Acute Haemophilus parainfluenzae endocarditis: a case report

INTRODUCTION: Numerous pathogens can cause infective endocarditis, including Haemophilus parainfluenzae. H. parainfluenzae is part of the H. aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae group that may cause about 3% of the total endocarditis cases, and is characterized by a subacute course and large vegetations. CASE PRESENTATION: Acute H. parainfluenzae endocarditis developed in a 54-year-old woman, with no underlying predisposing factors. The patient presented with fever of 3 days duration and a severe headache. Magnetic resonance imaging of the brain revealed multiple cerebral emboli with hemorrhagic foci. Upon suspicion of endocarditis, cardiac transesophageal ultrasonography was performed and revealed massive vegetations. The patient underwent emergency mitral valve replacement, and was further treated with ceftriaxone. Blood cultures grew H. parainfluenzae only after valve replacement, and a 6-week course of ceftriaxone was prescribed. CONCLUSION: We underline the typical presentation of large vegetations in H. parainfluenzae endocarditis, which are associated with embolic phenomena and resulting severity. Although the majority of the few cases reported in the literature are subacute in progress, our case further underlines the possibility that H. parainfluenzae endocarditis may develop rapidly. Thus, awareness of the imaging characteristics of the pathogen may enhance early appropriate diagnosis and therapeutic response.