The epidemiology and etiology of diarrhea

Diarrhea in young children

3-4 episodes /child / year

3200 000 death / year

Causes about 30% of infant death in developing countries

80% death due to diarrhea occur in first years of life

Diarrhea is an important cause of malnutrition

Three clinical types of diarrhea

1. Acute watery diarrhea dehydration ,potassium loss

2. Bloody diarrhea tissue damage, toxemia

3. Persistent diarrhea malnutrition

Host factors that increase susceptibility to diarrhea

Failing to breast - feed until at least 2 years

Malnutrition

Measles

immunosuppression

Behavioral risk factors for diarrhea

Inadequate breast feeding

Using feeding bottles

Eating food hours after cooking it

Drinking contaminated water

Not washing soiled hands

Not disposing of feces

Prevention of diarrhea ( host factors)

Breast feed at least 2 years

Give plenty of good food ,start at age 4-6month

Immunize against measles

Fluids for home therapy

ORS solution

Water

Food - based fluids soup rice water Yoghurt drink Glucose water

Age of diarrhea

1. Most diarrhea episodes occur during the first 2 years of life

2. Incidence is highest in the age group 6-11 month

Declining levels of maternally acquired antibodies The lack of active immunity in the infant The introduction of food

seasonality

In temperate climate ; bacterial diarrhea occur more frequently during the warm

season whereas the peak Viral diarrhea particularly rotavirus is

during the winter

In the tropical areas; rotavirus diarrhea occurs throughout the year and

increasing in cool month Whereas bacterial diarrheas peak during warmer ,rainy season

The incidence persistent diarrhea follows the same seasonal pattern as that acute watery diarrhea

Etiology of diarrhea

Rotavirus Enterotoxigenic Escherichia coli Shigella Campylobacter jejuni cryptosporidium Vibrio cholera salmonella (Non thyphoid ) Entropathogenic Escherchia coli

Pathogenic mechanisms ( viruses)

Replicate within the villous epithelium of small bowel

Patchy epithelial cell destruction and villous shortening

The Loss of normally absorptive villous cells Replacement immature , secretary ,crypt- like cells

Loss of disaccharides , especially lactose

Pathogenic mechanisms )bacteria)

Mucosal adhesion to avoid being swept away Entrotoxicogenic E.coli ,vibrio .cholera

Toxins that cause secretion that reduce the absorption of Na and increase the secretion of chloride

Entrotixigenic E.coli , v.cholera

Mucosal invasion occurs in the colon and distal ileum and destroying mucosal epithelial cells and cause bloody diarrhea

Shigella ,C.jejuni ,entroinvasive E. coli and salmonella

Pathogenic mechanisms )protozoa)

Mucosal adhesion and cause shortening of the villi G,lambelia , cryptosporidum

Mucosal invasion in the colon or ileum and causing micro absess and ulcer

E, histolitica

Campilobacter jejuni

C,jejuni causes disease mostly in infants

C,jejuni also infects animals and spread by contact with their

feces or consumption of contaminated food , milk , or water

C,jejuni can cause watery diarrhea or dysentery

Fever may be preset and episodes are not sever and last 2-5 days

Erythromycin shorten the illness

cryptosporidium

This parasite causes diarrhea in infants immunodeficient patients , and a variety of domestic animals

Infection is frequent in developing countries

Most episodes of illness occur in the first year of life

Diarrhea is usually neither severe nor prolonged

Diarrhea is sever in malnutrition , or AIDS , immunodeficient patients

Prevention of diarrhea

Give only breast milk for first 4-6 month

Do not use feeding bottle

Prepare and store food safely

Use clean water for drinking

Wash hands when soiled

Dispose of faeces safely

Treatment of acute diarrhea the main points

Replace lost water and salt

Continue to feed

Benefit of antibiotics in acute diarrhea

Helpful for patients with ; 5-15% Bloody diarrhea Suspected cholera with severe dehydration

No practical value for others because ; 85-95%

Ineffective for pathogen Pathogen not known

Treatment acute diarrhea other points

Only give antibiotic for ;

Bloody diarrhea Suspected cholera with severe dehydration

Only give anti protozoals ;

No response to treatment for shigella Proven amebiasis

Treatment of diarrhea

1. Replacement of fluids and electrolytes

2. Feeding should be continued in all types of diarrhea

3. Antimicrobial and anti parasitic agents should not be used

Treatment of diarrhea1. Antimicrobial and anti parasitic agents should not be

used exception is ;

