Sacroiliitis and endocarditis in the absence of fever: an unusual clinical presentation following diarrhea in a young patient

We present a case of a 23-year-old woman who developed afebrile left-sided sacroiliitis and tricuspid valve endocarditis caused by Staphylococcus aureus, one week after experiencing a bout of diarrhea. The patient presented with bilateral lower extremity weakness and left sacroiliac joint pain, without fever. Diagnostic workup, including laboratory tests, imaging studies, and synovial fluid analysis, confirmed the diagnosis of S. aureus septic arthritis. The patient subsequently developed tricuspid valve endocarditis, diagnosed by transthoracic echocardiography. Management involved a prolonged course of intravenous clindamycin, as the patient had an allergic reaction to vancomycin. This case highlights the importance of considering infectious etiologies in patients presenting with musculoskeletal complaints, even in the absence of fever, and underscores the potential for hematogenous spread of infection from one site to another. Further research is needed to elucidate the pathophysiological mechanisms underlying afebrile presentations of serious infections and to identify risk factors for atypical clinical manifestations.