Paediatrics JC117: A Child With Loose Bowel Flashcards
GE in children
Etiology + Management vary with geographic region, socioeconomic situations, health service provision
BUT Majority of principles hold true
History taking of GE in children
- Clarification of chief complaint
- Definition: **Alteration in normal bowel movement characterised by change in stool **consistency to loose / watery, with ↑ **frequency + **volume
- ***Acute / Chronic
- ***Character: Water vs bloody, Presence of mucus
—> Watery stool without blood / mucus: Enterotoxin, Virus, Protozoan
—> Blood stool with mucus (indicate mucosal inflammation, death of mucus-secreting cells in gut, capillary breakage): Cytotoxin-producing bacteria, Enteric parasites - ***Frequency
- ***Volume
- Severity assessment
- No. of episodes (tricky in infants with nappies)
- Frequency
- Estimated amount (as judged by parents)
- Consistency
—> no absolute cutoff, only indicate change from baseline / normal pattern (depend on age, breast-feeding) - Concurrent symptoms
- **Vomiting
- **Fever
- Poor appetite (quantify intake!)
- ***Abdominal pain (often presents as Irritability, crying episodically (cramps, drawing up legs) not consolable!) —> Intussusception -
**Dehydration / **Impaired perfusion
- **Cry without tears
- **Dry lips
- **Cool limbs
- **Urine output
- ***Tiredness
- Risk factors: Frequent profuse watery diarrhoea, Vomiting, Poor fluid intake, Concurrent fever (↑ insensible water loss)
- Signs (parents can’t tell!): Pulse, Capillary refill, Sunken anterior fontanelle - Source (for infective cause)
- What is the source
- Usual intake
- **Change in content
- **Change in preparation: person, method, utensils
- **Unhygienic food (e.g. undercooked food, raw food, eating out)
- **Known contacts with persons having similar symptoms + hand hygiene not practised well (infective dose for adults much higher)
- ***Nursery (outbreak)
- Occupations of family members: cooks, kitchen workers (e.g. salmonella), health care workers - ***Epidemiological + Etiological considerations
- Setting (Child-care centres, Institutions, Hospitals)
- Family members, close contacts
- Food-borne / Water-borne diarrhoea occurring after common exposure
- Antimicrobial-associated diarrhoea
- Diarrhoea of travellers
- Diarrhoea in immunocompromised hosts (consider rarer pathogens)
- History of chronic diarrhoea / underlying GI diseases - ***What has been done
- Did mother give sufficient fluid?
- How well does he tolerate?
- Any medications taken?
- Seen a doctor? What was done? - Past health, other related history
- **Past health: recurrent diarrhoea? (suspect primary GI disease)
- **Growth (failure to thrive?)
- **Diet pattern (compare to baseline)
- **Birth history (prior GI problem, preterm baby: NEC (Necrotising enterocolitis) related to prematurity, previous surgery, short gut syndrome)
- ***Immunisation (rotavirus vaccine)
- Family history
- Social history
DDx of acute-onset ***bloody stool, fever, abdominal cramps
- ***Campylobacter
- ***Shigella
- ***Salmonella
- C. difficile
- Yersinia enterocolitis
- Vibrio parahaemolyticus
- Enteroinvasive E. coli
- ***Enterohaemorrhagic E. coli (O157:H7)
- ***Initial presentation of IBD
Formulation of DDx of Acute + Chronic diarrhoea
Acute diarrhoea
1. Infective diarrhoea (most common cause of GE)
- Bacterial vs **Viral (>90% in children: **Rotavirus 輪狀病毒, **Norovirus 諾沃克病毒)
- **Secretory vs ***Inflammatory (mucus, blood in stool)
- Food intolerance
- Lactose - Osmotic agents
- ***Toddler’s diarrhoea (∵ sudden ↑ intake of fruit juice, sucrose, sweeteners) - Drugs
