acute gastroenteritis
DESCRIPTION
Acute Gastroenteritis. Jie Chen , MD ,phD Children Hospital Zhe Jiang University. 教学目标. 1. 掌握小儿腹泻病的病因分类及临床表现; 2. 掌握小儿腹泻病的诊断和治疗原则. Diarrhea. Diarrhea is a clinical syndrome of diverse etiology associated with many influencing factors - PowerPoint PPT PresentationTRANSCRIPT
Acute GastroenteritisAcute Gastroenteritis
Jie Chen , MD ,phD
Children Hospital
Zhe Jiang University
教学目标教学目标
1. 掌握小儿腹泻病的病因分类及临床表现;
2. 掌握小儿腹泻病的诊断和治疗原则
Diarrhea Diarrhea
Diarrhea is a clinical syndrome of diverse etiology associated with many influencing factors
• In pediatrics, diarrhea is defined as an increase in the– Fluidity– Volume of the stool – Frequency
Relative to the usual habits of each individual
Classification of Diarrhea in InfantClassification of Diarrhea in Infant
• Acute diarrhea:
– Short in duration( less than 2 weeks)
• Persistent or chronic diarrhea:
– 2 weeks or more
Gastroenteritis or enteritis
Systemic infection
Overfeeding
Antibiotic association
Post infectionSecondary dissacaridase deficiencyIBSFood allergy , et al
Type of diarrheaType of diarrhea
• Acute watery diarrhea – (80% cases)
• Dysentery – (10%cases)
• Persistent or chronic diarrhea– (10%cases)
Infective Non infective
Viruses Bacteria Parasites
Fungi
Food Allergy
Symptomatic
Overfeeding
Intolerance
Climate
Etiology of DiarrheaEtiology of Diarrhea
Common Infectious Causes of Diarrhea Common Infectious Causes of Diarrhea
• Viruses Rotavirus
Astrovirus
Calicivirus (including norovirus)
Enteric adenovirus (serotypes 40 and 41)
Common Infectious Causes of Diarrhea Common Infectious Causes of Diarrhea
• Bacteria – Campylobacter jejuni – Escherichia coli
• EPEC; ETEC; EITC; EHEC; EAEC– Shigella – Salmonella– Yersinia enterocolitica– Staphylococcus aureus – Clostridium difficile– Vibrio cholerae– Vibrio parahemolyticus
Common Infectious Causes of Diarrhea Common Infectious Causes of Diarrhea
• Parasites
– Entamoeba histolytica (ambiasis)
– Giardia lamblia
– Cruptosporidium parvum
• Fungi
– Candida albicans
EpidemiologyEpidemiology :: FecesFeces——mouthmouth routeroute
WaterFood
Infected Animal
Infected Person
Person
Mechanisms of diarrheaMechanisms of diarrhea
• Osmotic
• Secretory
• Mucosal inflammation (invasion)
• Motality
Mechanisms of DiarrheaMechanisms of Diarrhea
OsmoticDefect
Digestive enzyme deficiencies
Ingestion of unabsorbable solute
ExampleViral infection
Lactase deficiency
Sorbitol /magnesium sulfate
CommentStop with fasting
No stool WBCs
Mechanisms of DiarrheaMechanisms of Diarrhea
SecretoryDefect Increased secretion Decreased absorptionExample Cholera Toxinogenic E.coliComment Persists during fasting No stool leukocytes
Mechanisms of DiarrheaMechanisms of Diarrhea
InvasionDefect
InflammationDecreased colonic reabsorptionIncreased motility
ExampleBacterial enteritis
CommentBlood, mucus and WBCs in stool
Mechanisms of DiarrheaMechanisms of Diarrhea
Increased motility
DefectDecreased transit time
Example:
Irritable bowel syndrome
Common infectious causes of diarrhea Common infectious causes of diarrhea and their virulent mechanismand their virulent mechanism
• Viral diarrhea (osmotic)• Rotavirus
• Bacterial diarrhea– Enterotoxinogenic enteritis (secretory)
• ETEC• Vibrio cholerae
