Ahmad Hormati - PowerPoint Presentation

Slide1

Ahmad

Hormati

Assistant Professor of Gastroenterology

Qom University of Medical Sciences.

Email:

hormatia@yahoo.com

http://hormatigi.ir/

Slide2

Approach to Diarrhea

Slide3

Acute Diarrhea

Slide4

Definitions

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

Acute

— ≤14 days in duration

Persistent diarrhea

— more than 14 days in duration

Chronic

— more than 30 days in duration

Slide5

Introduction

One of the five leading causes of death worldwide

Most cases

of acute diarrhea are due to

infections

with

viruses

and

bacteria

and are self-limited.

Noninfectious etiologies

become more common as the course of the diarrhea persists and becomes chronic. Noninfectious causes of diarrhea include

drug

s,

food allergies

, primary gastrointestinal diseases such as

inflammatory bowel disease

, and other disease states such as

thyrotoxicosis

and the

carcinoid

syndrome

.

Slide6

Most cases of acute infectious gastroenteritis are probably viral,

In contrast, bacterial causes are responsible for most cases of severe diarrhea

Slide7

DIAGNOSTIC APPROACH

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).

Slide8

Physical examination:

fever

, which suggests infection with :

invasive bacteria (Salmonella,

Shigella

, Campylobacter)

Enteric viruses, or

Cytotoxic

organism such as Clostridium

difficile

or

Entamoeba

histolytica

Evidence of

extracellular

volume depletion

(

eg

, decreased skin

turgor

, orthostatic hypotension

Slide9

Bloody diarrhea

E.coli

O157:H7 (Most common)

Less common bacterial causes :

Shigella

,

Campylobacter,

Salmonella species

Slide10

Fecal leukocytes and occult blood

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.

Slide11

Lactoferrin

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)

Slide12

When to obtain stool cultures

Slide13

When to obtain stool cultures

we recommend obtaining stool cultures on initial presentation in the following groups of patients:

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

Slide14

When to obtain stool for ova and parasites

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

)

Three specimens should be sent on consecutive days (or each specimen separated by at least 24 hours

)

Slide15

TREATMENT

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.

Slide16

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

Slide17

Enterohemorrhagic

E. coli

Antibiotics should be avoided

in patients with

suspected

or

proven

infection with

enterohemorrhagic

E. coli (EHEC).

why

There is no evidence of benefit from antibiotic therapy for EHEC infection

there is concern about an increase in the risk of hemolytic-

uremic

syndrome that might be mediated by an increase in the production or release of Shiga toxin when antibiotics are administered

EHEC infection should be suspected in patients with

bloody diarrhea

,

abdominal pain and tenderness

, but

little or no fever

.

Slide18

Clostridium

difficile

Patients with acute diarrhea should be questioned carefully about prior antibiotic therapy and other risk factors for C.

difficile

infection.

The appropriate therapy for this infection is:

Discontinuation of antibiotics, if possible,

Consideration of

metronidazole

or

vancomycin

if the symptoms are more than mild or worsen or persist

Slide19

When to treat

Those with moderate to severe travelers' diarrhea

as characterized by more than four unformed stools daily, fever, blood, pus, or mucus in the stool.

Those

with more than eight stools per day

volume depletion

symptoms for

more than one week

those in whom

hospitalization is being considered

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.

Slide20

Empiric antibiotic therapy

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

fluoroquinolone

-resistant campylobacter infection

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

Slide21

Symptomatic therapy

The

antimotility

agent

loperamide

(Imodium) may be used in patients with acute diarrhea in whom fever is absent or low grade and the stools are not bloody

The dose of

loperamide

is two tablets (4 mg) initially, then 2 mg after each unformed stool, not to exceed 16 mg/day for ≤2 days.

Diphenoxylat

e

has central opiate effects and may cause cholinergic side effects

Slide22

Symptomatic therapy

patients should be cautioned that treatment with these agents may mask the amount of fluid lost, since fluid may pool in the intestine.

Thus, fluids should be used aggressively when

antimotility

agents are employed.

