Pharmacokinetics and Pharmacodynamics of Extended Infusion Versus Short Infusion Piperacillin-Tazobactam in Critically Ill Patients Undergoing CRRT.

BACKGROUND AND OBJECTIVES: Infection is the most common cause of death in severe AKI, but many patients receiving continuous RRT do not reach target antibiotic concentrations in plasma. Extended infusion of ß-lactams is associated with improved target attainment in critically ill patients; thus, we hypothesized that extended infusion piperacillin-tazobactam would improve piperacillin target attainment compared with short infusion in patients receiving continuous RRT. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted an institutional review board-approved observational cohort study of piperacillin-tazobactam pharmacokinetics and pharmacodynamics in critically ill patients receiving continuous venovenous hemodialysis and hemodiafiltration at three tertiary care hospitals between 2007 and 2015. Antibiotic concentrations in blood and/or dialysate samples were measured by liquid chromatography, and one- and two-compartment pharmacokinetic models were fitted to the data using nonlinear mixed effects regression. Target attainment for piperacillin was defined as achieving four times the minimum inhibitory concentration of 16 µg/ml for >50% of the dosing cycle. The probabilities of target attainment for a range of doses, frequencies, and infusion durations were estimated using a Monte Carlo simulation method. Target attainment was also examined as a function of patient weight and continuous RRT effluent rate. RESULTS: Sixty-eight participants had data for analysis. Regardless of infusion duration, 6 g/d piperacillin was associated with ≤45% target attainment, whereas 12 g/d was associated with ≥95% target attainment. For 8 and 9 g/d, target attainment ranged between 68% and 85%. The probability of target attainment was lower at higher effluent rates and patient weights. For all doses, frequencies, patient weights, and continuous RRT effluent rates, extended infusion was associated with higher probability of target attainment compared with short infusion. CONCLUSIONS: Extended infusions of piperacillin-tazobactam are associated with greater probability of target attainment in patients receiving continuous RRT.

HIV, rods, and the muscles--a discussion about HIV-associated nemaline rod myopathy.

This case reports a 21-year-old, homosexual African-American male who presented to our facility with a two-week history of progressive proximal muscle weakness. Quadriceps muscle biopsy showed a diagnosis of Nemaline Rod Myopathy, the presenting disease of his HIV infection. A review of the literature shows 13 prior case reports of similar disease process, often as the presenting symptom of the HIV disease. Anecdotal reports of effective treatment regimens include steroids and intravenous immune globulin; our patient had a profound response to high-dose steroids. This case report discusses this rare presentation of HIV in hopes to increase awareness amongst clinicians as the incidence and prevalence of HIV increases.

Carcinomatous meningitis secondary to transitional cell bladder cancer.

We report a patient with carcinomatous meningitis secondary to known transitional cell carcinoma of the bladder. The patient presented with multiple focal neurological signs and symptoms. Diagnosis was suggested by magnetic resonance imaging and confirmed by analysis of the cerebrospinal fluid. He received whole brain radiotherapy despite a poor prognosis. To our knowledge, this is only the fifth reported case of neoplastic meningitis due to bladder cancer with confirmatory imaging and cytology and only the fourth reported case that presented with cranial nerve involvement.

Laboratory markers as predictors of mortality in patients with Clostridium difficile infection.

Previous studies have identified laboratory markers for severe Clostridium difficile infection (CDI). The most consistent of these markers is the presence of marked leukocytosis. We examined the validity of these markers as predictors of mortality in patients with CDI. We excluded patients with preexisting hematologic conditions that would be expected to impair their ability to demonstrate leukocytosis. On univariate analysis, marked leukocytosis (P = 0.02), thrombocytopenia (P = 0.008), and increased blood urea nitrogen (P < 0.001) and creatinine (P = 0.001) levels were found to be significantly associated with mortality in patients with CDI. However, on logistic regression analysis, only renal impairment was found to be an independent predictor (odds ratio, 5.07). Importantly, in our study, leukocytosis was not an independent predictor after adjustment for other variables, which may be due to our selection criteria when adjusting for confounding variables. We are therefore of the opinion that in immunocompromised hosts who are leukopenic at the time of CDI diagnosis, other laboratory markers should be identified to serve as indicators for severe disease.

Langerhans cell histiocytosis, a case of Letterer Siwe disease.

An 8-month-old male infant presented with a progressively worsening generalized rash of 5-6 months duration, fever, poor feeding, and abdominal distension. An initial laboratory workup revealed anemia, thrombocytopenia, and hepatosplenomegaly. The patient was started on i.v. antibiotics, and a working diagnosis of Langerhans cell histiocytosis was reached that was later confirmed with a skin biopsy. Subsequently, the patient received first-round chemotherapy with vinblastine and prednisone, on which he appeared to improve clinically; however, he soon relapsed. He then received combination salvage therapy with cladribine (2CdA) and cytarabine (Ara-C) for three cycles. The patient responded well to this regimen with resolution of his condition. The patient was then referred for a bone marrow transplant.

Does PPI therapy predispose to Clostridium difficile infection?

Clostridium difficile infection (CDI) has emerged as a problem of epidemic proportions. Previous exposure to broad-spectrum antibiotics remains the most important predisposing factor for the disease. However, PPIs are increasingly being overprescribed and recent research has, therefore, focused on the association between PPI therapy and CDI. While the data remain observational, increasing evidence exists for at least a modest association between PPI use and CDI.

Harbingers for Clostridium difficile-associated diarrhea.

PURPOSE: : Recent research has recognized surrogate markers for Clostridium difficile-associated diarrhea (CDAD). Among the most consistently identified markers are the leukocyte count, platelet count, and albumin level. Previous investigators failed to exclude patients with hematologic disorders that may have confounded their results. Therefore, the exclusion of this subset from our study lends it a unique perspective. METHODS: : We undertook a retrospective review of inpatients at our institution that were diagnosed with nosocomial diarrhea and subsequently had a stool sample sent for C. difficile toxins A and B. Patients with major hematologic disorders were excluded. RESULTS: : A total of 77 C. difficile-positive patients and 91 C. difficile-negative patients were studied. Patients with CDAD had a significantly higher leukocyte and platelet count but a lower albumin level compared with patients without CDAD. CONCLUSION: : Our results support the conclusion of preceding studies that leukocytosis, thrombocytosis, and hypoalbuminemia are reliable clinical predictors for CDAD even after careful exclusion of confounding factors.