Allah

Gastroenteritis

Definition of Gastroenteritis

It is a clinical syndrome caused by a variety of pathogenes.

It is Diarrheal disease of children. Commonly affecting children under five years of age, with a peak of incidence in those under 2 years.(maximum incidence from 6 months- 12 m.).

WHO classification of diarrhea according to its onset

A- Acute [ < 14 days as in gastroentritis]

Persistent > or= 14 daysChronic : if recurrent or long

lasting .

Characteristics of acute diarrhea versus persistent diarrhea

Acute diarrhea Sudden onset

Usually self limited [within 3-5 days] unless child dies from dehydration.

Persistent diarrhea May be sudden or

insidious but stool [frequency & characteristics] vary from day to day.

May lead to permanently impaired growth or even death.

Acute diarrhea versus persistent diarrhea

Most often caused by pathogenic organisms.

Children 1 to 30 months are more susceptible.

May initially be related to a specific organism but, intestinal damage, malabsorption and other bacteria keep it going.

Malnourished children are more susceptible.

Acute diarrhea versus persistent diarrhea

Fever and/ or vomiting may or may not be accompany.

May result in rapid dehydration.

Neither fever nor vomiting is common.

Dehydration is usually mild but enough to suppress appetite.

Causative agents of gastroenteritis

Bacterial

Viral

Protozoal

Bacterial: A- E.Coli: Enterohemorrhagic [most serious] Enteroinvasive [dysentry] Enteropathogenic [common in hospital

infection (among neonates) ] Enterotoxigenic [ watery diarrhea] Others as, shigella, salmonella, cholera,

staph., campylobacter jejuni, clostridium perfringes.

Viral:Rota virus [the commonest in 25-40%]Enteroviruses [Coxsackie, ECHO

[enteric cytopathogenic human orphan], polio, norwalk, adenoviruses

Virus A hepatitis (anicteric gastroenteritis)

Measles virus and other viruses especially with low body immunity.

continue

Protozoal: Giardia lamblia, in the first part of small

intestine.[recurrent, bulky, pale, foul smelling stool].

E.hystolytica: dysentry by invasion of mucosal cells. Children causing persistent diarrhea.

Balantidium coli. Cryptosporidium: common in malnourished

and immuno-compromised

Reservoirs:

Man (cases & carriers) &Animals.Modes of infection: ingestion of contaminated water,

food, milk or meat.

Predisposing factors

1- Environmental factors: unsanitary environment. 2- Host factors: For the child: Age: <5 ys (more common under 2 ys),

maximum incidence from 6-12 months. Malnutrition Severe infection as after measles, tonsilitis,

otitis media. Immuno-suppression or immuno-deficiency.

Continue predisposing factors

3- Agent factors:Bacterial agents more in summer and

viral agents more in winter.

Diarrhea & mal/ or under nourishment relationship

Diarrhea causes damage of the mucosal lining of the intestine Malabsorption.

The malabsorption loss of nutrients with subsequent malnutrition.

Appetite with diarrhea more malnutrition, also malnutrition may depress appetite especially with protein deficiency.

Malnutrition will lowered body immunity especially with the current anorexia.

Also with abuse of antimicrobials, immune system is depressed.

All these will repeated infections either upper respiratory and or gastroentestinal.

These infections more anorexia, more malnutrition and more diarrhea.

Clinical picture

Mild: self limited, no fever + diarrhea<5 times/ day.

Severe: Fever, vomiting, diarrhea up to 20 times /day with subsequent dehydration.

Dehydration: sunken eyes– dry mouth—oliguria—acidosis—depressed anterior fontanel---apathy—mental confusion. skin elasticity

Assessment of diarrhea patients for dehydration

Condition: No dehydrationGeneral: well alert.Eyes: normalMouth & tongue: moist.Thirst: not thirsty.Skin pinch: go back

quickly.Status: no signs of

dehydration.

-: some dehydration.-:Restless, irritable*. -: sunken.-: Dry.

-:Thirsty, drink eagerly*.

-:go back slowly*.

-: if the patient has 2 or more signs including at least one sign *, there is some dehydration

Assessment of diarrhea patients for dehydration

Condition: Severe dehydration.General: Lethargic, unconscious,

floppy *.Eyes: very sunken & dry.Mouth &tongue: very dry.Thirst: drinks poorly or not able

to drink *.Skin pinch: go back very slowly*.Status: if the patient has 2 or >,

including at least one sign*, there is severe dehydration

N.B. In children >5 ys, &

adults, other signs for severe dehydration are:

1- Absent radial

pulse. 2- Low blood

pressure.

Type of dehydration [it depends on sodium level]

Isotonic dehydration:There is a loss of both water +sodium.Sodium serum concentration normal.Osmolality is normal.Complaints:There are signs of dehydration with

thirst.

Types of dehydration

Hypertonic (hyper-natremic) dehydration: Causes: Increase osmotic pressure in the intestinal

lumen by intake of fluids with high concentration of Na and /or glucose.

