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Diarrhea Department of Pediatrics Soochow University Affiliated Children’s Hospital Aim and Claim • Understanding the incidence and aetiology of gastroenteritis • Familiar with clinical featurs and diagnosis of gastroenteritis • Get hold of the management of dehydration Definition In epidemiological studies, Diarrhea is defined as: Passage of three or more loose or watery stools in a 24-hour period, a loose stool being one that would take the shape of a container. Definition In Pediatrics, Diarrhea is defined as an increase in the : • Fluidity • Volume of stools • Number relative to the usual habits of each individual. Importance of Diarrhea In under five children Diarrhea is a leading cause of: –Mortality(死亡率) –Morbidity(发病率) –Malnutrition(营养不良) High Childhood Mortality 3.2 million deaths/ year in <5y Children High Childhood Morbidity 1.3 billion episodes / year in <5y children Diarrhea Malnutrition Major Contributor to Malnutrition If: Diarrhea + Malnutrition In Malnourished Children the RISK of DEATH form Diarrhea is: 4 fold that of well nourished children Types of Diarrhea • Acute watery diarrhea 10 • Dysentery (Bloody diar.) • Persistent diarrhea 10 80 Acute Watery Dysentery Persistent Morphology of Intestinal Mucosa The small intestinal mucosa comprises 2 main structures: Villi(刷状缘): Covered mainly (90%) by tall columnar absorptive cells (enterocytes) having a microvillar brush border, and Goblet cells Crypts of Lieberkuhn(隐窝): Covered mainly by short columnar secretory cells without brush border Brush border (microvilli) Tight junction “Niche”for bacteria between cells Mucus layer Goblet cell Enterocyte Small Intestinal Mucosa Defense barriers of the enterocytes: 1-Physical barrier: mucus 2-Bacteriological (flora) 3- Immunological : Secretory IgA Defense Barriers of Enterocytes 1. Physical Barrier: – The mucus secreted by goblet cells opposes penetration of pathogens – Tight junctions between enterocytes 2. Bacteriological Barrier: – Saprophytic Flora occupy enterocytic “niches” thus preventing their occupation by foreign pathogens 3. Immunological Barrier: – Secretory IgA included in the mucus neutralizes the action of bacteria and Viruses Etiology of Acute Diarrhea Etiology of Acute Diarrhea Viruses: Rotavirus(轮状病毒), Enteric Adenovirus(腺病毒), Calicivirus(杯状病毒), Astrovirus(星状病毒)(70 – 80% of infectious diarrhea cases) Bacteria: Salmonella(沙门氏菌), Shigella(志贺氏菌), Campylobacter jejuni(空肠弯曲菌) Yersinia Enterocolitica(耶尔 森氏菌) Escherichia coli (ETEC,EAEC, EIEC,EHEC,EPEC) Clostridium difficile(艰难梭菌)(10 – 20% of cases) Parasites: Entamoeba histolytica(阿米巴滋养体), Giardia Lamblia (梨形鞭毛虫), Cryptosporidium(隐孢子虫)(10% of cases) Etiology: Fecal-Oral Transmission Infected Animal Infected Person Food Water Susceptible person Etiology of Acute Diarrhea The most important causes of acute diarrhea in developing countries are: • Rotavirus • Enterotoxigenic Escherichia coli • Shigella • Campylobacter jejuni • Cryptosporidium Rotavirus Pathogenesis of Rotavirus Diarrhea Rotavirus invades the absorptive enterocytes of villi but spares crypt cells. The viruses replicates and infected enterocytes are destroyed Pathogenesis of Rotavirus Diarrhea 11 2 1- Infected absorptive ente- rocytes are killed causing patchy epithelial cell destruction and villous shortening 2- Destroyed absorptive cells are rapidly replaced by cells that migrate from the crypts. Villi become covered with immature non-absorptive secretory cells having: -no brush border - no brush border enzymes Rotavirus No brush border Osmotic diarrhea Enterotoxigenic Organisms Vibrio Cholerae Enterotoxigenic E.Coli Pathogenesis of Enterotoxigenic Diar. 1-Enterotoxigenic Bacteria secrete an Enterotoxin 2-Toxin stimulates the production of C-AMP (cyclic adenosine mono-phosphate) 3-Increased C-AMP leads to: Inhibition of absorption of Na+ & Cl- from the cells of villi Stimulation of secretion of Cl- from crypt cells Enterotoxigenic E. coli Secretory diarrhea Pathogenesis of Secretory Diarrhea X NET SECRETION +++++ Entero-Invasive Organisms Shigella Pathogenesis of Invasive Diarrhea Invasive organisms like Shigella, Campylobacter jejuni, enteroinvasive E.coli, etc.: Invade and destroy the mucosal epithelial cells in colon and distal part of ileum(回肠). Formation of micro-abscesses and superficial ulcers; hence the presence of: Red and white blood cells in stools Visible blood in the stools. These organisms produce also toxins that lead to: Tissue damage Increased mucosal secretion of water and electrolytes Entero-Invasive Organisms Enterotoxin Destruction Clinical Features Viral infection may cause a prodromal illness followed by vomiting and diarrhea. The vomiting may precede diarrhea and is not usually bile or bloodstained. Abdominal pain and blood or mucus in the stools suggests an invasive bacterial pathogen. The severity of diarrhea may be underestimated if it pools in the large bowel watery stool is mistaken for urine in the nappy. Stool Characteristics and Determining Their Source Stool Characteristics • • • • • • • • Appearance bloody Volume Frequency Blood bloody Ph Reducing substances WBCs power Serum WBCs Small Bowel Watery Large Increased Possibly positive but never gross blood Possibly <5.5 Possibly positive <5/high power field Normal Large Bowel Mucousy and/or Small Increased Possibly grossly >6.5 Negative Possibly >10/high field Possible leukocytosis, bandemia Stool Characteristics and Determining Their Source Stool Characteristics Organisms Small Bowel Large Bowel Viral Rotavirus Adenovirus Calicivirus Astrovirus Norwalk virus Invasive bacteria E Coli Shigella species Salmonella species Campylobacter species Yersinia species Aeromonas species Toxic bacteria Toxic bacteria E coli Clostridium difficile Clostridium perfringens Cholera species Vibrio species Parasites Parasites Giardia species Entamoeba organisms Cryptosporidium species Clinical Findings of Dehydration mild Lose of body 5(%) weights Thirst + of tears + Sunken eyes Sunken fontanel Skin and mucous slightly dry membranes Urine output normal status intact moderate 6~9(%) + + + + dry decreased irritable severe >10(%) + + + + Absence parched decreased Mental lethargy coma,shock signs Assessment Of Dehydration Assessment of Dehydration 4 Important Signs: General condition (sensorium): Lethargic / irritable / normal Eyes : Sunken / normal Mouth (offer a drink & watch the child): Drinking poorly / drinking eagerly / drinking normally Skin turgor (skin pinch): Returns very slowly / returns slowly / returns immediately Assessment of Dehydration SIGNS G General condition Eyes E M Mouth & S No signs of dehydration well, alert normal Some (mod.) Severe dehydration dehydration restless, lethargic, irritable unconscious sunken sunken normal thirsty, drink poor or unaDrinking eagerly ble to drink Skin pinch returns rapidly returns slowly very slowly Always start from Red Column 2 or more signs in 1 column indicate that the child falls in that column Assessment of Dehydration • Severe dehydration will have two of these signs: – Sensorium(general condition): lethargic or unconscious – Sunken eyes – Drinking poorly or not at all – Very slow skin pinch (more than 2 seconds) Assessment of Dehydration • Some dehydration will have two of these signs: – Restlessness or irritability – Sunken eyes – Drinking eagerly – Slow skin pinch • No dehydration – No signs or less than 2 signs Assessment of Dehydration Severity Infants (weight <10 kg) Children (weight >10 kg) Mild dehydration 5% or 50 mL/kg 3% or 30 mL/kg Moderate dehydration 6%-9% or 60-90 mL/kg 6% or 60 mL/kg Severe dehydration >10% or >100 mL/kg 9% or 90 mL/kg Differential Diagnosis(1) Young infants(aged 2-12weeks)—pyloric stenosis— vomiting Older infant and toddlers(aged 1-2years)— intussusception—vomiting ,abdominal pain and redcurrant jelly Differential Diagnosis(2) Appendicitis Crohn Disease Irritable Bowel Syndrome Malabsorption Syndromes Meckel Diverticulum Protein Intolerance Short Bowel Syndrome Ulcerative Colitis Management Objectives Prevent dehydration, if there are no signs of dehydration; Preat dehydration, when it is present; Prevent nutritional damage, by feeding during and after diarrhoea; and Reduce the duration and severity of diarrhoea, and the occurrence of future episodes, by giving supplemental zinc. ORT OR therapy(ORT) is the cornerstone of treatment, especially for small bowel infections that produce a large volume of watery stool output. A 5-cc or 10-cc syringe without a needle is a very useful tool. The syringe can be used to quickly place small amounts of fluid in the mouth of a child who is uncooperative. Diet A strong body of evidence now suggests that resuming the prediarrhea diet is perfectly safe and must be encouraged, In an incident of worsening of diarrhea proven to be secondary to a clinically important lactose malabsorption in infants positive for rotavirus, a very transient use of lactose-free formulas (5-6 d) can be considered. Strong evidence in the literature demonstrates that the continued use of breast milk is actually beneficial in children with acute diarrhea. Special Information Anti-diarrheal agents and antiemetics are notrecommended for use in children with AGE. Antimicrobial therapies are recommended only for selected children with AGE who present with special risks or evidence of a serious bacterial infection (SBI). Probiotics (Lactobacillus GG) have been shown to reduce the duration of diarrhea and the duration of shedding of rotavirus. Lactobacillus GG may be considered as adjunctive therapy. Summary The causes of GE are viruses(70—80%),bacteria(10—20%)and parasites(10%) Patients may present diarrhoea,vomiting,abdominal pain and fever The stool may be watery,mucuous ,bloody or pyic Dehydration is classed as mild,moderate and severe.According to dehydration,you can estimate fluid deficit. GE need to differentiate varieties of diarrhoea Management of GE Quiz Physical parameters associated with degree of dehydration( Table: Clinical Findings of Dehydration ) How to estimate fluid deficit (Table: Assessment of Dehydration)