ACUTE GASTROENTERITIS IN CHILDREN

1. ACUTE GASTROENTERITIS IN CHILDREN

3. Epidemiology of acute diarrhea: developed versus developing countries.

5. NON-INFECTIOUS CAUSES • ERRORS IN FEEDING ( WRONG FORMULA, WRONG DILUTION) • FOOD INTOLERANCE • INFLAMMATION OF THE GUT • CELIAC DISEASE • GUT SURGERY • MUCOVISCIDOSIS • INFECTIONS OUTSIDE DIGESTIVE

6. Bacterial gastroenteritis • ± Bloody diarrhea • Child appears systemically ill : sepsis • Greater degree of dehydration • Abdominal pain • Raised inflammatory markers • Stool culture will show leucocytes > 5 /hpf Extra abdominal organ involvement : Bacteremia - osteomyelitis - meningitis - endocarditis

7. Common pathogens • Campylobacter • Salmonella • Shigella • Yersinia • Pathogenic E.coli Cause 10 – 15 % of diarrheal illness Under developed nations consider vibrio species

8. DiarrheagenicEscherichia coli. All forms cause disease in children in the developing world, but enterohemorrhagic E. coli (EHEC, including E. coli O157:H7) causes disease more commonly in the developed countries. • Enterotoxigenic E. coli (ETEC) — traveler’s diarrhea, diarrhea in infants and children in developing countries. • EnteropathogenicE. coli (EPEC) — children < 2 years; chronic diarrhea in children; rarely causes disease in adults. • EnteroinvasiveE. coli (EIEC) — bloodymucoiddiarrhea; feveriscommon. • EnterohemorrhagicE. coli (EHEC) — bloodydiarrhea; severe hemorrhagiccolitisandthehemolytic uremic syndrome in 6–8%; cattle are the predominant reservoir. • EnteroaggregativeE. coli (EAggEC) — waterydiarrhea in youngchildren; persistent diarrhea in childrenandadultswithhumanimmunodeficiency virus (HIV).

9. E.Coli O157H7 • Epidemic / sporadic outbreaks • Contaminated food, partially cooked beef • Verotoxin producing EHEC • Affects 3 – 5yr olds • Prodromal gastroenteritis followed by > acute renal insufficiency > hemolytic anemia > thrombocytopenia

10. Campylobacter is prevalent in adults and is one of the most frequently isolated bacteria from the feces of infants and children in developing countries. • Asymptomatic infection is very common in developing countries and is associated with the presence of cattle close to dwellings. • Infection is associated with watery diarrhea and on occasion dysentery (acute bloody diarrhea). Peak isolation rates are found in children 2 years of age and younger.

11. • Guillain–Barré syndrome is a rare complication. • • Poultry is an important source of Campylobacter infections in developed countries. • • The presence of an animal in the cooking area is a risk factor in developing countries.

12. Shigellaspecies. • There are 160 million infections annually in developing countries, primarily in children. • It is more common in toddlers and older children than in infants. • S. sonnei — mildest illness; seen most commonly in developed countries. • S. flexneri — dysenteric symptoms and persistent illness; most common in developing countries. • S. dysenteriae type 1 (Sd1) — produces Shiga toxin, as does EHEC. It has caused devastating epidemics of bloody diarrhea with case-fatality rates approaching 10% in Asia, Africa, and Central America.

13. Vibrio cholerae. • • Many species of Vibrio cause diarrhea in developing countries. • • V. cholerae serogroups O1 and O139 cause rapid and severe depletion of volume. • • In the absence of prompt and adequate rehydration, hypovolemic shock and death can occur within 12–18 h after the onset of the first symptom. • • Stools are watery, colorless, and flecked with mucus.

14. • Vomiting is common; fever is rare. • • In children, hypoglycemia can lead to convulsions and death. • • There is a potential for epidemic spread; any infection should be reported promptly to the public health authorities.

15. Salmonella. • • All serotypes (> 2000) are pathogenic for humans. • • Infants and the elderly appear to be at the greatest risk. • • Animals are the major reservoir for Salmonellae. • • There is an acute onset of nausea, vomiting, and diarrhea that may be watery or dysenteric.