- Laxative
Chronic diarrhoea
- Repeated episodes otherwise unexplained by other causes
- Osmotic, Secretory, Malabsorptive, Motility, Inflammatory, Infective, Metabolic (***記: OSMMIIM)
Acute infective GE: Etiology
***Rotavirus 輪狀病毒:
- most common cause of GE in children
- across community + hospital
Bacterial GE:
- **Salmonella
- **Campylobacter
- ***E. coli (O157, Non-O157)
Protozoal GE:
- ***Cryptosporidium (uncommon, consider after travelling, immunocompromised)
Pathogens associated with travelling:
1. **Salmonella (most common)
2. **Campylobacter, E. coli, Cryptosporidium
3. ***Shigella, Giardia, Entamoeba (Indian subcontinent, Sub-Saharan, Southern Africa)
Acute GE: Duration + Natural history
Diarrhoea:
- usually lasts for ***5-7 days
- most stop within 2 weeks
Vomiting:
- lasts for ***1-2 days
Factors associated with more prolonged course:
- Co-infection of enteric pathogens (e.g. Salmonella + Rotavirus)
- Bloody / Mucoid stool (∵ indicate inflammation of GI epithelium + poor absorption of fluid —> require longer recovery)
- Malnutrition
- Indiscriminate use of antibiotics (∵ impair recovery of normal flora)
DDx of Diarrhoea / Vomiting
GE
DDx other than GE:
1. **Non-enteric infections
- **Pneumonia
- **UTI
- **Meningitis
- Acute otitis media
- Toxic shock syndrome
-
**Non-infective GI disorders
- IBD: UC, Crohn’s, Celiac disease
—> **failure to thrive, weight loss, prolonged / bloody diarrhoea - ***Surgical disorders
- Bowel obstruction
- Intussusception
- Ischaemic bowel
- Acute appendicitis
—> bilious vomiting, severe / localised abdominal pain, blood diarrhoea, rebound tenderness, abdominal distension, mucoid / bloody stools - Drug-related
Assessment of dehydration + shock
- Risk factors for dehydration:
- children <1 yo (esp. <6 months)
- low birthweight
- **>=5 diarrhoeal stools in previous 24 hours
- **>=2 vomiting in previous 24 hours
- not been offered / not been able to tolerate supplementary fluids before presentation
- ***stopped breastfeeding during the illness (no other routes of hydration)
- signs of malnutrition - S/S (***記: Cardiovascular, Respiratory, Hydration status, Mental status)
- Perfusion:
—> Capillary refill
—> Cool limbs
—> Pulse
—> Lips, BP (usually normal until severe dehydration ∵ compensation by HR)
—> Skin mottling (self notes)
—> Oral mucosa
- Hydration status
—> Skin turgor (Flaccid (SpC Paed))
—> Anterior fontanelle
—> Eyes
—> Urine output
—> Oral mucosa (self notes) - Mental status
- Red flags:
—> Unwell appearance
—> Tachycardia
—> Tachypnea
—> Sunken eyes
—> Reduced skin turgor
—> Altered responsiveness
Hypernatraemic dehydration
Dehydration with plasma Na >150 mmol/L
- “Doughy skin” not reliable to identify patients with hypernatraemia dehydration (no reduced skin turgor)
- Severity of dehydration more often underestimated compared with normo-natraemic dehydration
- Suspect hypernatraemia dehydration if there are any of following of **CNS disturbance:
1. **Jittery movement
2. Increased muscle tone
3. Hyper-reflexia
4. **Convulsions
5. Drowsiness / **Coma
Practical considerations for hospitalisation
When should a child with GE be hospitalised?
1. Red flag signs for significant **dehydration
2. Risk factors for significant **ongoing loss (esp. with severe vomiting compromising chance of success with oral rehydration —> need IV route)
3. Patients with grossly **bloody stool (i.e. blood loss —> need to exclude surgical causes)
4. Patients with **immunocompromised states (use of immunocompromised drugs, cytotoxic agents superimposed by opportunistic organisms)
When to take blood?
