Computed tomography colonography: ready for prime time for colon cancer screening?

In 2008, results from the landmark American College of Radiology Imaging Network (ACRIN) trial provided evidence supporting the use computed tomography colonography (CTC) as a comparable alternative to colonoscopy for colorectal cancer (CRC) screening. Subsequently, however, the United States Preventive Task Force decided against a recommendation in support of CTC for CRC screening. Following soon after, the Centers for Medicare and Medicaid Services (CMS) made noncoverage decision for the use of CTC in CRC screening. Since that decision, there have been a number of publications on CTC and CRC screening with a strong push from the radiology community to reassess CTC as a viable option. The purpose of this review was to address focused questions concerning the use of CTC in CRC screening, through an analysis of the available scientific evidence in an effort to provide recommendations for clinicians, patients, and payors who may evaluate the role of CTC for CRC screening.

The role of antibiotics in the treatment of infectious diarrhea.

Infectious diarrhea is a significant cause of morbidity and mortality and a common complaint in clinical practice. Routine empirical use of antibiotics for infectious diarrhea should be avoided because of the self-limited nature of most cases, the cost of antibiotics, and the potential to worsen the already significant problem of antibiotic resistance of enteric pathogens. For patients with severe invasive or prolonged diarrhea or who are at high risk of complications, such as the elderly, diabetics, cirrhotics, and immunocompromised patients, empirical treatment with a quinolone antibiotic for 3 to 5 days can be considered. Antibiotic treatment can be highly effective for Shigella, ETEC, and V. cholerae infections, and metronidazole is indicated for C. difficile colitis. The impact of antibiotics for other specific pathogens is modest, and antibiotic therapy should be reserved for the same group of patients who would be considered for empirical treatment. The most significant problem in the antibiotic treatment of infectious diarrhea is the progressive increase in resistance among enteric pathogens; only the prudent use of antimicrobials in all areas of daily practice can limit or delay the impact of this serious problem.

Emerging foodborne pathogens: keeping your patients and your families safe.

Changes in food production and societal pressures have led to a continuing increase in the incidence of foodborne illness. Many pathogens are associated with specific foods, e.g., E. coli O157:H7 with hamburgers or Salmonella with eggs. The U.S. Food and Drug Administration has recently approved irradiation for sterilization of meat, but public acceptance of irradiated food is low. Because contaminated foods are seldom detected before they reach store shelves, care in food preparation by professional and home cooks is crucial.

Antimicrobial treatment of intra-abdominal infections.

There have been several recent changes that influence the management of intra-abdominal infections. These changes include important developments in antibiotic resistance such as increases in pneumococcal resistance, emergence of multi-drug-resistant enterococcal isolates, and decreasing sensitivity of anaerobes and gram-negative rods. In addition there are new antibiotics such as piperacillin/tazobactam, and new antibiotic dosing regimens such as single daily dosing of aminoglycosides. In this article, we will review the therapeutic approach to intra-abdominal infections with special emphasis on the various forms of peritonitis, cholecystitis, cholangitis, and diverticulitis. Several new concepts about the treatment of enterococcus, the management of bacterial and fungal peritonitis, and the prevention of spontaneous bacterial peritonitis will also be reviewed. Specific recommendations for the management of the different infections including antibiotic doses and costs will be provided. Finally the role of invasive procedures in the management of some of the infections will be explored.

Once weekly azithromycin therapy for prevention of Mycobacterium avium complex infection in patients with AIDS: a randomized, double-blind, placebo-controlled multicenter trial.

We conducted a randomized, double-blind, placebo-controlled multicenter trial of azithromycin (1,200 mg once weekly) for the prevention of Mycobacterium avium complex (MAC) infection in patients with AIDS and a CD4 cell count of < 100/mm3. In an intent-to-treat analysis through the end of therapy plus 30 days, nine (10.6%) of 85 azithromycin recipients and 22 (24.7%) of 89 placebo recipients developed MAC infection (hazard ratio, 0.34; P = .004). There was no difference in the ranges of minimal inhibitory concentrations of either clarithromycin or azithromycin for the five breakthrough (first) MAC isolates from the azithromycin group and the 18 breakthrough MAC isolates from the placebo group. Of the 76 patients who died during the study, four (10.5%) of 38 azithromycin recipients and 12 (31.6%) of 38 placebo recipients had a MAC infection followed by death (P = .025). For deaths due to all causes, there was no difference in time to death or number of deaths between the two groups. Episodes of non-MAC bacterial infection per 100 patient years occurred in 43 azithromycin recipients and 88 placebo recipients (relative risk, 0.49; 95% confidence interval, 0.33-0.73). The most common toxic effect noted during the study was gastrointestinal, reported by 78.9% of azithromycin recipients and 27.5% of placebo recipients. Azithromycin given once weekly is safe and effective in preventing disseminated MAC infection, death due to MAC infection, and respiratory tract infections in patients with AIDS and CD4 cell counts of < 100/mm3.

