Download Acute Diarrhea

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Diarrhea -working definition is:
three or more loose or watery stools per day or
 definite decrease in consistency and increase in
frequency based upon an individual baseline
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 Acute
— ≤14 days in duration
 Persistent diarrhea — more than 14 days in
duration
 Chronic — more than 30 days in duration
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One of the five leading causes of death worldwide
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Most cases of acute diarrhea are due to infections
with viruses and bacteria and are self-limited.
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Noninfectious etiologies become more common as
the course of the diarrhea persists and becomes
chronic.
Noninfectious causes of diarrhea include :
drugs,
food allergies,
primary gastrointestinal diseases such as
inflammatory bowel disease, and
other disease states such as thyrotoxicosis and the
carcinoid syndrome.
Most
cases of acute infectious gastroenteritis are probably
viral,
In contrast, bacterial causes are responsible for most
cases of severe diarrhea
careful
history
Duration of symptoms
 Frequency and characteristics of the stool
 Complete past medical history (identify
immunocompromised host)
 Important to ask about recent antibiotic use
 A food history may also provide clues to a
diagnosis:
 Within 6 hr
Staphylococcus aureus or
Bacillus cereus
 Within 8 to 16 hr
Clostridium perfringens
 More than 16 hr
viral or bacterial infection (
enterotoxigenic or enterohemorrhagic E. coli).
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 Physical
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examination:
fever, which suggests infection with :
invasive bacteria (Salmonella, Shigella,
Campylobacter)
 Enteric viruses, or
 Cytotoxic organism such as Clostridium
difficile or Entamoeba histolytica
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Evidence of extracellular volume
depletion (eg, decreased skin turgor,
orthostatic hypotension
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E.coli O157:H7 (Most common)
Less common bacterial causes :
Shigella,
Campylobacter,
Salmonella species
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Sensitivity and specificity ranging from 20 to 90
percent
Because of these concerns about test
performance, the role of testing for fecal
leukocytes has been questioned .
However, the presence of occult blood and fecal
leukocytes supports the diagnosis of a bacterial
cause of diarrhea
Uptoate:
we perform this examination in addition to
obtaining a bacterial culture in high risk
patients.
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Lactoferrin is a marker for fecal leukocytes,
but its measurement is more precise
sensitivity and specificity ranging from 90
to100 percent in distinguishing inflammatory
diarrhea (eg, bacterial colitis or inflammatory
bowel disease) from noninflammatory causes
(eg, viral colitis, irritable bowel syndrome)
low rate of positive stool cultures in most
reports (1.5 to 5.6 percent)
most infectious causes of acute
diarrhea are self-limited
it is reasonable to continue symptomatic therapy
for
several days before considering further
evaluation
we recommend obtaining stool cultures on initial
presentation in the following groups of patients:
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Immunocompromised patients, including those
infected with HIV
Patients with comorbidities that increase the risk
for complications
Patients with more severe, inflammatory diarrhea
(including bloody diarrhea)
Patients with underlying inflammatory bowel
disease in whom the distinction between a flare
and superimposed infection is critical
Some employees, such as food handlers
Persistent diarrhea (associated with Giardia,
Cryptosporidium,and Entamoeba histolytica)
 Persistent diarrhea with exposure to infants in
daycare centers(associated with Giardia and
Cryptosporidium)
 Diarrhea in a man who has sex with men (MSM) or
a patient with AIDS (associated with Giardia and
Entamoeba histolytica in the former, and a variety
of parasites in the latter).
 A community waterborne outbreak (associated
with Giardia and Cryptosporidium)
 Bloody diarrhea with few or no fecal leukocytes
(associated with intestinal amebiasis)
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Three specimens should be sent on consecutive days (or
each specimen separated by at least 24 hours)
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Begins with general measures such as hydration
and alteration of diet.
Antibiotic therapy is not required in most cases
since the illness is usually self-limited.
Oral rehydration solutions:
Oral rehydration solutions were developed
following the realization that, in many small
bowel diarrheal illnesses, intestinal glucose
absorption via sodium-glucose cotransport
remains intact.
