoring and follow-up. Conclusion: This case presents an atypical and challenging presentation of Whipple's disease and the importance of proactive testing for neurological involvement.