16. • Fever develops in 70% of affected children. • • Bacteremia occurs in 1–5%, mostly in infants. • • Enteric fever — Salmonella typhi or paratyphi A, B, or C (typhoid fever). • • Diarrhea (with or without blood) develops, and fever lasting 3 weeks or more.

17. Rotavirus. • • Leading cause of severe, dehydrating gastroenteritis among children. • • One-third of diarrhea hospitalizations and 500 000 deaths worldwide each year. • • Nearly all children in both industrialized and developing countries have been infected with rotavirus by the time they are 3–5 years of age. Neonatal infections are a common occurrence, but are often asymptomatic. • • The incidence of clinical illness peaks in children between 4 and 23 months of age. • • Rotavirus is associated with gastroenteritis of above-average severity.

18. Rotavirus • Faeco – oral transmission • 6 – 24 months of age • Sudden onset watery diarrhea and vomiting with little abdominal pain • Self limiting in healthy individuals • 1 – 6 day duration Seasonal - temperate climates: “winter gastro” - tropical climates: summer peak • Treatment : symptomatic

19. Adenovirus. • Adenovirus infections most commonly cause illness of the respiratory system. However, depending on the infecting serotype and especially in children, they may also cause gastroenteritis. Parasiticagents Giardia intestinalis, Cryptosporidiumparvum, Entamoebahistolytica, andCyclosporacayetanensismostcommonlycause acute diarrhealillness in children. • These agents account for a relatively small proportion of cases of infectious diarrheal illnesses among children in developing countries.

20. Clinical evaluation The initial clinical evaluation of the patient should focus on: • Assessing the severity of the illness and the need for rehydration • Identifying likely causes on the basis of the history and clinical findings

22. ONSET

24. Approach to Peds Dehydration • Initial Resuscitation • Determine % dehydration • Define the type of dehydration • Determine the type and rate of rehydration fluids

25. Degree of Dehydration Mild dehydration (3-5%) Moderate dehydration (6-9%) Sever dehydration (10-15%)

26. The skin pinch is less useful in infants or children with marasmus or kwashiorkor, or obese children

27. Parameters of dehydration 3-5% 6-9% >10% Mental status N ill , not toxic lethargic Respiratory Rate N tachypnoea acidotic Capillary refill N <2s 2 – 4s > 4s Blood pressure N N hypotensive Urine output N to down down minimal The best 3 individual examination signs are: Prolonged Cap refill time Abnormal Skin turgor Abnormal resp pattern

28. Three major classes of dehydration based on relative losses of Na and Water • Isonatremic dehydration (80%) • Hypernatremic dehydration (15%) • Hyponatremic dehydration (5%)

29. Dehydration • Volume depletion - contraction of total IV plasma pool • Dehydration – loss of plasma-free water disproportionate to loss of sodium Isonatremic volume depletion : most common in “dehydrated” children --- VOLUME DEPLETION Na and H20 lost in proportionate quantities Excessive extrinsic loss of fluids Hyponatremic volume depletion Volume depletion with hyponatremia Plasma volume contraction with free water excess e.g child with diarrhea given tap water to replenish losses Hypernatremic volume depletion Volume depletion + dehydration Plasma volume contraction + free water loss

30. Isonatremic dehydration • By far the most common • Equal losses of Na and Water • Na = 130-150 • No significant change between fluid compartments • No need to correct slowly

31. Hypernatremic Dehydration • Water loss > sodium loss • Na >150mmol/L • Water shifts from ICF ( intracelular fluid) to ECF • Child appears relatively less ill • More intravascular volume • Less physical signs • Alternating between lethargy and hyperirritability

32. Hypernatremic Dehydration • Physical findings • Dry doughy skin • Increased muscle tone • Correction • Correct Na slowly • If lowered to quickly causes • massive cerebral edema • intractable seizures

33. Hyponatremic Dehydration • Sodium loss > Water loss • Na <130mmol/L • Water shifts from ECF to ICF • Child appears relatively more ill • Less intravascular volume • More clinical signs • Cerebral edema • Seizure and Coma with Na <120