– Entero-invasive enteritis (invasion)• Campylobacter jejuni• EIEC• Shigella species• Salmonella tymphimurium• Yersinia enterocolitica
Rotaviruses attach and replicate in the mature enterocytes at the tips of small intestinal villi
Destroy villus tip cells, variable degrees of villus blunting mononuclear inflammatory infiltrate in the lamina propria
Impairment of digestive functionsdiscreasing hydrolysis of disaccharides
Impairment of absorptive functionsthe transport of water and electrolytes via glucose and amino acid co-transporters
An imbalance in intestinal fluid absorption to secretion
Malabsorption of complex carbohydrates, particularly lactose
Other than digested into monosaccharide, lactose be lysis into organic acid, hyper-osmosis Watery stool
Pathogenesis of Rotavirus enteritisPathogenesis of Rotavirus enteritis
enterotoxigenic organisms
Ingestion small bowel mucosa and proliferate
activates cellular guanylatecyclase
Heat-stable enterotoxin
promote the net secretion of water and chloride
increased intracellular concentrations of cAMP
activates cellular adenylcyclase
binds to receptors of epithelial cells
Heat-labile enterotoxin
decrease absorption of sodium and chloride by villous cells
increased intracellular concentrations of cGMP
Watery diarrhea
Pathogenesis of enterotoxinogenic Pathogenesis of enterotoxinogenic enteritisenteritis
• The mucosa is not destroyed during
this process
• An imbalance in the ratio of intestinal
fluid absorption to secretion, so
watery stoolwatery stool may occur in clinical
observation
Pathogenesis of enterotoxinogenic Pathogenesis of enterotoxinogenic enteritisenteritis
Invasive enteropathogen
Ingestion Gut lumenColon and rectum mucous membrane
proper
Extensive destruction of the epithelial layer Inflammation: Hyperemia, swelling, heavy neutrophil
infiltration, inflammatory exudate
The desquamation, ulceration, and formation of microabscesses in the colonic mucosa inhibit absorption of
water
stools that are frequent and scanty and that contain blood inflammatory cells and mucus
Pathogenesis of invasive enteritisPathogenesis of invasive enteritis
Clinical manifestationClinical manifestation
Gastrointestinal symptom
Systemic symptom
Dehydration and electrolyte disturbancesDehydration
Hypokalemia
Metabolic Acidosis
Hypocalcemia /Hypomagnesemia
DehydrationDehydration
• Excessive loss of water, • especially loss of extracellular fluid
Degree of dehydrationDegree of dehydration
Dehydration Mild Moderate SevereDecrease in body weight
3% ~ 5 %(50ml / kg)
5 ~ 10 %(50 ~ 100ml / kg)
10 % ~ 15%(100 ~ 120ml / kg)
Mental Well, alertIrritable/Restless/
thirstyLethargic/coma
Fontanel/Eye Sunken ± Sunken Severely sunken
Skin turgor Normal ± Decrease Markedly decrease
Mouth+tongue normal sticky Dry
Tears present Decrease Absent
Urine Mild oliguria oliguria Anuria
Blood pressure
heart rate
Pulse
Capillary refill
Normal
Normal
Tachycardia little
≤ 2 seconds
Hypotension
Tachycardia with weak pulse
≥ 3 seconds
Type of dehydrationType of dehydration
Isotonic Isotonic
(isonatremic)(isonatremic)Hypertonic Hypertonic
(hypernatremic)(hypernatremic)Hypotonic Hypotonic
(hyponatremic)(hyponatremic)
Loses H2O = Na H2O > Na H2O < Na
Plasma osmolality
Normal Increase Decrease
Serum Na+ Normal Increase
>150mmol/L
Decrease
<130mmol/L
ECV
ICV
Decrease maintained
Decrease