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The composition of the oral rehydration
solution (per liter of water) recommended by
the World Health Organization consists of:
3.5 g sodium chloride
 2.9 g trisodium citrate or 2.5
g sodium bicarbonate
 1.5 g potassium chloride
 20 g glucose or 40 g sucrose
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Those with moderate to severe travelers' diarrhea as
characterized by more than four unformed stools daily,
fever, blood, pus, or mucus in the stool.
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Those with more than eight stools per day
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volume depletion
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symptoms for more than one week
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those in whom hospitalization is being considered
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Immunocompromised hosts
Signs and symptoms of bacterial diarrhea such as fever,
bloody diarrhea (except for suspected EHEC or C. difficile
infection
Presence of occult blood or fecal leukocytes in the stool.
empiric therapy:
 An oral fluoroquinolone ( ciprofloxacin
500 mg twice daily, norfloxacin 400 mg
twice daily, or levofloxacin 500 mg once
daily) for three to five days in the absence
of suspected EHEC or fluoroquinoloneresistant campylobacter infection
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 Azithromycin
(500 mg PO once daily for
three days) or erythromycin (500 mg PO
twice daily for five days) are alternative
agents if fluoroquinolone resistance is
suspected
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The benefit of specific dietary recommendations other than
oral hydration has not been well-established in controlled
trials.
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Adequate nutrition during an episode of acute diarrhea is
important to facilitate enterocyte renewal
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Boiled starches and cereals (eg, potatoes, noodles, rice, wheat,
and oat) with salt are indicated in patients with watery diarrhea;
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crackers, bananas, soup, and boiled vegetables may also be
consumed
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Foods with high fat content should also be avoided
In addition, secondary lactose malabsorption is common
following infectious enteritis and may last for several weeks to
months. Thus, temporary avoidance of lactose-containing foods
may be reasonable
 Chronic
diarrhea affects approximately 5 percent
of the population
The principal causes of diarrhea depend upon the
socioeconomic status of the population.
 In developing countries, chronic diarrhea is frequently
caused by:
 chronic bacterial, mycobacterial and parasitic
infections, although functional disorders,
malabsorption, and inflammatory bowel disease are
also common.
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 In
developed countries, common causes are :
 irritable bowel syndrome (IBS), inflammatory bowel
disease, malabsorption syndromes (such as lactose
intolerance and celiac disease), and chronic infections
(particularly in patients who are
immunocompromised).
 Optimal
strategies for the evaluation of patients
with chronic diarrhea have not been established
 Recommendations have been derived mostly
from expert opinion and from experience
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selection of specific tests, timing of referral,
and the extent to which testing should be
performed depend upon an appraisal of the
likelihood of a specific diagnosis, the
availability of treatment, the severity of
symptoms, patient preference, and
comorbidities.
1) A clear understanding of what led the patient
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to complain of diarrhea(eg, consistency or
frequency of stools, the presence of urgency or
fecal soiling)
Stool characteristics (eg, greasy stools that float
and are malodorous may suggest fat
malabsorption while the presence of visible blood
may suggest inflammatory bowel disease)
Duration of symptoms, nature of onset (sudden
or gradual)
Travel history
Risk factors for HIV infection
Weight loss
7) Whether there is fecal incontinence (which
may be confused with diarrhea)
8) Occurrence of diarrhea during fasting or at
night (suggesting a secretory diarrhea)
9) Family history of IBD
10) The volume of the diarrhea (eg, voluminous
watery diarrhea is more likely to be due to a
disorder in the small bowel while small-volume
frequent diarrhea is more likely to be due to
disorders of the colon)
11) The presence of systemic symptoms, which
may indicate inflammatory bowel disease (such
as fevers, joint pains, mouth ulcers, eye redness)
12) All medications (including over-the-counter drugs
and supplements)
13) A relevant dietary (including possible use of sorbitolcontaining products and use of alcohol)
14) Association of symptoms with specific food
ingestion (such as dairy products or potential food
allergens)
15) A sexual history (anal intercourse is a risk factor for
infectious proctitis and promiscuous sexual activity is a
risk factor associated with HIV infection) ·
16) A history of recurrent bacterial infections (eg,
sinusitis, pneumonia),which may indicate a primary
immunoglobulin deficiency.
The physical examination rarely provides a specific
diagnosis.
