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Missing parasites?

August 3, 2010 By micrognome 1 Comment
adult sandfly

So you missed this morning’s Tropical Medicine Breakfast and left the usual culprits to clear up the remains of breakfast. You missed a treat in more ways than one. With apologies to our out-of-town brethren who really do it tough, here are the electronic versions of the two Leishmaniasis units you missed.

  1. Leishmaniasis 1: clinical tropical medicine
  2. Leishmaniasis 2: clinical parasitology & entomology

For those working towards the ACTM Fellowship exam there are some useful on-line learning resources:

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Abdominal pain in an overseas resident

June 27, 2010 By micrognome 1 Comment
CT upper abdomen showing hepatic lesion

Clinical case of upper abdominal pain in overseas resident

A 54 year old businessman presents with right upper quadrant pain after spending the last six months living in Java.

An ultrasound scan revealed gallstones. A laparoscopic cholecystectomy was then performed. At this point a lesion was observed on the surface of the liver, but not biopsied.

Four months later, on another return visit to Australia, the patient re-presented with fever, a cough and pain radiating to his shoulder tip. He was admitted to a district hospital and a chest X-ray performed. Changes consistent with right lower lobe consolidation were observed and intravenous antibiotics (i.v. Ticarcillin/Clavulanic acid) commenced. The patient did not improve and was transferred to a larger hospital.

After 7 days of intravenous antibiotics he coughed up a large quantity of viscous, brown phlegm with a paste-like consistency. These CT scan views were obtained at this point:

CT thorax after coughing up 'anchovy paste'

 

CT upper abdomen showing hepatic lesion

 

The patient’s serum was sent to the Microbiology laboratory with the following result:

Entamoeba histolytica titre > 1:4096

This was seen under the microscope in the paste-like sample of phlegm:

Microscope view of patient's sputum, showing microbe with internalised red cells

 

Q1   What do the CT scans show?

  • CT thorax: peri-mediastinal opacity
  • CT upper abdomen: smooth-walled lesion within liver

Q2   What object was seen under the microscope?

  • amoebic trophozoite  (Entamoeba histolytica) containing erythrocytes

Q3   What pathological process explains these observations?

  • amoebic liver abscess with trans-diaphragmatic extension and rupture into a bronchiole or bronchus, probably during coughing

Q4   What treatment would you recommend?

  • 750 mg Metronidazole i.v. x3 doses x 10 days
  • followed by paromomycin x3 doses

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Barefoot answers

April 7, 2010 By micrognome Leave a Comment

What is the infection?

Cutaneous larva migrans (CLM).

This is caused by infection with animal hookworm larva (typically a dog or cat species,  eg Ancylocystoma braziliense).

Infection is acquired via direct inoculation when a human comes into skin contact with faeces containing the larva (often on a beach or a riverbank). The larva cannot complete its usual life cycle in a human, hence it wanders around the epidermis causing an intense pruritic reaction. CLM, sometimes known as creeping eruption or “ground itch”, is common in tropical regions including northern Australia. It most commonly affects the feet, but can occur on any part of the body.

Secondary bacterial infection is not uncommon

What is the treatment?

CLM will eventually resolve without treatment when the larva(e) dies, but this can take many weeks. Systemic therapy options include albendazole, ivermectin or thiabendazole.

Topical therapies include:

  • Cryotherapy (eg ethyl chloride, liquid nitrogen) or other trauma to the leading edge of the lesion (to kill the migrating larva)
  • Thiabendazole cream applied to the lesions (not available on prescription in Australia; may be available via compounding pharmacies).

MMWR Morb Mort Wkly Rep. Outbreak of Cutaneous Larva Migrans at a Children’s Camp — Miami, Florida, 2006 (December 14, 2007 / 56(49);1285-1287.

The Stafinator, 7th April.

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