Download Diarrhea

‫المرحله الخامسه‬
‫اطفال‬
LEC 1
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GIT
DIARRHOEA in INFANCY & CHILDHOOD
Objectives
.To define diarrhea & gastroenteritis





To differentiate between the types of diarrhea.
To know the mechanism of each type.
To know the etiologies of GE.
To know the risk factors of GE.
To know the clinical features of GE & how clinically
evaluate the degree of dehydration.
 How can investigate a patient with GE?
Acute Gastroenteritis in Children
The term gastroenteritis captures the bulk of infectious cases of
diarrhea. The term diarrheal disorders is more commonly used to
denote infectious diarrhea in public health settings, although several
noninfectious causes of gastrointestinal illness with vomiting and/or
diarrhea are well recognized.
The term gastroenteritis denotes infections of the gastrointestinal tract
caused by bacterial, viral, or parasitic pathogens
Diarrhea
:Refers to
.Abnormal increase in frequency and liquidity of fecal discharges
OR
Stool output >10 g/kg/24 hr, or more than the adult limit of 200 g/24 hr.
EPIDEMIOLOGY OF CHILDHOOD DIARRHEA
‫المرحله الخامسه‬
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Diarrheal disorders in childhood account for a large proportion (18%) of
.childhood deaths
with an estimated 1.5 million deaths per year globally, making it the
second most common cause of child deaths worldwide..
TYPES OF DIRRHEA
i.
ii.
iii.
Acute watery diarrhea (<14 days
Dysentery (visible blood in stool.
Persistent diarrhea (>14 days .
MECHANISM OF DIARRHEA
The basis for all diarrhea is disturbed intestinal solute transport; water
movement across intestinal membranes is passive and is determined by
both active and passive fluxes of solutes, particularly sodium, chloride,
.and glucose
The pathogenesis of most episodes of diarrhea can be explained by
secretory, osmotic, or motility abnormalities or a combination of these
Mechanisms of Diarrhea
:Secretory
Defect
Increased secretion
Decreased absorption
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Examples
)Activation of cAMP: Cholera, toxinogenic E.coli(LT
Shigella, Salmonella, Campylobacter jejuni
Pseudomonas aeruginosa
Activation of cGMP: E. coli (ST) , Yersinia enterocolitica
toxin
Comments
Persists during fasting
No stool leukocytes
Osmotic
Defect present
Digestive enzyme deficiencies
Ingestion of unabsorbable solute
Examples
Malabsorption: Disaccharidase deficiencies (lactase )(rota virus cause
)lactase def
Excessive intake of carbonated fluid
Excessive intake of non absorbable solute: Lactulose
Comments
Stop with fasting
No stool WBCs
‫اطفال‬
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•
•
•
•
•
•
Stool volme
Stool Na
Fasting
Ion gap
Stool PH
Reducing
subst
•
•
•
•
•
•
Moderately
increase
<200ml/24h
< 70mEq/l
diarrhea stop
>100mosm/kg
<5
+ve
LEC 1
•
•
•
•
•
•
‫اثل‬.‫د‬
Large volume
>200ml/24h
>70
Diarrhea continue
< 100
>6
-ve
NOTE
The stool osmolality is indicated by the electrolytes and the ion gap is
.100 mOsm/kg or less
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The ion gap is calculated by subtracting the concentration of electrolytes
:from total osmolality
Ion gap = Stool osmolality – [ (stool Na + stool K) × 2]
PATHOLOGY
1.Noninflammatory Diarrhea
Through
i.
ii.
iii.
enterotoxin production by some bacteria
destruction of villus (surface) cells by viruses
adherence by parasites, and by bacteria.
2.Inflammatory Diarrhea
usually caused by bacteria that
directly invade the intestine
produce cytotoxins with consequent fluid, protein, and
(erythrocytes, leukocytes) that enter the intestinal lumen.