Dysentery

Suspected cholera with sever dehydration

Persistent diarrhea when trophozoites or cysts of giardia or trophozoites of E,hystolytica are seen in feces or intestinal fluid or pathogenic enteric bacteria are identified by stool culture

Pathophysiology of watery diarrhea

Pathophysiology of watery diarrhea

Normally absorption and secretion of water and electrolytes occur throughout the intestine

Water and electrolytes are simultaneously absorbed by the villi and secreted by the crypts

More than 90% of the fluid entering the small intestine is absorbed

Only 100-200cc of water excreted each day in formed stools

Absorption and secration

Villus Active absorption of Na Na absorbed with glucose and aminoacids

Crypt ; Active secretion of choloride

Pathophysiology of watery diarrhea

Watery diarrhea is caused by a disturbance in the mechanism of transport of water and electrolytes in the small intestine

Intestinal transport mechanisms are also the basis for the management of diarrhea

Intestinal absorption water and electerolytes

Absorption water from the small intestine is caused by osmotic gradients that created when Na are actively absorbed

Mechanisms of the watery diarrhea There are several mechanisms for Na absorption

1. Na is linked to the absorption of chloride ion

2. Absorbed directly as Na ion

3. Exchanged for hydrogen ion

4. Or linked to the absorption of organic substances such as glucose or certain amino acids

Intestinal secretion of water and electrolytes Secretion of water and electrolytes normally occurs in the

crypts

Na is transported from the ECF into the epithelial cell

Na is then pumped back into the ECF by Na k ATPase

Secretory stimuli cause chloride ions to pass through the luminal membrane of the crypt cells into the bowel lumen

Osmotic gradient that causes water and electrolytes to flow passively from the ECF into the bowel

Mechanisms of the watery diarrhea

There are two principal mechanisms ;1. Secretion2. Osmotic action

intestinal infection can cause diarrhea by both mechanisms.

• Secretory diarrhea is more common Both mechanisms may occur in a single

individual

Secretory diarrhea There is abnormal secretion of water and electrolytes

into the small bowel

Absorption Na by the villi is impaired

Secretion chloride in the crypt cell cotinuous or increased

fluid secretion and Loss water and Na as watery stools , and dehydration

Causes of secretory diarrhea

Toxicogenic bacteria

Vibrio cholerae E,choli Campilobacter Shigella Salmonella

Enteric viruses ritaviruse

Osmotic diarrhea

Water and electrolytes move rapidly across the epithelium of small bowel mucosa to maintain osmotic balance

Diarrhea can occur when a poorly absorbed osmotically active substance is ingested

Osmotic diarrhea If the substance is isotonic solution causing diarrhea

but not dehydration (lactose , glucose , magnesium sulfate )

If non absorbed substance is hypertonic solution water move from the ECF into the gut ,that causes diarrhea with dehydration and hypernatremia

Causes of osmotic diarrhea

Product unabsorbed solution

Milk lactose ,small organic acids

Sweetened drink sucrose , glucose

Laxative salts magnesium sulfate

Isotonic dehydration

This is the most type of dehydration Losses of water and Na are in the same proportion

There is a balanced deficit of water and Na Serum Na concentration is normal (130-150 m mol / l ) Serum osmolality is normal (275-295) Hypovolemia occurs as a result of loss of extra cellular

fluid

Hypernatremic dehydration

There is loss of water excess of Na It is usually results from ; ingestion of hypertonic fluid that not efficiently absorbed Insufficient intake of water or low –solute drink

There is a deficit of water and Na deficit of water is greater

Serum Na concentration is elevated (>150 mmol/l) Serum osmolality is elevated (>295m osmol/l ) Thirst is severe and the child is very irritable Sezures may occur (Na >165 mmol /l)

Hyponatremic dehydration

There is loss of Na excess of water It is usually from ; drink large amounts of water or hypotonic fluid with low

Na IV infusion 5%glucose without Na

There is deficit of water and Na but the deficit of Na is greater

Serum Na concentration is low (<130 mmol /l) Serum osmolality is low (<275 mosmol /l) The child is lethargic , infrequently seizures

Metabolic acidosis during diarrhea a large amount of bicarbonate may be

lost in the stool if the kidneys have normal function much of lost bicarbonate is replaced

when patients have hypovolemia ; Excessive production of lactic acid there is poor renal flow and fail the compensating

mechanism

Serum bicarbonate concentration is reduced (<10 mmol/l) Arterial PH is reduced (<7.10) Breathing become deep and rapid Vomiting is increased

