Approach to acute diarrhoea

Approach to Acute Diarrhea
PRESENTER:DR.ABHINAV KUMAR

DEFINITIONS
• Diarrhea is defined as the passage of loose or watery stools, typically
at least three times in a 24-hour period
• It reflects increased water content of the stool, whether due to
impaired water absorption and/or active water secretion by the
bowel.
Duration of symptoms:
• Acute — 14 days or fewer in duration
• Persistent diarrhea — more than 14 but fewer than 30 days in
duration

EPIDEMIOLOGY
• World Health Organization (WHO) and UNICEF, there are about two
billion cases of diarrheal disease worldwide every year
• 1.9 million children younger than 5 years of age perish from diarrhea
each year, mostly in developing countries.
• 18% of all the deaths of children under the age of five and means that
more than 5000 children are dying every day as a result of diarrheal
diseases.
• Of all child deaths from diarrhea, 78% occur in the African and South-
East Asian regions.

Resource-limited countries
• In a systematic review of 23 prospective studies of diarrheal disease
in individuals older than five years
• Diarrhea morbidity rates
• 30 episodes/100 person-years among adults in southeast Asia
• 88 episodes/100 person-years in the eastern Mediterranean region
• Rates had not changed substantially over 30 years

Risk factors
• Crowding and poor sanitation
• Contaminated food and water
• Direct contact with an infected individual may also contribute to
the spread of epidemic dysentery due to S. dysenteriae.

Acute watery diarrhea
• non-epidemic situation, enterotoxigenic E. coli is the most common
cause.
• epidemic disease, V. cholerae is endemic in approximately 50
countries in Asia, Africa, and Central and South America, where
predictable seasonal outbreaks occur.
• Norovirus, Campylobacter species, nontyphoidal
Salmonellae, Aeromonas species, and enteroaggregative E. coli are
other pathogens that can cause acute watery diarrhea.

Causative agents and pathogenic
mechanisms
Diarrheagenic Escherichia coli
• The distribution varies in different countries, but enterohemorrhagic E. coli
(EHEC, including E. coli O157:H7) causes disease more commonly in the
developed countries.
• Enterotoxigenic E. coli (ETEC) causes traveler’s diarrhea.
• Enteropathogenic E. coli (EPEC) rarely causes disease in adults.
• Enteroinvasive E. coli (EIEC) causes bloody mucoid (dysentery) diarrhea;
fever is common.
• Enterohemorrhagic E. coli (EHEC) causes bloody diarrhea, severe
hemorrhagic colitis, and the hemolytic uremic syndrome in 6–8% of cases;
cattle are the predominant reservoir of infection.

Diarrheagenic Escherichia coli
• Pediatric details. Nearly all types cause disease in children in the
developing world:
– Enteroaggregative E. coli (EAggEC) causes watery diarrhea in
young children and persistent diarrhea in children with human
immunodeficiency virus (HIV).
– Enterotoxigenic E. coli (ETEC) causes diarrhea in infants and
children in developing countries.
– Enteropathogenic E. coli (EPEC) causes disease more commonly in
children < 2 years, and persistent diarrhea in children.
– * EIEC and EHEC are not found (or have a very low prevalence) in
some developing countries.

Campylobacter
– Asymptomatic infectionvery common in developing countries and
is associated with the presence of cattle close to dwellings.
– Infection is associated with watery diarrhea; sometimes dysentery.
– Guillain–Barré syndrome 1 in 1000 of people with Campylobacter
colitis; it is thought to trigger about 20–40% of all cases of Guillain–
Barré syndrome.
– Poultry is an important source of Campylobacter infections in
developed countries, and increasingly in developing countries, where
poultry is proliferating rapidly.
– The presence of an animal in the cooking area is a risk factor in
developing countries.

Pediatrics
• Campylobacter is one of the most frequently isolated bacteria from
the feces of infants and children in developing countries
• peak isolation rates in children 2 years of age and younger.

Vibrio cholerae:
– Many species of Vibrio cause diarrhea in developing countries.
– All serotypes (>2000) are pathogenic for humans.
– V. cholerae serogroups O1 and O139 are the only two serotypes
that cause severe cholera, and large outbreaks and epidemics.
– In the absence of prompt and adequate rehydration, severe
dehydration leading to hypovolemic shock and death can occur
within 12–18 h after the onset of the first symptom.
– Stools are watery, colorless, and flecked with mucus; often
referred to as “rice- watery” stools.

