Reprinted with permission from Medscape. Serologic tests such as ELISA and agar gel diffusion are more than 90 percent sensitive, but these tests often become negative within a year of initial infection. Approximately 75 percent of infected patients have leukocytosis, but mucosal invasion does not cause eosinophilia.
Liver function tests usually are normal but may show minimal elevation of alkaline phosphatase, even in the presence of large abscesses. To avoid misdiagnosis, patients with suspected ulcerative colitis must be tested for E.
Intestinal barium studies may be useful in identifying possible amebomas, but biopsy is required to confirm the diagnosis and rule out neoplasia. Liver imaging studies, such as ultra-sonography, computed tomography Figure 6 , magnetic resonance imaging, and nuclear medicine scans, can reveal abscesses as oval or round hypoechoic cysts, usually in the right lobe of the liver. Risk of complications increases with cysts of more than 10 cm, multiple cysts, superior right lobe involvement, or any left lobe involvement.
Repeat studies may be confusing by showing larger abscesses in improving patients. Although two thirds of abscesses resolve within six months, approximately 10 percent of abscesses persist for more than a year. Primary: Mebendazole Vermox , mg orally once Secondary: Pyrantel pamoate Pin-Rid , 11 mg per kg maximum of 1 g orally once; or albendazole Valbazen , mg orally once If persistent, repeat treatment in two weeks.
Do not give to children younger than two years. Treat household contacts. Clean bedrooms, bedding. Adults: Metronidazole Flagyl , mg orally three times daily for five to seven days Pregnant women with mild symptoms: consider deferring treatment until after delivery. Pregnant women with severe symptoms: paromomycin Humatin , mg orally four times daily for seven to 10 days; metronidazole is acceptable.
Children: albendazole, mg orally for five days Asymptomatic carriers in developed countries: treat using regimen for adults or children. Asymptomatic carriers in developing countries: not cost-effective to treat because of high reinfection rate. Use proper sewage disposal and water treatment flocculation, sedimentation, filtration, and chlorination.
Consume only bottled water in endemic areas. Water treatment options: Boil water for one minute Heat water to 70 C F for 10 minutes Portable camping filter Iodine purification tablets for eight hours Daycare centers: Proper disposal of diapers Proper and frequent handwashing.
Albendazole, mg orally once Mebendazole, mg orally twice daily for three days Pyrantel pamoate, 11 mg per kg maximum of 1 g once Iron supplementation is beneficial even before diagnosis or treatment initiation. Packed red blood cells as needed can minimize risk of volume overload in severely hypoproteinemic patients.
Confirm eradication with follow-up stool examination two weeks after discontinuation of treatment. Intestinal disease: use both luminal amebicide for cysts and tissue amebicide for trophozoites.
Use proper sanitation to eradicate cyst carriage. Avoid eating unpeeled fruits and vegetables. Drink bottled water. Use iodine disinfection of nonbottled water. Iodoquinol Yodoxin , mg orally three times daily for 20 days. Paromomycin, mg orally three times daily for seven days. Diloxanide furoate Furamide , mg orally three times daily for 10 days available from CDC. Metronidazole, mg orally three times daily for 10 days. Metronidazole, mg orally three times daily for five days, then paromomycin, mg three times daily for seven days.
Chloroquine Aralen , mg orally per day for two days, then mg orally per day for two to three weeks higher relapse rates. Pyogenic abscess is ruled out; there is no response to treatment in three to five days; rupture is imminent; pericardial spread is imminent.
Information from references 1 , 2 , 5 , 7 , 9 , 17 , 19 , and Treatment and prevention strategies for parasite infections are summarized in Table 1. Paromomycin Humatin. Iodoquinol Yodoxin. Diloxanide furoate Furamide. Tetracycline, erythromycin. Not active for liver abscesses; frequent GI disturbances; tetracycline should not be administered to children or pregnant women; must be used with luminal agent. Anorexia, nausea, vomiting, and metallic taste in nearly one third of patients at dosages used; disulfiram-like reaction with alcohol; rare seizures.
Chloroquine Aralen. Occasional headache, pruritus, nausea, alopecia, and myalgias; rare heart block and irreversible retinal injury. In: Rakel R, ed. Conn's Current therapy Philadelphia: Saunders, —5. Already a member or subscriber? Log in.
Interested in AAFP membership? Learn more. GARY L. He received his medical degree from the Uniformed Services University of the Health Sciences and completed a residency in family medicine at Naval Hospital Jacksonville.
Address correspondence to Corry J. Reprints are not available from the authors. The authors indicate that they do not have any conflicts of interest. Sources of funding: none reported. The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U.
