Parasitic infections

Red flags

Consider urgent referral for patients with the following:

Red flags occur from complications of dehydration from gastroenteritis, from extensive secondary bacterial infection and from the presence of parasites in vital organs
Dehydration from gastroenteritis
Marked anaemia
Deteriorating renal function
Abnormal LFT
Extensive crusting and secondary infection of the skin associated with scabies
Altered conscious level
Tapeworm cysts in liver, brain, myositis
Visual problems (toxocara)
Myocarditis (toxocara)

Features that may lead to more urgent categorisation

Hepatic cysts

Parasitic infections are common in Australia and simple infections include:

Skin and hair
- Head and body lice
- Pubic lice
- Scabies
Gastrointenstinal
- Intestinal helminth (whipworm, threadworm, hookworm, tapeworm)
- Giardia lamblia
- Blastocystis, Dientamoeba fragilis
Other
- Cysticercosis
- Toxoplasmosis
- Toxocara

Other important information for referring practitioners

Lifestyle changes

Encourage good personal hygiene habits especially after toileting and food preparation
Encourage regular worming of pets

Medical management

Pediculosis (head and body lice)

Use hair conditioner & comb through, immersing the comb in hot water will kill lice and eggs
If using anti lice shampoo ensure complete treatment of all parts of the scalp and retreat 1 week later. Use nit comb to remove all eggs (nits).
- Main treatment compounds are:
  - Pyrethrins
  - Perimethrin and bioallethrin
  - Organophosphates (malathion or malison)
  - Herbal and essential oils

Scabies

If neglected can lead to extensive secondary infection and serious health consequences, especially in remote communities. Consider urgent referral.
Consider this diagnosis for unexplained dermatitis of recent onset, recurrent impetigo with itch, unexplained pruritis
Look for typical burrows, consider skin scrapings
Used scabicidal cream from neck down and treat all family members, even if asymptomatic
Use permethrin cream and leave on for 24 hrs. Other treatments are:
- Benzoyl benzoate (irritating)
- Gamma benzene hexachloride (potential neurotoxin)
- Ivermectin (potential side effects in young and very elderly)
Repeat in 1 week
Wash all clothes and bedding in hot water and iron or heat dry
Treat pruritis with emollients and steroid creams and treat secondary infection
Reassure that pruritis takes up to 4 weeks to settle

Gastrointestinal

Helminth infection
- Suspect threadworm if unexplained pruritis ani
- A wide range of antihelminthics are available over the counter, these are:
  - Mebendazole, Pyrantel, (OTC)
  - Albendazole (tapeworm and hydatid) PBS listed
  - Ivermectin (strongyloidiasis and onchocerciasis) PBS listed
  - Praziquantel (Brachylaima cribbi from snails ingestion) is prescription only not PBS listed
Giardia, blastocystis, dientamoeba
- Suspect if persistent diarrhoea or intermittent diarrhoea
- Diagnose on stool microscopy or PCR
  - The multiplex PCR assay currently available produces many positives for blastocystis and dientamoeba, the significance of which remains unclear
- Treat with Metronidazole or Tinidazole
- Often resolves without treatment

Referral requirements

A referral may be rejected without the following information.

Essential referral information

Reason for referral e.g. multiple treatment failures
Presence of any red flags
Duration of infection and symptoms
Main symptoms and signs
Microscopy/pcr evidence of infection
Microscopy and culture of secondary infection in case of extensive scabies

Additional referral information (useful for processing the referral)

Liver ultrasound if hepatic cysts present

Out of catchment

Metro North Health is responsible for providing public health services to the people who reside within its boundaries. Special consideration is made for patients requiring tertiary care or services that are not provided by their local Hospital and Health Service. If your patient lives outside the Metro North Health area and you wish to refer them to one of our services, inclusion of information regarding their particular medical and social factors will assist with the triaging of your referral.

Clinical Modifiers (where relevant)

Impact on employment
Impact on education
Impact on home
Impact on activities of daily living
Impact on ability to care for others
Impact on personal frailty or safety
Identifies as Aboriginal and/or Torres Strait Islander

Reason for Referral (essential)

To establish a diagnosis
For treatment or intervention
For advice and management
For specialist to take over management
Reassurance for GP/second opinion
For a specified test/investigation the GP can’t order, or the patient can’t afford or access
Reassurance for the patient/family
For other reason (e.g. rapidly accelerating disease progression)
Clinical judgement indicates a referral for specialist review is necessary

Clinical Information (essential)

Presenting symptoms (evolution and duration)
Physical findings
Details of previous treatment (including systemic and topical medications prescribed) including the course and outcome of the treatment
Body mass index (BMI)
Details of any associated medical conditions which may affect the condition or its treatment (e.g. diabetes), noting these must be stable and controlled prior to referral
Current medications and dosages
Drug allergies
Alcohol, tobacco and other drugs use