 However, a number of findings can provide clues
These include:
1) findings suggestive of IBD (eg, mouth ulcers, a skin
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rash, episcleritis, an anal fissure or fistula,
2) the presence of visible or occult blood on digital
examination,
3) abdominal masses or abdominal pain
4) evidence of malabsorption (such as wasting,
physical signs of anemia, scars indicating prior
abdominal surgery)
5) Lymphadenopathy (possibly suggesting HIV
infection),
6) Abnormal anal sphincter pressure or reflexes
(possibly suggesting fecal incontinence)
7) Palpation of the thyroid and examination for
exophthalmos and lid retraction may provide
support for a diagnosis of hyperthyroidism.
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A large number of tests are available for
diagnosing specific causes of diarrhea
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There is no firm rule as to what testing should be
done.
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The history and physical examination may
point toward a specific diagnosis for which
testing may be indicated
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The minimum laboratory evaluation in most patients
should include :
a complete blood count and differential,
erythrocyte sedimentation rate,
thyroid function tests,
serum electrolytes,
total protein and albumin,
stool occult blood
most patients require some form of endoscopic
evaluation and mucosal biopsy (either
sigmoidoscopy, colonoscopy, or sometimes upper
endoscopy), depending upon the clinical setting
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Another useful way to guide specific testing is to
attempt to categorize diarrhea as:
watery diarrhea(secretory or osmotic)
fatty diarrhea
inflammatory diarrhea
 continues
despite fasting
 is associated with stool volumes >1 liter/day
 occurs day and night (in contrast to osmotic
diarrhea)
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Although usually unnecessary, the distinction
between an osmotic and a secretory diarrhea can
also be established by measuring stool
electrolytes and calculating an osmotic gap.
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(290 - 2 ({Na+} + {K+})
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An osmotic gap of >125 mOsm/kg suggests an
osmotic diarrhea
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while a gap of <50 mOsm/kg suggests a
secretory diarrhea
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Further testing in patients with secretory diarrhea
may include:
1)
stool cultures to exclude chronic
infection,
2)
imaging of the small and large bowel
3)
selective testing for secretagogues,
such as gastrin or vasoactive
intestinal polypeptide
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Further testing in patients with osmotic
diarrhea may be unnecessary if the osmotic
agent can be identified based upon the history.
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An example is inadvertent ingestion of sorbitol
(such as in sugarless candies) or lactose in
patients who have lactose intolerance.
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Temporary avoidance of lactose-containing foods
can help establish the diagnosis of lactose
intolerance in patients who were unaware of the
diagnosis.
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Testing the stool for laxatives may occasionally
be required if laxative abuse is suspected.
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Laxative abuse can be suggested by the
presence of melanosis coli on sigmoidoscopy
or colonoscopy.
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Inflammatory diarrhea should be suspected in
patients with:
clinical features suggesting inflammatory bowel
disease,
clinical features suggesting C. difficile infection
those at risk for opportunistic infections such as
tuberculosis
those with a travel history.
Serum markers of acute inflammation (such as the
sedimentation rate and C-reactive protein levels
fecal leukocytes and Fecal calprotectin
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Diagnosis can usually be established by:
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sigmoidoscopy or colonoscopy or
by analysis of stool specimens (ie, culture or
testing for C. difficile toxin).
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Fatty diarrhea (steatorrhea) should be suspected
in patients who report greasy, malodorous stools
and those who are at risk for fat malabsorption,
such as patients with chronic pancreatitis.
A variety of tests can be used to confirm the
diagnosis.
Currently, the gold standard for diagnosis of
steatorrhea is quantitative estimation of stool
fat.
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empiric therapy may be warranted in certain
situations:
◦ · When comorbidities limit diagnostic evaluation.
◦ · When a diagnosis is strongly suspected.
Examples include a daycare worker who develops
diarrhea after a known outbreak of Giardiasis
a patient who develops diarrhea following limited (<100
cm) ileal resection in whom bile acid malabsorption is
likely,
a patient with known recurrent bacterial overgrowth,
and an otherwise healthy patient with suspected lactose
intolerance
THE END
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Symptomatic therapy is indicated when the
diagnosis has been made but definitive treatment
is unavailable.
A variety of medications can help relieve
symptoms, including loperamide, anticholinergic
agents, and intraluminal adsorbents (such as
clays, activated charcoal, bismuth, fiber and bile
acid binding resins).