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Practicesuidelines Guidelines on Acute Infectious Diarrhea in Adults

mi do bo ge mi sp an tir

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Herbert L. DuPont, M.D., and The Practice Parameters Committee of the American College of Gastroenterology Arlington,Virginia GuidelinesCommiltee, ACG PracticePorarneters TlrcAmerit'unCollegerlt'Gastroenterology,

ar el

uation, management,the internationaltraveler, and the immunocompromisedpatient.

Guidelines for clinical practice are intended to suggest preferable approachesto particular medical problems as established by the interpretation and collation of scientifically valid research, derived from an extensivereview of published literature. When data are not available that will withstand objective scrutiny, a recommendation may be made based on a consensusof experts' Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health care problem, the physician should selectthe course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. These guidelines are also approved by the governing boards of the American Gastroenterology Association and the American Society of Gastrointestinal Endoscopy. Expert opinion is solicited from the outset for the document. Guidelines are reviewed in depth by the Committee, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time. The following guidelines are intended for adults and not for pediatric patients.

ttt al

IMPORTANCE OF DIARRHEA In the United States acute diarrhea is one of the most common diagnosesin generalpractice. Acute diarrheacan be defined as the passageof a greater number of stools of decreasedform from the normal lasting less than 14 days.It is generally associatedwith other signs or symptoms suggestingentericinvolvement including nausea,vomiting, abdominal pain and cramps, increasein intestinal gas-related complaints, fever, passageof bloody stools (dysentery), tenesmus(constantsensationof urge to move bowels), and fecal urgency.When diarrhealastsas long as l4 days,it can be considered persistent.Many restrict the term chronic dianhea to indicate illness lasting at least I month. In this review, diagnosis and treatment of acute and persistent diarrhea will be consideredbecauseboth tend to be shortterm illnesses,infectious agents characteristicallyproduce both, and the testsproceduresand treatmentsof both fbrms o f d i a r r h e as h o w s i m i l a r i t i e s . The annual rate of diarrheal illness in the United States and western Europe among adults averagesabout one episode per personper year (1,2). In one study, it was estimated that for a single year, 99 million casesof gastroenteritis or acutediarrheaoccurredamong adultsin the United States(1). In this study, half of the personswith gastroenteritis or diarrheahad restriction of their activities for more than a full day, a physicianwas consultedin 8.2 million of the cases,250,000 persons were hospitalized,1.9 million personssaw a physicianyet were not hospitalized,and more than 90 million experiencedillness without seekingmedical attention.In a secondstudy,it was fbund that gastroenteritis and acutediarrheaaccountedtor 1.57oofhospitalizationsof adults >20 yr of age in the United States (3). Sixty-two percentof the admissionsfor diarrheawere in adultsgreater than 20 yr of age.In this study and othersmost of the deaths associatedwith diarrheal illness in the United States occurredin the elderly (3-5).

INTRODUCTION In developing the guidelinesfor evaluationand management of the patient with acute diarrhea,the fbllowing maimportanceof diterial is divided into eight subheadings: arrhea,patient evaluation,noninf'ectiousand extraintestinal causes.empiric therapyin selectedpatients,laboratoryevalReceivetlMar. 11, 1997: ucceptedJuh' 16, 1997

