Lessons Learned From a Case of Behcet's Disease Presenting With Fever and Life-Threatening Venous Thromboembolism.

Infection mimics pose a challenge in the world of infectious diseases. Fever of unknown origin (FUO) requires careful consideration for a broad range of diagnoses. The answer often lies in a careful history and dedicated clinical examination. A delay in diagnosis can result in greater morbidity for the patient. We present the diagnostic challenges in a patient with an infection mimic, Behcet's disease (BD), who presented with recurrent venous thromboembolism (VTE) and fever of unknown origin (FUO). We present the case of a 53-year-old male of Irish Caucasian ethnicity who presented with a history of fevers and recurrent VTE at a university hospital in Dublin, Ireland. Past medical history includes schistosomiasis, which was treated following a trip to sub-Saharan Africa. Our patient was previously diagnosed with a provoked deep vein thrombosis (DVT). He went on to experience four subsequent episodes of VTE, including DVT, pulmonary embolism (PE), and cerebral venous sinus thrombosis (CVST) while on different forms of anticoagulation. On each of these occasions, there was a concern for sepsis due to fevers > 38°C and a C-reactive protein (CRP) > 200 mg/L. The infection workup included routine laboratory tests, blood and urine cultures, CT of the abdomen and pelvis (CTAP), echocardiogram, and PET-CT, all of which were unrevealing. However, a focused clinical examination revealed evidence of subtle scrotal and oral ulceration, pustulation, and erythema at several sites in his upper limb following venesection and cannulation. In this context, a diagnosis of Behcet's disease was considered. A diagnosis of Behcet's disease can only be confidently made after the exclusion of other potential etiologies. In this case, we had to consider a broad range of infectious (malaria, schistosomiasis, rickettsial disease, and endocarditis) and noninfectious (malignancy, antiphospholipid syndrome (APS), myeloproliferative disorders, and paroxysmal nocturnal hemoglobinuria (PNH)) diseases. A delay in diagnosis comes at the cost of increased morbidity and mortality for the patient. A detailed history and clinical examination are key, in addition to a high index of suspicion. Following the induction of high-dose steroid, our patient is doing very well on maintenance adalimumab. From an anticoagulation perspective, he is warfarinized and has not had any further episodes of VTE.