Spider Bites

Learning Points

Understanding of common Aust spiders.

Recognition of common clinical presentation, & ED management.

Highlight some common misinformation about spider bites.

Spider’s

Australia is home to 1000’s of different spiders.

The big two are: Red Back and Funnel Web.

White tail gets blamed for everything.

Majority of spider bites cause localised symptoms only.

Spider Bites

Can be broken into 3 groups:

1. Big Black spider’s – suspect funnel-web!

2. Redback spiders – look for clinical effect.

3. All other spiders - generally minor effects.

Aussie Spiders!

Red Back Spider

Redback Spider

RBS most common envenoming is Aust. 5-10 000 each year.

Clinical features distressing – but not life threatening.

RBS live in dry-dark areas.

Peak bite season January – April.

The women are the problem!

Consider RBS

Children:

Inconsolable crying

Acute abdomen

Priapism

Clinical Presentation

Isbister, G. (2006). Spider bite: a current approach to management. Aust Prescriber. 29(6), 156-149.

Redback Spider

Beware of atypical presentations

Ongoing symptoms weeks-months consider psych!

Emergency DepartmentManagement.

Pre-hospital:

Reassure, ICE-pack, simple analgesia.

In ED:

2 approaches:

Provide analgesia/antimetics – if Sx resolve D/C.

Antivenom: 2 x 500units of CSL RBS iv over 30min. (monitor for reactions).

Rpt if Sx not improved after 2 hours.

Antivenom effectiveness currently being studied. (RAVE2)

Funnel-web spider

Funnel-web spider

Most dangerous spider in Australia.

Comprise 40 species in 2 genera.

Big black spider bite = FWS bite until patient has been observed for 4/24.

Found in QLD and NSW.

The males are the problem

Clinical Presentation Hx of being bitten by big black spider with fangs.

Localised:

Severe bite site pain with fang marks.

Local erythema & swelling are NOT present.

Systemic:

General: agitation, vomiting, headache, abdo pain.

Autonomic: sweating, salivation, piloerection, lacrimation.

Cardio: HT, tachycardia, hypotension, bradycardia, APO.

Neuro: muscular fasciculation's or spasm, coma.

Children:

Sudden severe illness with inconsolable crying, salivation, vomiting or collapse.

Emergency Department Management.

Pre-hospital:

Apply PIB- T/F to hospital that has antivenom.

In ED:

Manage in Resus area – full monitoring!

Look out for– resp failure, hypo/hypertension, APO, & coma.

Antivenom: give 2 x 125units of CSL Funnel-web Spider Antivenom – RPT if needed.

Cardiac arrest: Give 4 ampoules undiluted antivenom.

White Tail Spider

White-tailed spider

Common spider found around Australia.

Often blamed for causing necrotic arachnidism.

Venom has shown NO definitive toxic components.

Clinical Presentation

Localised:

Painful bite

3 local reaction can occur:1. Severe local pain <2 hours duration

2. Local pain & a red mark lasting <24hours.

3. Persistent & painful red lesion, which does not break down or ulcerate – may last 5-12 days.

Other features of nausea, malaise, vomiting & headache may occur.

Delayed puritus can occur in up to 20% of cases.

Differential Diagnosis!

Infection

Diabetic ulcer

Pyoderma gangrenosum

Squamous cell carcinoma

Erythema nodosum

Chemical burn

Localised vasculitis

Factitious injury

Traumatic.

Emergency DepartmentManagement.

Look for other causes and treat them. Diabetic ulcers Infections (MRSA)

Simple analgesia/antiemetic if required.

Provide reassurance and education!

Questions

Take Home Points

Patient’s with signs of envenoming shouldn’t be D/C at night.

Antivenom carries risk and reactions.

Consider analgesia first in RBS.

Look for other cause before blaming the white tail!

Thank-you