Decrease +++
Decrease +++
Increase
Thirst ++ +++ +/-
Skin turgor ++ Not lost +++
Mental state Irritable/lethargic Very irritable Lethargy/coma
shock In severe cases Uncommon Common
Metabolic AcidosisMetabolic Acidosis
• Pathogeny– lose of large amount of basic substances from
gastrointestinal tract– too much acid metabolite
• Blood gas analysis pH nomarl HCO3- CO2 pH HCO3- CO2
• Degree– Mild HCO3
- 18~13 mmol / L– Moderate HCO3
- 13~9 mmol / L– Severe HCO3
- <9 mmol / L
hypokelemiahypokelemia
• Pathogeny– Lake of intake– Loss of potassium from gastrointestinal
tract• Blood electrolytes analysis
– K+ < 3.5 mmol/L
HypokelemaHypokelema
• Clinical manifestation– Nervous system
• depressed– Muscle
• inertia of limbs , muscular tension down , severely retardant paralysis , respiratory muscle paralysis
– Heart• heart rate increasing, arrhythmia, Adams -
Stokes syndrome, heart rate decreasing , atrioventricular block, heart sound lowering,
• Cardiogram– U wave appearing , U≥T , flattened T wave,
Laboratory and Imaging StudiesLaboratory and Imaging Studies
• Initial laboratory evaluation – CBC – Stool examination: mucus, blood, and leukocytes– Gas and electrolytes analysis – BUN, Cr, and urinalysis for specific gravity
• Rapid test for Rotavirus• Stool cluture
• for patients with fever, profuse diarrhea, and dehydration or if HUS is suspected
• Stool evaluation for parasitic agents – identification of the organism in the stool
• Blood culture• uncommom
Diagnosis & Differential Diagnosis Diagnosis & Differential Diagnosis
Diarrhea?
Watery, loose stools without or only a
minute amount of WBC
Epidemic dataStool cultureSerous assay
Stool cultureSerous assay
Shigella EIEC CJ
Salmonella Yersinia
Virus ETECEPEC
WBC and RBC, mucus in stools
Acute stagePersisting or
chronic diarrhea
Antibiotic associate diarrhea
Infective
Non-infective Allergic state? Symptomatic diarrhea? Inappropriate feeding? food intolerance Lack of disaccharidase? Immunodeficience? Malnutrition? Malabsorption ? etc.
Persisting infection?
Entamoeba histolytic
Giardia lamblia Cryptosporidium
Staphylo CD
Candida
TreatmentTreatment
• Primarily supportive– Fluid therapy
• Rehydration• Correcting acidosis• Potassium supplement • Correcting ongoing loss
– Managing secondary complication resulting from mucosa injury
• Antibiotic treatment – for only some bacterial and parasitic causes of
diarrhea
• Start food as soon as possilble
Fluid Management of DehydrationFluid Management of Dehydration
• Calculate 24-hr water needs
– Calculate maintenance water
– Calculate deficit water
• Calculate 24-hr electrolyte needs
– Calculate maintenance sodium and potassium
– Calculate deficit sodium and potassium
• Select an appropriate fluid (based on total water and electrolyte needs)
– Administer half the calculated fluid during the first 8 hr, first subtracting any boluses from this amount
– Administer the remainder over the next 16 hr
• Replace ongoing losses as they occur
Fluid TherapyFluid Therapy
• Deficit of water and electrolytes– Water Deficit: Percent dehydration × weight
– Sodium Deficit:Water deficit × 80 mEq/L
– Potassium Deficit:Water deficit × 30 mEq/L
• Ongoing loss– After they occur
– Sodium: 55 mEq/L
– Potassium: 25 mEq/L
– Bicarbonate: 15 mEq/L
• Maintenance– 0-10kg 100 mL/kg