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AJG - November 1997

GUIDELINES ON ACUTE INFECTIOUSDIARRHEA IN ADULTS

Although statisticallythe rate of diarrheain adults in the United States and other industrialized regions is approximately one episode per person per year, diarrhea actually does not occur in all persons annually. Food- and waterborne outbreaksinvolving a relatively small subsetof the generalpopulation and recunent bouts of illness in others make up the bulk of the casesof the illness. Diarrhea is a specialproblem among adults who are exposedto children and nontoilet-trainedinfants particularly in a day care setting, travelers to tropical and semitropical regions, homosexualmales,personswith underlyingimmunosuppression. and those living in an unhygienic environment and having exposureto contaminatedwater or fbods. PATIENT EVALUATION Most casesof diarrhea are managedby the affected patient or by a family member without need for medical attention. Recommendation l. Medical evaluation should occur for a subset of patients with more severe illness. Specific indications for medical evaluation include: profuse watery diarrhea with dehydration; dysentery, passage of many small volume stools containing blood and mucus; fever (temperature> 38.5'C, l0l.3"F); passageof > 6 unformedstools/24h or a duration of illness > 48 h; diarrheawith severeabdominal pain in a patient above the age of 50 yr; diarrhea in the elderly (>70 yr of age) or the immunocompromisedpatient (AIDS, after transplantation,or receipt of cancer chemotherapy). Indications.formedical evaluation. Dehydration,defined as dry mucous membranes,decreasedurination, and tachycardia,is the most common complication of a small bowel secretorydiarrhea and should be promptly evaluated and treated (6). Osmotic diarrhea seen in patients with small intestinalinjury due to an infectious agent who attempt to ingestcarbohydratesor other substances(magnesium,salts, fiber) may present with watery diarrhea and dehydration. Patients with dysentery will have more intense and prolonged illness without antimicrobial therapy (7). Fever is usually a finding associatedwith an invasive pathogenthat produces intestinal inflammation. These cases optimally will be studied for etiologic agents and many will benefit from antimicrobial therapy (8). Similarly more intensediarrhea(>6 unformed stools/24h) and that lasting more than 48 h should be evaluated for cause of illness or treated empirically (8, 9). Patients with severe abdominal pain particularly if above the age of 50 yr may have a complicatingillnesssuchas ischemicbowel disease(10).Diarrhea in the elderly is more likely to be severeand possibly fatal (4, l1), and patientswho are immunocompromised usually havecomplicatedand difficult to managedianhea (12).

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Recommendation 2. The clinical and epidemiologic history is central to patient medical evaluationand management. The history. From the standpoint of functional impairment from the illness, diarrheamay be categorizedas mild (no changein normal activities),moderate(fbrced changein activities),or severe(disability generally with confinement to bed). In Table 1 the clinical syndromesseen in enteric infections are detailed along with suspectedcauseand anatomic location of the diseaseprocess.Assessmentof the severity of illness, presenceof dehydration, character of stool pattern,presenceof fever, vomiting, or dysenteryoften will help to focus the evaluation to determine the likely causeof the illness. When diarrhealasts as long as 2 wk, a different list of etiologic agents and conditions should be consideredwhen compared with the person with acute diarrhea.When fever (oral temperature> 38.5"C,or l0l.3"F) is present,the patient has intestinalinflammation characteristically due to invasive bacteria (Shigella, Salmonella, Campylobacter),one of the enteric viruses. or a cytotoxic organismresulting in mucosal histologicdamageand inflammation (C. dfficile or Entamoebahistolytica). Finally, in taking a history epidemiologic factors and associations should be considered(Table 2). In the homosexualmale with diarrhea,threediseasetransmission or clinical scenariosmay explain the entericdisease (13). First, becauseof the sexual practicesof many homosexual men, there is an increasedrate of fecal oral transmission of all agents showing this route of spread.This includes Shigella, Salmonella,Campt'ktbacter,and the intestinal protozoa. Second,in homosexualmales who have been the recipients of anal intercourse,direct rectal inoculation of a pathogen(seeTable 1) may lead to proctitis ( l3) associatedwith rectal pain and tenesmusand passageof small volume stoolsolten containingblood and mucus.The third setting of diarrhea in a homosexualmale is when the individual has developedAIDS (12) (see Managementof the ImmunocompromisedPatient with Diarrhea section). Foodborne or waterborne outbreaksof diarrhea are becoming more common (14-16). The incubationperiod of resultant illness and the predominant symptoms ofien will help the clinician to determine the cause of the outbreak based on clinical grounds. When diarrhea and vomiting occurswithin 6 h of exposureto a food item, food poisoning secondaryto the ingestion of preformed toxin of Staphylococcusaureusor Bacillus cereusshouldbe suspected.When the incubationperiod of an outbreakof diarrhealdiseaseis 8-14 h, Clostridiumperfringens enteric infection shouldbe suspected.When the incubationperiod is greaterthan l4 h and vomiting is the prominent feature of the diarrheal disease,viral agentsshould be suspected.When fever and or dysentery is present in a majority of casesduring an outbreak, the invasive pathogensshould be consideredsuch as Shigella, Salmonella, or Catnpl,lobacter.Other pathogens can oroducethe sameclinical featuresof an invasive oatho-