Vibrio cholerae
– Vomiting is common; fever is typically absent.
– There is a potential for epidemic spread; any infection
should be reported promptly to the public health
authorities.
–
Pediatric details. In children, hypoglycemia can lead to
convulsions and death.

Acute bloody diarrhea
• Shigella speciesS. flexneri most important
• Other causes in resource-limited settings include
• Campylobacter jejuni,
• enteroinvasive and
• enterohemorrhagic E. coli,
• nontyphoidal Salmonella species,
• Entamoeba histolytica,
• Schistosoma mansoni

Shigella species:
• Hypoglycemia, associated with very high case fatality rates (CFRs) (43% in
one study)
• S. sonnei is common in developed countries, causes mild illness, and may
cause institutional outbreaks.
• S. flexneri is endemic in many developing countries and causes dysenteric
symptoms and persistent illness; uncommon in developed countries.
• S. dysenteriae type 1 (Sd1) — the only serotype that produces Shiga toxin,
as does EHEC.
• epidemic serotypeCFRs can be as high as 10% in Asia, Africa
• For unexplained reasons, this serotype has not been isolated since the year
2000 in Bangladesh and India.

Pediatrics
• An estimated 160 million episodes occur in developing
countries, primarily in children. It is more common in toddlers
and older children than in infants.

CLINICAL FEATURES
Cholera
• A "rice-water" appearance of
stool flecked with mucous is
suggestive of cholera
• sudden vomiting and
abdominal cramping but not
frank pain or tenesmus.
• Fever is uncommon in cholera.
Shigellosis
• frequent passage of small liquid
stools that contain visible
blood, with or without mucous.
• Abdominal cramps and
tenesmus are common
• Fever and anorexia common
Diarrhea is the passage of loose stools, typically at least three times in 24
hr
Watery diarrhea  nonbloody
Dysentery  diarrhea with visible blood.

Salmonella:
– Enteric fever — Salmonella enterica serovar Typhi and Paratyphi A, B,
or C (typhoid fever)
– fever lasts for 3 weeks or longer; patients may have normal bowel
habits, constipation or diarrhea.
– Animals  Reservoir
– Humans only carriers
– In nontyphoidal salmonellosisacute onset of nausea, vomiting, and
diarrhea that may be watery or dysenteric in a small fraction of
cases.
– The elderly and people with immune-compromised status for any
reason appear to be at the greatest risk.

Pediatrics
• Infants and children with immune-compromised status for
any reason (e.g., severe malnourishment) appear to be at the
greatest risk.
• Fever develops in 70% of affected children.
• Bacteremia occurs in 1–5%, mostly in infants.

Viral agents
• In both industrialized and developing countries, viruses are the
predominant cause of acute diarrhea, particularly in the winter season.
• Rotavirus:
1/3rd diarrhea hospitalizations and 500,000 deaths worldwide each
year.
Associated with gastroenteritis of above-average severity
• Pediatric details:
– Leading cause of severe, dehydrating gastroenteritis among children.
– get infected by the time they are 3–5 years of age.
– Neonatal infections are common, but often asymptomatic.
– The incidence of clinical illness peaks in children between 4 and 23
months of age.

Viral agents
Human caliciviruses (HuCVs):
• Belong to the family Caliciviridae—the noroviruses and sapoviruses
(previously called “Norwalk-like viruses” and “Sapporo-like viruses.”
• Noroviruses are the most common cause of outbreaks of gastroenteritis,
affecting all age groups.
• Pediatrics Sapoviruses primarily affect children. This may be the second
most common viral agent after rotavirus, accounting for 4–19% episodes
in young children.
Adenovirus
• infections most commonly cause illnesses of the respiratory system.
• Pediatrics: depending on the infecting serotype, this virus may cause
gastroenteritis especially in children.

Parasitic agents
• Cryptosporidium parvum, Giardia intestinalis, Entamoeba histolytica,
and Cyclospora cayetanensis: these are uncommon in the developed
world and are usually restricted to travelers.
• Pediatrics. Most commonly cause acute diarrheal illness in children.
– Relatively small proportion of cases of infectious diarrheal illnesses
among children in developing countries.
– G. intestinalis has a low prevalence (approximately 2–5%) among
children in developed countries, but as high as 20–30% in developing
regions.
– Cryptosporidium and Cyclospora are common among children in
developing countries; frequently asymptomatic.

