Transcript Document 7312682

The epidemiology and etiology of diarrhea
Diarrhea in young children
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3-4 episodes /child / year
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3200 000 death / year
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Causes about 30% of infant death in developing countries
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80% death due to diarrhea occur in first years of life
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Diarrhea is an important cause of malnutrition
Three clinical types of diarrhea
1.
Acute watery diarrhea
2.
Bloody diarrhea
3.
Persistent diarrhea
dehydration ,potassium loss
tissue damage, toxemia
malnutrition
Host factors that increase susceptibility to diarrhea
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Failing to breast - feed until at least 2 years
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Malnutrition
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Measles
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immunosuppression
Behavioral risk factors for diarrhea
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Inadequate breast feeding
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Using feeding bottles
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Eating food hours after cooking it
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Drinking contaminated water
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Not washing soiled hands
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Not disposing of feces
Prevention of diarrhea ( host factors)
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Breast feed at least 2 years
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Give plenty of good food ,start at age 4-6month
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Immunize against measles
Fluids for home therapy
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ORS solution
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Water
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Food - based fluids
soup
rice water
Yoghurt drink
Glucose water
Age of diarrhea
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2.
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Most diarrhea episodes occur during the first 2 years of life
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
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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
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Rotavirus
Enterotoxigenic Escherichia coli
Shigella
Campylobacter jejuni
cryptosporidium
Vibrio cholera
salmonella (Non thyphoid )
Entropathogenic Escherchia coli
Pathogenic mechanisms ( viruses)
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Replicate within the villous epithelium of small bowel
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Patchy epithelial cell destruction and villous shortening
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The Loss of normally absorptive villous cells
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Replacement immature , secretary ,crypt- like cells
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Loss of disaccharides , especially lactose
Pathogenic mechanisms )bacteria)
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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)
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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
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C,jejuni causes disease mostly in infants
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C,jejuni also infects animals and spread by contact with their
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feces or consumption of contaminated food , milk , or water
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C,jejuni can cause watery diarrhea or dysentery
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Fever may be preset and episodes are not sever and last 2-5 days
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Erythromycin shorten the illness
cryptosporidium
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This parasite causes diarrhea in infants
immunodeficient patients , and a variety of domestic animals
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Infection is frequent in developing countries
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Most episodes of illness occur in the first year of life
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Diarrhea is usually neither severe nor prolonged
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Diarrhea is sever in malnutrition , or AIDS , immunodeficient
patients
Prevention of diarrhea
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Give only breast milk for first 4-6 month
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Do not use feeding bottle
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Prepare and store food safely
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Use clean water for drinking
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Wash hands when soiled
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Dispose of faeces safely
Treatment of acute diarrhea the main points
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Replace lost water and salt
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Continue to feed
Benefit of antibiotics in acute diarrhea
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Helpful for patients with ;
Bloody diarrhea
Suspected cholera with severe dehydration
5-15%
No practical value for others because ;
Ineffective for pathogen
Pathogen not known
85-95%
Treatment acute diarrhea other points
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Only give antibiotic for ;
Bloody diarrhea
Suspected cholera with severe dehydration
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Only give anti protozoals ;
No response to treatment for shigella
Proven amebiasis
Treatment of diarrhea
1.
2.
3.
Replacement of fluids and electrolytes
Feeding should be continued in all types of
diarrhea
Antimicrobial and anti parasitic agents should not
be used
Treatment of diarrhea
1.
Antimicrobial and anti parasitic agents should not be
used exception is ;
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Dysentery
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Suspected cholera with sever dehydration
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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
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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
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Active absorption of Na
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Na absorbed with glucose and aminoacids
 Crypt ;
 Active secretion of choloride
Pathophysiology of watery diarrhea
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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
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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
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Or linked to the absorption of organic substances
such as glucose or certain amino acids
Intestinal secretion of water and electrolytes
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Secretion of water and electrolytes normally occurs in the crypts
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Na is transported from the ECF into the epithelial cell
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Na is then pumped back into the ECF by Na k ATPase
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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
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1.
2.
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There are two principal mechanisms ;
Secretion
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
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There is abnormal secretion of water and electrolytes into the
small bowel
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Absorption Na by the villi is impaired
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Secretion chloride in the crypt cell cotinuous or increased
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fluid secretion and Loss water and Na as watery stools , and
dehydration
Causes of secretory diarrhea
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Toxicogenic bacteria
Vibrio cholerae
E,choli
Campilobacter
Shigella
Salmonella
 Enteric viruses
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ritaviruse
Osmotic diarrhea
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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
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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
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Milk
lactose ,small organic acids
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Sweetened drink
sucrose , glucose
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Laxative salts
magnesium sulfate
Isotonic dehydration
 This is the most type of dehydration
 Losses of water and Na are in the same proportion
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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
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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
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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
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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
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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
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Serum bicarbonate concentration is reduced (<10 mmol/l)
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Arterial PH is reduced (<7.10)
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Breathing become deep and rapid
 Vomiting is increased
Metabolic effect of watery diarrhea
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Loss of water and salt
hypovolemia shock
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Excess loss of bicarbonate
acidosis
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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
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The signs of hypokalemia may include ;
General muscular weakness
Cardiac arrhythmias
Paralytic ileus
Oral rehydration therapy
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ORT is based on the principle that intestinal absorption of
Na is enhanced by the active absorption of glucose and
aminoacids
Oral rehydration therapy
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ORT is based on the principle that intestinal absorption of Na is
enhanced by the active absorption of glucose and aminoacids
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This process is normal during secretory diarrhea
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If patients with secretory diarrhea drink an isotonic salt solution
without glucose or aminoacids Na is not absorbed
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When a balanced isotonic solution of glucose and salt is given
glucose linked Na absorption occurs and this is accompanied
the absorption of water
by
ORS
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an osmolality similar to or less than plasma
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The concentration of Na should be sufficient to replace the Na
deficit
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The ratio of glucose to Na should be at least 1:1
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The concentration K should be 20 mmol/l
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The concentration base should be 10 mmol /l for citrate or
citrate or 30 mmol/l for bicarbonate
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Na= 90 k=20 Cl=80
Hco3=30 Glucose =111
When ORT is not effective
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Severe repeated vomiting
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Severe diarrhea >15 cc /kg /h
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Glucose malabsorption
ORT inappropriate for
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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
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Ask, look and feel for dehydration
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General condition?
Well , alert?
Restless ,irritable?
floppy,lethargic, or unconscious?
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Assessing the patient with diarrhea
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Eyes:normal? Sunken? Very sunken and dry?
Tear: have tear?
Mouth and tongue: wet? dry?very dry?
Thirst: drinks normal?drinks eagerly?drinks
poorly?
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Skin pinch: immediately? Slowly(>2se) ? very
slowly?
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Additional sign: anterior fontanel?pulse? Breathing?
Determine the degree of dehydration and
select tereatment
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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
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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
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Explain 3 rules for treating diarrhea at home:
Give the child more fluid for prevent dehydration
2.
Give the child plenty of food to prevent malnutrition
3.
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
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Treatment plan a to treat dirrhea at home
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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
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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
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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
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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 !!