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Vol. 92. No. I l. 1997

AJ(

T,qst-nI C I ini r:a I Sy-ndromes Assoc i at ed w it h Di a r rhe u Syndrome

Clinical Features

Anatomic Location

Gastroenteritis

Stomach and small intestine

N a u s e a .v o m i t i n g a n d u l t e r l diarrhea

Acute watery (often secretory) diarrhea Colitis and proctitis

Small intestine,colon may be involved Colitis:colonicinllammation d o c u m e n t e db e y o n d l 5 c m .

Voluminous stools,upper abdominal pain and cramps Many small volume stools,fecal urgency, tenesmus,and dysentery

Persistent,>l.l days, diarrhea

Proctitis: inflammation confined to distal 15 cm of colon Small intestine,colon may be Clinical f-eatureswill dependupon intestinal location of disease involved process

SuspectedEtiology Viral agentsor preformed toxrn produced by S. auretts or B. cereus. any enteric pathogen Any enteric pathogen

St(

Shigella, Camp-vlobactermost common, also consider Salmonello,Shigatoxin producing E. coli (.e.g.0:157 H:1) i n r a s i v eE . c o l i . E . h i . s t u l v t i c u . Aeromonas spp, noncholera ViDrlos, Chlo n,-dia t rachomati s, infl ammatory bowel diseasetin a recipient of anal intercourseconsiderNei t st rirt gonorrhoeae, herpessimplex. Ch lamyclictt ra(homat is, Treponenru pallidum

St
12 h in which vomiting is the (see likely etiologic agents) predominant symptom Duodenal intubation or l4-c-d-xylose breath In a patient with persistentdianhea not respondingto empiric therapy test C. dfficile toxin assay

Flexible sigmoidoscopywith biopsy of abnormalities

Flexible sigmoidoscopyand upper endoscopywith biopsy of abnormalities

Homosexual male with moderateto severe diarrhea,any patient with persistentdiarrhea and clinical colitis (see Table l) not respondingto antimicrobial therapy or without diagnosisafter laboratory evaluation Any patient with persistentdianhea without evidence of colitis (see Table l) and without responseto empiric therapy

V. cholerae and noncholeraVlbrlos

Y. enterocolitica

C. diJJicile Rotavirus, enteric adenovirus(type 40, 41), Norwalk virus,* and other small round structured viruses G i a rd i a, C ryp tosp or i di um, rarely Strongy ktide s stercoralis, small bowel bacterialovergrowth syndrome See causesof colitis and proctitis (Table I above)

Causesof colitis and proctitis (Table 1 above) as well as upper intestinal int'ectionby Giardiu, C rt'pxtsporidium, C.'-clospora, M icrospori di um, cytomegalovirus,HlY, M 1"cobacteri um avi um intracellulare complex

