GIT pdf - د. اثل - Muhadharaty

Fifth stage

Pediatric

Lec-1

.د

ثل

1/1/2016

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.

Stool output >10 g/kg/24 hr, or more than the adult limit of 200 g/24 hr.

EPIDEMIOLOGY OF CHILDHOOD DIARRHEA

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

Acute watery diarrhea (<14 days

ii.

Dysentery (visible blood in stool.

iii.

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

Secretory:

Defect



Increased secretion



Decreased absorption

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

•

Large volume
>200ml/24h

•

>70

•

Diarrhea continue

•

< 100

•

-ve

• Moderately

increase

<200ml/24h

•  < 70mEq/l
•   diarrhea stop
•   >100mosm/kg
•  < 5
•   +ve

•  Stool volme
•  Stool Na
•  Fasting
•  Ion gap
•  Stool PH
•  Reducing

subst

NOTE

The stool osmolality is indicated by the electrolytes and the ion gap is 100 mOsm/kg or less .

The ion gap is calculated by subtracting the concentration of electrolytes from total
osmolality:

PATHOLOGY

1.Noninflammatory Diarrhea

Through

enterotoxin production by some bacteria

ii.

destruction of villus (surface) cells by viruses

iii.

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 cells (erythrocytes, leukocytes)
that enter the intestinal lumen.

Some enteropathogens possess more than one virulence property

Ion gap = Stool osmolality – [ (stool Na + stool K) × 2]

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 .

Viral gastroenteritis

Viral gastroenteritis (“stomach flu”)
rotavirus

ii.

noroviruses (small round viruses such as Norwalk-like virus and caliciviruses)

iii.

sapovirus

iv.

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 diarrhoea no blood
and pus in stool

Bacterial gastroenteritis

Escherichia Coli

gram-negative bacilli

ii.

major groups of diarrheagenic E. coli :

iii.

enterotoxigenic E. coli (ETEC)

iv.

enteroinvasive E. coli (EIEC)

enteropathogenic E. coli (EPEC)

vi.

Shiga toxin–producing E. coli (STEC)also known

vii.

as enterohemorrhagic E. coli (EHEC)

viii.

enteroaggregative E. coli (EAEC).

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 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 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

Allergy to milk or its components

ii.

Malabsorption

iii.

Endocrinopathies

iv.

Poisoning

Neoplasia e.g.: neuroblastoma

vi.

IBD

vii.

Drugs / medications

viii.

Traveller’s Diarrhoea

Diarrhea

1.watery

2.bloody

Watery diarrhea

Viral enteritis

Enterotoxin producing bacteria:

Escherichia coli

Klebsiella organisms

Clostridium perfringens

Vibrio species

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

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
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.

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