Percentage of hypochromic erythrocytes and reticulocyte hemoglobin equivalent predictors of response to intravenous iron in hemodialysis patients.

INTRODUCTION: Reticulocyte hemoglobin content and percentage of hypochromic red cells are incorporated into the European best practice guidelines on anemia management in chronic kidney disease. Sysmex XN analyzer (Sysmex Corporation, Kobe, Japan) reports reticulocyte hemoglobin equivalent (Ret-He) and the hypochromic fraction of erythrocytes (%Hypo-He). Our aim was to assess the value of these parameters, in terms of the sensitivity and specificity for detecting functional iron deficiency, in hemodialysis (HD) patients. METHODS: Forty HD patients in the maintenance phase of erythropoietin therapy were included. Intravenous iron supplementation was interrupted at least 3 weeks before recruitment. Two samples were analyzed for each patient: the baseline after the iron-free period and the second sample after 4 weeks of IV iron administration. Hemogram and biochemical parameters of the iron status were measured. Patients were classified as responders or nonresponders to an iron load; responders had an increase in Hb of at least 10 g/L after iron administration, compared to the baseline. To identify the efficiency of the test for predicting the response to iron administration, receiver operating characteristic analysis (ROC) was performed. RESULTS: According to the established criteria, 21 patients were responders and 19 nonresponders. ROC analysis results: Ret-He area under curve (AUC) was 0.84 (95% CI 0.64-0.93), at cutoff 30.8 pg, sensitivity 78.7%, and specificity 87.2%. % Hypo-He AUC was 0.78 (95% CI 0.64-0.91), at cutoff 2.4%, sensitivity 72.2%, and specificity 88.1%. CONCLUSIONS: % Hypo-He and Ret-He are reliable parameters for the study of erythropoiesis status in HD patients.

Stability of noisy Metropolis-Hastings.

Pseudo-marginal Markov chain Monte Carlo methods for sampling from intractable distributions have gained recent interest and have been theoretically studied in considerable depth. Their main appeal is that they are exact, in the sense that they target marginally the correct invariant distribution. However, the pseudo-marginal Markov chain can exhibit poor mixing and slow convergence towards its target. As an alternative, a subtly different Markov chain can be simulated, where better mixing is possible but the exactness property is sacrificed. This is the noisy algorithm, initially conceptualised as Monte Carlo within Metropolis, which has also been studied but to a lesser extent. The present article provides a further characterisation of the noisy algorithm, with a focus on fundamental stability properties like positive recurrence and geometric ergodicity. Sufficient conditions for inheriting geometric ergodicity from a standard Metropolis-Hastings chain are given, as well as convergence of the invariant distribution towards the true target distribution.

Sonography in acute appendicitis: diagnostic utility and influence upon management and outcome.

A study is made of the diagnostic utility of echography in clinically suspected appendicitis, and its influence upon patient management and outcome. A total of 374 consecutive patients with possible appendicitis were prospectively evaluated by ultrasound. Two groups were established: group A (high clinical probability, > or =0.70) and group B (moderate clinical probability, 0.20-0.60). In group-A patients (n = 105, 28%), prevalence of appendicitis = 0.90) underwent surgery regardless of the echographic findings. In group B (n = 269, 72%), prevalence of appendicitis = 0.28) surgery was performed in the event of positive echography, whereas negative echographic findings did not definitively discard appendicitis. The diagnostic utility of echography was evaluated by applying the Pauker-Kasirer threshold approach to clinical decision making. The influence of ultrasound upon outcome was in turn evaluated by contrasting the total appendectomized patients (190 of 374) with a series of 181 individuals subjected to appendectomy prior to the introduction of echography. The probability of appendicitis in the presence of positive echography was 0.95 in group A (sensitivity = 0.92) and 0.89 in group B (sensitivity = 0.91). The probability of appendicitis in the event of negative ultrasound was 0.58 in group A (specificity = 0.55) and 0.03 in group B (specificity = 0.95) . In 46% of cases the echographic findings led to a change in therapeutic regimen. In addition, the incidence of negative appendectomies was significantly reduced (19.3 vs 11.6% with echography; p = 0.03), as was the delay in establishing a diagnosis (under 6 h in 68.5 vs 84.2% with echography; p = 0.002) and the number of medical acts required (three in 71.3 vs 84.1% with echography; p = 0.001). There was no significant reduction in the incidence of perforated appendicitis (17.1 vs 17.9% with echography), in the number of postoperative complications (13.8 vs 7.6% with echography), or in the days of hospital stay (4.44 vs 4.80 with echography). Echography proved useful in group B, and was generally of little utility in group A. The technique had a positive influence on treatment, with management reorientation in a considerable number of patients, and on outcome, since ultrasound contributed to establishing an earlier diagnosis, with a reduction of unnecessary appendectomies.

Pseudochylothorax. Report of 2 cases and review of the literature.

We report 2 cases of pseudochylothorax and review 172 published cases. Tuberculosis is by far the most frequent cause of pseudochylothorax, accounting for 54% of all caes, with a remarkable association with previous collapse therapy and long-term effusions. The remaining etiologies, including rheumatoid arthritis, are infrequent. Tuberculous pseudochylothorax is usually sterile. Successful treatment of an acute tuberculous pleurisy does not preclude the development of long-term complications such as pseudochylothorax. We do not recommend pleural biopsy initially because of its low yield for etiologic diagnosis. Currently, adenosine deaminase (ADA) values in pleural fluid are not useful to sustain diagnosis or therapeutic decisions. We advise draining only symptomatic cases and treating patients with positive Ziehl-Neelsen stain or Lowenstein culture, and those with growing effusions of suspected tuberculous origin, with antituberculous chemotherapy. Pulmonary decortication should be the last therapeutic step for recurrent and symptomatic cases.

[Renopleural fistula secondary to xanthogranulomatous pyelonephritis]. / Fístula renopleural secundaria a pielonefritis xantogranulomatosa.

A case is presented of renopleural fistula secondary to xantogranulomatous pyelonephritis in an 18-year-old female patient. Although the renopleural communication was not observed radiologically, concomitant clinical signs, bacteriological isolation of E. coli in renal and pleural content and surgical findings, confirmed the existence of such fistula.