Table of Contents
- infection caused by the amoeba Entamoeba histolytica
- usually transmitted by the fecal-oral route
- amoebiasis is estimated to cause 70,000 deaths per year world wide
- it is often endemic in regions of the world with limited modern sanitation systems, including Mexico, Central America, western South America, South Asia, and western and southern Africa.
- 90% are asymptomatic
- can remain latent in an infected person for several years
- 10% develop gastroenteritis after an incubation period usually 2-4 weeks, which ranges from mild diarrhoea to severe dysentery (severe ulceration of the gastrointestinal mucosal surfaces occurs in less than 16% of symptomatic cases)
- it is an uncommon cause of traveller's diarrhoea
- a granulomatous mass (known as an amoeboma) may form in the wall of the ascending colon or rectum due to long-lasting immunological cellular response
- NB. inflammatory caecal area masses in returned travellers may be due to:
- ascaris - usually pulmonary symptoms in 1st 2 weeks with cough, wheeze, maybe eosinophilia
- hookworm may cause eosinophilic enteritis
- strongyloidiasis may rarely cause eosinophilic oophoritis
- appendiceal abscess
- Crohn's disease
- 10% of invasive cases result in spread to almost any organ, but in particular, the liver.
- complications include:
- subdiaphragmatic abscess
- perforation of diaphgram to pericardium and pleural cavity
- perforation to abdominal cavital (amoebic peritonitis)
- perforation of skin (amoebic cutis)
- can occur at skin around site of colostomy wound, perianal region, region overlying visceral lesion and at the site of drainage of liver abscess
- urogenital tract amoebiasis derived from intestinal lesion can cause amoebic vulvovaginitis (May's disease), rectovesicle fistula and rectovaginal fistula.
other invasive spread
- can occur from hepatic lesion by haemotagenous spread and also by perforation of pleural cavity and lung.
- may cause lung abscess, pulmono pleural fistula, empyema lung and broncho pleural fistula.
- amoebic meningoencephalitis
- amoebic intracerebral abcess
- stool microscopy - cysts shed in stool but may need 3 samples to detect as shedding is not constant
- serologic tests are available - positive after 2wks of infection
- infections occur in both the intestine and in the intestinal wall and/or liver.
- Thus, two different classes of drugs are needed to treat the infection, one for each location.
amoebiasis.txt · Last modified: 2014/12/19 00:17 by 127.0.0.1