- Do NOT routinely perform blood biochemical testing
- Measure plasma Na, K, urea, creatinine, glucose if:
- IV fluid therapy required (to know baseline)
- S/S suggest **hypernatraemia
- infant with unexplained drowsiness: rule out **hypoglycaemia - Measure venous blood acid-base status + **chloride concentration if shock suspected / confirmed
- dehydrated to a point of **lactic acidosis
- never take ABG (too invasive)
Acidosis in GE
Causes:
1. **Loss of HCO3 in acute diarrhoea
2. **Lactic acidosis in hypovolaemia shock (∵ impaired perfusion)
To distinguish between 2:
1. Normal Anion gap: HCO3 loss
2. ↑ Anion gap: Lactic acidosis (Impaired tissue perfusion)
(Anion gap = [Na] - [Cl] - [HCO3])
Stool microbiological investigations
Community setting:
- Most acute GE in children are viral in origin
- Even if illness is caused by bacteria enteric infections —> most children do ***NOT require anti-microbial treatment
- Identification of specific pathogen not generally required
Hospital setting:
- Routine
- Isolation, Infection control purpose (PCR panel)
When necessary?
1. Diarrhoea + Systemic illness (e.g. High fever, Sepsis)
- ***Septic workup before administration of empirical antibiotic therapy
- Presence of **mucus / **blood in stool
- Bacterial / amoebic dysentery would require anti-microbial therapy
- **Enterohaemorrhagic E. coli O157:H7 associated with **Haemolytic uraemic syndrome (HUS) (acute kidney failure, low RBC, low Plt) (uncommon)
- **Antibiotic-related pseudomembranous colitis, caused by C. difficile (oral vancomycin, metronidazole)
- Non-infective conditions e.g. if stool culture repeatedly negative —> **IBD should be considered - Returning traveler
- Immunocompromised hosts (suspect opportunistic organisms)
- Diarrhoea with prolonged course
***Fluid management
Indication:
1. Primary prevention of dehydration in children with GE but without clinical dehydration
- **Continue breastfeeding + other milk feeds
- **Encourage fluid intake
- Discourage fruit juices + carbonated drinks (esp. those at risk of dehydration) (e.g. Pocari, glucose drinks: not better than water)
- Offer oral rehydration solution (ORS) as ***supplemental fluid (for those at risk of dehydration)
- Rehydration in children with GE with dehydration (more common)
- **Oral rehydration therapy (1st choice)
—> replace fluid deficit (estimated by clinical S/S or body weight loss) in first 3-4 hours of rehydration phase (e.g. estimate **5% fluid loss —> if children is 10kg —> 500ml fluid replacement within 3-4 hours)
—> continue breastfeeding + milk feeds
—> **Small + **Frequent feeding (avoid giving large amount within short period)
—> avoid fruit juices / carbonated drinks
- IV fluid therapy
—> Signs of **shock
—> **Impaired conscious state (hard to take fluid orally, also check electrolyte imbalance)
—> Child with red flag S/S, showing clinical evidence of deterioration despite OR therapy
—> **Failure of oral rehydration e.g. intolerance due to persistent vomiting
—> **Paralytic ileus (peristalsis impaired (signs: abdominal distension, hypoactive bowel sounds) —> absorption impaired)
ORS solutions
- High-osmolarity solution (now not used anymore, previously for Malaria, Cholera)
- Low-osmolarity solution
- ↓ need for unscheduled IV fluid for treatment of dehydration in children with diarrhoea (compared to high-osmolarity)
- greater ↓ in stool output + vomiting (compared to high-osmolarity)
- only concern: HypoNa risk (compared to high-osmolarity) - Rice-based ORS (starch-based)
- rice starch broken down into glucose by polysaccaridase + disaccharidase at brush border of intestinal villi
- ***Na-glucose co-transporter promotes absorption of salts + water in lumen of intestinal villi
—> help co-absorption of glucose + electrolytes across brushborder
