By Carol A. Kemper, MD, FACP

Point-of-Care Syphilis Testing

Cause LM, et al. Novel syphilis test distinguishes active vs past infections. Clin Infect Dis 2015; Doi:10.1093/cid/civ243.

Not only has the introduction of the “reverse paradigm testing” for syphilis improved our ability to detect syphilis infection, especially acute primary infection, it has confused many  and has caused undue stress for some individuals who were surprised to learn their blood tests are consistent with “previously treated” syphilis infection. Often, screening EIA or CEA tests for syphilis antibodies do not reflex to confirmatory tests, leaving days of uncertainty for a patient regarding the true nature of the result and whether the disease is active or inactive. I’ve had sobbing 20- and 80-year-olds in my office, who would have preferred never to know they’ve had previous (treated) syphilis infection; the information can also be distressing for couples. There are times when I wish we could return to the previous testing methods, which screened only for active infection.

At least some of this problem could be resolved with more rapid confirmation or point-of-care testing. A newer point-of-care test, called a dual path platform (DPP) immunochromatographic screening assay, provides both treponemal and non-treponemal testing at once, using whole blood, serum, or plasma (Chembio Diagnostic Systems, Medford NY). Such tests are often referred to as lateral flow tests or strip tests, which are user-friendly, relatively inexpensive to perform, are stable for long periods without refrigeration, and provide rapid results. They are especially useful in rural areas or third-world countries.

In a high-risk population, based on tests of 1005 samples, the sensitivity of the DDP treponemal test was 89.8% and the specificity was 99.3%. For the non-treponemal portion of the test, the sensitivity was 94.2% and the specificity was 62.2%. Concordance of the test, with reference RPR and immunoassays, was 94.3% for high titre infections and 90% for low titre infections. Concordance of the DDP assay for past/treated infection was only 27.5%, but half of inactive infections were accurately recognized as inactive  and 22.8% were not recognized at all.

This method of screening would be easier for clinicians to interpret, and prevent unnecessary treatment of some inactive infections. While a small number of active infections would be missed, some individuals would be saved from the embarrassment and stigma of finding out they have treated infection. The advantages of this test, which has not been approved by the United States Food and Drug Administration, in terms of ease of use and cost, would need to be balanced against the somewhat lower test accuracy.

Revised Urinary Catheter Use Guidelines

Meddings J, et al. The Ann Arbor Criteria for appropriate urinary catheter use in hospitalized medical patients: Results obtained by using the RAND/UCLA Appropriateness Method. Ann Intern Med 2015;162 (9) S:S1-S34.

Every day on ward rounds, many hospitals apply daily use criteria for urinary catheters based on recommended guidelines. These include such criteria as critical illness, bladder outlet obstruction, and monitoring fluid status. While these criteria seem reasonable, they are not entirely evidence-based, and are sometimes ambiguous or loosely applied by day-shift nursing staff evaluating daily Foley use. For example, patient request for comfort or for incontinence, especially in patients with limited mobility (or an unwillingness to get out of bed), remains a gray area for nursing staff, who simply do no wish to tussle with a patient’s expressed wishes.

A 15-member multi-disciplinary panel has submitted a revised guideline for Foley catheter use in hospitalized medical patients, based on a review of the literature for 299 potential scenarios for catheter use. Several recent U.S. and European guidelines, and an extensive literature review, informed this process, and a risk-benefit analysis was developed for the different uses. Scenarios for both continuous use catheters and intermittent straight catheters were evaluated  both for the inpatient and the outpatient setting. Many common uses for catheters  especially intermittent catheterization  were debunked, and others for indwelling Foley use were clarified, including the use in critical care settings, the appropriate use for urine collection and measurement, and comfort care.

Areas of controversy were resolved using the RAND/UCLA method  which does not require a consensus or a majority vote, but rather a weighted recommendation based on the opinions of the committee members or, at times, outside clinical experts.

Specifically, for 105 possible uses for Foley catheterization in hospitalized patients, only 43 were found to be appropriate, 48 were inappropriate, and 14 were uncertain. Some of these scenarios and patient characteristics were sufficiently similar, allowing consolidation of the recommendations  providing a list of 12 appropriate indications for catheter use and 9 inappropriate recommendations for Foley catheter use in hospitalized patients. A summary of these criteria follows, with justification for each, footnotes, and clinical examples provided in the body of the article :