Some enteropathogens possess more than one virulence property
ETIOLOGY OF DIARRHEA
Infectious Diarrhea
Gastroenteritis is due to infection acquired through the feco-oral
.route or by ingestion of contaminated food or water
Gastroenteritis is associated with poverty and poor environmental
.hygiene
cells
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Viral gastroenteritis
i.
ii.
iii.
iv.
v.
Viral gastroenteritis (“stomach flu”)
rotavirus
noroviruses (small round viruses such as Norwalk-like virus and
caliciviruses)
sapovirus
enteric adenoviruses
astroviruses
Rotavirus
Rotavirus invades the epithelium and damages villi of the upper small
intestine and in severe cases involves the entire small bowel and
colonRotavirus is the most frequent cause of diarrhea during the winter
months. Vomiting may last 3 to 4 days, and diarrhea may last 7 to 10
.days
Dehydration is common in younger childrenUsually cause watery
no blood and pus in stool
diarrhoea
Bacterial gastroenteritis
Escherichia Coli
ii.
iii.
iv.
v.
vi.
vii.
viii.
a. gram-negative bacilli
major groups of diarrheagenic E. coli :
enterotoxigenic E. coli (ETEC)
enteroinvasive E. coli (EIEC)
enteropathogenic E. coli (EPEC)
Shiga toxin–producing E. coli (STEC)also known
as enterohemorrhagic E. coli (EHEC)
enteroaggregative E. coli (EAEC).
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Shigella
:Four species of Shigella are responsible for bacillary dysentery
S. dysenteriae
S. flexneri
S. boydii
S. sonnei
It is most common in the 2nd and 3rd year of life, infection in the 1st 6
)mo of life is rare (may be due to Breast feeding
The colon is the target organ for shigellae
:Symptoms
generalized toxicity
.urgency, and painful defecation characteristically occur
watery → bloody mucoid stools
Convulsions, headache, lethargy, confusion, nuchal rigidity, or
.hallucinations may be present before or after the onset of diarrhea
Salmonella
Salmonella causes 2 clinical syndromes in humans: a GE that is usually
self-limited, and typhoid fever that is a relatively severe systemic illness
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classically caused by S. typhi. Nontyphoidal strains of Salmonella can also
cause a severe bacteremic illness in some circumstances.
CLINICAL MANIFESTATIONS.
:Acute Enteritis
mild to severe watery diarrhea
Bloody diarrhea
Campylobacter
The organism invades the mucosa of the jejunum, ileum, and colon,
.producing enterocolitis
DISEASES IN HUMANS: Gastroenteritis, bacteremia, Guillain-Barré
syndrome
.Acute Gastroenteritis
Watery or bloody diarrhea
The abdominal pain is periumbilical; cramping but may mimic
.appendicitis or intussusception
Yersinia Enterocolitica
Infants & young children characteristically have a diarrheal disease,
whereas older children usually have acute mesenteric lymphadenitis
mimicking appendicitis or Crohn disease. Arthritis, rash, and
spondylopathy may develop.
Parasitic gastroenteritis
Entamoeba histolytica
Clinical presentations range from asymptomatic cyst passage to
amebic colitis, amebic dysentery, ameboma, and extraintestinal disease
.as amebic liver disease
Amebic colitis, gradual onset of colicky abdominal pains and
frequent bowel movements (6–8/day). Diarrhea is frequently associated
with tenesmus. Stools are blood stained and contain a fair amount of
mucus with few leukocytes. Generalized constitutional symptoms and
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signs are characteristically absent, with fever documented in only ⅓ of
patients.
Giardia Lamblia
It infects the duodenum and small intestine
Clinically: asymptomatic, acute infectious diarrhea (insidious onset of
progressive anorexia, nausea, gaseousness, abdominal distention,
watery diarrhea) or chronic diarrhea with persistent GIT signs and
.symptoms, including FTT and abdominal pain or cramping
There is usually no extraintestinal spread.
Non-infectious diarrhea
i.
ii.
iii.
iv.
v.
vi.
vii.
viii.
