Does this patient have acute cholecystitis?

Robert L. Trowbridge, MD; Nicole K. Rutkowski, MD; Kaveh G. Shojania, MD

JAMA. 2003;289:80-86.

Context  Although few patients with acute abdominal pain will prove to have cholecystitis, ruling in or ruling out acute cholecystitis consumes substantial diagnostic resources.

Objective  To determine if aspects of the history and physical examination or basic laboratory testing clearly identify patients who require diagnostic imaging tests to rule in or rule out the diagnosis of acute cholecystitis.

Data Sources  Electronic search of the Science Citation Index, Cochrane Library, and English-language articles from January 1966 through November 2000 indexed in MEDLINE. We also hand-searched Index Medicus for 1950-1965, and scanned references in identified articles and bibliographies of prominent textbooks of physical examination, surgery, and gastroenterology. To identify relevant articles appearing since the comprehensive search, we repeated the MEDLINE search in July 2002.

Study Selection  Included studies evaluated the role of the history, physical examination, and/or laboratory tests in adults with abdominal pain or suspected acute cholecystitis. Studies had to report data from a control group found not to have acute cholecystitis. Acceptable definitions of cholecystitis included surgery, pathologic examination, hepatic iminodiacetic acid scan or right upper quadrant ultrasound, or clinical course consistent with acute cholecystitis and no evidence for an alternate diagnosis. Studies of acalculous cholecystitis were included. Seventeen of 195 identified studies met the inclusion criteria.

Data Extraction  Two authors independently abstracted data from the 17 included studies. Disagreements were resolved by discussion and consensus with a third author.

Data Synthesis  No clinical or laboratory finding had a sufficiently high positive likelihood ratio (LR) or low negative LR to rule in or rule out the diagnosis of acute cholecystitis. Possible exceptions were the Murphy sign (positive LR, 2.8; 95% CI, 0.8-8.6) and right upper quadrant tenderness (negative LR, 0.4; 95% CI, 0.2-1.1), though the 95% CIs for both included 1.0. Available data on diagnostic confirmation rates at laparotomy and test characteristics of relevant radiological investigations suggest that the diagnostic impression of acute cholecystitis has a positive LR of 25 to 30. Unfortunately, the available literature does not identify the specific combinations of clinical and laboratory findings that presumably account for this diagnostic success.

Conclusions  No single clinical finding or laboratory test carries sufficient weight to establish or exclude cholecystitis without further testing (eg, right upper quadrant ultrasound). Combinations of certain symptoms, signs, and laboratory results likely have more useful LRs, and presumably inform the diagnostic impressions of experienced clinicians. Pending further research characterizing the pretest probabilities associated with different clinical presentations, the evaluation of patients with abdominal pain suggestive of cholecystitis will continue to rely heavily on the clinical gestalt and diagnostic imaging.

     

Dialysis access related infections

Infection is a common cause of morbidity and mortality in end-stage renal disease patients. Unintentional pathogens are introduced into an immunocompromised host during hemodialysis and peritoneal dialysis by means of the access (arteriovenous fistula, arteriovenous graft, central venous catheter, or peritoneal dialysis catheter). Gram positive organisms are most common with Staphylococcus aureus and coagulase negative Staphylococcus predominating. Preventive measures are mandatory and the key to decreasing infection rates.     

Effects of increasing syringe availability on syringe-exchange use and HIV risk: Connecticut, 1990–2001

Syringe-exchange programs (SEPs) in Connecticut operate with caps on the number of syringes exchanged per visit. We investigated the effects of legislation increasing the cap on drug injectors' access to clean syringes through the SEPs in New Haven and Hartford. The mixed design of this study included longitudinal and crosssectional data from individuals and ecological data from program operations. Five parameters—syringe return rate, syringes per visit to the SEP, syringe reuse rate, syringe human immunodeficiency virus (HIV) prevalence, and syringe sharing—were monitored through syringe tracking and testing of SEP syringes and by interviewing injectors. Two increases in the cap—from 5 to 10 and then from 10 to 30—had little effect on the five parameters that measured injectors' access to clean syringes. In contrast, access to clean syringes increased when the New Haven SEP first began operations, when syringes first became available at pharmacies in Hartford, and when the agency running the Hartford SEP changed. Legislation providing piecemeal increases in the cap may not, by themselves, be sufficient to increase injectors' access to clean syringes and decrease the risk of human immunodeficiency virus transmission in this population.     

