Vomiting, Diarrhoea, Abdominal Pain & Fluid Therapy

1. Vomiting, Diarrhoea, Abdominal Pain&Fluid Therapy Department of Paediatrics CUHK

2. Vomiting • vomiting • forceful ejection of gastric contents • often preceded by nausea and retching • possetting • gentle expulsion of gastric contents with swallowed air (“wind”) • regurgitation • similar to possetting, but larger loss • retching • laboured rhythmic respiratory activity that precedes vomiting

3. Vomiting process • patent upper GI tract • retro-peristalsis • lower esophageal sphincter relaxation • contraction of abdominal muscles and diaphragm Mechanism of vomiting

4. CNS irritation • infection • raised ICP • drugs / poisons • metabolites • infection/inflammation • gastroenteritis • viral • bacterial • toxin • immunological • cow-milk • coeliac • food allergy • inflammatory • appendicitis • mesenteric adenitis • Incompetent LES • possetting • reflux • hiatus hernia • GI obstruction • pyloric stenosis • intussusception • volvulus • strangulated hernia • Hirschsprung • tumour • post-operative ilieus Causes of Vomiting

5. Diarrhoea • Diarrhoea: increase in frequency (> 3 times) and change in character of stool (volume and liquidity) • Lead to rapid dehydration and progressive acidosis • Acute - within 2 weeks • Chronic or persistent - beyond 2 weeks • WHO: 2.6 episodes/child/year, global mortality 3.3 million/year

6. Infective gastroenteritis

7. Acute gastroenteritis • Morbidity in developed world, yet mortality in developing world • Complicated in developed world with secondary lactase deficiency • Complicated in developing world with recurrent episodes and malnutrition, like deficiency of zinc, vitamin A etc, • Especially affecting children < 2 years

8. Infective causes of diarrhoea and vomiting Viruses Bacteria Rotavirus Enteroinvasive E. coli Adenovirus Camphylobacter jejuni Coronavirus Salmonella sp. Astrovirus Shigella sp. Calcivirus Vibrio cholera Parvovirus Yersinia enterocolitica Echovirus Protozoa Bacterial toxins Giardia lamblia Enterotoxic E. coli Crytosporidium Staphylococcus aureus Entamoeba histolytica Bacillus cereus Malaria Clostridium difficile

9. Bacterial Gastroenteritis • Salmonella, E coli (EPEC, EIEC, EHEC, VTEC-0157), Shigella (neurotoxin), Yersinia, Campylobacter • Adherence and invasion of bacteria to gut structures • Bloody diarrhoea, Fever, Tenesmus, Severe or persistent symptoms • Antibiotic use, Clostridium(toxin is common in healthy newborn)

10. Cholera • cause secretory diarrhoea • enterotoxin production leading to generation of intracellular cAMP (adenyl cyclase) • result in stimulation of the chloride channel leading to fluid and electrolytes secretion • could also cause increased production of prostaglandins • absorption of fluid and e- remains intact

11. Virus Gastroenteritis • Rotavirus attacks the villus epithelium of the small intestine • Norwalk virus - vomit • Enteric adenoviruses • increase in epithelial renewal with crypt proliferation, interfering the process of maturation • repair takes 4 - 5 days, affected by chronic protein-calorie malnutrition

12. Rotavirus gastroenteritis • Most common cause in infants and young children (6 - 12 months), occurs in winter • Within two days of exposure, low grade fever,anorexia, & vomiting lasting up to 48 hours. Watery diarrhea and cramps follow • Highly infective, resistant to drying and chlorine in tap water. Nosocomial outbreaks occur in hospital and nurseries • Fecal-oral transmission

13. Rotavirus gastroenteritis • Infect the villi of small intestine, causing damage to transport mechanisms, secondary lactase deficiency and malabsorption • Local IgA response, no life-long protection • Diagnosis by viral antigen detection • Self-limiting disease with complete recovery • Prevention by improving overall standard of nutrition and hygiene (handwashing, disposal of diapers), ?oral vaccine

14. Norwalk / Norwalk-like / Norovirus • Norwalk virus was named after the strain that was responsible for an outbreak of gastroenteritis in a school in Norwalk, Ohio, USA • Recently approved name: Norovirus, a RNA virus • More common during cooler months • As of November 17, there were 41 reported cases of viral gastroenteritis caused by Norwalk-like virus, affecting about 1,000 persons and occurring in institutions like schools, child care centres and homes for the elderly.

