,Emergencies
Anaphylaxis (Type 1 Hypersensitivity)
Definition: Severe, life-threatening, generalised OR systemic hypersensitivity reaction which is likely when BOTH of
the following criteria are met:
o Life-threatening airway and/or breathing and/or circulation problems
o Sudden onset and rapid progression of symptoms
Cause: T1 hypersensitivity (occurs usually in minutes, but a delayed type 1 can occur in hours... if not previously
exposed but constantly being exposed [e.g. dermatological substance applied to skin] then T1 can occur in 1-2 d
[antibodies form as not previously sensitized, and when they do T1 reaction occurs])
o Allergen reacts w/ IgE antibody on mast cell causing RAPID release of stored histamine
o Causes capillary leakage mucosal edema shock +asphyxia
o Variable in presentation
Rapid
Slow onset, sometimes biphasic (i.e. 2nd reaction)
Common causes:
o Food Peanut, fish/shellfish, milk, eggs
o Drug Antibiotic, NSAIDs, opioid, IV contrast
o Venom Bee, wasp
Features: Hx of previous sensitivity OR recent drug exposure
o Initial Generalised itching, urticaria, erythema, rhinitis, conjunctivitis
o Intermediate Angioedema, stridor, wheeze, itchy throat, palpitations, tachycardia, anxiety
o Late (can progress here quickly!) Shock, cyanosis, hypotension
DDx: Life-threatening asthma, septic shock, ?epiglottitis
Ix: Mast cell tryptase (AFTER emergency management, then repeat sample 1-2hr later)
Rx: ABCDE – Get full obs (if temp high, Abx; listen to lung sounds – if global wheeze, bronchodilat nebs)
o First: Call for help – anesthetist
Secure airway (?intubate) + High flow O2 + Lie patient FLAT + Raise legs
Remove precipitant (e.g. penicillin IV infusion)
IM Adrenaline into anterolateral middle thigh
Adults 500mcg – 0.5mL of 1:1000 – repeat every 5min if necessary
Children:
o <6yr = 150mcg
o 6-12 = 300mcg
o >12 = 500mcg
NB: IV adrenaline ONLY used by trained + experienced staff; dose is 50mcg (0.5mL of 1:10000)
IV fluid challenge (if hypotensive, 1-2L in young, fit, healthy)
o Refractory:
IV Chlorphenamine 10mg IM/Slow IV (symptomatic relief, no evidence for airway resolution)
≥12 = 10mg; 6-12 = 5mg; 6mo – 6yr = 2.5mg; <6mo = 250mcg/kg
IV Hydrocortisone 200mg IM/IV (symptomatic relief, plus prevent 2nd acute reaction)
≥12 = 200mg; 6-12 = 100mg; 6mo – 6yr = 50mg; <6mo = 25mg
o Still refractory: ITU + Salb+Ipra Nebs (consider aminophylline)
o Stable: Admit ALWAYS for overnight observation (secondary reaction to allergen occurs in >20% within 8hr)
o Discharge: 2x epi-pens at all times, allergy clinic appt
IM ADRENALINE USED WHEN NOT INDICATED WILL **NOT** HARM A PATIENT! HAVE LOW THRESHOLD
,
, Chapter 1 – Neonatology
Perinatal Definitions
Gestational age Age measured from LMP (in weeks + days)
Live birth Delivered fetus/conceptus with signs of life, irrespective of gestational age
Spontaneous abortion/miscarriage Delivered conceptus w/o signs of life <24wk
Stillbirth Delivered fetus w/o signs of life >24wk
Perinatal mortality All stillbirths + neonatal deaths <1wk post-delivery
Neonatal mortality Death amongst live births (any gestational age) <4wk post-delivery
Neonatal period 28 days post-delivery; if pre-term, 44 weeks post-LMP
Pre-term <37wk (10%)
Term birth 37-42wk delivery
Post-term >41+3 (5%)
Low birth weight <2.5kg (5%)
Very low birth weight <1.5kg (0.5%)
Extremely low birth weight <1kg
Small for gestational age <10th %ile
Large for gestational age >90th %ile
