Anaphylactic Shock

Anaphylactic Shock

   Acute hypersensitivity reaction

Cause

• Allergy to pollens, some drugs (eg. penicillins, vaccines, aspirin) or certain foods (eg. eggs,

   fish, cow’s milk, nuts, some food additives)

• Reaction to insect bites, eg. wasps and bees

Clinical features

• Sudden collapse

• Hypotension

• Excessive sweating

• Thin pulse

Differential diagnosis

• Other causes of shock, eg. bleeding, severe dehydration

Management

# Determine and remove the cause

# Keep patient warm

# Secure the airway

# Restore the BP: lay the patient flat and raise the feet

# adrenaline (epinephrine) injection 1 in 1000 (1mg/mL) 0.5−1mg IM

#  repeat initially (several times if necessary) every 10 minutes according to

    BP, pulse rate and respiratory function until improvement occurs

child: see dose table below

# Administer 100% oxygen

 this is of prime importance

# Give an antihistamine as useful adjunctive treatment, eg. promethazine hydrochloride

   25−50mg by deep IM or slow IV (give <25mg/min as a diluted solution of 2.5mg/mL in water

   for injections, max: 100mg)

child

 # 1−5 yrs: 5mg by deep IM

 # 5−10 yrs: 6.25−12.5mg by deep IM

 # repeat dose every 8 hours for 24−48 hours to prevent relapse

To prepare the diluted solution: dilute each 1mL of promethazine hydrochloride injection

 25mg/mL with 9mL of water for injections

In severely affected patients:

# hydrocortisone 200mg IM or slow IV stat child <1 yr: 25mg; 1−5 yrs: 50mg; 6−12 yrs:

   100mg − helps to prevent further deterioration

# Repeat adrenaline and hydrocortisone every 2−6 hours prn depending on the patient's

   progress

sodium chloride 0.9% infusion 20mL/kg by IV infusion over 60 mins − start rapidly then

adjust rate according to BP