If diarrhea continues for more than 4 weeks, it is considered as chronic diarrhea. Chronic diarrhea requires evaluation to rule out underlying pathology. Compared to causes of acute diarrhea, most of the causes of chronic diarrhea are noninfectious.
Principle of treatment of chronic diarrhea:
Treatment of chronic diarrhea depends on the specific cause of diarrhea and it is directed towards the cause of diarrhea, which may be curative, suppressive, or empirical. If the cause can be removed or eradicated, the treatment of chronic diarrhea is curative as with resection of a colorectal cancer, antibiotic administration for Whipple’s disease, or discontinuation of a drug (if any drug is the cause of chronic diarrhea).
For many chronic conditions, diarrhea can be controlled by suppression of the underlying mechanism which is causing the chronic diarrhea. Examples are elimination of dietary lactose for lactase deficiency or gluten (gluten free diet) for celiac sprue, use of glucocorticoids or other anti-inflammatory agents for idiopathic IBDs (inflammatory bowel diseases), adsorptive agents such as cholestyramine for ileal bile acid malabsorption etc. Other examples are use of proton pump inhibitors such as omeprazole for the gastric hypersecretion of gastrinomas, somatostatin analogues such as octreotide for malignant carcinoid syndrome, prostaglandin inhibitors such as indomethacin for medullary carcinoma of the thyroid, and pancreatic enzyme replacement if there is any pancreatic insufficiency.
But if the specific cause or mechanism of chronic diarrhea can not be pinpointed, empirical therapy may be beneficial. For example loperamide, is often helpful in mild or moderate watery diarrhea. For those with more severe diarrhea, codeine or tincture of opium may be beneficial. Such antimotility agents should be avoided with IBD, as there may be precipitation of toxic megacolon. Clonidine, an alpha-2 adrenergic agonist, may allow control of diabetic diarrhea.
Fluid and electrolyte replacement is an important and essential component of management for all cases of chronic diarrhea. Replacement of fat-soluble vitamins may also be necessary in patients with chronic steatorrhea (lipids can not be absorbed or fat malabsorption).
Diarrhea is loosely defined as passage of abnormally liquid or unformed stools at an increased frequency and with a typical Western diet stool weight of more than 200 grams can be considered as diarrhea.
Principle of treatment of acute diarrhea:
In acute diarrhea the most important part of treatment is the replacement of lost fluid and electrolytes. Fluid replacement should be gradual and over a period of time. In mild cases of acute diarrhea fluid replacement is all that may be required. Oral sugar-electrolyte solutions used in sports as drinks or designed formulations should be started promptly with severe diarrhea to limit dehydration, as severe ehydration is the major cause of death in severe diarrhea. If dehydration is very severe, especially infants and the elderly, require IV (intravenous) re-hydration for maintaining patients’ health.
If the dehydration is moderate as seen in non-febrile and non-bloody diarrhea, anti-motility and anti-secretory agents such as loperamide can be used. But drugs like loperamide should be avoided if the diarrhea patient is suffering from febrile dysentery, which may cause prolongation of diarrhea.
Role of antibiotics in acute diarrhea:
Use of antibiotics may sometimes reduce the severity and duration of diarrhea in some selected cases. Ciprofloxacin (500 mg twice a day for 3 to 5 days) is used by many doctors’ for treatment of severely ill patients with febrile dysentery empirically without diagnostic evaluation. If the cause of diarrhea is suspected to be due to giardiasis, metronidazole (250 mg 4 times a day for 7 days) can be used successfully. Antibiotic coverage has to be given whether or not a causative organism is discovered in patients who are immune deficient, have mechanical heart valves or recent vascular grafts, or are elderly.
Antibiotic prophylaxis should be given for certain patients traveling to high-risk countries in whom the likelihood or seriousness of acquired diarrhea would be especially high, including those with immunocompromise, IBD (inflammatory bowel disease e.g. ulcerative colitis), hemochromatosis, or gastric achlorhydria (absence of acid in stomach). For prophylaxis the use of trimethoprim/sulfamethoxazole (Bactrim), ciprofloxacin, or rifaximin (rifaximin not be suitable for invasive disease) may reduce bacterial diarrhea in such travelers by 90%. Finally, physicians should be vigilant to identify if an outbreak of diarrheal illness is occurring and to alert the public health authorities promptly, which may reduce the ultimate size of the diarrhea affected population.