Anaphylaxis (Type 1 Hypersensitivity)
Definition: Severe, life-threatening, generalised OR systemic hypersensitivity reaction which is likely when BOTH of
the following criteria are met:
o Life-threatening airway and/or breathing and/or circulation problems
o Sudden onset and rapid progression of symptoms
Cause: T1 hypersensitivity (occurs usually in minutes, but a delayed type 1 can occur in hours... if not previously
exposed but constantly being exposed [e.g. dermatological substance applied to skin] then T1 can occur in 1-2 d
[antibodies form as not previously sensitized, and when they do T1 reaction occurs])
o Allergen reacts w/ IgE antibody on mast cell causing RAPID release of stored histamine
o Causes capillary leakage mucosal edema shock +asphyxia
o Variable in presentation
Rapid
Slow onset, sometimes biphasic (i.e. 2nd reaction)
Common causes:
o Food Peanut, fish/shellfish, milk, eggs
o Drug Antibiotic, NSAIDs, opioid, IV contrast
o Venom Bee, wasp
Features: Hx of previous sensitivity OR recent drug exposure
o Initial Generalised itching, urticaria, erythema, rhinitis, conjunctivitis
o Intermediate Angioedema, stridor, wheeze, itchy throat, palpitations, tachycardia, anxiety
o Late (can progress here quickly!) Shock, cyanosis, hypotension
DDx: Life-threatening asthma, septic shock, ?epiglottitis
Ix: Mast cell tryptase (AFTER emergency management, then repeat sample 1-2hr later)
Rx: ABCDE – Get full obs (if temp high, Abx; listen to lung sounds – if global wheeze, bronchodilat nebs)
o First: Call for help – anesthetist
Secure airway (?intubate) + High flow O2 + Lie patient FLAT + Raise legs
Remove precipitant (e.g. penicillin IV infusion)
IM Adrenaline into anterolateral middle thigh
Adults 500mcg – 0.5mL of 1:1000 – repeat every 5min if necessary
Children:
o <6yr = 150mcg
o 6-12 = 300mcg
o >12 = 500mcg
NB: IV adrenaline ONLY used by trained + experienced staff; dose is 50mcg (0.5mL of 1:10000)
IV fluid challenge (if hypotensive, 1-2L in young, fit, healthy)
o Refractory:
IV Chlorphenamine 10mg IM/Slow IV (symptomatic relief, no evidence for airway resolution)
≥12 = 10mg; 6-12 = 5mg; 6mo – 6yr = 2.5mg; <6mo = 250mcg/kg
IV Hydrocortisone 200mg IM/IV (symptomatic relief, plus prevent 2nd acute reaction)
≥12 = 200mg; 6-12 = 100mg; 6mo – 6yr = 50mg; <6mo = 25mg
o Still refractory: ITU + Salb+Ipra Nebs (consider aminophylline)
o Stable: Admit ALWAYS for overnight observation (secondary reaction to allergen occurs in >20% within 8hr)
o Discharge: 2x epi-pens at all times, allergy clinic appt
IM ADRENALINE USED WHEN NOT INDICATED WILL **NOT** HARM A PATIENT! HAVE LOW THRESHOLD
,
, Chapter 1 – Neonatology
Perinatal Definitions
Gestational age Age measured from LMP (in weeks + days)
Live birth Delivered fetus/conceptus with signs of life, irrespective of gestational age
Spontaneous abortion/miscarriage Delivered conceptus w/o signs of life <24wk
Stillbirth Delivered fetus w/o signs of life >24wk
Perinatal mortality All stillbirths + neonatal deaths <1wk post-delivery
Neonatal mortality Death amongst live births (any gestational age) <4wk post-delivery
Neonatal period 28 days post-delivery; if pre-term, 44 weeks post-LMP
Pre-term <37wk (10%)
Term birth 37-42wk delivery
Post-term >41+3 (5%)
Low birth weight <2.5kg (5%)
Very low birth weight <1.5kg (0.5%)
Extremely low birth weight <1kg
Small for gestational age <10th %ile
Large for gestational age >90th %ile