15. * 截至二零零三年十月 Up to October 2003

16. 二零零三年* 受諾沃克類病毒影響人數 Number of Persons Affected of Norwalk-like Disease 2003* 中學 Secondary school 醫院 Hospital 4% 1% 小學 Primary school 19% 安老院舍 Elderly home 幼稚園 Kindergarten 48% 4% 幼兒中心 Child care centre 10% 院舍 Institutions 家居 Home 9% 5% *截至二零零三年十月。 *Up to October 2003

17. Norovirus gastroenteritis • Incubation 1 - 2 days • Usually self-limited, lasts 1 - 10 days • Symptoms • Vomiting • Diarrhoea • Fever • Abdominal cramps • Headache

18. Clinical Approach to a child who presents with vomiting or diarrhoea

19. History: Vomiting • Onset • Present since birth ? • Present since weaning ? • Present since introduction of new food? • Sudden or gradual ? • Vomit • Size, frequency and timing to feed • Undigested food ? bile ? blood ? coffee-ground ?

20. History: Diarrhoea • Onset • Sudden or gradual ? • Stool • Volume, frequency and timing to feed • Loose, watery, rice watery • Blood, mucus, steatorrhoea

21. History: • Associated symptoms • Abdominal pain / Abdominal distension • Fever • Change in appetite / feeding habit • Weight loss ? or gain ? • General: playfulness, activities, urine output • Social history • Family members having vomiting / diarrhoea • Recent traveling

22. Examination • Full examination is necessary in all children • General examination • Activity • Nutritional status • Weight and Height (and compare with previous) • Temperature • Anaemia • Jaundice • Degree of dehydration • Cleft palate • Neurological

24. In hypertonic dehydration, signs not prominent because of intracellular dehydration; skin of doughy consistency with abnormal behaviour

25. Examination • Abdomen: Inspection • Distension • Constipation • Gastroenteritis • Obstruction / Ileus • Coeliac Disease • Surgical Scar

26. Examination • Abdomen: Palpation • Local tenderness • Generalized tenderness • Guarding and rebound tenderness • Peritoneal irritation • Masses • Organomegaly • Pyloric mass • Sausage shaped mass • Hernial orifices • Genitalia

27. Examination • Abdomen: Auscultation • Bowel sounds • Normal • Hyperactive: irritation, obstruction • Diminished, absent: paralytic ileus • Abdomen: Rectal examination • Anal fissures • Sphincter • Faeces • Blood • Masses

28. Investigations • Ordered according to index of suspicion • Examine stool for consistency, blood, mucus, and steatorrhoea • Stool for bacterial culture and virus isolation Positive yield ~50% • Commonest: rotavirus • Commonest bacterial: Salmonella • Stool for Clostridial difficile toxin • Blood for cell counts, U&Es, culture

29. Investigations • Test feed for infant 2 to 10 weeks • Examine urine for RBC, WBC and organism under microscope, urine for culture • AXR: Supine, Erect for intestinal obstruction • USG abdomen

30. Treatment • Rehydration • Rehydration • Rehydration fluid and electrolytes • Oral glucose-electrolyte solution • Intravenous glucose-electrolyte solution • Nutritional treatment - continuation of breast feeding (lactadherin), or formula feeding

31. Principles of fluid replacement : volume required= maintenance + deficit + ongoing loss

32. Daily fluid requirement Fluid First 10 kg 100 ml/kg/day Second 10 kg 50 ml/kg/day After first 20 kg 20 ml/kg/day Increase by 10% per degree Celcius rise in body temperature Electrolytes Sodium 3 mmol/kg/day Potassium 2 mmol/kg/day For a 25-kg boy Daily fluid requirement for a 25-kg boy = 1000 ml + 500 ml + 100 ml = 1600 ml Daily Na requirement = 75 mmol Daily K requirement = 50 mmol

33. Fluid deficit calculation Volume depleted = estimated % of dehydration x body weight For a 25 kg boy with 10 % dehydration Volume deficit (1 L water = 1 kg) = 10% x 25 kg = 2.5 L

34. Fluid ongoing loss • Most difficult • Measure stool output and volume of vomitus

35. Oral versus intravenous fluid replacement therapy

36. AAP Practice Parameter 1996 • ORS is the preferred treatment for fluid and electrolyte losses caused by diarrhoea in children who have mild to moderate dehydration • Use of cola, fruit juice and sports beverages is not recommended • Inappropriate electrolyte content • Too much carbohydrate

