Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
The most common manifestations of giardiasis are diarrhea
and abdominal pain,
particularly cramping; however, diarrhea is not invariable and occurs in 60% to
90% of patients. Other common manifestations include bloating,
nausea with or
without vomiting,
malaise, and fatigue. Fever is unusual. The severity of
the symptoms may vary greatly from mild or no symptoms to severe symptoms.
Stools may be foul smelling when the Giardia interferes with the absorption of
fat from
the intestine (malabsorption). The illness or the malabsorption may cause loss
of weight.
Symptoms and signs of giardiasis do not begin for at least
seven days following infection, but can occur as long as three or more weeks
later. In most patients the illness is self-limiting and lasts 2-4 weeks. In
many patients who are not treated, however, infection can last for several
months to years with continuing symptoms. Children with chronic infection may
fail to thrive. Some patients recover from their giardiasis, with or without
treatment, but symptoms continue, perhaps because of a condition referred to as
postinfectious irritable bowel syndrome. the cause of the continuing symptoms is
not clear but may be due to bacterial overgrowth of the small intestine.
How is giardiasis diagnosed?
The best single test for diagnosing giardiasis is antigen testing of the stool. For
antigen testing, a small sample of stool is tested for the presence of Giardial
proteins. The antigen test will identify more than 90% of people infected with
Giardia. Giardia also can be diagnosed by examination of stool under the
microscope for cysts or trophozoites; however, it takes three samples of stool to diagnose 90%
of cases. Despite requiring three samples of stool, microscopical examination of
stool identifies other parasites in addition to Giardia that can cause diarrheal
illness. Therefore, microscopical examination of stool has value beyond
diagnosing giardiasis, for example, it can diagnose other parasites as the cause of a patient's illness.
Other tests that can be used for diagnosing giardiasis are collection and
examination of fluid from the duodenum or biopsy of the small intestine, but
these require tests that involve expense and discomfort. The string test is a more comfortable
method for obtaining a sample of duodenal fluid. For the string test, a gelatin
capsule that contains a loosely-woven string is swallowed. One end of the string
protrudes from the capsule and is taped to the patient's outer cheek. Over
several hours, the gelatin capsule dissolves in the stomach, and the string
uncoils, with the last 12 inches or so passing into the duodenum. In the
duodenum the string absorbs a small amount of duodenal fluid. The string then is
untapped from the cheek and is removed. The collected duodenal fluid is
expressed from the string and is examined under the microscope. Although more
comfortable than some of the other tests, it is not clear how sensitive the
string test is, for example, does it diagnose 60% (not very good) or 90% (very good) of
cases of giardiasis.
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary source of travelers' diarrhea. Enterotoxigenic E. coli is the cause of up to 70% of all cases of travelers' diarrhea. There are five unique classes of E. coli that causes gastroenteritis. Other bacteria responsible for travelers' diarrhea include
Campylobacter, jejuni, shigella, and salmonella. Viruses such as rotavirus and Norwalk virus (norovirus) and giardia lamblia a parasite may cause travelers' diarrhea. Prevention is careful eating and drinking of water.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.
Children's health is focused on the well-being of children from conception through adolescence. There are many aspects of children's health, including growth and development, illnesses, injuries, behavior, mental illness, family health and community health.
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