Another potential problem is that both drugs may facilitate the development of the hemolytic-

uremic

syndrome (HUS) in patients infected with EHEC

Slide23

Symptomatic therapy

Bismuth

subsalicylate

(Pepto-Bismol) has also been used for symptomatic treatment of acute diarrhea.

compared with placebo, bismuth

subsalicylate

is significantly better but compared with

loperamide

,

loperamide

is better

A role for bismuth

subsalicylate

may be in patients with

significant fever and dysentery, conditions in which

loperamide

should be avoided

.

Two tablets every 30 minutes for eight doses

Slide24

Probiotics

Probiotics

, including bacteria that assist in

recolonizing

the intestine with non-pathogenic flora, can also be used as alternative therapy.

Probiotics

is useful in treating

traveler's diarrhea

diarrhea and

acute non-specific diarrhea in children

.

Slide25

Dietary recommendations

The benefit of specific dietary recommendations other than oral hydration has not been well-established in controlled trials.

Adequate nutrition during an episode of acute diarrhea is important to facilitate

enterocyte

renewal

Boiled starches and cereals (

eg

, potatoes, noodles, rice, wheat, and oat) with salt are indicated in patients with watery diarrhea;

crackers, bananas, soup, and boiled vegetables may also be consumed

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

Slide26

Chronic Diarrhea

Slide27

EPIDEMIOLOGY

Chronic diarrhea affects approximately 5 percent of the population

More than $350,000,000 annually from work-loss alone

Slide28

ETIOLOGY

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.

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

).

Slide29

EVALUATION

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

The 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

.

Slide30

History

A clear understanding of what led the patient 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

Slide31

History

Whether there is fecal incontinence (which may be confused with diarrhea)

Occurrence of diarrhea during fasting or at night (suggesting a

secretory

diarrhea)

Family history of IBD

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)

The presence of systemic symptoms, which may indicate inflammatory bowel disease (such as fevers, joint pains, mouth ulcers, eye redness)

Slide32

History

All medications (including over-the-counter drugs and supplements)

A relevant dietary (including possible use of

sorbitol

-containing products and use of alcohol)

Association of symptoms with specific food ingestion (such as dairy products or potential food allergens)

A sexual history (anal intercourse is a risk factor for infectious

proctitis

and promiscuous sexual activity is a risk factor associated with HIV infection) ·

A history of recurrent bacterial infections (

eg

, sinusitis, pneumonia),which may indicate a primary immunoglobulin deficiency.

Slide33

Slide34

Physical examination

The physical examination rarely provides a specific diagnosis. However, a number of findings can provide clues These include:

findings suggestive of IBD (

eg

, mouth ulcers, a skin rash,

episcleritis

, an anal fissure or fistula,

the presence of visible or occult blood on digital examination,

abdominal masses or abdominal pain

Slide35

evidence of

malabsorption

(such as wasting, physical signs of anemia, scars indicating prior abdominal surgery)

Lymphadenopathy

(possibly suggesting HIV infection),

Abnormal anal sphincter pressure or reflexes (possibly suggesting fecal incontinence)

Palpation of the thyroid and examination for

exophthalmos

and lid retraction may provide support for a diagnosis of hyperthyroidism

.

Slide36

laboratory evaluation

A large number of tests are available for diagnosing specific causes of diarrhea

There is no firm rule as to what testing should be done.

The history and physical examination may point toward a specific diagnosis for which testing may be indicated

Slide37

laboratory evaluation

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, and stool occult blood

mos

t patients require some form of

endoscopic

evaluation and mucosal biopsy

(either

sigmoidoscopy

, colonoscopy, or sometimes upper

endoscopy

), depending upon the clinical setting

Slide38

Slide39

Another useful way to guide specific testing is to attempt to categorize diarrhea as:

watery diarrhea(

secretory

or osmotic)

fatty diarrhea

inflammatory diarrhea

Slide40

Slide41

Secretory

diarrhea

continues despite fasting

is associated with stool volumes >1 liter/day

occurs day and night (in contrast to osmotic diarrhea)

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.

