Unusual cardiac complications of Staphylococcus aureus endocarditis.

Bacterial endocarditis is a complex disease that is associated with significant morbidity and mortality. Staphylococcus aureus is an organism commonly responsible for acute bacterial infective endocarditis. Patients many times develop an acute fulminant infection resulting in multiple complications, even in the face of adequate therapy. We report an unusual case of S. aureus acute bacterial infective endocarditis in an immunocompromised patient resulting in multiple cardiac complications, including bacterial pericarditis with effusion, mycotic aneurysm of one of the coronary arteries, a valvular vegetation leading to an aneurysmal dilatation at the mitral-aortic junction (intervalvular fibrosa), and a fistulous communication between the left ventricle and left atrium. We present detailed echocardiographic images of these anomalies, which were subsequently confirmed intraoperatively. The patient underwent open heart surgery with pericardial patch repair of the mitral-aortic intervalvular fibrosa aneurysm and fistula.

A cluster of nosocomial herpes simplex virus type 1 pneumonia in a medical intensive care unit.

We report a cluster of 3 cases of nosocomial herpes simplex virus type 1 (HSV-1) pneumonia occurring in close temporal and physical proximity during a 1-week period, which suggested a common source. HSV-1 nosocomial pneumonia occurs in immunocompetent intubated patients and presents as otherwise unexplained profound and/or prolonged hypoxemia (decreased F(IO2), increased P(O2), and decreased A-a gradient) and "failure to wean." The diagnosis of HSV-1 pneumonia is determined by demonstration of characteristic cytopathologic findings (Cowdry type A inclusion bodies) in distal respiratory epithelial cells from bronchoscopic specimens. Acyclovir therapy results in rapid improvement and ability to wean.

Lack of value of repeat stool testing for Clostridium difficile toxin.

Twenty years ago, Clostridium difficile was first established as a cause of pseudomembranous colitis and antibiotic-associated diarrhea.C. difficile diarrhea is a widely recognized problem in the inpatient setting, with potentially significant morbidity and mortality. Antibiotics, and some chemotherapy agents, can potentially cause C. difficile colitis/diarrhea. The most commonly implicated agents are ampicillin, clindamycin, and cephalosporins. Diarrhea during antibiotic therapy is common and may be caused by C. difficile. Testing for C. difficile differentiates diarrheas into C. difficile positive and C. difficile negative. C. difficile can be carried asymptomatically as normal gastrointestinal flora, and in adults who have received antibiotic therapy, carrier states can be as high as 46%. Hospitalized patients are often colonized with C. difficile. C. difficile produces 3 virulence factors: an enterotoxin (toxin A), a cytotoxin (toxin B), and a substance to inhibit bowel motility. Different tests can be used to detect these toxins. The most widely used test is the enzyme immunoassay (EIA) for toxin A, toxin B, or both. The EIA C. difficile toxin assay has sensitivity and specificity ranges of 50% to 90% and 70% to 95%, respectively. Diagnostically, C. difficile cell culture cytotoxin assay remains the gold standard with sensitivity and specificity of 93% and 89%, respectively. Because of lack of confidence of the EIA for C. difficile, some clinicians assume an initial negative result may represent a false-negative test, and repeat testing is often done. We evaluated the value of repeat stool testing for C. difficile toxin A and B by EIA in inpatients with nosocomial diarrhea on antibiotics.

Fever of unknown origin: chronic lymphatic leukemia versus lymphoma (Richter's transformation).