Overview of causative agents in diarrhea

Character of symptoms
Diarrhea of small bowel
• origin is typically watery,
of large volume, and
associated with
abdominal cramping,
bloating, and gas
• Weight loss can occur if
diarrhea becomes
persistent.
• Fever is rarely a
significant symptom and
occult blood or
inflammatory cells in the
stool are rarely identified
Diarrhea of large intestinal
• origin often presents
with frequent, regular,
small volume, and often
painful bowel
movements.
• Fever and bloody or
mucoid stools are
common, and red blood
cells and inflammatory
cells can be seen
routinely on stool
microscopy.

Medical history
• recent antibiotic useC. difficile infection
• PPI’sincrease the risk of infectious diarrhea),
• complete past medical history ( immunocompromised host or the
possibility of nosocomial infection)
• pregnancy increases the risk of listeriosis following infections of
contaminated meat products or unpasteurized dairy products
approximately 20-fold
• cirrhosis has been associated with Vibrio infection,
• hemochromatosis has been associated with Yersinia infection.

Linking the main symptoms to the causes of acute
diarrhea—enterohemorrhagic E. coli (EHEC)

Clinical features of infection with selected
diarrheal pathogens

Epidemiologic clues
• evaluating the incubation period,
• history of recent travel in relation to regional prevalence of different
pathogens,
• unusual food or eating circumstances,
• professional risks,
• recent use of antimicrobials,
• institutionalization,
• HIV infection risks.

Patient history details and causes of acute
diarrhea

Incubation period and likely causes of
diarrhea

Assessment of dehydration using the
“Dhaka method”

Laboratory evaluation
• For acute enteritis and colitis, maintaining adequate intravascular
volume and correcting fluid and electrolyte disturbances take priority
over identifying the causative agent.
• Presence of visible blood in febrile patientsinvasive pathogens,
such as Shigella, Campylobacter jejuni, Salmonella, or Entamoeba
histolytica.
• Stool cultures are usually unnecessary for immune-competent
patients who present with watery diarrhea, but may be necessary to
identify Vibrio cholerae

• Numerous fecal leukocytes, suggesting an invasive bacterial infection.
• Microscopic evidence of Entamoeba trophozoites containing red blood
cells provides sufficient basis for treating for amoebic dysentery instead
of shigellosis
• Notably, finding cysts or trophozoites without red blood cells in a bloody
stool does not indicate that Entamoeba is the cause of illness, since
asymptomatic infection is frequent among healthy persons in resource-
limited countries.
• Cholera can be diagnosed using dark field microscopy, in which motile
Vibrios appear as "shooting stars."

General laboratory tests
• Not routinely warranted for most patients with acute diarrhea
• Substantial volume depletionserum electrolyteshypokalemia or
renal dysfunction
• Complete blood count does not reliably distinguish bacterial
etiologies
• A low platelet counthemolytic-uremic syndrome
• Leukemoid reaction is consistentC. difficile infection
• Blood cultures should be obtained in patients with high fevers or who
appear systemically ill.

Patient details and bacterial testing

Pediatrics
• Identification of a pathogenic bacterium, virus, or parasite in a stool
specimen from a child with diarrhea does not indicate in all cases that it
is the cause of illness.
• Serum electrolytes
• Hypernatremic dehydration is more common in well- nourished children
and those infected with rotavirus
• features irritability, increased thirst disproportionate to clinical
dehydration, and a doughy feel to the skin.
• Requires specific rehydration methods.

Stool cultures
Indications
Severe illness
• profuse watery diarrhea with signs of hypovolemia
• passage of ≥6 unformed stools per 24 hours
• severe abdominal pain
• need for hospitalization
Other signs or symptoms concerning for inflammatory diarrhea
• bloody diarrhea
• passage of many small volume stools containing blood and mucus
• temperature ≥38.5ºC (101.3ºF)

High-risk host features
• age ≥70 years
• comorbidities, such as cardiac disease, which may be exacerbated by
hypovolemia or rapid infusion of fluid
• immunocompromising condition (including advanced HIV infection)
• inflammatory bowel disease
• Pregnancy
Symptoms persisting for more than one week
Public health concerns (eg, diarrheal illness in food handlers,
healthcare workers, and individuals in day care centers)

Performance
• A routine stool culture will identify
Salmonella,
Campylobacter,
Shigella
• E. coli O157:H7 can be isolated on sorbitol-MacConkey plates or
identified with antigen testing or polymerase chain reaction of stool.