* Norwalk virus detection is presently done only in a researchlaboratory

Recommendation 3. In patientswith fever (oral temperature> 38.5'C, or 101.3'F) plus either leukocyte-, lactoferrin-, or hemoccultpositive stools or in patients with acute dysentery or in patientswith moderateand severetravelers' diarrhea,antimicrobial therapy may be given empirically (Table 4). Empiric therapy for presumed bacterictl diathea. In patients with fever and either fecal leukocyte-,lactoferrin-,or hemoccult-positivestools, inf-ectionwith invasive bacterial pathogenssuch as Shigella,Salmonella,and Campylobacter shouldbe considered(17, l8). A majority of patientswith numerous fecal leukocytes will respond favorably to antimicrobial therapy (19-21). Finding hemoccult-positive stool in patients with acute diarrhea has the same clinical significanceas finding numerousfecal leukocytes(18, 22). The samepathogensassociatedwith the presenceof numerous l'ecalleukocyteswill generallybe found in patientswith acute dysenteric disease(23, 24). Patients with travelers' diarrhea,particularly those with moderateto severeillness are characteristicallyinfected with bacterial pathogensand their illness is shortenedby antimicrobial therapy (25*21). Recommendation 4. Patientswith diarrhea lasting 2 to 4 wk without systemic symptoms or dysentery may be studied for causeof

illness or may be treatedempirically with anti-Grardia therapy (Table 4). Empiric treatmentof presumedgiardiasis. While many clinicians would pref'erto evaluatethe patient with persistent diarrhea for cause of illness some elect to treat empirically for presumed giardiasis. This approach is reasonablein view of the importance of Giardia in this syndrome(28) and becauseat least half of studiedstools of patientswith giardiasiswill be negativefor the parasite (29, 30). Work-up of those failing to respond to empiric therapy for Giardict(usually stool enzymeimmunoassay) may then be indicated.The most frequently used empiric therapy of presumedgiardiasisis metronidazole(seeTable 4), which also may be eff'ectiveagainsta small bowel bacterialovergrowth syndromeassociatedwith persistent diarrhea, a problem occasionally seen after an enteric i n f e c t i o n( 3 1 ) .

LABORATORY EVALUATION Laboratory testsand proceduresmay be used to evaluate patients with illness calling for medical evaluation (see above)and fbr other patientsin whom a definablepathogen is suggestedby the history (Tables I and 2).

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for Empiric

and Specific Antimicrobial

Therapt

SuggestedAntimicrobial Therapy

Indication for Antimicrobial Therapv F e v e r( o r a l t e m p e r a t u r e> 3 8 . 5 ' C o r 1 0 1 . 3 ' F )t o g e t h e r with one ol the following: dysentery(grossly bloody stools) or those with leukocyte-, lactof'errin-,or h e m o c c u l t - p o s i t i vset o o l s Moderate to severetravelers' diarrhea Persistentdiarrhea (possible Graruliainf'ection) Shigellosis

Intestinal salmonellosis

Campylobacteriosis EnteropathogenicE. coLi diarrhea (EPEC) EnterotoxigenicE colr diarrhea (ETEC) EnteroinvasiveE. colr diarrhea (EIEC) EnterohemorrhagtcE. coLi diarrhea (EHEC)

Aeromonas diarrhea Noncholera Vibrb dianhea Yersiniosis Giardiasis

in InJectious Diarrheu

Quinolone:'kNF 4(X) mg, CF 500 m, OF 300 rng b.i.d. for 3-5 days (see text)

Quinolone:+ NF 400 mg. CF 500 mg, OF 300 rng b.i.d. for 1-5 days (see text) Metronidazole250 mg g.i.d. fcrr 7 days If acquired in the U.S. give TMP/SMX 160/tt(X)mg b.i.d. for 3 days, if acquired during internationaltravel treat as f'ebriledysentery(above)l check to be certain of susceptibilityto drug employed If healthy host with mild or moderatesymptoms, no therapyi fbr severediseaseor that associatedwith f'ever and systemictoxicity or other important underlying condition (see text) use TMP/SMX 160 mg/t3(X)mg or quinolone:'kNF 400 rng, CF 500 mg, OF mg bid lbr 5 to 7 days dependingon speedof response Erythrornycin stearate500 mg h.i.d. for 5 days Treat as f'ebriledysentery Treat as moderateto severetravelers' diarrhea Treat as shigellosis Antin'ricrobialsare generally withheld except in particularly severecasesin which usefulnessof thesedrugs is uncertaln (see text) Treat as febrile dysentery Treat as febrile dysentery For most cases,treat as febrile dysentery,for severecases give ceftriaxone 1 g q.d. lY fbr 5 days Metronidazole250 mg q.i.d. for 7 days or (if available) tinidazole 2 gr in a single dose or quinacine 100 mg t.i.11.