Prediction of relapse after treatment of coccidioidomycosis.

Relapse after apparently successful treatment of coccidioidomycosis has been a problem with both amphotericin B and the azoles. We conducted a retrospective cohort study of 34 patients who required therapy for coccidioidomycosis between 1973 and 1993; 10 relapsed and 25 (one patient received two courses of therapy) did not relapse during follow-up. The mean time to relapse after completion of therapy was 7.3 months (range, 1-21 months). All 34 patients responded clinically to therapy. A fourfold or greater decrease in titers of antibody, as determined by complement fixation (CF), during therapy was seen in seven (78%) of nine patients who relapsed and 17 (85%) of 20 patients who did not relapse (P = .956). There was no significant difference between relapsers and nonrelapsers in terms of the lowest CF titer during therapy, the CF titer at the end of therapy, or the peak CF titer. The risk of relapse was increased among those with a peak CF titer of > or = 1:256 (relative risk [RR] = 4.7; 95% confidence interval [CI] = 1.4-16.1), as compared with patients who did not mount such a high antibody response. Similarly, the risk of relapse was higher among those with serially negative coccidioidin skin tests (CSTs) than those with serially positive CSTs (RR = 4.8; 95% CI = 1.2-19.5). We conclude that clinical response, lowest CF titer, end-of-therapy CF titer, and decrease in the CF titer of at least fourfold are not predictive of relapse in patients with coccidioidomycosis. Negative serial coccidioidin skin tests and a peak CF antibody titer of > or = 1:256 are independently associated with increased risk of relapse.

Reliability of a history of previous varicella infection in adults.

CONTEXT: Apparent second episodes of varicella are reported in immunocompetent hosts, but laboratory confirmation of prior immune status has rarely been possible. OBJECTIVE: To evaluate adult patients with varicella who claimed to have had previous varicella to determine whether they had true second episodes or primary cases with inaccurate clinical histories. DESIGN: Adult subjects with varicella who enrolled in an antiviral treatment trial were interviewed about a history of varicella. The clinical course of varicella was documented prospectively in all subjects. Serum samples that predated the acute illness were obtained from the US Navy's central serum storage facility for subjects who reported a previous episode of varicella. These stored samples were tested in parallel by enzyme-linked immunosorbent assay, latex agglutination, and Western blot for IgG antibodies to varicella-zoster virus (VZV). PARTICIPANTS: Twenty military personnel with varicella and a history of the disease. SETTING: A military hospital in San Diego, Calif. MAIN OUTCOME MEASURE: Presence or absence of antibodies to VZV. RESULTS: Twenty (10.8%) of 184 adults with serologically confirmed acute varicella reported a prior history of varicella. The clinical course of these 20 patients did not differ from those with no history of varicella. Serum samples that had been collected a mean of 12.4 months (median, 12 months; range, 3 days to 34 months) before the incident episode were available for 19 subjects. All 19 serum samples lacked IgG antibodies to VZV. CONCLUSION: A history of previous varicella infection in adults with varicella may not be reliable. True second episodes of varicella are probably rare in immunocompetent adults.

Neurocognitive impairment in human immunodeficiency virus infection is correlated with sexually transmitted disease history.

BACKGROUND AND OBJECTIVES: Neurocognitive impairment is common in human immunodeficiency virus (HIV)-infected subjects. The relationship of sexually transmitted diseases to neurocognitive changes is unknown. GOAL: To establish whether HIV-infected patients with a history of syphilis or gonorrhea have a higher rate of neurocognitive dysfunction. STUDY DESIGN: Neurocognitive function was measured by a battery of quantitative tests in a 453-person HIV-infected cohort and a 219-person HIV-seronegative control group. Neurocognitive function was then correlated with histories of either syphilis or gonorrhea to assess for possible relationships between these sexually transmitted diseases and neurologic impairment. RESULTS: Human immunodeficiency virus-infected subjects with a history of either syphilis or gonorrhea tended to perform worse on neurocognitive testing than their counterparts. This difference could not be explained by educational attainment, age, race or CD4 cell count, and was not noted in the HIV-uninfected control subjects. CONCLUSIONS: Sexually transmitted diseases in HIV-infected subjects are correlated with neurocognitive impairment through an unidentified mechanism.

Falciparum malaria.

Falciparum malaria is one of the most common infectious illnesses in the world and can progress rapidly to coma and death in the nonimmune patient. The presentation is nonspecific, so blood smears must be made and read quickly. Proper therapy requires taking into account drug resistance, recognizing the signs of severe malaria, and proper treatment for complications. Long-sleeved clothing, bed nets, insecticides, and chemoprophylaxis can help prevent malaria, but the infection must be suspected in any traveler returning from an endemic area. This article reviews epidemiology, diagnosis, treatment, and prevention of falciparum malaria in the temperate zone.