• Culture for Campylobacterroutinely done by clinical laboratories.
• Aeromonas and most strains of Yersinia are possible pathogens (eg,
travelers’ diarrhea or foodborne outbreaks, especially in infants), the
laboratory needs to be notified
• Gastroenteritis due to Listeria should be considered in outbreaks of
febrile gastroenteritis with non-bloody diarrhea if routine cultures
are negative.
• Bacterial pathogens are generally excreted continuously, in contrast
to ova and parasites, which are often shed intermittently. Thus, a
negative culture is usually not a false negative, and repeat specimens
are rarely required.

Isolation of Vibrio species from stool
• suspected in seafood
• shellfish-associated disease,
• patients with cirrhosis,
• patients with profuse watery diarrhea,
• patients who have traveled to a country with ongoing cholera
transmission
• requires a selective media, such as thiosulfate, citrate, bile salts, and
sucrose, to suppress growth of other organisms.

Additional testing in specific circumstances
Bloody diarrhea
• potential pathogens, EHEC and Entamoeba
• bloody stools for Shiga toxin and fecal leukocytes or lactoferrin
• if the fecal leukocyte/lactoferrin test is negative test for amebiasis
• Bloody diarrhea can also be caused by intestinal amebiasis,
particularly in extended (>1 month) travelers to or migrants from
areas of the world where this infection is endemic

• Although the utility of fecal leukocytes in the evaluation of acute
diarrhea in general is limited because variability of performance of
this test
• the presence of bloody diarrhea in the absence of fecal leukocytes is
suggestive of amebiasis, as these organisms destroy leukocytes.
• fecal lactoferrin test is an agglutination assay that is also a marker for
fecal leukocytes but may have greater accuracy because of fewer
issues with user variability

• Noninfectious etiologies
• ischemic colitis
• inflammatory bowel disease,
• Risk factors for colonic ischemia  computed tomography &
endoscopy
• Endoscopy can be useful to evaluate patients with bloody diarrhea
for inflammatory bowel disease if their symptoms do not resolve.

Immunocompromised patients
• CD4 cell count <200 cells/microL or other AIDS-defining condition
culture as well as parasitic testing
• For patients who have concern for possible CMV infection (eg, HIV
patients with CD4 cell count <50 cells/microL, transplant recipients),
endoscopy with biopsy is the best diagnostic approach.
• Neutropenic enterocolitis in patients with severe neutropenia
(absolute neutrophil count <500 cells/microL) can present with
diarrhea in addition to fever and abdominal pain. Imaging with
computed tomography is warranted in such settings.

Men who have sex with men
• Receptive anal or oral-anal intercourse increases the risk of direct
inoculation or fecal-oral transmission of bacterial and parasitic
pathogens (in particular, Shigella, Giardia or E. histolytica)
• Microscopy for ova and parasites (three specimens on consecutive
days),
• antigen testing
• molecular methods

• Acute diarrhea in MSM can also be a manifestation of proctitis,
• sexually transmitted infections (chlamydia, gonorrhea, syphilis,
herpes simplex virus).
• Anoscopy can identify anorectal discharge or rectal mucosal friability,
which are suggestive of proctitis.
• Testing for these sexually transmitted infections and empiric
treatment for chlamydia and gonorrhea may be warranted in addition
to stool culture.

Indications for imaging
• Abdominal imaging is not typically warranted in patients with acute
diarrhea.
• Significant peritoneal signs or ileus, abdominal imaging (most
typically computed tomography) can be important to identify
potential complications
bowel perforation,
abscess,
fulminant colitis,
toxic megacolon,
intestinal obstruction.

Differential diagnosis of acute diarrhea in
children:
• Pneumonia—may occur together with diarrhea in developing
countries
• Otitis media
• Urinary tract infection
• Bacterial sepsis
• Meningitis

Prognostic factors in children

Treatment options and prevention
• Oral rehydration therapy (ORT) is the administration of appropriate
solutions by mouth to prevent or correct diarrheal dehydration
• Global ORS coverage rates are still less than 50%
ORT consists of:
• Rehydration—water and electrolytes are administered to replace
losses.
•
• Maintenance fluid therapy to take care of ongoing losses once
rehydration is achieved (along with appropriate nutrition).