37. ORS • Commercially available ORS contain 45-50mmol/l of sodium • Best suitable for maintenance • Can also be used in mild to moderate dehydrated otherwise healthy children • Taste better than the saltier solution • WHO recommended ORS • High sodium content 90mmol/l • Suitable for secretory diarrhoea eg. Cholera

38. ORS Therapy in mild to moderate dehydration • 50-100ml/kg ORS to be given over a 4-hour period • Replacement of stool (10ml/kg for each stool) and vomitus will require adding appropriate amounts of solution to the total • Administering in small but frequent amounts • 10 ml every two minutes = 500 ml over 4 hours • Labour intensive, time consuming

39. Intravenous fluid therapy • Although oral rehydration is encouraged, clinician must be prepared to administer IV fluids who do not respond to oral regimen • Severely dehydrated or who are in a state of shock must receive immediate and aggressive intravenous fluid therapy

40. 10-20ml/kg 0.9% NaCl Reassess Phase I: Treat shock (0 - 30 minutes) Phase II: Initial Rehydration (½ - 8 hours) Phase III: Continued Replacement (8 - 24 hours) Improved No Change Measure plasma electrolytes Calculate fluid deficit and maintenance Initial replacement with saline-dextrose solution Half the calculated fluid deficit plus maintenance Review plasma electrolytes and fluid status Replacement with saline-dextrose solution Half the calculated fluid deficit plus maintenance

41. Sodium replacement • Sodium deficit in mmol required = (140 - [Na+] x 0.65 x body weight in kg) • 0.65 is the volume of distribution of Na • Sodium replacement = sodium daily requirement + sodium deficit • If due to water intoxication (iatrogenic, SIADH) • Restrict fluid

42. Treatment of metabolic acidosis For full correction of acidosis, NaHCO3 required (mmol) = Base deficit x body weight x 0.3 In most cases, metabolic acidosis is self-corrected once dehydration corrected and hence effective circulation volume restored In rare situation, half of the calculated required NaHCO3 may be given: watch out for Na overload and pulmonary oedema

43. Hypertonic dehydration • Difficult to assess degree of dehydration, unless the child in clinically shock (>10% dehydration) • The plan • Fluid resuscitation 10-20 ml/kg NaCl over first 1 hr • replace total fluid deficit plus maintenance slowly over 48-72 hours • To lower serum sodium slowly:  10mmol/L/day • Rapid correction may cause cerebral oedema

44. Monitor • Body weight • Vital signs, heart rate, blood pressure, respiratory rate • Subsidence of signs of dehydration • Input and output charts • Continuous loss • Serum electrolytes • In severe cases blood glucose, blood gases, osmolality

45. Antibiotics in special circumstance • Salmonella GE in infant • Shigella with trimethoprim-sulfamethoxazole • Campylobacter with erythromycin • Cholera with tetracycline • Amoebic dysentery - giardiasis (metronidazole) • NB: drug resistance, promote carrier state, worsen the course of diarrhoea

46. Refeeding • Children who have diarrhoea and are not dehydrated should continue to be fed regular diet • Children who require rehydration should be fed regular diet as soon as they have been rehydrated • Early feeding of regular diet does not worsen the course or symptoms of mild diarrhoea and may reduce the duration of diarrhoea modestly

47. Refeeding • Avoid fatty foods and foods high in simple sugars • Rice, wheat, potatoes, bread and cereals (complex carbohydrate), lean meats, yogurt, fruits and vegetables are usually well tolerated • Most children who have diarrhoea will tolerate full-strength milk • Lactose-free formula may be used if secondary lactase deficiency is suspected

48. Antidiarrhoeal compounds • Decrease stool water and electrolyte losses • Change toward more formed stool • Relieve discomfort • False sense of security • Delaying more effective therapy • Generally not recommended

49. Drugs that alter intestinal motility • Loperamide • Decreases transit velocity • Increases the ability of gut to maintain fluid • Reduces stool losses, shortens the course of diarrhoea • Associates with serious adverse effect • Lethargy, ileus, respiratory depression and coma • Death has been reported

50. Drugs that alter secretion • Bismuth compounds, eg. Bismuth subsalicylate • Inhibit intestinal secretion • Modest beneficial effects • Dose of every 4 hours for 5 days • Theoretical risk of Reye syndrome from salicylate absorption