Currently, malignancies are more common than infections as a cause of fever of unknown origin (FUO) in adults. Many malignant disorders are associated with fever, which may either be of the hectic-septic variety resembling an infectious disease or prolonged and low-grade. Neoplasms with either kind of fever may present as an FUO. The malignancies usually associated with fever are lymphoreticular malignancies involving the blood, liver, spleen, or bone marrow. Most malignancies do not have fever, e.g., chronic lymphatic leukemia (CLL), as part of their clinical presentation. We present a case of long-standing CLL in an elderly woman who presented with an FUO. Initially, it was thought that her FUO was caused by CLL or a CLL-related opportunistic infection. The naprosyn test was used in this patient with CLL and FUO to differentiate a malignant from an infectious etiology. Her response to naprosyn indicated that the etiology of her FUO was neoplastic rather than infectious. The absence of tonsillar enlargement and peripheral adenopathy, as well as the presence of fever, argued against CLL as the cause of her fever. Computed axial tomography scans showed central adenopathy in addition to splenomegaly. The presence of fever, splenomegaly, and central adenopathy indicated that the cause of her FUO was a lymphoma (Richter's transformation) and not CLL.

Extended spectrum beta-lactamase-producing Klebsiella pneumoniae chronic ambulatory peritoneal dialysis peritonitis treated successfully with polymyxin B.

Peritonitis is not an infrequent complication of inpatients with chronic ambulatory peritoneal dialysis (CAPD). CAPD peritonitis may be related to the catheter or secondary to perforation of an intra-abdominal viscus. The most common organisms usually associated with CAPD peritonitis are Staphylococcus aureus and Staphylococcus epidermidis (coagulase-negative staphylococci). Rarely, aerobic gram-negative bacilli have been the causative agents of CAPD peritonitis. The treatment of CAPD peritonitis usually requires removal of the peritoneal catheter and treatment with parenteral antibiotics active against the causative pathogen. We report a case of CAPD-associated peritonitis caused by an extended spectrum beta-lactamase-producing strain of Klebsiella pneumoniae. The case presented had this strain of multidrug-resistant K. pneumoniae present in blood cultures and the peritoneal fluid. Extended spectrum beta-lactamase-producing bacteria, for example, K. pneumoniae, are multidrug-resistant and sensitive to few antibiotics. This isolate was intermediately sensitive to amikacin and meropenem, but the patient did not clinically improve on these 2 antibiotics. Polymyxin B therapy was initiated after lack of clinical improvement after dialysis catheter removal and 1 week of meropenem and amikacin therapy. The patient responded rapidly to therapy with polymyxin B. Polymyxin B has a unique mechanism of action on bacterial cells and is highly active against all multidrug-resistant gram-negative organisms except Proteus species and Serratia marcescens. No toxicity was observed during therapy. Polymyxin B is being used increasingly as a therapeutic alternative to multidrug-resistant gram-negative organisms.

Post-viral influenza Streptococcus pneumoniae pneumonia in an intravenous drug abuser.

Viral influenza is a seasonal cause of community-acquired pneumonia (CAP). Viral influenza may be caused by influenza A or B and affect any age group. Viral influenza A is usually more severe than influenza B in adults. Viral influenza may present as 3 clinical scenarios: viral influenza alone, viral influenza followed in 1 to 3 days by Staphylococcus aureus pneumonia, or viral influenza followed in 1 to 3 weeks by pneumonia caused by Streptococcus pneumoniae or Haemophilus influenzae. Intravenous drug abusers (IVDAs) are predisposed to a variety of infectious diseases but are not particularly predisposed to viral influenza. We present a case of a young IVDA who presented with influenza A pneumonia who subsequently developed S. pneumoniae CAP. The pneumonococcal suprainfection was severe and prolonged and characterized by a small cavity, empyema, pneumatoceles, and bronchopleural fistulae. S. pneumoniae pleural effusions are uncommon, but pleural empyemas are often demonstrated. Tracheobronchial fistulae and cavitation are rare complications of S. pneumoniae CAP in adults. To the best of our knowledge, this is the first case of post-viral influenza pneumococcal pneumonia in an IVDA.

Fever of unknown origin: subacute thyroiditis versus typhoid fever.

