Insect bites

transcript

By: Dr Ismah

Bee Centipide Scorpion

6 (75%)

Total: 8/101 cases2

The 18-year-old from Des

Moines, Iowa, was stung for the

first time when she was only

4 when a bee sting on

her neck made it swell to

the size of a "balloon."

1. History

2. Epidemiology

3. Bee?

4. Pathogenesis

5. Diagnosis

6. Management

7. Anaphylaxis

8. Prevention

• The first reports of stinging insect

allergy came from the Middle East

thousands of years ago

• 56.6 – 94.5% stung by Hymenoptera insect

at least once in live

• Fatal stings at least 40 cases each year in

USA and 16–38 cases in France.

• Systemic allergic reactions up to 3% of

adults and 1% of children.

• In children about 60 % of systemic sting

reactions are mild, whereas in adults

respiratory or cardiovascular symptoms

occur in about 70 %.

• Children also have a better prognosis than

adults with respect to the risk of systemic

reactions to re-stings. 7

• The name Hymenoptera is derived from

the Greek words "hymen" meaning

membrane and "ptera" meaning wings

• Honey bees are only capable of stinging a

person once.

• The honey bee is the only stinging insect that

leaves its stinger and venom sac in the skin of its

victim, due to the pointed configuration of the

stinger.

• Bumblebees rarely sting people because they

are non-aggressive and typically well

mannered

• They generally will sting only if provoked

• They nest in the ground or in piles of grass

clippings or wood

• Wasps build honey-comb nests under the

eaves of a house, or in a tree, shrub or

under furniture.

• They tend to be less aggressive than

yellow jackets and hornets, and mostly

feed on insects and flower nectar.

• They tend to be very aggressive insects,

and will often sting without provocation.

• They are commonly found around garbage

cans and picnic areas where food and

sugary drinks are abundant

• These insects may be very aggressive,

and a sting may be provoked by a minor

disruption in their environment.

• Hornets look very much like yellow jackets

and can be difficult to distinguish

• Bees release large amount of venom,

average 50–140 mcg/sting.

• Allergens constituting the venom include

• vasoactive amines,

• small polypeptides and enzymes,

• histamine, mast cell degranulating peptide,

• phospholipase A2 (PLA2), hyaluronidase,

• acid phosphatase and melittin

• Venom sacs may contain up to more than 300

mcg of venom

• Wasp, which are capable of repeated stings,

generally inject less venom per sting

• 10 to 31 mcg of venom/sting

Bumble bees

• 1.7 to 3.1 mcg of venom/sting

• 2.4 to 5.0 mcg of venom/sting

Yellow jacket wasp

Allergic responses to stinging

1. Localized cutaneous reactions

2. Systemic anaphylaxis

• Localized skin responses to biting insects

are caused primarily by vasoactive or irritant

materials derived from insect saliva, and rarely

occur from IgE-associated responses

• The majority of patients who experience

systemic reactions after Hymenoptera

stings have IgE-mediated

sensitivity to antigenic substances in the

venom.

• History

• Clinical manifestation

• Investigation

Categories

Large local

Generalized cutaneous

Systemic

Delayed

• Local: Insect bites are usually urticarial but may

be papular or vesicular, limited swelling <24 hrs

• Large local: an area of induration with a

diameter of 10 cm or more; which peaks

between 24 hours and 48 hours and then

subsides, may last for days

Generalized cutaneous reactions

• Typically progress within minutes and

include cutaneous symptoms of:

i. Urticaria

ii. Angioedema

iii. Pruritus

*beyond the site of the sting

• Rhabdomyolysis, acute renal failure, Guillain-

Barré syndrome, myasthenia gravis and

coagulopathy following multiple bee stings.

• Acute kidney injury (AKI) was seen in 21.0%

patients. Rhabdomyolysis was seen in 24.1%

patients, hemolysis in 19.2% patients, liver injury

in 30.1% patients, and coagulopathy in 22.5%

patients 7

• High creatinine level, shock, oliguria, and anemia

were risk factors for death 7

• Toxic reaction: in mass bee envenomation due to the direct action of large amount of venom, not due to allergic reaction

i. Fever

ii. Malaise

iii. Vomiting

iv. Nausea

*due to the chemical properties of the venom in large doses.

