What is Anaphylactic (Anaphylaxis) Shock? – Signs and Symptoms

Anaphylaxis is a severe, life-threatening, generalized or systemic hypersensitivity reaction. Though such situations can arise from very common instances in life, they are not to be taken lightly.

The term ‘anaphylaxis’ is derived from the Greek roots ‘ana’ (backward) and ‘phylaxis’ (protection or immunity). The most commonly identified causes are food, drugs and venom.

History:
The first recorded episode of anaphylaxis can be found in hieroglyphic recordings from 2640 BC on the death of an Egyptian Pharaoh after a wasp sting. A more modern description of anaphylaxis is described in a study from 1902 about immunizing dogs with Jellyfish toxin.

Incidence:
The incidence of anaphylaxis is underestimated in our country, owing to the problems of recognizing it. The criteria for inclusion vary in different studies and countries. Overall frequency of episodes of anaphylaxis lies between 30 and 950 cases per 100,000 persons per year.

What is Anaphylactic Shock

Signs and Symptoms:

• Skin-mucosal: Which occur in most of the cases, include swollen lips and tongue, generalized hives, pruritus, periorbital oedema, conjunctivas swelling.

• Respiratory: Common in 70 percent of episodes. These include nasal discharge, nasal congestion, and change in voice, choking sensation, stridor, wheeze, cough, and shortness of breath.

• Gastrointestinal: Common in 45 percent of episodes. These include nausea, abdominal cramps, vomiting and diarrhea.

• Cardiovascular: Common in 45 percent of episodes. These include collapse, hypotension and dizziness. Anaphylaxis may present as mild and resolve spontaneously due to the endogenous production of compensatory mediators.

Trigger:

Allergen Triggers (igE-dependent mechanism)

• Foods and additives like walnuts, peanuts, shellfish, fish, milk, eggs, strawberries, spices.

• Insect stings (hymenoptera venom) and insect bites (mosquitoes, horse flies, ants).

• Medications e.g. b-lactam antibiotics-penicillin, cephalosporin, vancomycin, non-steroidal anti-inflammatory drugs (NSAIDs).

• Contrast media (iodinated, technetium, fluorescein).

• Anesthetic drugs (sexamethonium, atracurium) Occupational allergens (natural rubber, latex, hair dye).

• Occupational allergens (natural rubber, latex, hair dye).

Non-Immunologic Trigger (direct activation of mast cells and basophiles)

• Medications (like opioids, some NSAIDS)
• Alcohol
• Physical factors (e.g. cold, heat, exercise, sunlight)

Time Course for Fatal Anaphylactic Reactions:

• Fatal food reactions cause respiratory arrest typically after 30-30 minutes
• Insect stings cause collapse from shock after 10-15 minutes
• Deaths due to intravenous medication occur commonly within 5 minutes
• Death never occurs more than 6 hours after contact with the trigger

Data indicates a dramatic increase in the rate of hospital admissions for anaphylaxis. This is from 0.5 to 3.6 admissions per 100,000 between 1990 and 2004 – an increase of 700 percent. The overall prognosis of anaphylaxis is good. Risk of death is increased in those with pre-existing health issues, especially asthma.

Steps of Action:
The specific treatment of an anaphylactic reaction depends on how efficiently you manage your next moments:

  • Call an ambulance immediately
  • Check if the hospital has enough resources
  • Patient positioning – Patients with airway and breathing difficulties may prefer to sit up

For patients with low blood pressure, lying flat or with elevated legs may be helpful. Patients, who are unconscious and are breathing, should be laid in recovery position. Pregnant patients should lie on their left side to prevent venacaval compression.

Discharge and Follow-up:
Patients who have had a suspected anaphylactic reaction should be treated and observed for at least 6 hours. Only after a senior physician has checked and advised, should a patient go home.

All Patients must be:

• Reviewed by a senior clinician.
• Given clear instructions to return to hospital if symptoms return.
• Considered for anti-histamines and oral steroid therapy for up to three days. This is helpful for treatment of urticaria and may decrease the chance of further reaction.
• Have a plan for follow-up, including referral to the patient’s general practitioner.

Remember:
All patients presenting with anaphylaxis should be referred to an allergy clinic to identify the cause and thereby reduce the risk of future reactions. Also, the patient should be educated to manage future episodes.

SOURCE: B-Positive Health Magazine

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