Anaphylactic shockT78.2

The most common triggers of anaphylactic shock are:

• Food (see below food allergy: peanuts, various types of nuts, milk, eggs, fish, shellfish, various food additives).
• Insecticides (see below insecticide allergy: bee, wasp, hornet)
• Drugs (see below drug reaction, undesirable: antibiotics, anti-inflammatory drugs, non-steroidal drugs, narcotics, antiepileptic drugs, muscle relaxants, X-ray contrast media [see below contrast media intolerance])
• Latex
• Physical triggers (cold, UV rays) or physical exertion (= exercise induced anaphylaxis) are rare as the maximum variant of cholinergic urticaria (see below urticaria, cholinergic).

Summative anaphylaxis: It is not uncommon for anaphylactic reactions to become symptomatic only after the simultaneous presence of one or more co-factors (see also food allergy). These combinations are particularly difficult to diagnose, as only their interaction triggers the anaphylaxis.

Classification from stage 0 - IV, see Table 1 In addition to the
symptoms listedinTab
.1, reflex bradycardia (Bezold-Jarisch reflex) or hypertension may occur, although less frequently. First signs are:

• Itching on the palms of the hands/foot soles or genitals
• metallic taste
• Tingling in the mouth and throat
• hot flash
• Unrest
• Reddening of larger areas of skin.

A biphasic shock reaction (can be expected in about 2% of patients). Biphasic reactions are observed 1 to max. 36 hours after the initial event.

Differential diagnosis of anaphylactic shock (var. n. Ludolph-Hauser et al.):

• Cardiovascular diseases:
  • vagovagal syncope
  • Non-anaphylactic shock (e.g. cardiogenic)
  • Hypertonic crisis
  • Capillary Leak Syndrome
  • Neuropsychiatric diseases
  • Hyperventilation tetany
  • Panic Attack
  • Globe hystericus
  • Epilepsy
  • Apoplexy
• respiratory diseases:
  • Asthma unrelated to anaphylaxis
  • Tracheal/bronchial obstruction
• Intoxications
• Pathological mediator release:
  • Mastocytosis
  • Carcinoid syndrome
• Urticaria diseases
• Angioedema (hereditary/acquired).

Venous, access as large-lumen as possible; oxygen supply, keep the airways clear, blood pressure control. If the shock is triggered by local injections or stitches in the extremities, the temporary ligature of the respective limb can soften the reaction.

Procedure:

• IMMEDIATELY: Stop allergen supply!
• Sedation of patient (and parents)
• Storage symptom-oriented: Flat storage is preferred.
• In unconsciousness: stable lateral position
• For hemodynamic instability: Trendelenburg position (legs up)
• For respiratory distress: sitting or semi-seated position
• Severity assessment: Identifying and treating the most threatening symptom
• Creating secure access
• In case of respiratory or circulatory problems, adrenalin i.m. and oxygen inh. should be given beforehand!
• In case of cardiovascular reaction or cardiac arrest, possibly intraosseous access

Adrenalin: As soon as symptoms like stridor, hypotension, dyspnea are present, 0.01mg/kgKG should be injected i.m. (see below).

From stage III or in acute respiratory distress inject adrenaline e.g. Suprarenin 1:1000 (1 ml contains 1 mg adrenaline = epinephrine) 0.3-0.5 ml slowly i.v., in case of laryngeal or glottic edema and acute respiratory distress inject a total dose up to 1 ml.

In highly acute cases, after diluting 1 ml of commercial epinephrine solution (1:1000) to 10 ml or using a ready-to-use epinephrine syringe (e.g. Anapen 300 µg, Anapen 150 µg, Fastjekt), 0.5-1.0 ml (= 0.05-0.1 mg epinephrine) is first injected slowly i.v. (0.1 mg/min) under pulse and blood pressure control; a maximum dose of 1 mg epinephrine should not usually be exceeded.

Autoinjector for intramuscular injection, weight-adjusted.

• >7,5-15kg: 150µg adrenalin
• >25-30kg: 300µg epinephrine
• >50kg: 300µg 0r 500µg epinephrine

Notice. If hemodynamic stabilization by volume administration and epinephrine is insufficient, administer vasopressors such as norepinephrine or dopamine 35 µg/kg/min (= 2.5 mg/min/70 kg bw) if necessary.

Volume substitution: I.v. administration of electrolyte solutions in stage I to II, from stage III plasma substitutes such as Ringer's solution, in exceptional cases gelatin preparations, low molecular weight dextran and hydroxyethyl starch solutions.

