Anaphylaxis

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Anaphylaxis

• Alex Pearce-Smith

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Scenario

• A patient who is well but has been called in for
  a medication review has just sat down. Suddenly
  the practice nurse bursts in and announces that a
  patient to whom she has just vaccinated seems to
  be having a severe reaction.

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In Groups/Pairs Think About.

• What do you do initially?
• What is your assessment?
• What are the signs of anaphylaxis?

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Assessment

• Excuse yourself from patient go straight to
  sick patient and assess - ?help ABCDE.
• Severe/Life threatening features in anaphylaxis.
• A Swelling, Hoarseness, Stridor.
• B RR, Wheeze, Sats lt92.
• C Pale, clammy, Low BP.
• D Confused/Drowsy/Coma.

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Recognising Anaphylaxis

• Anaphylaxis likely when ALL 3 criteria met
• Sudden onset and rapidly progressing symptoms.
• Life threatening Airway/Breathing/Circulatory
  problems.
• Skin/Mucosal changes (angio-oedema, flushing or
  urticaria)
• PMH and circumstances may help (ie given vaccine).

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Skin Changes

• Usually first feature but may be absent in upto
  20 of cases.
• May be subtle or dramatic.
• May be just skin, just mucosal or both.
• Maybe patchy or generalised erythematous rash.
• May be urticaria usually itchy.
• Angioedema is similar to urticaria but affects
  the deeper tissues usually eyelids and lips but
  sometimes mouth and throat.
• Not an indicator of severity most systemic skin
  reactions do not end up as anaphylaxis.

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Skin Presentations
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Differential Diagnoses

• Vasovagal attack.
• Panic attack.
• Idiopathic urticaria.
• Breath-holding episode in a child.

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Management

• ABC assessment indicates severe/life-threatening.
• Lie flat, feet up.
• Remove trigger (e.g. bee sting).
• IM adrenaline 0.5mg adult (over 12) less for
  children/babies.
• Oxygen.
• Fluid Challenge (crystalloid).
• Chloramphenamine and hydrocortisone.
• Some should be calling 999.

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Management

• Should go to hospital for further
  management/observation 6hrs minimum but most
  discharged by 24 hrs if good response.
• Various indicators for longer observation.
• Review by senior clinician before discharge.
• Specialist follow up in allergy clinic.

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Common Triggers

• Food (especially nuts)
• Drugs
• Antibiotics esp penicillin and cephalosporin
• Anaesthetic drugs
• Other drugs esp NSAIDs.
• Venom esp wasp stings.

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Mortality

• Less than 1 mortality.
• About 20 deaths per year in UK recorded due to
  anaphylaxis but may be underestimate.
• Asthmatics more at risk.
• Deaths happen quickly after contact with
  allergen.
• Food 30 mins.
• Venom 15 mins.
• IV medications 5 mins.

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In conclusion

• If severe or life-threatening symptoms and
  clinical suspicion of anaphylaxis give
  adrenaline.
• Remember ABC you may not get beyond A.

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For More Information

• For details about the recommended recognition and
  management of anaphylaxis including correct
  paediatric dosages etc go to Resuscitation
  Council Website.
• http//www.resus.org.uk/pages/reaction.pdf