ORS
• The new lower-osmolarity ORS has reduced concentrations of sodium
and glucose and is associated with less vomiting, less stool output,
lesser chance of hypernatremia, and a reduced need for intravenous
infusions in comparison with standard ORS

ORT
ORT is contraindicated
• initial management of severe dehydration
• children with paralytic ileus, frequent and persistent vomiting (more
than four episodes per hour)
• painful oral conditions such as moderate to severe thrush (oral
candidiasis).
• nasogastric administration of ORS solution is potentially life- saving
when intravenous rehydration is not possible and the patient is being
transported to a facility where such therapy can be administered.

Supplemental zinc therapy, multivitamins,
and minerals in children
• Zinc deficiency is widespread among children in developing countries.
• Routine zinc therapyadjunct to ORT
• Importantly reduce diarrhea episodes in children in developing
countries.
• Recommendation for all children with diarrhea is 20 mg of zinc per
day for 10 days.
• Infants aged 2 months or younger should receive 10 mg per day for
10 days.

Dietary recommendations
• adequate nutrition to facilitate enterocyte renewal.
• if patients are anorectic or have nausea and vomiting, a short period
of consuming only liquids will not be harmful.
• Boiled starches and cereals (eg, potatoes, noodles, rice, wheat, and
oat) with salt are indicated in patients with watery diarrhea,bananas,
soup, and boiled vegetables may also be consumed
• Foods with high fat content should be avoided until the gut function
returns to normal after a severe bout of diarrhea.
• Dairy products (except yogurt) may be difficult to digest  secondary
lactose malabsorption, which is common following infectious
enteritis and may last for several weeks to months.

TREATMENT
• Adequate fluid and electrolyte replacement and maintenance are
essential to the management of diarrheal illness.
• Antimicrobials are not routinely warranted, but they do play a role in
the treatment of bloody diarrhea and during diarrheal outbreaks.

Rehydration
• Fluid management, including the type and quantity of fluids to
administer, in an adult patient with diarrhea depends on the level of
volume depletion

None to moderate hypovolemia
• An improved, reduced osmolarity ORS solution,
• 75 mEq/L of sodium
• 75 mmol/L of glucose
• This reduced osmolarity solution reduces the need for
supplemental IV fluid therapy by 33 percent compared with the
previous standard WHO ORS solution

Severe hypovolemia
• Adults with severe hypovolemia should receive intravenous fluids
• Ringer’s lactate or Ringer’s lactate with 5 percent dextrose are
preferred, but normal saline can also be used.
• Normal saline is less preferable because it does not contain
potassium to replace losses nor a base to correct acidosis.

Antibiotic therapy
Watery diarrhea
• not typically indicated
• most cases resolve spontaneously
• important exception is the treatment of severe cholera in outbreak
settings
Dysentery
• with bloody diarrhea should be treated promptly with an
antimicrobial that is effective against Shigella.

Antimicrobial agents for the treatment of
specific causes of diarrhea

Approach to empiric therapy and diagnostic-directed
management of the adult patient with acute diarrhea

Empiric antibiotic therapy
• Severe disease (fever, more than six stools per day, volume depletion
warranting hospitalization)
• Features suggestive of invasive bacterial infection (bloody or mucoid
stools)
• Host factors that increase the risk for complications, including age
>70 years old and comorbidities such as cardiac disease and
immunocompromising conditions
• Prolonged disease (more than one week) that has not improved with
conservative measures
• Public health concerns (such as diarrheal illness in food handlers,
health care workers, and individuals in day care centers)

Efficacy
• Beneficial by reducing the duration of symptoms
by one to two days

Antimicrobial resistance
• due to the misuse and overuse of antibiotics in the treatment of
diarrheal diseases
• A recent study of diarrheal stool samples in rural western Kenya
determined that most persons had been treated with an
antimicrobial to which their isolate was resistant

Nonspecific antidiarrheal agents

Probiotics
• Lactobacillus GG has been shown to decrease duration of childhood
infectious diarrhea
• Saccharomyces boulardii may be effective in decreasing the duration
of C. difficile infection.
• Little value in taking probiotics at the same time as antibiotics.

Approach to acute diarrhoea

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