Anaphylaxis / Urticaria / Angioedema HSJ 29/02/12

Transcription

1 Anaphylaxis / Urticaria / Angioedema HSJ 29/02/12

2 Case Study Female, 42,? Penicillin Allergy After 1 tab amoxyl, tongue/throat swelling, lips, ears Collapse, given adrenaline Had amoxycillin several times before 2 months later stroked cat (on antibiotics) lip/eye swelling, itch face? Will react to traces in hospital RAST Penicillin neg SPT Neg Major and Minor determinants Strong Positive Amoxycillin proximal tracking, systemic itch Diagnosis Severe Allergy Amoxycillin, reaction to trace quantities

3 Case Study Female, 32, Anaphylaxis? Cause Generalised itch, urticaria, lip/tongue/throat swelling, wheeze Tryptase 22. Vigorous walk 1 hour before. Hand surgery week before. Ibuprofen/augmentin last doses 4 days before 2008 similar episode 2 weeks after surgery; pregant 2004 milder episode adter trimethoprim for cystitis Non-atopic RAST negative common allergens ESR, TFT, autoabs, baseline trytase NAD Diagnosis Idiopathic anaphylaxis non-specific triggers

4 Def Anaphylaxis Acute systemic allergic reaction At least one of : respiratory difficulty - laryngeal oedema, bronchospasm hypotension

5 Anaphylaxis - symptoms Erythema Pruritus Urticaria Angiooedema - face, eyes, lips, tongue, throat Hypotension Collapse, LOC Vomiting, abdo pain, diarrhoea Rhinoconjunctivitis

6 Prescribing information can be found on slide 22 Clinical features of anaphylaxis Laryngeal oedema Generalised pruritus Hypotension/collapse Bronchospasm Feeling of impending doom Onset usually within minutes

7 Mechanisms Anaphylaxis - IgE dependent systemic release of mediators inc histamine, leukotrienes, PGD2 from mast cells and basophils. Requires sensitisation and reexposure Anaphylactoid - as above but not IgE dependent

8 Ewan, P. W BMJ 1998;316: No Caption Found

9 Anaphylaxis - causes Idiopathic Anaphylactic Food -peanut, tree nuts, crustacea Antibiotics Insect venom Latex Allergen vaccines Animal proteins

10 Anaphylaxis - causes Anaphylactoid NSAIDs Radiocontrast media Opioids Muscle relaxants IVIG Blood products Physical factors - exercise, temperature

11 Percentage Prescribing information can be found on slide 22 Prevalence of anaphylaxis unknown but increasing % Causes of anaphylaxis among 179 patients at Mayo Clinic, Rochester, USA 20 14% 13% 19% 10 7% 0 Food Bee sting Medications Exercise Idiopathic Yocum MW, Khan DA. Mayo Clin Proc 1994:69:16-23

12 Anaphylaxis - Management ABC Fluids Oxygen Position Adrenaline Corticosteroids (200mg HC then oral) Antihistamines (10mg chlorpheniramine) B2 Agonists

13 Adrenaline I/M dose mg (0.5 ml of 1 in mg/ml solution) Earlier the better Epipen - Training Dose can be repeated IV if patient moribund or cardiac arrest Cardiac monitoring

14 Prescribing information can be found on slide 22 Who should be prescribed adrenaline auto-injectors? Auto-injectors are indicated when: Allergen is unavoidable Reaction is systemic Patient has history of severe reactions with respiratory difficulty and/or hypotension Or Patient has no such history, but is considered high risk Asthma History of mild food reactions McLean-Tooke et al. BMJ 2003;327:1332-5

15 Prescribing information can be found on slide 22 Additional considerations in prescribing auto-injectors No need for adrenaline if allergen is easily avoidable e.g. drug reactions Patients and carers must be ready, willing and able to use auto-injectors, and understand when to use them High-risk patients: asthma reaction to trace allergen repeated exposure likely e.g. healthcare worker & latex McLean-Tooke et al. BMJ 2003;327:1332-5

16 Urticaria (Hives): Skin reaction pattern characterized by transient, pruritic, edematous, lightly erythematous papules or wheals, frequently with central clearing 10

17 Urticaria Acute Allergy eg food, penicillin, venom Anaphylactoid eg NSAIDs Chronic Chronic idiopathic urticaria Urticarial vasculitis Physical urticaria - cold, pressure, cholinergic, dermatographism

18 Chronic idiopathic urticaria Autoimmune disease Associated with thyroid disease 40% have IgG against alpha subunit of IgE receptor Often coexists with angiooedema Resolves spontaneously over months/years Rx antihistamines/ LTRA/ ciclosporin

19 Angioedema Male, 48, NHS IT. Impromptu meeting with HSJ in A+E - massive lip swelling Recurrent episodes over 5-6 years, increasing frequency Regular A+E attender. Often steroids. Affecting work AH unhelpful. Various diets unhelpful SPTs Negative all foods TFT, C1 Esterase negative Diagnosis Idiopathic Angioedema Rx Tranexamic acid

20 Angioedema Male, 57, admitted on medical take, allergic reaction Woke 4am acute swelling of tongue, and throat, difficulty swallowing No rash/wheeze, slow to settle on ward with Ahs. Recurrent abdo pain PMH Ca prostate, Glaucoma, hypothyroidism Rx Aspirin, Diethylstilboestrol, Citalopram, Thyroxine No FH of angioedema IgE/ RAST normal C4 undetectable, ANA positive C1 Esterase undetectable Diagnosis Acquired C1 Esterase Deficiency (? Due to Ca Prostate) Rx C1 inhibitor concentrate for acute attacks Tranexamic acid for prevention v effective

21 Angioedema Isolated, may not be classed as anaphylaxis Causes : Idiopathic - may be associated with urticaria ACE inhibitors, NSAIDs, statins C1 esterase inhibitor deficiency (congenital, acquired)

22 Summary Anaphylaxis Systemic allergic reaction affecting ABC Most cases due to food, venom, drugs. All warrant referral Give adrenaline auto-injector if Allergen unavoidable Prev severe reaction Esp if asthma or reaction to trace Urticaria can be acute or chronic Not allergic if chronic. AH and refer if not controlled No need for adrenaline Angioedema Think drugs, heredity. Often idiopathic Adrenaline only if severe airway involvement Refer if recurrent