Diarrhea and Constipation

• DIARRHEA■ DEFINITION

• Diarrhea is loosely defined as passage of abnormally liquid orunformed stools at an increased frequency.

• Diarrhea may be further defined as

• acute if <2 weeks,

• persistent if 2–4 weeks,

• and chronic if >4 weeks in duration.

• Two common conditions, usually associated with the passage ofstool totaling <200 g/d, must be distinguished from diarrhea, becausediagnostic and therapeutic algorithms differ.

• Pseudodiarrhea, or the frequent passage of small volumes of stool, is often associated with rectal urgency, tenesmus, or a feeling of incomplete evacuation, and accompanies IBS or proctitis.

• Fecal incontinence is the involuntary discharge of rectal contents and is most often caused by neuromuscular disorders or structural anorectal problems.

• ■ ACUTE DIARRHEAMore than 90% of cases of acute diarrhea are caused by infectiousagents;

• these cases are often accompanied by vomiting, fever, and abdominal pain.

• The remaining 10% or so are caused by medications, toxic ingestions, ischemia, food indiscretions, and other conditions.

• Infectious Agents

• Most infectious diarrheas are acquired by fecal-oral transmission,

• Viral diarrhea:

• Most common cause of diarrhea,

• Winter and spring seasons,

• Childern,daycare centers,

• Rotavirus,adenovirus, calivirus ,entervirus ,Norwalk virus (RACE to Norwalk).

• Rotavirus is the most common cause of diarrhea in children.• No blood or WBC in stool.• Diarrhea – bacterial: invasive and toxigenic,• Diarrhea- Invasive:• Inflmmation (stool WBC) and bleeding (degree varies by pathogen).• E. coli 0157:H7• - entrohemorragic E. coli (gross blood in stool),• -undercooked humburger, raw milk, untreated water.• Causes HUS(in children), TTP( in elderly),• Antibiotic my increase risk of HUS.

• Shigella: -very infectious , -high fever, febrile seizure ( neurotoxins) ,bloody diarrhea, dysentery.

• -Incubation 2-6 days, -ciprofloxacin.

• Salmonella: -very common bacterial diarrhea,

• -watery or mucoid stools, - eggs , chickens, cafeteria food,

• - osteomyelitis can in sickler's (auto splenectomy)and after splenectomy,

• - ciprofloxacin.

• Campylobacter: - most common cause of bacterial diarrhea,

• - contaminated food and water ,-incubation 2-6 days,

• -bloody diarrhea ,fever, mimics IBD , appendicitis.

• - Erythromycin (children), fluoroqinolones (adults).

• -Acute infection is associated with development of Guillain-Barre syndrome.

• Yersinia enterocolitica: - invasive Gram negative bacteria, -can also mimics appendicitis, fever, colicky abdominal pain (may be prolonged)

• - diarrhea , may persist 10-14 days.

• - diagnosis , fecal Wright stain positive.

• Rx: supportive if uncomplicated, quinolones or TMP-SMX if complicated.

• Diarrhea – protozoan

• Giardia: - most common cause of water-borne diarrheal outbreak,

• Contaminated streams, pools , day care centers, (fecal –oral spread) sexually transmitted.

• -symptom begin 1-4 weeks, -

• Audible borborygmi, floating, frothy, foul smelling stools

• Stool specimens to identify cysts / trophozoites.

• Metronidazole , furazolidone.

• Amebiasis (Entamoeba histolitica):

• -spreads between family members and sexual partners,

• Fecal-oral contact and anal intercourse,

• -diarrhea can be bloody,

• -Extra- intestinal manifestations: liver abscess, pericarditis , pleuropulmonary disease , cerebral amebiasis,

• Wide variety of presentations, from asymptomatic cyst – passer to colitis to fatal cerebral amebiasis.

• Cryptosporidium:

• - most common cause of chronic diarrhea in AIDS ,- contaminated water supply,

• Children, animal handlers , immunocompromised.

• Ingestion of oocysts, trophozoites attack intestinal membrane ,

• 1 week incubation , severe watery diarrhea , abdominal pain,

• Diagnosis, oocysts in stool.

• Rx , fluid replacement , parmomycin plus azithromycin.

• Diarrhea- bacterial :

• Toxigenic bacteria produce enterotoxins.

• - food – borne infections

• - diarrhea is watery and voluminous,

• - minor fever, no septicemia , no WBC OR RBC in stool.

• Eg: staph ,E . Coli (toxigenic) most common cause of traveler s diarrhea, Clostridium perfringens , vibrio cholera, rice watery diarrhea, Bacillus cereus , 2 forms -violent vomiting (much like staph) , diarrheal(much like clostridia).

• CONSTIPATION

■ DEFINITION

• Because of the wide range of normal bowel habits, constipation is difficult to define precisely.

• Most persons have at least three bowel movements per week;

• however, low stool frequency alone is not the sole criterion for the diagnosis of constipation.

• Many constipated patients have a normal frequency of defecation but complain of excessive straining, hard stools, lower abdominal fullness, or a sense of incomplete evacuation.

• A careful history should explore the patient’s symptoms • and confirm whether he or she is indeed constipated based on• frequency (e.g., fewer than three bowel movements per week),• consistency (lumpy/hard), • excessive straining, • prolonged defecation time,• or need to support the perineum or digitate the anorectum to facilitate

stool evacuation.

• An unexpected disorder such as megacolon may also be detected bycolonic radiographs.

• Measurement of serum calcium, potassium, and thyroid-stimulating hormone levels will identify rare patients with metabolic disorders.

• The presence of weight loss, rectal bleeding, or anemia withconstipation mandates either,

• flexible sigmoidoscopy plus barium enema ,

• or colonoscopy alone, particularly in patients aged >40 years,to exclude structural diseases such as cancer or strictures.

• Constipation of recent onset may be a symptom of significant organic disease such as , tumor, anorectal irritation, or stricture.

• In idiopathic constipation, a subset of patients exhibits delayed emptying of the ascending and transverse colon with prolongation of transit (often in the proximal colon) .

• Outlet obstruction to defecation (also called evacuation disorders),• accounts for about a quarter of cases presenting with constipation and

may cause delayed colonic transit, • which is usually corrected by biofeedback retraining of the disordered

defecation.