Ver el código de «Acute diarrhea»

{{Adult top}} [[diarrhea (peds)]]
==Background==
[[File:Figure 34 01 10f.png|thumb|Gasterointestinal anatomy.]]
[[File:Layers of the GI Tract english.png|thumb|Layers of the Alimentary Canal. The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa.]]
*Almost all true diarrheal emergencies are of noninfectious origin
*85% of diarrhea is infectious in etiology
**[[Viruses]] cause vast majority of infectious diarrhea
**[[Bacteria]]l causes are responsible for most cases of severe diarrhea
***Foreign travel associated with 80% probability of bacterial diarrhea (see [[Traveler's Diarrhea]])

===Definitions===
*[[Diarrhea]]: Increased frequency of defection, usually >3 bowel movements per day
*Hyperacute: 1-6 hr
*Acute: less than 3 weeks in duration
*[[Gastroenteritis]]: Diarrhea with nausea and/or vomiting
*Dysentery: Diarrhea with blood/mucus/pus
*Invasive = Infectious

==Clinical Features==
[[File:BristolStoolChart.png|thumb|Bristol Stool Chart.]]
===History===
*Possible food poisoning?
**Symptoms occur within 6hr
*Does it resolve (osmotic) or persist (secretory) with fasting?
*Are the stools of smaller volume (large intestine) or larger volume (small intestine)
*[[Fever]] or [[abdominal pain]]? ([[diverticulitis]], [[gastroenteritis]], [[IBD]])
*[[GI bleeding|Bloody or melenic]]?
*Tenesmus? ([[shigella]])
*Malodorous? ([[giardia]])
*Recent travel? ([[Traveler's Diarrhea]])
*Recent antibiotics? ([[C. diff]])
*[[HIV]]/immunocompromised/high risk behaviors?
*Heat intolerance and anxiety? ([[thyrotoxicosis]])
*[[Paresthesias]] or reverse temperature sensation? ([[Ciguatera]])

===Physical Exam===
*[[Thyroid]] masses
*Oral ulcers, erythema nodosum, episcleritis, [[anal fissure]] ([[IBD]])
*[[Reactive arthritis]] ([[Arthritis]], [[conjunctivitis]], urethritis)
**Suggests infection with [[salmonella]], [[shigella]], [[campylobacter]], or [[yersinia]]
*Rectal exam for [[fecal impaction]]
*Guaiac
*[[Abdominal pain]] out of proportion to exam ([[mesenteric ischemia]])

==Differential Diagnosis==
{{Diarrhea DDX}}

==Evaluation==
[[File:Causes_of_Diarrhea.png|thumb]]
===Toxigenic v. Infectious===

{| class="wikitable"
|-
| '''Characteristic'''
| '''Toxic'''
| <span style="font-weight: bold">Infectious/Invasive</span><br/>
|-
| Incubation
| 2-12h
| 1-3d
|-
| Onset
| abrupt
| gradual
|-
| Duration
| <10-24h
| 1-7days
|-
| Fever
| No
| Yes
|-
| Abdominal Pain
| Minimal
| Yes, tenesmus
|-
| Systemic
| No
| Yes, myalgias, nausea and vomiting
|-
| Physical findings
| Nontoxic
| Toxic
|-
| Abdominal Tenderness
| No
| Yes
|-
| Stool Blood, WBCs
| No
| Yes
|}

===Indications for Workup===
Indicated for:
*Profuse watery diarrhea with signs of [[hypovolemia]]
*Severe [[abdominal pain]]
*[[Fever]] >38.5 (101.3) (suggests infection with invasive bacteria)
*Symptoms >2-3d
*Blood or pus in stool ([[E. coli]] 0157:H7)
*Recent hospitalization or antibiotic use
*Elderly or immunocompromised 
*Systemic illness with diarrhea (esp if pregnant ([[listeria]]))

===Stool Studies===
====Fecal leukocytes====
*Used to differentiate invasive from noninvasive infectious diarrheas
*Sn 50-80%, Sp 83% for presence of bacterial pathogen
*If patient has +leukocytes but negative infection consider IBD

====Stool culture====
*Plays minor role in ED evaluation
*Yield is only 1.5-5.5%
*Consider in patients with
**Immunosuppression
**Severe, inflammatory diarrhea (including bloody diarrhea)
**Underlying IBD (need to distinguish between flare and superimposed infection)

====O&P====
*Indicated if parasitic cause is suspected:
**[[Diarrhea]] >7d
**Untreated water
**[[AIDS]]
**Bloody diarrhea with few or no fecal leukocytes (intestinal [[amebiasis]])

====[[C. diff]] toxin====
*10% false negative rate
*Turnaround time for results varies by institution

====Chemistry====
*Warranted in severely dehydrated patients

====[[CXR]]====
*Consider if diarrhea + cough ([[Legionella]])