  • Acute urinary retention without bladder outlet obstruction; bladder outlet obstruction due to non-infectious, non-traumatic diagnosis; or chronic urinary retention with bladder outlet obstruction;
  • Stage 3 or 4 or unstageable pressure ulcers or similarly severe wounds of other types that cannot be kept clear of urine despite other management strategies;
  • Urinary incontinence in patients for whom nurses find it difficult to provide skin care despite other urinary management strategies  e.g., such as temporary immobility for a procedure or weight greater than 300 pounds;
  • Hourly measurement of urine volume required to provide treatment;
  • Daily (not hourly) measurement of urine volume that is required to provide treatment and cannot be assessed by other volume and urine collection strategies;
  • Single 24-hour urine sample for diagnostic test that cannot be obtained by other means;
  • Improvement in comfort when urine collection by catheter addresses patient and family goals in a dying patient;
  • Reduce acute, severe pain with movement when other urine management strategies are difficult;
  • Management of gross hematuria with clots;
  • Clinical condition for which intermittent or external catheter use would be appropriate but placement by an experienced nurse or practitioner was difficult or patient for whom bladder emptying was inadequate with non-indwelling strategies during this admission.

HIV and Meningococcal Vaccination Revisited

Miller L, et al. Elevated risk for invasive meningococcal disease among persons with HIV. Ann Intern Med 2014;160:30-37.

A number of fatal cases of invasive meningococcal disease (IMD) in men who have sex with men (MSM) in 2010 and 2012 in New York City and Los Angeles raised concerns about the risk for IMD in MSM and in persons with HIV/AIDS. Estimates of the incidence of IMD in NYC in 2012 were as high as 50-fold that of the general population (age-adjusted data); and the case-fatality rate for these cases was remarkably high (32%). More than half of the cases (54%) were HIV positive, although their average CD4 count, when available, was 525 cells/mm3, and 70% were virologically suppressed. Many of these cases occurred after hanging out in crowded bars and large social gatherings. Molecular studies suggest that the outbreak was caused by a common strain of meningococcal serogroup C. It is now believed that a more virulent strain of meningococcus began circulating among MSM, resulting in higher death rates.

The question remains whether the risk of IMD in MSM is due more to their social behaviors (frequent clustering in large groups, similar to the Haj) or to the presence of HIV-infection. Limited data suggested that HIV-infection may contribute to an increased risk of IMD, similar to the observed increased risk for pneumococcal infection (another encapsulated organism).

Miller and colleagues have provided some answers. Using surveillance data collected between 2000-2011 for persons aged 15 to 64 years, rates of IMD in NYC were compared between HIV positive and non-HIV positive. Cases were matched to vital statistics registry, and immunological data were collected. A total of 265 persons with IMD were reported during the study period, 45 of whom were HIV positive. Two patients were excluded from the analysis, as their IMD preceded their HIV diagnosis, and 3 were re-classified as HIV-non-infected. Thirty of these were male and 10 were female. Four of the 40 case patients with IMD and HIV died (10%) compared with 51 of 223 non-HIV-positive case patients (23%).

During this study period, the average annual incidence of IMD in NYC was 0.39 cases per 100,000. The relative risk of IMD for persons with HIV/AIDS was 10.0 (95% CI, 7.2 to 14.1). When the study period was broken into three-year intervals and analyzed, this increased relative risk remained fairly uniform, ranging from 8.2 to 11.8, with an average annual incidence ranging from 0.23 in 2009-2011 to a peak of 0.41 in 2000-2002. During the interval from 2000 to 2011, the relative risk for IMD was slightly higher for HIV-positive men than HIV-positive women (12.2 vs 7.6). When CD4 data was analyzed, the odds of IMD was 5.3 higher for persons with CD4 counts less than 200/mm3 compared with their HIV-positive counterparts with higher CD4 counts.

Thus, the risk of IMD in persons with HIV/AIDS in NYC since 2000 has been consistently higher than the age-matched non-HIV-positive population  and therefore the cases that received such dramatic attention the past 2-3 years were part of a pattern of increased risk for persons with HIV-infection.

While the CDC Advisory Committee on Immunization Practices states that “HIV infection is not an indication for routine vaccination with MenACWY,”1 the risk for IMD in persons with HIV-infection is clearly increased, especially for those with more advanced disease. Observations of microbiologic data for NYC cases found that 74% were vaccine-preventable serogroups (A, C, Y, and W), and that 87% of the cases in HIV/AIDS were potentially vaccine-preventable. It is known that meningococcal quadravalent vaccine is immunogenic in HIV-positive persons, at least as demonstrated in HIV-positive adolescents. Two doses administered at least two months apart are recommended for persons with HIV infection, if you choose to administer vaccine to your patients.

REFERENCE

  1. Recommended Adult Immunization Schedule, United States — 2015, CDC; http://www.cdc.gov/vaccines/schedules/downloads/adult/adult-combined-schedule.pdf.