C n ptospo rid i urn diarrhea

fbr 7 days Metronidazole750 mg t.i.d. fbr 5 l0 days plus a drug to treat cysts to prevent relapses:diiodohydroxyquin 650 mg t.i.d. for 20 days, or paromomycin 500 mg r.l.d. fbr l0 days or diloxanide furoate 500 mg t.i.ri. fbr l0 d None, fbr severecases,considerparomomycin 500 mg

Isospora diarrhea Ctt:losporu diarrhea

fbr 7 days r.1.21. TMP/SMX 160 rng/t100mg b.i.d. fbr 7 days TMP/SMX 160 rng/tt00 mg D.i.rl fbr 7 days

Intestinal anrebiirsis

i'Fluoroquinolones include nortloxacin (NF), ciprofloxacin (CF). and ofloxacin (OF).

Rec'ommendilion

Recommendcttion

5. The f-ecalleukocyte, lactof'errin,or hemoccult blood test is a useful screeningtest in patients with moderateto severe acute infectious diarrhea becausethey support the use of empiric therapyin the febrile patient (seeabove) and when negative may eliminate the need for stool culture in some casesof diarrhea. Laboraton screening. Fecal leukocytes, lactoferrin, or occult blood are fbund in diarrhea patients with difluse colonic inflammation(17, l8). The most commonly identified pathogensin patientswith a positive test result include: Aeromonas,Yersinia, Shigella, SalmoneLla,Cump,,-lobacter, noncholeraVibrios (17, l8), and Clostridium dfficile (32). Low numbersof fecal leukocvtesare found in patientswith intestinalamebiasis.

6. A stool culture shouldbe obtainedin a patientwith one of the following: severediarhea; a temperature> 38.5'C, or 101.3'F,(orally);passageof bloody stools;stoolscontain leukocytes,lactoferrin, or hemoccult blood; or, the patient with persistentdiarrhea has not been treated with antibacterial agentsempirically. Routine stool culture. The bacterial enteropathogens identified by normal stool culture are Shigella, Salmonella, CampyIobacter, Aer omonas, and Yer sinia. Severe(i ntense) diarrhea, moderate to high f'ever,dysentery,finding f'ecal leukocytes,lactoferrin, or hemoccult blood positive stools all are predictive of finding an identifiablebacterialenteropathogenswhen fecal samplesare submittedto the laboratory for culture. The bacterial pathogensmay cause more