Allergy to milk or its components
Malabsorption
Endocrinopathies
Poisoning
Neoplasia e.g.: neuroblastoma
IBD
Drugs / medications
Traveller’s Diarrhoea
Diarrhea
1.watery
2.bloody
Watery diarrhea
Viral enteritis
:Enterotoxin producing bacteria
Escherichia coli
Klebsiella organisms
Clostridium perfringens
Vibrio species
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:Parasitic GE
Giardia
Cryptosporidium
:Extraintestinal Infections
. Parenteral Diarrhea e.g.: otitis media & urinary tract infection
Bloody diaeehea
BACTERIAL
Shigella
Salmonella
Campylobacter
Yersinia enterocolitica
Invasive E. coli
NON-BACTERIAL
Amoebic dysentery
)Pseudomembranous enterocolitis (C. difficile toxin
)Ulcerative or granulomatous colitis (acute presentation
Necrotizing enterocolitis in neonates
RISK FACTORS FOR GASTROENTERITIS
Major risks include environmental contamination and increased
.exposure to enteropathogens
:Additional risks include
.Lack of exclusive or predominant breast-feeding
Young age
Immune deficiency
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Measles
Malnutrition, malnutrition increases severalfold the risk of diarrhea and
associated mortality.The risks are particularly higher with micronutrient
malnutrition; in children with vitamin A deficiency, the risk of dying from
diarrhea, measles, and malaria is increased by 20–24%. Zinc deficiency
increases the risk of mortality from diarrhea, pneumonia, and malaria by
13–21%.
CLINICAL MANIFESTATIONS
 Diarrhea, vomiting ,nausea, anoroxia, abdomenal distension,
abdominal cramps.
 Manifestation of complications: dehydration & electrolyte
disturbance.
 Extra intestinal: Fever, malaise, reactive arthritis, systemic spread
of M.O., Guillain- Barre Synd, HUS, hemolytic anaemia.
DIAGNOSIS OF GE
The diagnosis of gastroenteritis is based on clinical recognition, an
evaluation of its severity by rapid assessment, and confirmation by
appropriate laboratory investigations, if indicated.
CLINICAL EVALUATION OF DIARRHEA
Assess the degree of dehydration and acidosis and provide
rapid resuscitation and rehydration with oral or intravenous fluids
as required
Obtain appropriate contact or exposure history. This includes
information on exposure to contacts with similar symptoms,
intake of contaminated foods or water, child-care center
attendance, recent travel to a diarrhea-endemic area, and use of
antimicrobial agents.
Clinically determine the etiology of diarrhea for institution of
prompt antibiotic therapy, if indicated. Although nausea and
vomiting are nonspecific symptoms, they are indicative of
infection in the upper intestine. Fever is suggestive of an
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inflammatory process but also occurs as a result of dehydration or
co-infection (e.g., urinary tract infection, otitis media).
Fever is common in patients with inflammatory diarrhea.
Severe abdominal pain and tenesmus are indicative of
involvement of the large intestine and rectum. Features such as
nausea and vomiting and absent or low-grade fever with mild to
moderate periumbilical pain and watery diarrhea are indicative of
small intestine involvement and also reduce the likelihood of a
serious bacterial infection.
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LABORATORY STUDIES
 Initial laboratory evaluation of moderate to severe diarrhea
includes:
 electrolytes
 Blood sugar.
 BUN, creatinine
 Blood
pH , S. [HCO3]
 urinalysis for specific gravity as an indicator of hydration.
 CBP.
 GSE for:
 Macroscopical
 Microscopical.: mucus, blood, and leukocytes
 Chemical
 Stool cultures are recommended for patients with:
 fever
 profuse diarrhea
 if HUS is suspected.
 bloody diarrhea.
 in immunosuppressed children with diarrhea.
 ELISA for rotavirus..
 The diagnosis of E. histolytica is based on identification of the
organism in the stool. Serologic tests are useful for diagnosis of
extraintestinal amebiasis, including amebic hepatic abscess.
 Giardiasis can be diagnosed by identifying trophozoites or cysts in
stool; less often a duodenal aspirate or biopsy of the duodenum
or upper jejunum is needed.
 GUE
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