Diarrhea

6.07 Diarrhea

Presentation
Complaints may range from acute, copious diarrhea producing shock, to concern because an occasional stool is not well formed. Typically, there is crampy pain throughout the abdomen, especially before a diarrhea stool, and some irritation of the anus. Tenesmus (the frequent urge to defecate) can exist without diarrhea.
What to do:



Ask specifically about the frequency of stools, the volume (much liquid implies a defect in absorption in the small bowel, while tenesmus producing little more than mucus implies inflammation of the rectosigmoid wall), the character (color, odor, blood, or mucus) and the consistency (like water or just loose stool). Ask about travel, medications (including antibiotics), prior similar symptoms, and nocturnal symptoms (rare with functional disease).



Perform orthostatic vital signs and urinalysis and weigh pediatric patients. Any symptoms, fall in presssure, or pulse rise of more than 20 beats per minute after standing for a minute suggests hypovolemia. A urine specific gravity of 1.020 or greater also suggests hypovolemia, and ketones of 2+ or greater suggest starvation ketosis.



Perform a rectal examination and obtain a sample of stool for occult blood testing and for Wright's or Gram stain. If the rectal ampulla is empty, you can still swab the mucosa, and may get an even better specimen for stool culture. A spontaneous specimen is also good. If the patient has recently been on antibiotics, test the stool for clostridim difficile.



If there are any white cells in a 400x field, assume the problem is invasive or inflammatory (Campylobacter, Salmonella, Shigella, Entameba, ulcerative colitis, et cetera). Send a stool culture, prescribe ciprofloxacin 500mg bid x 3d, and schedule follow up. Ask the patient to bring a fresh stool sample in a specimen cup at follow up in case it needs to be examined for ova and parasites.



If there no white blood cells on microscopic examination of the stool, assume the diarrhea is due to a virus or toxin. Afebrile patients with limited diarrhea require no treatment eother than fluid and electrolyte replacement. These patients will not benefit from antibiotics, and require follow up only if they have continued diarrhea, abdominal pain, or fever.



Both classes of diarrhea are best treated with absorbent bulk laxatives, such as bran or ground psyllium seeds (Metamucil 1 tbsp in a glass of water up to qid).



To adsorb toxins and provide some binding effect, add Amphogel, Diasorb or Kaopectate, 1 tbsp qid, or bismuth subsalicylate (Pepto- Bismol) 2 tbsp each half-hour until symptoms subside, or to a total of eight doses (this does contain salycilates, and bismuth will turn stools black).



With infants and small children, oral rehydration therapy should be the main treatment. Antimicrobial drugs shouls be given only for dysentery (bloody diarrhea) and suspected cholera. Have the patients give an oral rehydration mixture with the goal of replacing the fluid lost. For every one cup of diarrhea lost, give a cup of the following recipe:



1/2 to 1 cup precooked baby rice cereal



2 cups water



1/4 teaspoon salt
Mix the rice cereal, water ans salt together until the mixture thickens but is not too thick to drink. Be sure the ingredients are well mixed. Have the parents give the mixture by spoon often and have them offer the child as much as he will accept (every minute if he will accept it). Even if the child is vomiting, the mixture can be offered in small amounts (1/2 - 1 tsp) every few minutes. Banana or other non-sweetened mashed fruit can help provide potassium. Alternatively, one can give commercial rehydration fluids sold in drugstores like Rehydralate, Ricelyte or Pedialyte.



During or after diarrhea, children should be given small meals frequently (six or more times a day) and actively encouraged to eat. Parents should use well-cooked staple starches that can be easily digested such as rice, corn, potatoes or noodles in a soft mashed form. For infants, they should use a thick porridge or semi-liquid pulp.



Patients with severe dehydration that cannot be reversed orally may require large amounts of intravenous fluids and occasionally must be admitted to the hospital.
What not to do:



Do not omit the rectal exam, which may disclose a fecal impaction or abscess.



Do not stop or reduce breast feeding when a baby has diarrhea. Infants with diarrhea should be breastfed as often and for as long as they want.



Do not give give or recommend sugary drinks such as Gatorade, sweetened commercial fruit drinks, cola drinks or apple juice, which may cause an osmotic diarrhea and a net loss of fluid.



Do not give additional aspirin-containing drugs to patients taking bismuth subsalicylate (Pepto-Bismol)
Discussion
Most cases of mild to moderate diarrhea (defined as no more than five unformed stools a day without fever, blood or significant cramps, pain, nausea or vomiting) can be handled without an investigation of the etiology.
 When you prescribe bran or psyllium, patients may remind you that they have diarrhea, not constipation, but, because these agents absorb water in the gut lumen, they can relieve both problems, and obviate the rebound constipation often produced by the narcotic and binding agents also used to treat diarrhea.
 The three commonest causes of diffuse colonic inflammation and thus fecal leukocyte exudate are Shigella, Salmonella and Campylobacter. Fecal leucocytes can also be a sign of ulcerative colitis and allergic colitis.
 Most bacterial diarrheas do not require treatment with antibiotics, which can produce a carrier state. The presumptive ciprofloxacin strategy described for the ED will suite most patients, but may have to be modified in follow up based upon the patient's course and stool culture results. Early empiric treatment of traveller's diarrhea with a single 500mg dose of ciprofloxacin can reduce the duration and severity of the illness.
 Infants can become severely dehydrated in short order with viral diarrhea. Old patients medicated for pain or psychosis can develop a fecal impaction which can also present as diarrhea. Irritable bowel syndrome, food allergy, lactose intolerance and parasite infestation can produce relapsing diarrhea, but the pattern may only become apparent on follow up.
References:



Sigel D, Cohen PT, Neighbor M et al: Predictive value of stool examination in acute diarrhea. Arch Pathol Lab Med 1987;111:715-718.



Salam I et al: Randomized trial of single-dose ciprofloxacin for traveller's diarhea. Lancet 1994;344:1537.



Margolis PA, Litteer T, Hare N et al: Effects of unrestricted diet on mild infantile diarrhea. Am J Dis Child 1990;144:162-164.