Archive for July 21st, 2009
Cutaneous Anthrax
N Engl J of Medicine July 9, 2009 V.361 N.2 p.178
Images in Clinical Medicine
A 17-year-old girl presented to the emergency department with a black necrotic lesion on her left cheek and periorbital edema. She had been well until 15 days before presentation, when she noticed a small, painless, pruritic papule on her face that quickly enlarged and developed a central vesicle. The vesicle burst, leaving a painless necrotic ulcer with a black, depressed eschar. Extensive edema of the eyelids developed and progressed over a period of 7 days. At presentation, she was afebrile, and there was no lymphadenopathy. A diagnosis of cutaneous anthrax was made and confirmed by Gram’s staining of the ulcer, which revealed gram-positive spore-forming bacilli consistent with Bacillus anthracis. The patient was from a northern Iranian village where exposure to contaminated soil and livestock products is common; no bioterrorism was suspected. Intravenous penicillin G (at a dose of 6 million units given every 6 hours for 10 days) was administered. On follow-up, the patient was well, and the eschar was healed, with very little skin atrophy.
abstract
http://content.nejm.org/cgi/content/full/361/2/178?query=TOC
Add comment July 21, 2009
Ántrax ó Carbunco
Revista Chilena de Infectología 2001
COMITÉ DE INFECCIONES EMERGENTES, SOCIEDAD CHILENA DE INFECTOLOGÍA DEPARTAMENTO DEL AMBIENTE, EPIDEMIOLOGÍA, MINSAL
Prepararon este documento: Cecilia Perret P.1, Leonardo Maggi C., Carlos Pavletic B., Rodrigo Vergara F., Katia Abarca V., Jeannette Dabanch P., Cecilia González C., Roberto Olivares C.,
Jaime Rodríguez T.
Full Text
http://www.scielo.cl/scielo.php?pid=S0716-10182001000400008&script=sci_arttext
Add comment July 21, 2009
When to Start Antiretroviral Therapy in Resource-Limited Settings
Annals of Internal Medicine 20 Jul 2009
Rochelle P. Walensky, MD, MPH; Lindsey L. Wolf, SB; Robin Wood, FCP, MMed, DTM&H; Mariam O. Fofana, AB; Kenneth A. Freedberg, MD, MSc; Neil A. Martinson, MBBCh, MPH; A. David Paltiel, PhD; Xavier Anglaret, MD, PhD; Milton C. Weinstein, PhD; and Elena Losina, PhD, for the CEPAC-International Investigators*
From the Massachusetts General Hospital, Brigham and Women’s Hospital, Harvard University Medical School, Harvard School of Public Health, and Boston University School of Public Health, Boston, Massachusetts; University of Cape Town, Cape Town, and Perinatal HIV Research Unit, Johannesburg, South Africa; Johns Hopkins University, Baltimore, Maryland; Yale School of Medicine, New Haven, Connecticut; and Université Victor Segalen Bordeaux 2, Bordeaux, France.
Background: The results of international clinical trials that are assessing when to initiate antiretroviral therapy (ART) will not be available for several years.
Objective: To inform HIV treatment decisions about the optimal CD4 threshold at which to initiate ART in South Africa while awaiting the results of these trials.
Design: Cost-effectiveness analysis by using a computer simulation model of HIV disease.
Data Sources: Published data from randomized trials and observational cohorts in South Africa.
Target Population: HIV-infected patients in South Africa.
Time Horizon: 5-year and lifetime.
Perspective: Modified societal.
Intervention: No treatment, ART initiated at a CD4 count less than 0.250 x 109 cells/L, and ART initiated at a CD4 count less than 0.350 x 109 cells/L.
Outcome Measures: Morbidity, mortality, life expectancy, medical costs, and cost-effectiveness.
Results of Base-Case Analysis: If 10% to 100% of HIV-infected patients are identified and linked to care, a CD4 count threshold for ART initiation of 0.350 x 109 cells/L would reduce severe opportunistic diseases by 22 000 to 221 000 and deaths by 25 000 to 253 000 during the next 5 years compared with ART initiation at 0.250 x 109 cells/L; cost increases would range from $142 million (10%) to $1.4 billion (100%). Either ART initiation strategy would increase long-term survival by at least 7.9 years, with a mean per-person life expectancy of 3.8 years with no ART and 12.5 years with an initiation threshold of 0.350 x 109 cells/L. Compared with an initiation threshold of 0.250 x 109 cells/L, a threshold of 0.350 x 109 cells/L has an incremental cost-effectiveness ratio of $1200 per year of life saved.