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AJG - November 1997

GUIDELINES ON ACUTE INFECTIOUSDIARRHEA IN ADULTS

prolongeddiarrheawhen comparedwith pathogen-negative nonspecificdiarrhea (25, 33, 34). Studiesin the United Stateshave found that stool studies arefrequently inappropriatelyorderedresultingin excessive medicalcosts(35). In two studies,stool culturesas obtained routinely in selectedlocations were found to have a positivity rate of 2Voor less,making the cost of the test between $900 and $1200 per pathogendetected(35, 36). Stool cultures should not be ordered routinely but reservedfor the a p p r o p r i a tpea t i e n ta n d s e t t i n g . Recommendation 7. Patientsnot treated with empiric antiparasitictherapy should be studied for parasitic causesof diarrhea if they have persistent diarrhea; diarrhea has followed travel to Russia, Nepal, or mountainous regions; they have been exposedto infants attendingday care centers;diarrheahas occurred in a homosexual male or a patient with AIDS; diarrheais part of a community waterborneoutbreak;or has bloody diarrhea with few or no fecal leukocytes. Laboratory evaluationfor parasites. Although less well studiedthan the value of routine stool culture, the common "O and P's" (ova and parasites)in patientswith obtainingof acutediarrheais not cost effective (37). As indicatedabove, patientswith giardiasisoften have persistentdiarrhea.The diarrhealillness associatedwith Cryptosporidium (28) and Entamoebahistolytica (38) may be protracted.Infection by Cryptosporidium, Giardia, or both, should be suspected wheneverdiarrheafollows trips to Russia (28,39); Cyclospora should be consideredin travelers to Nepal (40); and Giardia should be suspectedin personswho have recently traveled to mountainousareasor to recreationalwaters of North America (41). Among infants in day care centers, Giardia (42) and Cryptosporidium(43) are common causes of diarrheaand may be spreadto adult contactsbecauseof the low inoculum required for human infection (44, 45). Homosexualmales may be infected with a variety of parasites including Giardia and Entttmoebahi.stolytica.In patientswith AIDS-associateddiarrhea,parasitesrepresentthe major definablepathogens(46). The specific agentsto consider in this settingare mentionedbelow. Both Giardia (41) and Cryptosporidium(16) may causeextensivecommunity waterbomeoutbreaks.Numerousleukocytesare not usually found in the stools of patients with intestinal amebiasis becauseof the presence of uninflamed mucosa between ulcerations and because of the lytic effect of exotoxins producedby the organism (48). Therefore when a patient with diarrhea is passing bloody stools and there are few leukocytes,amebiasisshould be considered.Stools may be studiedby routine microscopic techniquesfor parasitic enteropathogensby a well-trained parasitologistor in the case of Giardia and Cryptosporidiwn, by a commercially available immunofluorescentantibody tests(49) or by diagnostic (50), which may be more sensitive enzymeimmunoassays than microscopicstudies(5 I, 52).

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Recommendation 8. In patients with certain epidemiologic findings, fecal samplesshould be collected and sent to the laboratory for specific enteropathogensincluding enterohemorrhagicE. coli. Vibrio cholerae, noncholera Vibrios, and Yersinia. Selected patients may be studied for the presenceof C. dfficile toxin, or viruses or they may be studiedby endoscopy (seeTable 3). Special bacterial enteropathogens.A number of bacterial enteropathogenswill not be detectedby routine stool culture. These pathogensinclude enterohemorrhagiccolitis producing E. coli 0157:H1 and other Shigatoxin producing E. coli (53), y. cholerae,other noncholeraVibrios (54), and Yersinia (55), although routine stool cultures will identify most of the strainsof Yersinia.Except for E. coli 0157:Hi , which is readily detectedby stool culture using specialized media, the other diarrheagenicE. coli are presently only detectedby researchlaboratories.Stool assaysfor C. dffi' cile toxin by tissue culture assayor enzyme immunoassay should be carried out in the patient who is currently receiving antimicrobialsor who has receivedantimicrobialsin the last 2 wk. In the case of food- or waterborneoutbreaks,in which the illness is associatedwith vomiting as the major clinical feature and the incubation period is > 12 h, viral agents should be considered (see Table 3). Homosexual maleswith diarrheaand any patientswith persistentdiarrhea not responding to empiric therapy may be evaluated by endoscopy. MANAGEMENT Fluid and Electrolyte Treatment Recommendation 9. In all patientswith diarrhearequiring medical evaluation, fluid and electrolyte therapy and alteration of the diet should be part of the management. Fluid therapy and diet alteration. For most cases of acute diarrhea,the most important form of therapy consists of t'luid combined with electrolytes (56). Whereas such treatmentis life saving for young infants in the developing world, in the United Statesthe most important adult groups in which special attention should be given to fluid therapy are the elderly and the immunosuppressed.For these persons solutions containing sodium in the range of 45 to 75 mEq/L are recommended(Pedialyte or Rehydrolyte solutions). In the nondehydratedotherwisehealthy person with acute diarrhea, sport drinks, diluted fruit juices, and other flavored soft drinks augmentedwith saltine crackers and broths and soupscan meet the fluid and salt needsin nearly all cases.For dehydrating cholera-like diarrhea more aggressivefluid therapy will be required. Here the ideal formulation of oral fluids is Na 60-90 mBq[. K 20 mEq/L, Cl 80 mEq/L, citrate 30 mEq/L, and glucose20 g/L. A homemade version of this form of oral rehydration solution fbr more severediarrheais to preparetwo separateglassesthat