Slide42

osmotic gap

(290 - 2 ({Na+} + {K+})

An osmotic gap of >125

mOsm

/kg suggests an osmotic diarrhea

while a gap of <50

mOsm

/kg suggests a

secretory

diarrhea

Slide43

Further testing in patients with

secretory

diarrhea may include:

stool cultures to exclude chronic infection,

imaging of the small and large bowel

selective testing for

secretagogues

, such as

gastrin

or

vasoactive

intestinal polypeptide

Slide44

Slide45

osmotic diarrhea

Further testing in patients with osmotic diarrhea may be unnecessary if the osmotic agent can be identified based upon the history.

An example is inadvertent ingestion of

sorbitol

(such as in sugarless candies) or lactose in patients who have lactose intolerance.

Temporary avoidance of lactose-containing foods can help establish the diagnosis of lactose intolerance in patients who were unaware of the diagnosis.

Slide46

Testing the stool for laxatives may occasionally be required if laxative abuse is suspected.

Laxative abuse can be suggested by the presence of

melanosis

coli on

sigmoidoscopy

or colonoscopy.

Slide47

Slide48

Inflammatory diarrhea

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

Slide49

Inflammatory diarrhea

Diagnosis can usually be established by:

sigmoidoscopy

or colonoscopy or

by analysis of stool specimens (

ie

, culture or testing for C.

difficile

toxin).

Slide50

Slide51

Fatty diarrhea

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

.

Slide52

Slide53

empiric therapy

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

Slide54

DEFINITION

Watery Diarrhea: 3 or more liquid or watery stools in 24 h

Dysentery: Presence of blood and/or mucus in stools

Persistent Diarrhea: Diarrhea lasting for 14 days or more

Slide55

TYPES OF DIARRHEA

Slide56

COMMON CAUSES OF DIARRHEA- BACTERIA

Vibrio cholera

Shigella

Escherichia coli

Salmonella

Campylobacter jejuni

Yersinia enterocolitica

Staphylococcus

Vibrio parahemolyticus

Clostridium difficile

Slide57

COMMON CAUSES OF DIARRHEA- VIRUS

Rotavirus

Adenoviruses

Caliciviruses

Astroviruses

Norwalk agents and Norwalk-like viruses

Slide58

COMMON CAUSES OF DIARRHEA- PARASITE

Entameba histolytica

Giardia lamblia

Cryptosporidium

Isospora

Slide59

COMMON CAUSES OF DIARRHEA-OTHERS

Metabolic disease

Hyperthyroidism

Diabetes mellitus

Pancreatic insufficiency

Food allergy

Lactose intolerance

Antibiotics

Irritable bowel syndrome

Slide60

TRANSMISSION

Most of the diarrheal agents are transmitted by the fecal-oral route

Some viruses (such as rotavirus) can be transmitted through air

Nosocommial transmission is possible

Shigella

(the bacteria causing dysentery) is mainly transmitted person-to-person

Slide61

SEASONALITY

Slide62

PERSON-AT-RISK

Cholera: 2 years and above, uncommon in very young infants

Shigellosis: more common in young children aged below 5 years

Rotavirus diarrhea: more common in young infants and children aged 1-2 years

E. coli

diarrhea: can occur at any age

Amebiasis: more common among adults

Slide63

TYPES OF

VIBRIO CHOLERA

Two major biotypes of

Vibrio cholera

that cause diarrhea are:

Classical

ElTor

Two common serotypes of

Vibrio cholera

that cause diarrhea are:

Inaba

Ogawa

Slide64

Vibrio cholerae

O139

Vibrio cholerae

in O-group 139 was first isolated in 1992 and by 1993 had been found throughout the Indian subcontinent. This epidemic expansion probably resulted from a single source after a lateral gene transfer (LGT) event that changed the serotype of an epidemic

V. cholerae

O1 El Tor strain to O139.

More information:

http://www.cdc.gov/ncidod/EID/vol9no7/02-0760.htm

Slide65

Vibrio vulnificus

The organism

Vibrio vulnificus

causes wound infections, gastroenteritis or a serious syndrome known as "primary septicema." 