In younger children less than 50 stings may prove lethal

Forty-eight patients died of organ injury following toxic reactions to the stings, whereas six died from anaphylactic shock from total of 1091 patients hospitalized 7 33

• Delayed/late

i. Nephrotic syndrome

ii. Vasculitis

iii. Neuritis

iv. Encephalopathy

“Rarely a biphasic course is observed with an early onset,

an apparent recovery and a subsequent relapse after 4-24

hours”

• Blood test

• UFEME

• Prink skin testing, to identify venom

specific IgE

• Stingers should be removed promptly by

scraping, with caution not to squeeze the venom

sac because doing so could inject more venom

• Hymenoptera VIT is highly effective (95-97%) in

decreasing the risk for severe anaphylaxis.

• The selection of patients for VIT depends on

several factors

• Price?

injection immunotherapy is less expensive than

sublingual immunotherapy with the cost per kit of

approximately $150 and about 3 or 4 kits required

over the time of the immunotherapy. Sublingual

treatment is between $500 and $1000 per year39

SYMPTOMS AGESKIN TEST/IN VITRO

RISK OF

SYSTEMIC

REACTION IF

UNTREATED

RECOMMENDE

Large local

reactionAny Usually not indicated 4-10

Usually not

indicated

Generalized

cutaneous

reaction

≤16 yr Usually not indicated 9-10Usually not

indicated

≥17 yrPositive result 20 Yes

Negative result — No

Systemic

reaction Any

Positive resultChild: 40

Adult: 60-70

Negative result— Usually no

• Anaphylaxis is a severe, life threatening,

generalised or systemic hypersensitivity reaction.

• It is characterized by rapidly (minutes to hours)

developing life threatening airway and/or

breathing and /or circulation problems usually

associated with skin and/ or mucosa changes.

Airways problem

Breathing problems

Circulation problems

• Airway swelling

• Hoarse voice

• Stridor

• Dyspnoea

• Wheeze

• Hypoxia

leading to

confusion

• Cyanosis

• Respirator

y arrest

• Shock

• Faintness

• Palpitation

• Cardiac

arrest

• Previous severe reaction.

• History of increasingly severe reaction.

• History of asthma.

• Therapies may include:

i. Oxygen

ii. Epinephrine

iii. Intravenous saline

iv. Steroids

v. Antihistamines

*If hypotensive persist despite adequate fluid (CVP>10),

obtain echocardiogram and consider infusing noradrenaline

as well as adrenaline.

** Dose of intravenous corticosteroid should be equivalent to

1-2mg/kg/dose of methylprednisolone every 6 hours (prevent

biphasic reaction).

• Oral prednisolone 1m/kg can be used in milder

• Antihistamine are effective in relieving cutaneous

symptoms but may cause drowsiness and

hypotension.

• Continue observation for 6-24 hours depending

on severity of reaction because of the risk of

biphasic reaction and the wearing off of

adrenaline dose.

• Prevention of further episodes.

• Education of patients and caregivers in the early

recognition and treatment of allergic reaction.

• An adrenaline auto injector should be prescribed

for those with history of severe reaction to food,

latex, insect sting, exercise and idiopathic

anaphylaxis and with risk factor like asthma.

• Frequent cleaning of surroundings, garbage cans

and decaying fruit makes it less attractive for

• Cracks in ceilings and walls should be sealed off

as they are potential nesting sites for colonies

• Best defence, when attacked by bees, is to run

to a place which can be sealed off, leaving the

bees outside 52

• While rescuing a victim of massive bee sting,

protective gear should be worn. Remove the

victim to a safe area, remove the stinger and

shift to hospital

• To kill bees, 1–3% foam or detergent water

mixture can be sprayed on the swarm of

attacking bees.

• Insecticide should be sprayed around the nests

at night, when they are less active 54

• History of exposure

+Types of bees

• Clinical course

• Anaphylaxis

• Management

• Prevention

1. Pediatric protocol 3rd ed

2. Insect Allergy by Prof. Dr. Saad S Al Ani, Senior Pediatric

Consultant, Khorfakkan hospital Sharjah, UAE

3. Allergy: Principles and Practice by Lieberman P, Elsevier Inc,

4. General entomology, http://www.cals.ncsu.edu

5. Indian Guidelines and Protocols: Bee Sting

6. Diagnosis Of Hymenoptera Venom Allergy, Eaaci Position

7. Xie C, Xu S, Ding F, Xie M, Lv J, et al. (2013) Clinical

Features of Severe Wasp Sting Patients with Dominantly

Toxic Reaction: Analysis of 1091 Cases. PLoS ONE 8(12):

e83164. doi:10.1371/journal.pone.008316456

Insect bites

Health & Medicine