– 11-20kg 1000 mL + 50 mL/kg for each 1 kg >10 kg– >20kg 1500 mL + 20 mL/kg for each 1 kg >20 kg*(max 2400mL)
– Sodium : 2 - 3 mEq/kg/day
– potassium : 1-2mEq/kg/day
Fluid TherapyFluid Therapy
• ORT– Mild to moderate dehydration from diarrhea
• Intravenous– With severe dehydration
– with uncontrollable vomiting
– unable to drink because of extreme fatigue, stupor, or coma
– with gastric or intestinal distention
Sodium Chloride
Tri-Sodium Citrate (bicarbonate)
Potassium Chloride
Glucose
ORS compositionORS composition
Type of ORSType of ORS
Solution Glu g/L
Na mEq/L
K mEq/L
Cl mEq/L
WHO 20.0 90 20 80
Rehydralyte 20.5 75 20 65
Pedialyte 20.5 45 20 35
Infanlyte 20.0 50 20 40
ORT ORT
• Mild: ORS 50 mL/kg within 4 hours
• Moderate: ORS 100 mL/kg over 4 hours to
• Supplementary ORS is given to replace ongoing
losses
– An additional 10 mL/kg of ORS is given for each
stool
• Breastfeeding should be allowed after rehydration
in infants who are breastfed
• usual formula, milk, or feeding for other patients
should be offered after rehydration
Intravenous treatmentIntravenous treatment
• Restore intravascular volume– Normal saline: 20 mL/kg over 20 min (repeat until
intravascular volume restored)
• Deficit of water and electrolytes– Solution: 5% dextrose in half NS + 20 mEq/L of potassium
chloride
• Ongoing loss– Solution: 5% dextrose in ¼ normal saline + 15 mEq/L
bicarbonate + 25 mEq/L potassium chloride
• Maintenance– Solution: 5% dextrose in ¼ normal saline + 20 mEq/L of
potassium chloride
Given over the first 8 hrs
Given over the next 16 hrs
Organisms AntibioticCampylobacter Jejuni
erythromycin
azithromycin
E. Coli EPEC: Indicated for infants younger than 3
months old with
ETEC: Usually none if endemic
TMP-SMZ or ciprofloxacin for traveler's
diarrhea
EIEC: Third-generation cephalosporin
TMP-SMZ
Ampicillin
EHEC: not recommend
EAEC: TMP-SMZ
Antibiotic Therapy Antibiotic Therapy
Organisms AntibioticShigella species
Third-generation cephalosporin
Ampicillin, TMP-SMZ†,
Salmonella Usually none (if ≥ 3 months old) for non
typhoid;
ampicillin, cefotaxime for S. typhi or
S.paratyphy
Yersinia enterocolitica
None for uncomplicated diarrhea; TMP-
SMZ; gentamicin or cefotaxime for
extraintestinal disease
C. difficile metronidazole,
vancomycin
Antibiotic Therapy Antibiotic Therapy
Organisms AntibioticE. histocolytica metronidazole followed by a luminal agent,
such as iodoquinol
G. lamblia Albendazole
Metronidazole
Furazolidone
Quinacrine
Cryptospodium Non specific treatment
Antibiotic Therapy Antibiotic Therapy
Complication _watery diarrheaComplication _watery diarrhea
• Hypovolemic shock
• Tetany & Convulsions
• Hypoglycemia
• Renal failure
Complication _dysenteryComplication _dysentery
• Toxic encephalopathy
• Hemolytic uremic syndrome (HUS)
• Intestinal abcess
• Protein losing enteropathy
• Arthritis
• Perforation
Dehydration Malnutrition
Mortality
Prognosis Prognosis
Global Impact of Enteric Disease Deaths Global Impact of Enteric Disease Deaths in young childrenin young children
Cholera120 000
ETEC380 000
Typhoid600 000
Average of 2.2 million deaths per year worldwide
Shigella670 000
Rotavirus450 000
WHO, 2000
PreventionPrevention
• Safe drinking water and food
– “Boil it, cook it, peel it, or forget it. "
• Hand washing
• Proper sanitation
• Vaccines