A 56–year–old male presented with generalized body aches, chills and fever for 8 days. Symptoms were associated with palpitation, sweating, headache, and dry cough. He denied any IV drug abuse. Physical exam showed tachycardia with irregularly irregular pulse, high grade fever of 40°C, precordium auscultation revealed normal heart sounds with no murmur. Site of pacemaker was intact with no tenderness or erythema, Lung exam revealed bilateral crackles, Initial blood tests revealed WBC of 12.400 with 22% band and hemoglobin of 10.1. ESR was 127. Chest X–ray showed bilateral multiple pulmonary infiltrates and pleural effusions. Initial management included blood culture and empirical antibiotics for presumed community acquired pneumonia. On day five, one set of blood culture grew Haemophilous Parainfluenzae. Transthoracic echocardiogram showed no vegetation. Despite of the antibiotics management, he remained febrile with worsening body aches and lethargy. Twelve sets of repeated blood cultures were negative. TEE was performed and showed large vegetation on the tricuspid valve. The diagnosis of Haemophilous Parainfluenzae infective endocarditis complicated by pulmonary septic emboli was made. He was treated with intravenous antibiotics for an additional 6 weeks. Physical examination, TEE and surveillance blood cultures were negative at the 3–month follow–up, and the patient had been well since.
Numerous pathogens can cause infective endocarditis (IE), including Haemophilus parainfluenzae. H. parainfluenzae is part of the HACEK group that may cause about 3% of the total endocarditis cases, and is characterized by a subacute course and large vegetations. Infective endocarditis has multifarious manifestations. Diagnosis can be challenging and its capacity to mimic other conditions may obscure the outcome in those cases where classic manifestations are not evident. In our case, we prematurely discounted the diagnosis of IE; despite he had no audible murmur and had a single positive blood culture for HACEK pathogen out of fourteen sets, several other findings like anemia, persistent fever, constitutional symptoms and elevated inflammatory markers, all these guided us to initiate a workup for infective endocarditis . Furthermore, our case emphasizes the relative insensitivity of the transthoracic echocardiogram and the importance of the transesophageal echocardiogram for the diagnosis of endocarditis. Likely the presence of pacemaker as a foreign body was only imminent risk factor in this case.
Our case emphasizes the importance of detection of HACEK group infective endocarditis. Although persistent bacteremia is a major criterion for the diagnosis of Infective Endocarditis, HACEK group organisms lack this feature since they are hard to grow on regular growth media. A thorough cardiac examination and evaluation with trans–thoracic and esophageal echocardiogram is a crucial step while initiating empiric antibiotics treatment.
Figure 1Transesophageal echocardiogram (TEE) illustrating large mobile echodensity (vegetation) on the tricuspid valve (arrow) and pacemaker wire crossing through the right atrium and tricuspid valve (arrow head). (RA: right atrium, RV: right ventricle).