Metabolic acidosis Serum bicarbonate concentration is reduced (<10

mmol/l)

Arterial PH is reduced (<7.10)

Breathing become deep and rapid

Vomiting is increased

Metabolic effect of watery diarrhea

Loss of water and salt hypovolemia shock

Excess loss of bicarbonate acidosis

Excess loss of K K deplation

hypokalemia

Patients with diarrhea often develop K depletion

When K and bicarbonate are lost together hypokalemia does not usually develop

The signs of hypokalemia may include ; General muscular weakness Cardiac arrhythmias Paralytic ileus

Oral rehydration therapy ORT is based on the principle that intestinal absorption of

Na is enhanced by the active absorption of glucose and aminoacids

Oral rehydration therapy ORT is based on the principle that intestinal absorption of Na is

enhanced by the active absorption of glucose and aminoacids

This process is normal during secretory diarrhea

If patients with secretory diarrhea drink an isotonic salt solution without glucose or aminoacids Na is not absorbed

When a balanced isotonic solution of glucose and salt is given glucose linked Na absorption occurs and this is accompanied by

the absorption of water

ORS an osmolality similar to or less than plasma

The concentration of Na should be sufficient to replace the Na deficit

The ratio of glucose to Na should be at least 1:1

The concentration K should be 20 mmol/l

The concentration base should be 10 mmol /l for citrate or citrate or 30 mmol/l for bicarbonate

Na= 90 k=20 Cl=80 Hco3=30 Glucose =111

When ORT is not effective

Severe repeated vomiting

Severe diarrhea >15 cc /kg /h

Glucose malabsorption

ORT inappropriate for

paralytic ileus abdominal distension

initial treatment of Severe dehydration because fluid must be replaced very rapidly

Patients who are unable to drink

Assessing the patient with diarrhea

Ask, look and feel for dehydration

General condition? Well , alert? Restless ,irritable? floppy,lethargic, or unconscious?

Assessing the patient with diarrhea

Eyes:normal? Sunken? Very sunken and dry? Tear: have tear? Mouth and tongue: wet? dry?very dry? Thirst: drinks normal?drinks eagerly?drinks

poorly? Skin pinch: immediately? Slowly(>2se) ? very

slowly? Additional sign: anterior fontanel?pulse? Breathing?

Determine the degree of dehydration and select tereatment

Two or more signs in one column including at least one key sign means that the patient falls in that category.

C-severe dehydration deficit equal more than 10% B- some dehydration ( mild or moderate ) deficit

equal 5-10% A-no dehydration

Assessing the child for other problems

Dysentry? Persistent diarrhea? Malnutrition? Feeding history? Pre-illness , feeding

during diarrhea and mother,s beliefs Physical finding? Sings of marasmus or

kwashiorkor?

Treatment plan a to treat dirrhea at home

Explain 3 rules for treating diarrhea at home:

1. Give the child more fluid for prevent dehydration 2. Give the child plenty of food to prevent malnutrition3. Take the child to the health worker if the child not get

better in 3 days or develops any of the following:Fever , eating or drinking poorly , bloody stool , marked thirst

, repeated vomiting , many watery stools

Treatment plan a to treat dirrhea at home

Give ORS at home if: they have been on treatment plan B or C They can not return to the health worker if

the diarrhea worse It is national policy give ORS to all

children

If the child will be given ORS at home

Age less than 24 months 50-100 ml after each loose stool and 500ml /day at home

2-10 year 100-200 ml after each loose stool and 1000ml / day

10 years or more as much as wanted and 2000ml/ day

Give a teaspoon every 1-2 minutes for under 2 year If a child vomits wait 10 minutes and then every 2-3

minutes

Treatment plan B to treat dehydration

Estimate the amount of ORS solution to be given during the 4 hours

To show the mother how to give ORS To continue breast- feeding To monitor treatment and reassess the child To identify patients who can not be treated

satisfactory After rehydration following planA

Treatment plan B Amount of ORS is75ml /kg in the 4 hours If the child wants more ORS give more The mother continue breast- feeding For infant < 6 month who are not breast – fed give

100-200 ml water after 4 hours reassess the child then select plan

A,B , C

Thanks…But it’s not the end !!

Thanks…

But it’s not the end !!