Presentation on theme: "Gastroenteritis in Children RR Kalebka. Definition Acute inflammation of the lining of the stomach and intestines caused by viruses, bacteria or their."— Presentation transcript:
Gastroenteritis in Children RR Kalebka
Definition Acute inflammation of the lining of the stomach and intestines caused by viruses, bacteria or their toxins and parasites. Presents commonly with diarrhea, abdominal cramps and vomiting. Common complaint in the ER Also significant cause of mortality in under-developed countries Person to person spread or ingestion of contaminated food or water Diarrhea : daily stools with mass > 15g/kg for children <2 > 200g for children 2 +
“Food poisoning” Common foods and pathogens involved with under cooked/ inappropriately stored foods. Ice cream, custard – S. aureus Eggs – Salmonella Dairy – Campylobacter/ Salmonella Meats – C. perfringens/ Salmonella Ground beef – Enterohemorrhagic E. coli Rice - Bacillus cereus
Water borne Viruses Shigella E. coli V. cholera E. histolytica Poor socio – economic conditions Lack of sanitation Overcrowding
Common viral pathogens
Rota virus 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
Norwalk agent “Epidemics” of diarrhea in communities Closed / semi closed communities School - age children, family contacts and adults affected Diarrhea, nausea and abdominal cramps Vomiting not prominent Self limiting 24 – 48 hours Treatment : supportive
Viral Gastroenteritis Summary Self limiting Usually no bloody stools Mild to moderate dehydration Generally not toxic Usually amenable to oral rehydration and/or overnight admission
Pathogenesis Invasion with mucosal ulceration and activation of inflammatory cascade, formation of abscesses e.g. Campylobacter, Salmonella, Shigella Generation of toxins e.g Staphylococcal food poisoning Shigella toxin Combination of above
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
Common pathogens Campylobacter Salmonella Shigella Yersinia Pathogenic E.coli Cause 10 – 15 % of diarrheal illness Under developed nations consider vibrio species
Salmonella Food borne outbreaks in summer Incubation 8 – 48 hrs Abdominal cramps / nausea May/may not have bloody stools White cell count marginally raised Stool methylene blue staining shows polymorphonuclear lymphocytes Rectal swab positive in most cases Complications - dehydration - dissemination - osteomyelitis - meningitis - endocarditis
Enteric fever Dissemination of certain salmonella S.typhi ----- typhoid fever Chills and fever, 40deg + Relative bradycardia Splenomegaly Macular rash Leucopenia
Shigella Swimming pools, water borne, travel ASx – mild gastroenteritis – bacillary dysentry Bacillary dysentry - profound inflammatory Rx - fever, abdominal pain, SICK ! - diffusely tender abdomen, not peritonitic - mucoid/bloody stools, tenesmus - toxin production causes CNS irritation - sheets of neutrophils with methylene blue stain Complications : dehydration, seizures, colonic perf.
E.coli Type of illness depends on viro type Enterohemorrhagic (EHEC) – HUS, haemorrhagic colitis Enteroaggregative (EAEC ) – persistent diarrhea in underdeveloped countries Enteropathogenic (EPEC) – leading cause of infantile diarrhea in africa Enteroinvasive (EIEC ) - similar to shigella dysentry
Cholera Water born Unsanitary conditions Toxin producing V.cholera Heat labile enterotoxin causes inhibition of Na+ reabsorbtion through adenyl cyclase activation Incubation 24 – 72 hours Severity of symptoms depends on “dose” of organisms Watery brown diarrhea becoming pale ( rice water ) Fluid loss can be MASSIVE
Approach to Gastroenteritis NB MANY sick children present with “gastro” Convenient diagnosis !! History General examination: How sick is the child ? Hydration/nutritional state System examination: exclude co- existing / underlying pathology Consider differential diagnosis.
Risk factors for dehydration Unable to consume water independently Unable to regulate temperature effectively Large surface area in relation to weight Larger evaporative losses - tachypnea - crying / tears
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
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
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
Parameters of dehydration 3-5% 6-9% >10% Mental status N ill, not toxic lethargic Heart rate N or up tachycardia marked tachy Pulse quality N N or down poor quality Respiratory Rate N tachypnoea acidotic Capillary refill N 4s Perfusion warm cool cool, mottled Blood pressure N N hypotensive Eyes N slightly sunken very sunken Tears N decreased absent Mucous membranes moist sticky dry Skin turgor recoil delayed markedly delayed Urine output N to down down minimal
ORS Vomiting not contraindication Rehydration modality of choice EXCEPT – Severe volume loss/shock - lethargy - electrolyte problems - significant co existing/underlying illness - acute abdomen/ obstruction - clinical judgment dictates otherwise Estimate severity Mild: 60ml/kg Moderate 80ml/kg 25% volume given each hour for 4 hours and reassess.
Failure of ORS Inability/unwillingness to ingest fluid Ongoing losses exceeding rate of replenishment Poor technique Poor motivation i.e. “ fed up” parent Problem of ongoing vomiting ? - continue with small volumes frequently Nasogastric tube an option : continuous administration of ORS Vomiting not a contraindication Safe and efficient alternative
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 !!!!
Replacement phase Existing deficit %dehydration x body weight x 10 = ml 50% given over first 8 hours, the rest over next 16hrs + Maintenance fluids Calculation : 100ml/kg first 10 kg 50ml/kg next 10kg 25ml/kg for each kg above 20kg Give fluids as 0.45%NaCl + 5% dextrose Add 10mmol KCl to each 500 ml NB. Ongoing losses !!!!! NB ½ darrows contains K
Electrolytes Acidosis Assess on blood gas Bicarbonate supplement : 1/3 x base deficit x body weight Hyponatremia Treat if Na < 125 Calculate Na deficit = (Desired Na – Measured Na) x 0.6 x kg Safe rate of change = 12mmol/L rise / day Hypernatremia pure free water deficit Calculate [(Na – 145) /2]x [4ml/kg] x wt (kg) Safe rate of change = 12mmol/L decline/day
Role of drugs Antibiotics not indicated in viral or uncomplicated bacterial Gastroenteritis May cause more harm than good e.g. prolonging carrier state of some Salmonella infections potentiation of toxin production by pathogenic e.coli Antibiotics are indicated in > gastroenteritis complicated by septicemia > cholera, shigellosis, enteric fever, amoebiasis, giardiasis NO antiemetics / anti motility agents Oral zinc given in developing countries decreases duration of symptoms
Don’t get caught out !! >Vomiting only – always consider another diagnosis e.g. poisoning, intestinal obstruction, appendicitis, intussusseption and metabolic causes >Children <3 mo rarely get “gastro” >Urinary tract infections, URTI’s,LRTI’s can present as “gastro”