Navy Medical Corps or the U. Navy at large. The authors thank Anthony J. Basic clinical parasitology. Norwalk, Conn. Pinworm infestations. In: Hoekelman RA. Primary pediatric care. Louis: Mosby, MacPherson DW. Intestinal parasites in returned travelers. Med Clin North Am. Laparoscopic appendectomy in children with Enterobius vermicularis. Surg Laparosc Endosc Percutan Tech. Anthelmintic drugs for treating worms in children: effects on growth and cognitive performance.
Cochrane Database Syst Rev. Evaluation of lactophenol cotton blue stain for detection of eggs of Enterobius vermicularis in perianal surface samples. Trop Doct. Procop GW. Gastrointestinal infections. Infect Dis Clin North Am. Parasitic infections of the gastrointestinal tract. Gastroenterol Clin North Am. Leder K, Weller P. In: Rose BD, ed. Infectious disease. Wellesley, Mass. Giardiasis surveillance—United States, — Infectious diarrhea from wilderness and foreign travel. In: Auerback PS, ed.
Wilderness medicine: management of wilderness and environmental emergencies. It's one of the top causes of diarrhea in the United States. Giardiasis jee-are-DYE-uh-sis is caused by the microscopic Giardia parasite. The parasite attaches itself to the lining of the small intestines in humans, where it causes diarrhea and interferes with the body's absorption of fats and carbohydrates from digested foods.
Giardiasis is very contagious, and can spread easily among families. In childcare centers or any facility caring for a group of people, or people who are traveling, giardiasis can easily pass from person to person.
Giardiasis spreads through water or food contaminated with the stool poop of someone who's infected. Animals mainly dogs and beavers who have giardiasis also can pass the parasite in their stool.
The stool can then contaminate public water supplies, community swimming pools, and water sources like lakes and streams. Uncooked foods that have been rinsed in contaminated water and surfaces contaminated by stool for instances, diaper pails and toilet handles also can spread the infection. The Giardia parasite can survive the normal amounts of chlorine used to purify community water supplies, and can live for more than 2 months in cold water.
As few as 10 of the microscopic parasites in a glass of water can cause severe giardiasis in a person who drinks it. In developing countries, giardiasis is a major cause of epidemic childhood diarrhea. But even people in developed countries can get the infection, especially children younger than 5. Young kids are more likely to have giardiasis than adults. So some experts think that our bodies gradually develop some form of immunity to the parasite as we get older.
But it isn't unusual for an entire family to be infected, with some family members having diarrhea, some just crampy abdominal pains, and others with no symptoms. Many people with giardiasis have no signs or symptoms of illness, even though the parasite is living in their intestines. When the parasite does cause symptoms, the illness usually begins with severe watery diarrhea. Giardiasis affects the body's ability to absorb fats from the diet, so the diarrhea contains unabsorbed fats. That means that the diarrhea floats, is shiny, and smells very bad.
These symptoms may last for 5 to 7 days or longer. If they last longer, a child may lose weight or show other signs of poor nutrition. Sometimes, after acute or short-term symptoms of giardiasis pass, the disease begins a chronic or more lasting phase.
It has not been found in the family members of those infected, indicating that person to person transmission is unlikely. Restitution of the immune status using antiretroviral therapy may allow clearance of the organisms. Blastocystis hominis is an organism that courts much controversy in terms of its pathogenicity, given that asymptomatic carriage has been widely noted.
Likewise, studies have noted its association with symptoms such as diarrhoea, bloating, abdominal pain and excessive flatus. Its presence in stool is a likely indicator that exposure to other organisms has occurred.
Where Blastocystis has been solely isolated and clinical symptoms are present, then a trial of treatment is warranted. While not a common cause of persistent diarrhoea, Strongyloides certainly is an organism that has long term consequences in those infected. Risk factors include travel to endemic areas, consuming contaminated water or contact with infected soil, usually through barefoot travel. Acute or chronic infections are usually asymptomatic, but can present with diarrhoea, urticaria and abdominal pain.
Chronic infections in patients with a cell mediated immunity defect due to high dose corticosteroid use, organ transplantation and HTLV-1 can potentially result in Strongyloides hyperinfection syndrome, which has a high mortality. Screening for the presence of Strongyloides in returned travellers with persistent diarrhoea or with eosinophila is warranted given that co-infection is possible. Current screening method includes agar plate culture or serology.
Seek specialist advice for the treatment of Strongyloides if an infection is detected. It is important to remember that diarrhoea is a common symptom of many other diseases; it may be a coincidence that travel preceded the episode. Patients who have persistent diarrhoea despite negative screening for stool parasites should be further investigated. Further aetiologies to consider are shown in Table 4.
