After Your Return: Diarrhea
Up to 40% of traveller’s to the tropics get Montezuma’s Revenge, Delhi Belly, or just plain old diarrhea. Most have a mild illness and get better within day or two. Others become quite ill, and vow never to return. And some remain unwell upon their return home. Gas, bloating, rumbling, cramps … it never seems to end.
The most common causes of Traveller’s Diarrhea are bacterial infections, such as E. coli, salmonella, shigella and campylobacter. These last three can make you particularly sick, sometimes with dysentery (fever, blood and pus in the stools). They usually have a brief incubation period of 24 to 48 hours. Therefore if it strikes you on the plane home or as you walk through your front door, you probably goofed on the last day of your vacation.
Parasites are a much less common cause of diarrhea in travellers. As well, they do not usually strike quite as acutely. The commonest parasitic infections included giardiasis and amebiasis. Two slightly newer or emerging infections are cryptosporidium and cyclospora. Many travellers and non-travellers alike seem to acquire Entamoeba coli, Endolimax nana, Entamoeba hartmanni and Dientamoeba fragilis. These latter amoebas are usually non-pathogenic, that is, they don't cause much in the way of illness. It is not necessary to travel abroad to acquire most of the above infections. They are available right here at home!
The diagnosis of these infections can sometimes be suspected clinically. The poor guy with fever, lower abdominal cramps, and blood streaked diarrhea probably has shigella. And the one who has been passing gas that curls your nose for two months, might have giardia. But the definitive diagnosis rests with examination of the stools.
Parasites are seen by looking at a concentrated sample under a microscope (O& P). It may be necessary to examine more than one specimen. Bacterial infections are detected by growing the bacteria (C&S). This is a picture of Giardia lamblia.
Treatment is based upon the causative agent, as well as the clinical state of the patient. Antibiotics, such as Cipro, may be used for the treatment of bacterial infections. Antiparasitics, such as metronidazole (Flagyl) or tinidazole are used to treat parasitic infections such as giardiasis and amebiasis. Patients who are asymptomatic at the time of diagnosis may not need treatment, but washing one’s hands remains a good idea!
What about those people who are not yet better, and in whom nothing can be found in the stools? Firstly, we might consider some other diagnosis, such as Lactose Intolerance (an inability to digest the lactose found in dairy products). This condition may follow almost any bowel infection. It is usually transient. A lactose free diet may help, as might products such as Lactaid or Lacteeze.
Inflammatory bowel disease (ulcerative colitis, Crohn’s Disease) is occasionally found in a returning traveller. This diagnosis would require further investigations such as colonoscopy and bowel biopsy.
Antibibiotic-induced colitis, caused by a bacterium, Clostridium difficile, occurs sometimes in travellers who have recently taken antibiotics. A special stool culture is needed for diagnosis.
Perhaps the most common diagnosis we are left with after a full investigation is a Post Infectious Irritable Bowel Syndrome. This means "I went to Mexico/India/Peru/Ethiopia, etc., I got sick, I got better …. But I’m still not back to the way I was before." One might suffer with gas, bloating, rumbling and abdominal discomfort. Your stools may be loose, ribbony, pellet-like, or all of the above. You may be sensitive to certain foods that didn’t bother you before. You shouldn’t be losing weight or noticing any blood in your stools. This condition usually improves with time, fibre, a careful diet and a positive attitude!