Gene- and viral-based therapies for brain tumors

Advances in understanding and controlling genes and their expression have set the stage to alter genetic material to fight or prevent disease with brain tumors being among one of the first human malignancies to be targeted by gene therapy. All proteins are coded for by DNA and most neoplastic diseases ultimately result from the expression or lack thereof with one or more proteins (e.g., coded by oncogenes or tumor suppressor genes, respectively). In theory, therefore, diseases could be treated by expression of the appropriate protein in the affected cells. Gene therapy is an experimental treatment that involves introducing genetic material (DNA or RNA) into cells, and it has made important advances in the past decade. Within this short time span, it has moved from the conceptual laboratory research stage to clinical translational trials for brain tumors. The most efficient approaches for gene delivery are based on viral vectors, which have been proven relatively safe in the CNS, despite occasional cases of morbidity and death in non-neurosurgical trials. However, the human response to various viral vectors can not be predicted in a reliable manner from animal experimentation, nor can size, consistency, and extent of experimental brain tumors in mouse models reflect the large, necrotic, infiltrative nature of malignant gliomas. Furthermore, the problem of delivering genetic vectors into solid brain tumors and the efficiency in situ gene transfer remains one of the most significant hurdles in gene therapy.     

Extraction of skin lesion texture features based on independent component analysis

Background/purpose: During the recent years, many diagnostic methods have been proposed aiming at early detection of malignant melanoma. The texture of skin lesions is an important feature to differentiate melanoma from other types of lesions, and different techniques have been designed to quantify this feature. In this paper, we discuss a new approach based on independent component analysis (ICA) for extraction of texture features of skin lesions in clinical images.
Methods: After preprocessing and segmentation of the images, features that describe the texture of lesions and show high discriminative characteristics are extracted using ICA, and then these features, along with the color features of the lesions, are used to construct a classification module based on support vector machines for the recognition of malignant melanoma vs. benign nevus.
Results: Experimental results showed that combining melanoma and nevus color features with proposed ICA-based texture features led to a classification accuracy of 88.7%.
Conclusion: ICA can be used as an effective tool for quantifying the texture of lesions.     

Managing Traps and Pitfalls During Initial Steps of an ECMO Retrieval Program Using a Miniaturized Portable System: What Have We Learned From the First Two Years?

The aim of this study was to provide early and mid‐term results of the newly established extracorporeal membrane oxygenation (ECMO) retrieval service in a tertiary cardiothoracic center using the miniaturized portable Cardiohelp System (Maquet, Rastatt, Germany). A particular attention was paid to organizational and logistic specifics as well as challenges and pitfalls associated with initial phase of the program. From January 2015 until January 2017 a heterogenic group of 28 consecutive patients underwent ECMO implantation in distant hospitals for acute cardiac, pulmonary or combined failure as a bridge‐to‐decision and were subsequently transported to our institution. Each cannulation was performed bedside on intensive care units (ICU) using the Seldinger's technique. Early outcomes and mid‐term overall survival with up to two‐year follow‐up along with the impact of ongoing cardiopulmonary resuscitation (CPR) on outcome were presented. Also, changes in hemodynamics and tissue perfusion factors 24 h after ECMO implantation were evaluated. ECMO implantations were performed in 15 distant departments with the median distance of 23(10;40) (maximum 60) km. A total of 15 patients (54%) were cannulated under CPR with the median duration of 30(20;110) (maximum 180) min. After 24 h of support there were significant improvements in SvO₂ (P = 0.021), mean arterial pressure (P = 0.027), FiO₂ (P = 0.001), lactate (P = 0.001), and pH (P < 0.001). The mean ECMO support duration was 96 ± 100 (maximum 384) hours, whereas 11 patients (40%) were weaned off support and discharged from hospital. Overall cumulative survival in patients without the need for CPR was 61.5% at one week and 38.5% at 1 month, 6 month, and 1 year, whereas patients requiring CPR survived in 40% at one week, and 33.3% at 1 month, 6 month, and 1 year (Log‐Rank (Mantel‐Cox) P = 0.374, Breslow (Generalized Wilcoxon) P = 0.162). Our initial experience shows that launching new ECMO retrieval programs in centers with sufficient ICU capacities and local ECMO experience can be feasible and associated with acceptable “real world” results despite the initial learning curve. Rapid logistical organization and team flexibility are the key points to ensure comparable survival of patients requiring prolonged CPR.