[ex. Drinking conc. fruit Juices ]

Serum Na water loss osmotic P. Complaints: Thirst Seizures due to hyper-natremia.

Type of dehydration

Hypotonic [hypo-natremic ] dehydration: Causes: Intake of fluids with very low concentration of

sodium. Ex., intravenous 5% glucose solution. There will be sodium loss with reabsorption of

water so this will lead to: Serum conc. of Na osmolality of serum Complaints: Lethargy with seldom seizures.

Acidosis in diarrhea

Caused by:1-Loss of bicarbonate ions, can't be

replaced by the kidney, because of the poor renal blood flow (hypovolemia).

2-Lactic acid concentration because of the hypovolemic shock [stress increase glucose burning].

Signs of acidosis

1- deep rapid respiration [ to compensate for by respiratory alkalosis].

2- vomiting.

3- Appetite.

Hypokalaemia with diarrhea

Potassium lost in stool.When both K &bicarbonates lost

together, hypokalemia doesn’t develop.Why?Because the acidosis that develop

causes K to move from intracellular to extracellular fluids in exchange for hydrogen ions.

When hypokalemia occur?

When acidosis is corrected without correction of K.

Signs:Muscle weaknessCardiac arrythmiaParalytic ileus especially when

associated with antiemetic drugs.

Diagnosis

1- clinically: from the clinical picture.2- Laboratory investigations:* Stool examination for detection of

parasitic infestations.* Stool culture for isolation of bacterial

agents.* Eliza or PCR for viral detection.* Serological testing for the antibody titre.

Prevention [ General prevention ]

1- Sanitary environment2- Health education to mothers about:A- Adequate nutrition:Exclusive breast feeding—proper

weaning—dietary supplementation.

Prevention [ general P.]

B- Prevention of infection:Water supply—animal milk—bottles&

teats (boiling)Hand washing—clean articles &

utensils.Discarding any feed remains.

Prevention [ general P.]

C- Medical care:Schedule of immunizationMedical check up and utilization of health

services.3- Prevention and control of any

systemic infections.

Prevention [ Specific prevention]

Specific prevention: vaccinations are available against some organisms as cholera, rota virus, virus A hepatitis, E.Coli.

These are especially indicated for travellers from non-endemic to endemic areas.

Control

1- Early case finding: By health awareness+ efficient health services. 2- Management of cases: at home if mild or at hospital if severe. A-Rehydration therapy: It replace water & electrolytes. ORS in packets, 5.5gm [ Na Cl---Na bicarbonate

{ acidosis}–K Cl [hypokalemia}—glucose {nutrient} ].

continue

ORS for mild and moderate cases.Nasogastric tube is indicated with

vomiting.Intravenous fluids in severe cases.B-Chemotherapy:Only in certain cases. Why?

Why antibiotics are not recommended as a first line therapy

1-most childhood diarrhea are caused by viral agents [25-40% of cases in Egypt are due to rota virus].

2-Many other cases are caused by parasites like Giardia and amoeba [not affected by antibiotics]

3-the use of many antibiotics may lead to secondary enteritis and persistent diarrhea because they destroy the flora of the intestine.

continue

4- Sensitivity studies show that most other cases are caused by bacteria which are resistant to the most frequently used antibiotics.

5-Using antibiotics when not indicated may reduce its effectiveness when needed [due to resistance].

Continue control

C-Diet therapy: If no dehydration continue feeding with fluid

intake. Cases with mild dehydration ORS+ milk.

Moderate cases initially give rehydration S. then fasting few hours (only fluids) until dehydration improves, then give milk and mashed starchy food [ Keep away of conc. Sweety fluids].

Severe cases are hospitalized until general condition improved and all signs of dehydration, acidosis are corrected then give milk +starchy food.

continue

D- Symptomatic treatment:For fever. Don’t give anti-emetics. Why?

1-Because correction of acidosis can stop vomiting.

2-It causes sedation and or precipitate paralytic ilieus.

Continue symptomatic tt

Don’t give anti-motility drugs. Why?

1- it keeps the toxins and pathogens inside the intestine.

2- It can cause ilius or respiratory failure.

Continue control

E- treatment of underlying diseases:MalnutritionSystemic infectionParasitic infestation

Web sites

At www.yahoo.com, yahoo groups,Dr.nihalsalah, files, ……-----------------------------------------www.esnips.com/user/drnehal

Sobhan Allah

Cholera

Causative agent

1- Vibrio cholera serogroup O1 including two biotypes:

Classical V. & El-Tor V. It live off the surface of intestinal mucosa and produce a

potent endotoxin damaging the cells. 2-A new serogroup O139 which have the same

cholera toxin, &It causes the same clinical picture of vibrio cholera O1.But differ from O1 in:

Lipopolysaccharide capsule structure Producing capsular antigen.

Virulence

Cholera produce a potent endotoxin which inhibits Na Cl absorption by intestinal villi.

It causes increase in bicarbonate with chloride secretion. All those factors cause change of osmolality extensive secretion of fluid & electrolytes.