V. vulnificus

infections are either transmitted to humans through open wounds in contact with seawater or through consumption of certain improperly cooked or raw shellfish.

This bacterium has been isolated from water, sediment, plankton and shellfish (oysters, clams and crabs) located in the Gulf of Mexico, the Atlantic Coast as far north as Cape Cod and the entire U.S. West Coast. 

Cases of illness have also been associated with brackish lakes in New Mexico and Oklahoma.

For more information:

http://hgic.clemson.edu/factsheets/HGIC3663.htm

Slide66

TYPES OF

SHIGELLA

The major serotypes of Shigella that cause diarrhea are:

Dysenteriae type 1 or

Shigella shiga

Shigella flexneri

Shigella sonnei

Shigella boydii

Slide67

TYPES OF

E. COLI

Six major types of

Escherichia coli

cause diarrhea

:

Enterotoxigenic

E. coli

(ETEC)

Enteroinvasive

E. coli

(EIEC)

Enteropathogenic

E. coli

(EPEC)

Enterohemorrhagic

E. coli

(

E. coli

O157:H7)

Enteroaggregative

E. coli

(EAggEC)

Diffuse adherent

E. coli

(DAEC)

Slide68

CLINICAL FEATURE: CHOLERA

Rice-watery stool

Marked dehydration

Projectile vomiting

No fever or abdominal pain

Muscle cramps

Hypovolemic shock

Scanty urine

Slide69

CLINICAL FEATURE:

E. COLI DIARRHEA

Watery stools

Vomiting is common

Dehydration moderate to severe

Fever

–

often of moderate grade

Mild abdominal pain

Slide70

CLINICAL FEATURE:

ROTAVIRUS DIARRHEA

Insidious onset

Prodromal symptoms, including fever, cough, and vomiting precede diarrhea

Stools are watery or semi-liquid; the color is greenish or yellowish

–

typically looks like yoghurt mixed in water

Mild to moderate dehydration

Fever

–

moderate grade

Slide71

CLINICAL FEATURE:

SHIGELLOSIS

Frequent passage of scanty amount of stools, mostly mixed with blood and mucus

Moderate to high grade fever

Severe abdominal cramps

Tenesmus

–

pain around anus during defecation

Usually no dehydration

Slide72

CLINICAL FEATURE:

AMEBIASIS

Offensive and bulky stools containing mostly mucus and sometimes blood

Lower abdominal cramp

Mild grade fever

No dehydration

Slide73

LABORATORY DIAGNOSIS

Stool microscopy

Dark field microscopy of stool for cholera

Stool cultures

ELISA for rotavirus

Immunoassays, bioassays or DNA probe tests to identify

E. coli

strains

Slide74

ASSESSMENT OF DEHYDRATION

Slide75

ASSESSMENT OF DEHYDRATION (contd.)

Slide76

ASSESSMENT OF DEHYDRATION (contd.)

Slide77

TREATMENT

Rehydration

–

replace the loss of fluid and electrolytes

Antibiotics

–

according to the type of pathogens

Start food as soon as possible

Slide78

COMPOSITION OF ORS

Slide79

AMOUNT OF SALT LOSS DURING DIARRHEA

Slide80

ANTIMICROBIAL AGENTS

Slide81

COMPLICATIONS:

WATERY DIARRHEA

Dehydration

Electrolyte imbalances

Tetany

Convulsions

Hypoglycemia

Renal failure

Slide82

COMPLICATIONS:

DYSENTERY

Electrolyte imbalances

Convulsions

Hemolytic uremic syndrome (HUS)

Leukemoid reaction

Toxic megacolon

Protein losing enteropathy

Arthritis

Perforation

Slide83

VACCINES

An oral cholera vaccine is available, which gives immunity to 50-60% of those who take the vaccine, and this immunity lasts only a few months.

No vaccines are available against shigellosis

A vaccine against rotavirus diarrhea has been withdrawn recently from the market.

Slide84

PREVENTION

Safe drinking water and food

“Boil it, cook it, peel it, or forget it. "

Hand washing

Proper sanitation

Slide85

Thank You