A Rare Case of Aortic Valve Endocarditis and Acute Meningitis Due to Haemophilus influenzae

HACEK organisms represent a rare but important group of causative pathogens in endocarditis. These bacteria have historically been associated with culture-negative endocarditis; however, modern laboratory techniques have made this less common. In this case, we present a 74-year-old man who presented with acute onset altered mentation, fever, and sepsis. He was ultimately found to have Haemophilus influenzae meningitis, cerebral empyema, aortic valve endocarditis, psoas myositis, and L2 - L3 diskitis with osteomyelitis. Although HACEK organisms are commonly found in the oropharynx and upper respiratory tract in humans, our patient did not report recent preceding dental or ENT procedures. H. influenzae is responsible for approximately 0.16% of all cases of bacterial endocarditis, representing a very limited subset. Although generally considered low virulent pathogens, this case demonstrates the unusual extent of infection from a HACEK organism, H. influenzae, causing aortic valve endocarditis as well as atypical non-cardiac sequelae, including acute meningitis.