====Imaging====
*Consider abdominal CT if abdominal tenderness or suspicion of surgical abdomen (e.g. [[appendicitis]], [[small bowel obstruction]], [[mesenteric ischemia]])
*[[Abdominal X-ray]] is almost never indicated given low sensitivity for pathology (e.g. [[obstruction]])

==Supportive Therapies==
===[[Oral rehydration therapy]]===
*Fluids should contain sugar, salt, and water
===Probiotics===
*Lactobacilli and bifidobacterium
*25% decrease in average duration of diarrhea (good evidence)
===Diet Modification===
*Eat: BRAT(Bananas, Rice, Applesauce and Toast) diet (no evidence)
*Avoid: [[Caffeine]] (increased gastric motility), raw fruit (increased osmotic diarrhea), lactose

===[[Bismuth subsalicylate]]===
*Consider when loperamide is contraindicated (high fever, dysentery)
*Dose: 30 mL or 2tab q30 min for 8doses; repeat on day 2
*Caution: may cause [[bismuth toxicity|bismuth encephalopathy]] in [[HIV]] patients

===[[Loperamide]]===
*2mg PO per dose
**Start: 4mg PO x1, then 2mg PO after each loose stool; Max: 16mg/day
*Contraindicated if suspect C. diff 

===[[Diphenoxylate/atropine]]===
*Dose: 4mg QID x2d
*2nd line agent (may cause cholinergic side effects)
*Contraindicated in pseudomembranous colitis, obstructive jaundice, and children <6y

==[[Antibiotics]] for Infectious Diarrhea==
*Most cases of diarrhea are NOT from infectious causes. If the patient suspects that there is blood in the stool but there is no abdominal pain, and no fever, the cause is unlikely to be from a bacterial cause.  Also avoid antibiotics in E. Coli 0157:H7 (EHEC) cases due the risk of [[Hemolytic Uremic Syndrome (HUS)]]''<ref name="practical guide"> Aranda-Michel J et al. Acute diarrhea: A practical review. AmJMed. 1999;106:670-676.</ref>
*The majority of patients, even with bacterial positive cultures, will recover from diarrhea illness without antibiotic therapy<ref>DuPont HL et al. Practice Parameters Committee of the American College of Gastroenterology. Guidelines on acute infectious diarrhea in adults. Am J Gastroenterol. 1997;92:1962-1975.</ref>

===Relative Indications for Antibiotics<ref>IDSA Practice Guidelines for the Management of Infectious Diarrhea. 2001. [http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/Diarrhea.pdf fulltext]</ref>===
*Suspected bacterial diarrhea 
*Bloody diarrhea (except for EHEC) with fever and systemic illness
*Occult blood or +fecal leukocytes
*Moderate to severe travelers' diarrhea (>4 stools/d, fever, blood, or mucus in stool)
*>8 stools/d
*Volume depletion
*>1wk duration
*Immunocompromised
*Toxic appearance

===Empiric Therapy===
{{Diarrhea Empiric Therapy}}

===[[Traveler's Diarrhea]]===
*Therapy should be based on the [[Traveler's diarrhea |geography of travel]]
'''Adult Options:'''
{{Travelers Diarrhea Antibiotics}}

'''Pediatric Options:'''
{{Travelers Diarrhea Pediatric Antibiotics}}

===Culture Specific Antibiotics===
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''Agent'''
| align="center" style="background:#f0f0f0;"|'''Treatment'''
|-
| [[Clostridium difficile]]||{{Severe Cdiff Antibiotics}}
|-
| [[Campylobacter jejuni]]||{{Campylobacter antibiotics}}
|-
| [[Entamoeba histolytica]]||{{Entamoeba diarrhea antibiotics}}
|-
| [[Giardia lamblia]]||{{Giardia antibiotics}}
|-
| [[Microsporidium]]||{{Microsporidium antibiotics}}
|-
| [[Cryptosporidium]]||{{Cryptosporidium diarrhea antibiotics}}
|-
| [[Salmonella]] (non typhoid)||{{Salmonella diarrhea antibiotics}}
|-
| [[Shigella]]||{{Shigella diarrhea antibiotics}}
|-
| [[Cholera|Vibrio Cholerae]]||{{Vibrio cholerae antibiotics}}
|-
| [[Yersinia enterocolitica]]||{{Yersiniae enterocolitica antibiotics}}
|}

==Disposition==
*Hospitalization should be individualized based on the patient's ability to tolerate oral hydration, have adequate social support, and also based on complicating comorbidities.
*Majority of patients can be treated as an outpatient
*Observation or admission is required for those with severe disease, and significant dehydration with other end organ complications

==See Also==
*[[Diarrhea (Peds)]]
*[[Traveler's Diarrhea]]
*[[Clostridium Difficile]]

==References==
<references/>

[[Category:GI]]
[[Category:ID]]
[[Category:Symptoms]]