Fever of unknown origin (FUO) is not infrequently a diagnostic dilemma for clinicians. Common infectious causes include endocarditis and abscesses in adults, and noninfectious causes include neoplasms and certain collagen vascular diseases, for example, polymyalgia rheumatica, various vasculitides, and juvenile rheumatoid arthritis (adult Still's disease). Subacute thyroiditis is a rare cause of FUO. Among the infectious causes of FUO, typhoid fever is relatively uncommon. We present a case of FUO in a traveler returning from India whose initial complaints were that of left-sided neck pain and angle of the jaw pain, which initially suggested the diagnosis of subacute thyroiditis. After an extensive FUO workup, when typhoid fever is a likely diagnostic possibility, an empiric trial of anti- Salmonella therapy has diagnostic and therapeutic significance. The presence of relative bradycardia, and response to quinolone therapy, was the basis of the clinical diagnosis of typhoid fever as the explanation for this patients FUO. This case illustrates the diagnostic difficulties in assessing patients with FUO with few diagnostic findings.

West Nile viral encephalitis mimicking hepatic encephalopathy.

West Nile encephalitis (WNE) has become endemic in the United States since 1999. The clinical spectrum of WNE includes aseptic meningitis, meningoencephalitis, or encephalitis with or without flaccid paralysis. The severity of WNE ranges from asymptomatic serum conversion to severe neurologic deficits or a fatal outcome. Several systemic disorders may present with encephalitis as part of the clinical presentation, for example, Legionnaires' disease, neoplasms with metastases to the central nervous system, Mycoplasma meningoencephalitis, brucellosis, Listeria, Rocky Mountain spotted fever, ehrlichiosis, and malaria. The most common infectious causes of encephalitis that need to be differentiated from WNE include herpes simplex virus 1, meningoencephalitis, and enteroviral meningoencephalitis. We present a case of apparent hepatic encephalopathy secondary to pancreatic carcinoma with liver involvement that presented as hepatic encephalopathy mimicking WNE. We conclude that patients presenting with encephalitis in the summer months should have serum/cerebrospinal fluid serologic studies sent for WNE even if an alternate explanation seems to explain the clinical syndrome.

Methicillin-resistant Staphylococcus aureus prosthetic aortic valve endocarditis with paravalvular abscess treated with daptomycin.

Prosthetic valves have been used extensively for severe cardiac valvular dysfunction for the past 3 decades. Prosthetic cardiac valves may be infected with organisms causing bacteremia, particularly gram-positive cocci. Staphylococcus epidermidis (coagulase negative staphylococci) and Staphylococcus aureus , both methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) strains, are the most frequent pathogens causing prosthetic valve endocarditis (PVE). Vancomycin has been the cornerstone of therapy for serious MRSA infections including bacteremia and endocarditis. Clinicians have noted that MRSA bacteremias treated with vancomycin often fail to clear even with prolonged therapy. Persistent or prolonged MRSA bacteremia unresponsive to vancomycin therapy has led to the treatment of these infections by other agents, that is, quinupristin, dalfopristin, linezolid, or daptomycin. These antibiotics have been found particularly useful in treating MRSA bacteremias unresponsive to vancomycin therapy. We report a case of a patient who presented with MRSA PVE complicated by perivalvular aortic abscess with persistent MRSA bacteremia unresponsive to vancomycin therapy. The patient's MRSA bacteremia was cleared with daptomycin therapy (6 mg/kg/d). Because the patient refused surgery, daptomycin therapy was continued in hopes of curing the endocarditis and sterilizing the perivalvular aortic abscess. Transesophageal echocardiogram revealed a decrease in abscess in the aortic perivalvular abscess after 1 week of daptomycin therapy. The patient made an uneventful recovery. The cure of PVE and perivalvular abscesses usually requires removal of the prosthetic device and abscess drainage. In this case, in which surgery was not an option, medical therapy of PVE and a decrease in size of the aortic perivalvular abscess were accomplished with daptomycin therapy. Daptomycin is an alternative to vancomycin therapy in patients with prolonged or persistent MRSA bacteremia secondary to endocarditis or abscess.