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 !!