Referral for specialist follow up is warranted when the history and examination are suggestive of potential cancer ie. Table 5 shows advice that can be given before travel. The advice should be memorable and to the point rather than long winded or overly detailed. A brochure or a travelling item such as a bookmark or a post-travel booking card can help reinforce this advice.
Table 6 provides examples of simple messages that can be given to travellers. Australian Family Physician. Search for: Search AFP. Filter Relevance Date. Issues by year. Volume 41, Issue 10, October Parasitic causes of prolonged diarrhoea in travellers Diagnosis and management. Background Prolonged infectious diarrhoea in the returning traveller is generally caused by protozoal and occasionally by helminth parasites.
Objective This article provides a framework for the diagnosis, management and prevention of the diseases that cause persistent diarrhoea in the traveller. Discussion A large proportion of disease is caused by Giardia lamblia, Cryptosporidium parvum and Entamoeba histolytica. However, given the ease of travel with comorbid conditions such as human immunodeficiency virus, there is an expanding list of organisms that can cause persistent diarrhoea.
Prevention strategies need to be initiated before travel and should consist of simple but memorable advice. Noninfectious causes of diarrhoea should be considered as diarrhoea can be a prominent feature of conditions such as hyperthyroidism or coeliac disease.
Diagnosis As with all diagnostic processes, it begins with a complete history focusing on the onset and nature volume, character, consistency of the diarrhoea as well as the presence of blood or mucus in the stool.
Key history points in the returned traveller with diarrhoea How long have the symptoms been occurring? What is the nature and character of the stool? Have you noticed any other changes with your bowel habit eg. What were your bowels like previously? Had you previously had episodes of this type of stool? Have you ever been investigated for any gastrointestinal disease eg. Do you have any medical conditions? Do you know your HIV status? What medications have you been taking?
Have you taken antibiotics in the past 2 months? Travel history is very important. Ask the patient to bring in their itinerary so nothing is missed. Systematically go through the patient's journey — when, where and what they did. Look for potential risks or behaviours regarding eating, drinking or exposure Table 2.
Physical examination in the patient with persistent diarrhoea Assess hydration status — with a large volume of diarrhoea comes a loss of total body water and subsequent hypovolaemia Assess nutritional status — malabsorptive diarrhoea could result in loss of muscle mass, fat wasting or vitamin deficiencies General physical examination — look for localising signs that may indicate a contributing disease such as malaria hepatosplenomegaly or a noninfective disease such as hyperthyroidism tachycardia, tremor Investigations The role of laboratory investigations is twofold: first, to define the aetiological agent of the diarrhoea, and second, to delineate comorbid conditions such as malaria or thyroid disorders.
Table 3. Blastocystis hominis Blastocystis hominis is an organism that courts much controversy in terms of its pathogenicity, given that asymptomatic carriage has been widely noted.
Table 5. Avoid walking around in bare feet in mud or rainforest areas If HIV positive or immunocompromised, you are at a greater risk of more chronic debilitating disease. Simple advice for patients to avoid diarrhoeal illness while travelling The ABCD of avoiding diarrhoea Avoid anything that may be contaminated with faecal material. Water and food are the biggest culprits Bottled water is the safest option.
Check seals and method of purification Clean and Cover: Wash hands thoroughly using an alcohol based cleanser. Cover your feet Disease: if you are immunocompromised, you are at risk of a wider range of disease. Take extra caution and tell your physician this when you get unwell so they can look for different pathogens Remember: it's all about hands, feet and mouth when it comes to diarrhoea Hands Wash your hands using an alcohol-based cleanser before and after toileting and eating Feet Parasites can burrow their way into your body: shoes are a great way to stop this happening Mouth Think about what you put in your mouth: is it likely to be contaminated with unseen faeces?
Key points Persistent diarrhoea in the traveller is most commonly caused by protozoan parasites. Giardia is the most common organism, followed by Cryptosporidium and E. Stool microscopy combined with antigen-specific enzyme immunoassays give the highest sensitivity of detection. Infection with E. Be alert for postinfection lactase deficiency causing ongoing diarrhoea after effective treatment.
Consider nonparasitic causes of diarrhoea in your differential diagnoses, including C. Prevention is achieved by educating travellers before travel and advising on simple strategies to avoid infections, namely avoiding contaminated water and food sources and covering the feet. Conflict of interest: none declared. Med J Aust ;—9. Am J Trop Med Hyg ;— Statement on persistent diarrhea in the returned traveller.
An Advisory Committee Statement. The returned traveller with diarrhoea.
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