2.16 CME

Approche des réactions allergiques sévères

Conférencier: Dr Imran Shareef

Consultant Emergency Medicine, King\'s College Hospital, NHS Foundation Trust, Hyderabad

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Description

Anaphylaxis is a medical emergency that requires quick diagnosis and treatment. Basic equipment and medication should be easily accessible in the doctor's office. Lieberman et al. have explained this in considerable detail. Patients with severe anaphylactic symptoms should get routine treatments before being transported to the hospital. Interventions include high-flow oxygen, cardiac monitoring, and intravenous (IV) access. These precautions are recommended for an asymptomatic patient with a history of severe reaction who has been re-exposed to the triggering chemical. For patients with exclusively local reactions, additional measures beyond basic life support (BLS) are unnecessary. The prognosis of patients with anaphylaxis is determined by the severity of the first reaction and their treatment response. Patients with non-life-threatening symptoms may be followed for 4-6 hours after successful treatment.

Résumé

  • Allergic reactions are sensitivities to allergens, which can be anything ingested, inhaled, or touched. Mild reactions involve itching or stomach upset, while severe reactions, or anaphylaxis, involve lip swelling and airway obstruction. Anaphylaxis requires a compromised airway, breathing, or circulation and occurs within seconds to minutes of exposure.
  • Common causes of anaphylaxis are drugs like penicillin, foods like peanuts and shellfish, and insect bites. Initial exposure sensitizes the immune system, while subsequent exposure triggers an overwhelming response through mast cell degranulation, releasing inflammatory mediators. Family history of allergies and sterile upbringing can increase the risk of anaphylaxis. Skin reactions may not always be present, and patients may experience a feeling of throat closure, voice changes, and circulatory collapse.
  • Diagnosis of anaphylaxis is largely clinical, based on temporal history and symptoms. Mass cell tryptase blood tests can be used to exclude anaphylaxis. The initial treatment is immediate intramuscular (IM) epinephrine to address airway, breathing, or circulation compromise. High-flow oxygen and beta-agonists like albuterol can also be administered. Steroids may be given depending on local guidelines.
  • For ongoing issues with hypotension, IV fluid challenges with normal saline or ring lactate can be given. Continuous monitoring of vital signs is necessary, and epinephrine doses may be repeated. Patients may require intubation.
  • EpiPens containing .3mg epinephrine are prescribed to patients for self-administration in case of future anaphylactic reactions. Patients should carry at least two EpiPens. Complications of untreated anaphylaxis include airway obstruction, cardiac arrest, and respiratory arrest. Patients should be observed for 4-6 hours after treatment.
  • Discharge advice includes identifying and avoiding allergens. Patients should be counseled on what to do and what to avoid, as well as how to access help should a reaction reoccur.

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