34. Hyponatremic Dehydration • Correction • Must again be performed slowly unless actively seizing • Rapid correction of chronic hyponatremia thought to contribute to…. Central Pontine Myelinolysis • Fluctuating LOC • Pseudobulbar palsy • Quadraparesis

35. Electrolytes 1 Hypernatremia : Na > 145meq/L Causes : - Water loss > electrolyte loss e.g. diarrhea - Pure water depletion -Sodium excess – improper mixing of formula Plasma tonicity increases ……. Cellular dehydration Complications – cerebral hemorrhage, seizures,paralysis, encephalopathy Clinically : abdominal wall skin doughy Hyponatremia Na < 135meq/L Causes : - supplementation of fluid losses with hypotonic fluids - loss from GI tract Plasma tonicity decreases …….. Cellular oedema Complications - cerebral oedema Clinically : tenting of skin on abdominal wall

36. Electrolytes 2 • Potassium Serum potassium may not reflect true potassium Usually potassium depletion, initially not significant Consider as part of replacement fluids when adequate urine output obtained • Acidosis Bicarbonate loss in stools Decreased renal perfusion – less acids excreted Decreased tissue perfusion – lactic acid production

37. Laboratory • CBC • Inflamatory tests • Stoolanalysis of leucocytes • Stool cultures • Measurement of serum electrolytes is only required in children with severe dehydration or with moderate dehydration (hypernatremic dehydration requires specific rehydration methods — irritability and a doughy feel to the skin are typical manifestations and should be sought specifically) • Tests such as BUN and bicarbonate are only helpful when results are markedly abnormal • A normal bicarbonate concentration reduces the likelihood of dehydration • No lab test should be considered definitive for dehydration

38. DIFFERENTIAL DG

39. DIFFERENTIAL DG • Meningitis • • Bacterial sepsis • • Pneumonia • • Otitis media • • Urinary tract infection

40. Prevention • Water, sanitation, andhygiene: • • Safe water • • Sanitation: houseflies can transfer bacterial pathogens • • Hygiene: hand washing • Safe food: • • Cooking eliminates most pathogens from foods • • Exclusive breastfeeding for infants • • Weaning foods are vehicles of enteric infection • Micronutrient supplementation: the effectiveness of this depends on the child’s overall immunologic and nutritional state; further research is needed.

41. Rotavirus: in 1998, a rotavirus vaccine was licensed in the USA for routine immunization of infants. In 1999, production was stopped after the vaccine was causally linked to intussusception in infants. • Currently, two vaccines have been approved: a live oral vaccine (RotaTeq™) made by Merck for use in children, and GSK’s Rotarix™.

42. Principles of appropriate treatment for children with diarrhea and dehydrationWGO Practice Guidelines

43. Oral rehydration solution (ORS)mmol/L constituents • Sodium75 • Chloride65 • Glucose, anhydrous75 • Potassium20 • Citrate10 • Total osmolarity245 • For all children with diarrhea: 20 mg zinc for 14 days. • In children who are in hemodynamic shock or with abdominal ileus, ORT may be contraindicated. For children who are unable to tolerate ORS via the oral route (with persistent vomiting), nasogastric feeding can be used to administer ORS.

44. Oral rehydration solutions (ORS)

45. ORT • Oral rehydration therapy • Appropriate for mild to moderate dehydration • Safer • Less costly • Administered in various clinical settings • Fluid replacement should be over 3-4hrs • 50ml/kg for mild dehydration • 100ml/kg for moderate dehydration • 10ml/kg for each episode of vomiting or watery diarrhea

46. Minimal or no dehydration.

47. Mild to moderate dehydration

48. ORT • Contraindications to ORT • Severe dehydration (≥10%) • Ileus or intestinal obstruction • Unable to tolerate (Persistent vomiting) • Signs of shock • Decreased LOC (Level of consciousness) or unconscious • Unclear diagnosis • Psychosocial situations

49. Severe dehydration.

50. Resuscitation • Emergency resuscitation phase Re – expansion of intravascular space Iso tonic crystalloid – 0.9%NaCl = 20ml/kg over 20 minutes Ringers Plasmalyte Reassess after each bolus Repeat up to 60ml/kg No improvement ? Reassess for other pathology e.g septic shock NB NB check glucose !!!!