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T a e r - c5 S\-nptomutic Treatmetlt oJ Acute Diarrhea

Phlil"l:91.s.lqT, Loperan.ride(lmodium)

Drphenoxylatewith a t r o p i n e( L o m o t i l )

Tincture of opium

B i s m u t hs u b s a l i c y l a t e (Pepto-Bisrnol)

Octre0tide

Indication/Perspective Acute diarrhea,f'ever is absentor low grade, dysenteryis not present/minirnalcentral opiate effects, the pref'erredsymptomatic drug when used fbr most nonf'ebrile,nondysentericcases Acute diarrhea,t-everis absentor low grade, dysenteryis not presenVhascentral opiate eff'ects,with overdose liability. atropine may cause side eflects without of lering antidianheal efl'ects Acute diarrhea,fever is absentor low grade, dysenteryis not present/occasionallyuseful in HlV-associated diarrhea when the saf'erloperamideis not Any fbrm of acute diarrhea/inmost casesis less efl'ective than loperan'rideand cannot be cornbined w i t h a n t i m i c r o b i a l ssl h o u l d n o t b e u s e d i n H I V positive patients with diarrhea AlDS-associateddiarrhea not respondingto other treatment/considered last resort therapy for these patients,once symptoms are controlled, the patient should be startedon other more convenient preparations

are consumedalternately.The first contains8 ouncesof orange.apple.or other fruit juice (supplyingpotassium),% teaspoonof honey or corn syrup, and I pinch table salt; the secondglasscontains8 ouncesclearwaterplus I /4 teaspoon of baking soda (56). During a bout of acute diarrhea,calories (energy) should be provided to facilitate enterocyterenewal (56). Diet fol(potatoes,noolows clinical course.Boiled starches/cereals dles/rice, wheat, oat) with some salt representideal foods during episodesof watery diarrhea.Crackers,bananas,yogurt, soup, and boiled vegetablescan also be used.When stools are formed, diet may return to normal as tolerated. Many authoritieswould excludemilk productsearly in the illness but clinical lactose intoleranceis not commonly found in casesof acutediarrhea. NonspecificTherapy Rec'onunendcttion 10. When nonspecific therapy is desired, loperamide is the drug of choice for most casesof diarrhea. Svmptomatictreatment o.f acute diarrhea. In Table 5 a brief perspectiveon the useof symptomaticallyacting drugs is provided.The antimotilitydrugs(loperamide,diphenoxylate with atropine, and tincture of opium) are the most etfectivedrugs directedto treatingsymptoms.They work by slowingthe intraluminalf'low of liquid facilitatingintestinal absorption(57). Loperamideis generallythe recommended agent fbr most casesof diarrhea when symptomatic treatment is used becauseof saf'etyand expected efficacy in which stool numberis generallyreducedby approximately 807c(58. 59). Diphenoxylatemay not be the ideal antimotility drug. althoughit is lessexpensivethan the pref-erred loperamide.Diphenoxylatepossessescentral opiate eff'ects