Results of Sensitivity Analysis: Initiating ART at a CD4 count less than 0.350 x 109 cells/L would remain cost-effective over the next 5 years even if the probability that the trial would demonstrate the superiority of earlier therapy is as low as 17%.
Limitation: This model does not consider the possible benefits of initiating ART at a CD4 count greater than 0.350 x 109 cells/L or of reduced HIV transmission.
Conclusion: Earlier initiation of ART in South Africa will probably reduce morbidity and mortality, improve long-term survival, and be cost-effective. While awaiting trial results, treatment guidelines should be liberalized to allow initiation at CD4 counts less than 0.350 x 109 cells/L, earlier than is currently recommended.
Primary Funding Source: National Institute of Allergy and Infectious Diseases and the Doris Duke Charitable Foundation.
abstract
http://www.annals.org/cgi/content/abstract/0000605-200908040-00138v1?papetoc
http://www.annals.org/cgi/reprint/0000605-200908040-00138v1.pdf
Add comment July 21, 2009
Systematic Review: T-Cell–based Assays for the Diagnosis of Latent Tuberculosis Infection: An Update
Annals of Internal Medicine 5 August 2008 V.149 N.3 p.177-184
REVIEW
Madhukar Pai, MD, PhD; Alice Zwerling, MSc; and Dick Menzies, MD, MSc
From McGill University and Montreal Chest Institute, Montreal, Quebec, Canada.
Background: Interferon-–release assays (IGRAs) are alternatives to the tuberculin skin test (TST). A recent meta-analysis showed that IGRAs have high specificity, even among populations that have received bacille Calmette–Guérin (BCG) vaccination. Sensitivity was suboptimal for TST and IGRAs.
Purpose: To incorporate newly reported evidence from 20 studies into an updated meta-analysis on the sensitivity and specificity of IGRAs.
Data Sources: PubMed was searched through 31 March 2008, and citations of all original articles, guidelines, and reviews for studies published in English were reviewed.
Study Selection: Studies that evaluated QuantiFERON-TB Gold, QuantiFERON-TB Gold In-Tube (both from Cellestis, Victoria, Australia), and T-SPOT.TB (Oxford Immunotec, Oxford, United Kingdom) or its precommercial ELISpot version, when data on the commercial version were lacking. For assessing sensitivity, the study sample had to have microbiologically confirmed active tuberculosis. For assessing specificity, the sample had to comprise healthy, low-risk individuals without known exposure to tuberculosis. Studies with fewer than 10 participants and those that included only immunocompromised participants were excluded.
Data Extraction: One reviewer abstracted data on participant characteristics, test characteristics, and test performance from 38 studies; these data were double-checked by a second reviewer. The original investigators were contacted for additional information when necessary.
Data Synthesis: A fixed-effects meta-analysis with correction for overdispersion was done to pool data within prespecified subgroups. The pooled sensitivity was 78% (95% CI, 73% to 82%) for QuantiFERON-TB Gold, 70% (CI, 63% to 78%) for QuantiFERON-TB Gold In-Tube, and 90% (CI, 86% to 93%) for T-SPOT.TB. The pooled specificity for both QuantiFERON tests was 99% among non–BCG-vaccinated participants (CI, 98% to 100%) and 96% (CI, 94% to 98%) among BCG-vaccinated participants. The pooled specificity of T-SPOT.TB (including its precommercial ELISpot version) was 93% (CI, 86% to 100%). Tuberculin skin test results were heterogeneous, but specificity in non–BCG-vaccinated participants was consistently high (97% [CI, 95% to 99%]).
Limitations: Most studies were small and had limitations, including no gold standard for diagnosing latent tuberculosis and variable TST methods and cutoff values. Data on the specificity of the commercial T-SPOT.TB assay were limited.
Conclusion: The IGRAs, especially QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube, have excellent specificity that is unaffected by BCG vaccination. Tuberculin skin test specificity is high in non–BCG-vaccinated populations but low and variable in BCG-vaccinated populations. Sensitivity of IGRAs and TST is not consistent across tests and populations, but T-SPOT.TB appears to be more sensitive than both QuantiFERON tests and TST.
abstract
http://www.annals.org/cgi/content/abstract/149/3/177?etoc
Add comment July 21, 2009