Caution. Dextrans may be given only after pretreatment with low-molecular-weight dextran hapten because of the risk of the existence of preformed antibodies against dextrans.

Antihistamines: From stage I to II clemastine (e.g. Tavegil) or dimetindene (e.g. Fenistil) 1-2 amp. i.v.

Theophylline (e.g., Euphyllin): For bronchial dilation from stage III 0.12-0.24 g i.v.

Glucocorticoids: From stage II, concomitant high-dose glucocorticoids such as methylprednisolone (e.g., Urbason) 500-1000 mg i.v.; dose may be repeated as needed.

β 2 -Sympathomimetics: For obstructive respiratory symptoms, supplemental injection of a β-sympathomimetic such as terbutaline sulfate (e.g., Bricanyl) 0.5-1 amp. of 0.5 mg s.c., up to a maximum of 2 mg/day.

Dosage recommendations in children:

• Epinephrine 0.005-0.01 mg/kg bw as bolus; 0.05-0.5 µg/kg/min as continuous infusion (endotracheal 2-3 times higher).
• Dopamine 1.5-2.5 µg/kg/min as continuous infusion.
• Norepinephrine 0.05-1.0 µg/kg/min as continuous infusion.
• H1 antagonists, e.g., fenistil 0.1-0.5 mg/kg bw i.v. or Tavegil 0.025-0.05 mg/kg bw i.v.
• H2 antagonists, e.g., Tagamet 2.5-5.0 mg/kg bw i.v.
• Crystalloid solutions, e.g., Ringer's lactate 20-30 ml/kg bw (repeat possibly every 20-30 min).
• Colloids, e.g., HES 10-20 ml/kg bw.
• Prednisolone 2-5 mg/kg bw i.v. (max 20 mg/kg bw).
• Theophylline 5 mg/kg bw as a slow bolus; 0.5-1.0 mg/kg bw/hour as a continuous infusion.

Formulation and practical instruction for the handling of an emergency set, in particular the adrenaline auto-injectors (Jext®, Fastjekt®, Emerade® 150ug from 15 kg, 300ug from 30kg, 500ug from 60kg).

Staging and symptoms of anaphylactic immediate reactions

• Case 1) A 17-year-old male patient, who underwent intubation anaesthesia for an uncomplicated, planned knee surgery, suffered anaphylactic shock during the induction phase. He was administered the following medications during anesthesia: thiopental, propofol, remifentanil, suxamethonium; he also received amoxicillin and Clexane. The planned surgery was subsequently postponed.
• Laboratory: Total IgE (20,5 kU/l); Tryptase (4,57µg/l); Remark: Normal values. Basophil degranulation test with 5 different concentrations of thiopental gave a positive reaction at 250 µg/ml.
• Allergological diagnosis: Prick test: positive reaction to thiopental. All further skin tests (prick and intracutaneous tests) for the above mentioned drugs as well as different latex extracts and soy. Latex extracts and soy did not show positive reactions.
• Diagnosis: Anaphylactic shock to the anaesthetic Thiopental.

• Case 2) During a cystoscopy a 62-year-old patient suddenly developed flushing symptoms, a generalized urticarial exanthema and sudden unconsciousness with a drop in blood pressure (shock stage III).
• During the cystoscopic procedure, a lubricant was used which contained lidocaine and chlorhexidine, among others. Furthermore, the patient received 200 mg ciprofloxacin p.o. immediately before the procedure.
• Laboratory: Total IgE (25,5 kU/l); Tryptase (4,20µg/l); Remark: Normal values.
• Allergological diagnostics: Prick-, intracutaneous- and epicutaneous tests with local anaesthetics and antibiotics, chlorhexidine digluconate, chlorhexidine acetate and different latex extracts (latex was also provoked conjunctivally). Oral provocation test with ciprofloxacin. Subcutaneous provocation test with lidocaine.
• Results: In the prick test, the patient showed a positive reaction to ciprofloxacin and chlorhexidine digluconate. In epicutaneous testing, chlorhexidine showed an immediate reaction.
• Diagnosis: Anaphylactic shock to the disinfectant chlorhexidine.

1. Dybendal T et al (2003) Screening for mast cell tryptase and serum IgE antibodies in 18 patients with anaphylactic shock during general anaesthesia. Acta Anaesthesiol Scand 47: 1211-1218
2. Guideline of the German Society for Allergology and Clinical Immunology (DGAI) and Medical Association of German Allergologists (ÄDA). Recommendations for the practical implementation of specific immunotherapy with allergens (hyposensitization). AWMF Guidelines Register No. 061/013
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