AJG

Reco

Dose and Administration 2 tablets (4 mg) initially then 2 mg after each unfbrmed stool not to exceed 8 mg/ day (OTC dose) or l6 mg/day (prescription dose) 65 yr of age) (ll). Other risk factors for bacteremia include HIV infectionand AIDS (82); uremia (83); malignancy,includinghematologic,lymphatic,and solid tumors (84); after renal transplantation(85); and congenital and acquired immunodeficienciesincluding corticosteroid use (86). There are other conditionsthat may predisposepatients to localized extraintestinalinfection when Salmonella gastroenteritisdevelops.This includespatientswith an aortic aneurysm,prosthetic heart valve, vascular graft, or orthopedic prosthesis.Antimicrobialsare indicatedfbr casesof intestinalsalmonellosiscomplicatedby any one of these conditions as well as fbr otherwise healthy persons with f'ebrileillness,systemictoxicity or dysentericdisease. For all practical purposes, all patients with intestinal salmonellosisillness severeenough to lead to hospitalization should be given antimicrobial therapy (Table 4). Camltylobacter-Recommendationl6: Patientswith culture-proven Campylobacter inf'ection are treated with an antimicrobialagentto shortenillness,althoughdevelopment of antimicrobial resistanceis becoming a problem. Treatment of Campylobacter diarrhea'. Cunpylobac'ter resemblesSalmonella in many ways. First they both show an animal, often poultry, reservoir fbr human inf-ection. Second,antimicrobialresistanceoccurs commonly during therapyor over time in a population(87).Erythromycinwill shorten the duration of Camp,vbbacter dianhea (88). lf susceptibleto the drugs, the fluoroquinolones(89) are effective against campylobacteriosis. Unfbrtunately,quin-

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olone resistanceis increasing worldwide among Campr-lobacter isolates(87, 90, 9l). It is necessaryto confirm in vllro susceptibilityof infecting strainsof Campylobacter.In addition to erythromycin, azithromycin may be used in quinolone-resistant CampyIobact er infections ( 87). DiarrheagenicE. coli: There are four major diarrheagenic E. coli: enteropathogenicE coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasiveE. coli (EIEC), and enterohemonhagic E. coli (EHEC). EPEC diarrhea is primarily a problem of infant populations.The related HEp-2 cell adherentE coli arepathogensofboth children and adults(33, 92). The diarrhea causedby HEp-2 cell adherentE. coli tends to be persistent (33, 93). These strains have been shown to be causesof prolonged diarrhea in patients with AIDS in Zambia (94). EPEC and HEp-2 cell adherentE. coli are highly resistantto most antimicrobialsexceptthe newer quinolones(95). It is not known whetherantimicrobialswill shortenthe illness. ETEC diarrheawill respondto antimicrobialtherapy(21, 25,96). This form is the major causeof travelers' diarrhea. TMP/SMX or the quinolones remain standardtherapy for infection dependingupon susceptibility.

TABLE 6 Prevention

of Travelers'

AJC

Diarrhea

All Travelers Diet and BeveragePrecautions Consumeonly safe items while in high risk area, including airplane leaving area: l) Steaming hot fbods and beverages(e.g. cooked foods, coffee, tea) 2) Acidic foods (e.g. citrus) 3) Dry foods (e.g. bread) 4) Foods with high sugar content (e.g. syrups,jellies) 5) Carbonateddrinks (e.g. bottled soft drinks and beer); bottled, uncarbonatedwater may not be safe SelectedTravelers Those who wish prophylaxis BSS* 2 tablets with meals and at bedtime (8 tablets/day) (62Vc effective in eliminating diarrhea) Those who might be encouragedto take prophylaxis include those with underlying illness: AIDS, prior gastric surgery and those taking proton pump inhibitors (omeprazole),or those who cannot afford an 8 hour illness (e.g. politician, honeymoon couple, or weekend scuba diver) Antimicrobial agent (same drug used normally for therapy (Table 4) in single daily dose during time at risk (907c effective in eliminating dianhea) Use of prophylactic antimicrobialsis controversial * BSS, bismuth subsalicylate.

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