Allergie à lˈarachide

Peanut allergy, which is frequent in the United States and was much less so in Europe up to the mid-eighties, has become a major problem in many industrialized countries. Peanut consumption is high in Eastern Europe, the United Kingdom, The Netherlands, Germany and France. The frequency of peanut allergy is between 0.5 and 0.7% in the general population. Two million Americans are now thought to be affected. In France peanuts are one of the most frequent allergens, lying second (27.4%) to egg in food allergies in children, and holding first place in food allergies in children aged over 3 years. Sensitization occurs through ingestion, contact even if indirect, and inhalation. The symptoms, which affect the skin and the respiratory or gastrointestinal tract, appear a few minutes to a few hours after exposure. Serious reactions (anaphylactic shock, life-threatening reactions, sudden death) have been described. Asthma has a significantly higher association with peanut allergy than with other allergies, taken overall. As with other food allergies, diagnosis is based on history, prick-tests, screening for specific serum IgE and food challenge whose modalities (labial and oral challenge) are debated. For the time being, elimination is the only form of treatment. The development of a modified allergen as immunogenic as possible but practically without allergenic effects should give immunotherapy new impetus. Patients with severe peanut allergy should carry a card or wear a distinctive bracelet indicating their condition as well as an emergency kit including in particular epinephrine.     

Allergie alimentaire à la noix du Brésil : à propos de cinq cas chez l’enfant d’âge préscolaire

Five cases of allergy to Brazil nuts are reported in children under 6 years of age. All patients have other atopic diseases and reacted in a few minutes. Sensitivity to other nuts and peanuts is investigated. With a history of allergy to any nuts, a patient should always be tested for the other nuts.     

Inhibiteurs de la pompe à protons et clopidogrel (Plavix®) : une liaison dangereuse ?

Proton pump inhibitors (PPI) and antiplatelet agents, especially aspirin and clopidogrel, are among the most prescribed medications worldwide. Their co-administration is justified by the increased risk of gastrointestinal bleeding related to the antiplatelet therapy. The issue of the interaction between PPI and clopidogrel has been raised with the emergence of the concept of “high on-clopidogrel platelet reactivity” (or “clopidogrel resistance”) together with the discovery of the role of CYP2C19 isoform in the pharmacokinetics of those two medications. Indeed, CYP2C19 is involved in the conversion of the clopidogrel pro-drug into its active metabolite and is involved in the metabolisation of PPI into inactive metabolites, acting as substrates/inhibitors of CYP2C19. Despite their heterogeneity, most pharmacodynamic studies have shown a decreased clopidogrel antiplatelet effect when associated to PPI, especially those with the highest CYP2C19 inhibiting activity (omeprazole, lansoprazole, rabeprazole). On the other hand, clinical studies are inconclusive. Retrospective studies have shown an increased risk of major cardiovascular events or mortality when clopidogrel and PPI are associated in comparison with clopidogrel alone, particularly in the patients with the higher cardiovascular risk. However, the two prospective randomized studies published so far did not find any interaction and confirmed the benefit of PPI on the gastrointestinal bleeding. As a conclusion, as the clinical studies are not conclusive, the French health authorities have recently removed the alert about this interaction. PPI and clopidogrel can thus be co-prescribed.     

L’hypo-albuminémie contribue-t-elle à l’aggravation de l’insuffisance cardiaque ?

BackgroundHypoalbuminemia has now emerged as a powerful prognosticator in heart failure regardless of age, clinical presentation, left ventricular ejection fraction and usual prognostic markers. Growing evidence is that this prognostic value persists after adjusting for causative factors for hypoalbuminemia such as malnutrition, inflammation and liver dysfunction.ObjectiveTo address the prognostic relevance of hypoalbuminemia in frail elderly patients with well-characterized cardiogenic pulmonary edema at high risk for adverse outcome, beyond causative factors for low serum albumin levels. Serum albumin was measured after clinical stabilization to avoid hypervolemia.ResultsIn all, 67 patients with a mean age of 86 years were included. Hospital mortality was 30%. Patients who died and who survived were similar in age, ejection fraction, BNP concentration, serum creatinine, serum hemoglobin, total bilirubin and prealbumin. Patients who died had lower serum albumin levels (P < 0.001), higher blood urea nitrogen (P = 0.03) and higher C-reactive protein (P = 0.02). In multivariate analysis, serum albumin was the sole independent predictor of hospital death (P < 0.01), after adjusting for malnutrition (prealbumin P = ns), inflammation (C-reactive protein P = ns) and liver dysfunction (total bilirubin P = ns).ConclusionSerum albumin is a powerful prognosticator in frail elderly patients with acute cardiogenic pulmonary edema even after adjusting for main causative factors. These results suggest that hypoalbuminemia may contribute to the worsening of heart failure given the physiological properties of serum albumin that includes antioxidant activity and plasma colloid osmotic pressure action. Further studies are critically needed to address the relevance of prevention and correction of hypoalbuminemia in heart failure.     

« Allergie à l'iode » : le point sur la question

Objective. – The aim of this literature review is to suggest a diagnostic and a preventive attitude in patients having presented an immediate hypersensitivity reaction due to an iodinated drug.Data sources. – Literature review. Data were searched in the Medline database from 1967 to 2004 in English and French language. Complementary references were selected from the bibliography of selected references or from authors' personal databases. The following key-words were used separately or combined: Hypersensitivity, Immediate; Allergy; Contrast Media; Povidone-Iodine; Iodine; Iodine Compounds; Iodides; Amiodarone; Seafood, Parvalbumins; Tropomyosin.Study selection. – Randomized studies, epidemiological studies, original articles, clinical cases, and letters to the editor were selected.Data synthesis. – The implication of iodine has never been demonstrated during allergic hypersensitivity reactions due to iodinated drugs. However, IgE-mediated allergic hypersensitivity reactions have been published with contrast media or iodinated antiseptics and will be described in this development. In a wider sense, allergic hypersensitivity reactions due to seafood are evoked because often improperly considered as a risk factor of allergic reaction to iodinated drugs. The allergenic determinant responsible of patient sensitization is not known for iodinated contrast media, but is probably due to povidone in case of iodine povidone. In fish, the allergen is described as the protein M. There has also been strong immunological evidence that tropomyosin is a cross-reactive allergen among crustaceans and molluscs (shellfishs). In case of hypersensitivity reaction occurring with iodinated drug, an allergological assessment is required to confirm the immune mechanism, to identify the culprit drug or substance and to identify a cross-reactivity especially with iodinated contrast media.Conclusion. – Asking a patient if he/she is "allergic to iodine" is a question that should be avoided because its significance is null. A diagnosis of drug allergy, essentially relying on clinical symptoms, biological tests and cutaneous tests, is required to take adequate preventive measures.     

Thrombose coronaire : physiopathologie et traitement à l’ère de la médecine personnalisée

Coronary thrombosis remains the leading cause for cardiovascular death in France. Great advances have been made in the knowledge of the basic mechanism involved in coronary thrombogenesis and in antithrombotic treatments. They have led to substantial survival benefit after myocardial infarction and enabled development of tailored therapeutic strategies, especially for high-risk patients. Direct oral anticoagulants have now entered the game for secondary prevention after coronary thrombosis.