Although animal studies have shown that the immunomodulator ipilimumab causes inflammation of the myocardium, clinically significant myocarditis has been observed only infrequently. We report a case of suspected acute coronary syndrome without a culprit lesion on cardiac angiography and takotsubo cardiomyopathy (TC)-like appearance on echocardiography in a patient with metastatic melanoma who received four standard doses of ipilimumab. Apical ballooning, hyperdynamic basal wall motion, systolic anterior motion of the mitral valve, and associated severe left ventricular outflow tract obstruction were present. Restaging with positron emission tomography-computed tomography done soon after discharge incidentally revealed increased fludeoxyglucose uptake in the apex. This case illustrates that a TC-like syndrome might be caused by autoimmune myocarditis after ipilimumab treatment although this was not biopsy-confirmed. Post-marketing surveillance should capture cardiac events occurring in patients treated with ipilimumab to better document and clarify a relationship to the drug, and biopsies should be considered. Physicians utilizing this novel agent should be aware of the potential for immune-related adverse events.

Risk factors for nephrotoxicity onset associated with polymyxin B were identified. In conjunction with susceptibility and other pharmacokinetic/pharmacodynamic data, our results can be used to optimize treatment for MDR Gram-negative infections.

I nfections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) have been associated with poor outcomes. An overall mortality rate of 48% is reported for patients with CRKP, compared to 26% for those with carbapenem-susceptible K. pneumoniae infections (1). CRKP isolates confer resistance through the production of K. pneumoniae carbapenemases (KPCs), which are able to hydrolyze all currently available ␤-lactams, including carbapenems (2). Due to additional mechanisms of resistance commonly found in KPC-producing isolates, they often demonstrate resistance to other antimicrobial classes, including fluoroquinolones and aminoglycosides (2, 3). This limits therapeutic choices, as polymyxins (polymyxin B or colistin) and tigecycline may be the only antibiotics that retain in vitro and in vivo microbiological activity.CRKP infections are often treated with combination therapy (4, 5); however, the choice of agents is both limited and challenging. Combination therapy with aminoglycosides, if susceptibility is preserved, carries an increased risk of nephrotoxicity. Due to a high volume of distribution, low blood levels, and high MIC, tigecycline is a "last resort" option, particularly for bloodstream infections. High MICs of carbapenems preclude achieving therapeutic levels even with pharmacodynamically optimized dosing strategies. Although in vitro synergy against CRKP has been observed when polymyxin B is used in combination with rifampin, cefepime, aminoglycosides, carbapenems, or tigecycline, testing methods are nonstandardized, and therefore the clinical effect of synergy remains unclear (3,(6)(7)(8). Limited data have demonstrated survival benefits of combination therapy using polymyxin B or colistin with carbapenems and/or tigecycline for patients with CRKP bacteremia (4, 5). Given the frequently encountered challenges of combination therapy, we aimed to describe the outcomes for patients with CRKP infections treated with polymyxin B monotherapy and to identify risk factors for treatment failure. MATERIALS AND METHODSStudy design. This was a retrospective study in a tertiary care academic medical center in New York City. The study population included adult patients (aged Ն18 years) with CRKP infections who received polymyxin B monotherapy for Ն72 h. Only the first treatment course was included.Microbiology. Cases were identified from a microbiology lab report of CRKP isolates from 1 January 2007 to 15 August 2011 and by review of medical records. The Vitek-2 system (bioMérieux) used by our microbiology laboratory has built-in analysis software (version R05.01) that enables it to identify resistance phenotypes. Isolates were included if the ertapenem/imipenem MIC was reported as resistant by Vitek-2. For tigecycline and polymyxin B, susceptibility was defined as an MIC of Յ2 mg/liter by Etest, according to Food and Drug Administration (FDA) breakpoints for Enterobacteriaceae and Clinical and Laboratory Standards Institute (CLSI) breakpoints for Acinetobacter baumannii, respectively. Data collection. Patient...

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This is the first case report to describe a successful transition to a ketamine infusion in a patient with AHS and transaminitis.