What’s new in April for Medicine features: Urticaria and Angioedema, Advance Care Planning, Approach to the Patient with Kidney Disease, Approach to the Patient with Cough, Disorders of the Pleura, Mediastinum, and Hilum.
JUSTIN R. CHEN, MD
DAVID A. KHAN, MD
Division of Allergy & Immunology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
Delayed Urticarial Allergic Reaction to Red Meat
For immunoglobulin E (IgE)-mediated food allergy, the cutaneous eruption should become evident within 1 hour of ingestion and almost invariably by 2 hours. As a rule, symptoms occurring on the following day are not consistent with IgE-mediated food allergy. One notable exception is an IgE-mediated reaction to galactose-alpha-1,3-galactose, which manifests as a delayed allergic response of between 3 and 6 hours to mammalian red meat products in individuals previously bitten by the lone star tick endemic to the south-central United States.
LAUREN JODI VAN SCOY, MD
MICHAEL GREEN, MD, MS
BENJAMIN LEVI, MD, PhD
Departments of Humanities and Pediatrics, Penn State College of Medicine, Hershey, PA
Advance Care Planning Interventions
To address the many challenges associated with advance care planning (ACP), a variety of resources have emerged, ranging from workbooks to multimedia, Web-based guides, decision aids, community-based programs, and even games. An innovative approach that uses a collection of video imagery to inform patients and families about ACP is Video Images of Disease for Ethical Outcomes (VIDEO). Developed by a team of clinicians and academics, VIDEO tools have been shown to improve people’s understanding of various life-threatening conditions, as well as medical decision making related to those conditions. These include ACP videos that address end-of-life decision making in the context of dementia, advanced cancer, and hospitalization, as well as treatment options such as cardiopulmonary resuscitation and mechanical ventilation.
AJAY K. SINGH, MBBS, FRCP (UK), MBA
Brigham and Women’s Hospital, Boston, MA
JAMEELA A. KARI, MD, FRCP (UK), FRCPCH
King Abdulaziz University, Jeddah, Saudi Arabia
Serial Assessment of the Glomerular Filtration Rate to Evaluate Kidney Function
Most commonly, when evaluating the presence or degree of kidney dysfunction, clinicians will measure blood urea nitrogen and serum creatinine as part of the “renal panel.” However, increasingly common and in many centers now is the glomerular filtration rate (GFR), calculated using the Modification of Diet in Renal Disease (MDRD) prediction equation (the eGFR). Serial assessment of the GFR can allow the clinician to determine the course of the underlying disease by demonstrating either rapid or slow rates of decline in kidney function. Accurate determination of kidney function also helps the clinician make adjustments in the dosing of pharmacologic agents so as to prevent the accumulation of drugs and metabolites and, thereby, potential toxicities.
CHRISTOPHER H. FANTA, MD
Partners Asthma Center, Pulmonary and Critical Care Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
Automated Cough Counters
A number of subjective and objective tools have been developed recently to assess cough severity. An encouraging development to aid in the assessment of new antitussives is the automated cough counter. Researchers will now be able to make objective measurements of cough frequency rather than relying exclusively on reported cough symptoms such as recorded in cough diaries and visual analogue scales describing cough severity. Approved devices are available that appear to accurately distinguish cough from throat clearing, snoring, and ambient background noises. They are compact and noninvasive, with a long battery life for extended recording times. Their role is currently limited to cough research rather than clinical practice.
ANDREW D. LERNER, MD
DAVID FELLER-KOPMAN, MD
Division of Pulmonary and Critical Care Medicine, Johns Hopkins Hospital, Baltimore, MD
Peripheral Pain Treatment in Fibromyalgia
Several studies have shown that N-terminal pro–brain natriuretic peptide (NT-pro-BNP) is elevated in pleural fluid as a result of heart failure, with pooled sensitivity and specificity of 94% shown on meta-analysis. NT-pro-BNP is most useful in patients with pleural effusions attributable to heart failure who have already undergone diuresis as transudative effusions in this setting typically have a higher protein content and may be misclassified as exudates according to standard criteria. As pleural fluid NT-pro-BNP correlates extremely well with serum NT-pro-BNP, some authors suggest that the serum measurement alone can be used.
As seen in Scientific AmericanTM Medicine.
Figure of the Month: The Figure of the Month for March is entitled Model of Hemoglobin Molecule (Figure 1 from Red Blood Cell Function and Disorders of Iron Metabolism).