Resistance

A delicate organism, sensitive to sunlight, heat, acidity, dryness and chlorine.

In most contaminated articles it live [ 1-3 days].

May live in water for 3-4 weeks & in vegetables and fruits.

2315 case (2007)

Occurrence

Many cholera pandemics have been reported , ex. The epidemic in Egypt in 1947.

El-Tor vibrio spread in pandemics, in 1977, 1978, in 1993.

In 1994, The O139 vibrio was isolated in 7 countries[Pakistan, bangaladish, nepal, Malysia, China, serilanka, India].

Also, cholera outbreaks occurred among the refugees in Zaire in July.

Incubation period

I.P:From few hours to 5 days [2-3 days].

Clinical picture

It is an acute infection of the small intestine. It is characterized by :

Acute, profuse, painless watery diarrhea [ Rice water stool ] with mucous and electrolytes.

Occasionally vomiting, Anxiety, dehydration and acidosis,

ending by circulatory collapse + renal failure.

Reservoirs

1- Human R.: cases Carriers [all types of carriers including chronic]

2- Environmental R.Recently observed in association with

zooplankton in brackish water or estuaries.

Susceptibility

1- Risk increase with achlorohydria 2- People with blood group O are exposed

more to el-Tor +O139. 3-Infection with V.Cholera O1 give protection

against O1[ classical+ El-Tor]. 4- Infection with El-Tor give protection against

El-Tor only. 5-In endemic areas young ages but in newly

infected areas usually adults more.

Modes of transmission

By ingestion:1- Direct: person to person mainly in

children [in sporadic cases].2- Indirect: water borne cause

epidemics and outbreaks. Also, in Food:by flies, soiled hands and utensils.

Diagnosis

1- Clinical picture2- Laboratory: Stool examination + rectal swab, vibrio

appear in the dark ground illumination microscopy.

Stool culture

Prevention

1- Environmental sanitation2- Health education3-Specific prevention:

Chemoprophylaxis Vaccination

Chemoprophylaxis

By tetracycline 500mg 4 times/day.By furoxone 100mg 4 times/ day.Indications:For travelers to endemic areas.For carriersFor contactsFor pilgrims on their coming back.

Vaccination

By a parenteral vaccine (old vaccine) Preparation: a whole cell, heat killed, phenol

preserved. Dose: twice with1-4weaks apart, ½ ml 1st dose

then 1 ml 2nd dose. Booster dose/ 6months. Route: I.m or S.C Effect: 50% Protective 6 days after vaccination up to 6

months.

Continue vaccination

Indications:To travelers to& from endemic areasContactsTo residents of endemic areas dring

outbreaks.

continue vaccination

New oral vaccines in some countries:

(A)- First oneNature: live attenuated vaccine (O1 strain). Dose: a single dose Route: Oral. Effectiveness: about 80-85% protection (About 85% protection against classic vibrios

and about 60-70% in El-Tor vibrios.

Continue vaccination

(B)-Second oneNature: Inactivated O1 strain plus B-subunit

of cholera toxin. Dose: 3 doses Given one day apart. Route: oral vaccine Effectivenes: From 58% to 85% protection They give protection up to 6 months. Indications: For travelers to and from endemic areas For contacts

Recently, WHO informations

In 2006, WHO published official recommendations for Oral Cholera Vaccine use in complex emergencies.

The use of the parenteral cholera vaccine has never been recommended by WHO due to its low protective efficacy and the high occurrence of severe adverse reactions.

Recently, WHO informations

C-Third One An internationally licensed oral cholera vaccine

(OCV) is currently available on the market and is suitable for travellers.

Effectiveness: It was proven safe and effective (85–90%) after six months in all age groups, declining to 62% at one year among adults) and is available for individuals aged two years and above.

Dose:It is administered in two doses 10-15 days apart and given in 150 ml of safe water.

Its public health use is relatively recent. Within the past few years several immunization campaigns were carried out with WHO support.

A live attenuated vaccine for cholera O139 are being tested

International measures

In the past a vaccination certificate for travelers from & to endemic areas was asked. It was valid 6 days after 2nd dose of parenteral vaccine up to 6 months. Otherwise quarantine measures were done for 5 days in a special place.

Chemoprophylaxis were given instead of parenteral vaccinefor travellers, especially for pilgrims on coming back.

Now oral vaccaines are indicated and given for international travelers by some countries as they are more effective than the old parenteral one.

Control

1- for cases: notification, isolation at home or in hospital , disinfection, treatment [antibiotics, rehydration therapy], release after 3 negative slool examinations.

The dead bodies are soaked in formalin first.

Conltrol

2- for contacts: Segregation {no school, no work} and stool

examination . If +ve for vibrio, give chemotherapy. If –ve, then release after 3 negative

examinations Chemoprophylaxis New oral vaccines are indicated if they are

available.

Continue control

General epidemic measures: Declaration and notification of the disease to

WHO. Health education for the public Investigate water and food sources, channels

of infection Environmental sanitation: Closure of swimming pools, superchlorination

of water.