- evidence: ↓ duration of diarrhoea in children + more significant effect in those with Cholera
***Oral rehydration strategy
Principle: **Small + **Frequent feeds
Aim: To replace **fluid deficit over 4 hours
- Ensure appropriate amount of **maintenance fluid is administered to the child
- Monitor for ***ongoing loss + replace accordingly
- Assess for fluid intolerance
- May need to adjust strategy of rehydration according to child’s response to oral rehydration therapy
—> Key: Reassess + Reassess + Reassess
***Total fluid needed: Fluid deficit + Maintenance fluid volume + Ongoing loss
Fluid deficit (SpC Paed + Felix Lai):
- BW x % dehydration x 1000 —> 1% dehydration —> 10ml/kg fluid deficit
Ongoing loss (Felix Lai):
- Each watery / loose stool = 5 ml/kg
- Each vomiting episode = 2 ml/kg
***Maintenance fluid volume calculation (記)
Per day (***記: 100, 50, 20)
0-10 kg: 100 ml/kg
10-20 kg: 1000 ml + 50 ml/kg for each kg >10
>20kg: 1500 ml + 20 ml/kg for each kg >20
***Total fluid needed: Fluid deficit (5%) + Maintenance fluid volume + Ongoing loss
Example: 10kg child
- Fluid deficit: 500ml
- Maintenance fluid volume: 1000ml
- Ongoing loss: depends
—> Total fluid needed = 500ml + 1000ml + Ongoing loss
IV fluid rehydration
- WHO: correct fluid deficit completed in 3-6 hours
- Attempt ***early + gradual introduction of OR therapy during IV therapy
- If tolerated —> stop IV fluid + complete rehydration with oral rehydration therapy
***Treatment of Shock
Shock
—> Rapid IV infusion of **0.9% NaCl (20 ml/kg)
—> Persistent signs of shock
—> Another Rapid IV infusion of **0.9% NaCl (20 ml/kg)
—> Consider possible ***causes of shock other than dehydration
—> Signs of shock resolved —> Continue rehydration with IV fluid
—> Persistent signs of shock —> Consult intensive care specialist
Treatment of hypernatraemic dehydration
Isotonic solution e.g. 0.9% NaCl for fluid deficit replacement + maintenance
- replace fluid deficit **slowly (over 48 hours)
- **monitor plasma Na frequently
- aim at reduce Na at a rate of ***<0.5 mmol/L/hour
Fluid management after rehydration
- Encourage breastfeeding + other milk feeds
- Encourage fluid intake
- Prevent recurrence of dehydration by replacing ongoing loss form diarrhoea with **additional ORS (e.g. **5-10 ml/kg per large watery stool), esp. for at-risk groups:
- children <1 yo (esp. <6 months)
- low birthweight
- >=5 diarrhoeal stools in previous 24 hours
- >=2 vomiting in previous 24 hours - Restart OR therapy if dehydration recurs after rehydration
Nutritional management
- Re-introduce usual feeding early, including solid food
- No evidence that dilute milk is of benefit, give ***full-strength milk as usual
- Available evidence shows ***no benefit from special milk formulas e.g. lactose-free / soy-based formula
Anti-emetics
- Target CNS / GI
- Have SE + not target primary cause of GE
- NOT recommend as routine use in management of GE
- Promethazine (Phenergan)
- Anti-H1
- Anticholinergic
- Anti-dopaminergic activity —> ***extrapyramidal symptoms: dystonic reactions of facial / skeletal muscles, oculogyric crisis, NOT use in children - Metoclopramide (Maxolon)
- Anti-D2 —> ***extrapyramidal symptoms: dystonic reactions of facial / skeletal muscles, oculogyric crisis, NOT use in children
- weak Anti-5HT3 activity - Ondansetron (Zofran)
- Potent
- highly-selective Anti-5HT3
- can ↓ occurrence of persistent vomiting, success of oral rehydration —> ↓ use of IV fluid
- but frequency of stool passage ↑ with ondansetron
—> alter natural course of GE (may make situation worse)
—> ∵ result of retention of fluids + toxin that would have been eliminated through vomiting (由嘔變痾)
—> most children have self-limiting vomiting —> routine use of ondansetron NOT recommended
Anti-diarrhoeal agents
Commonly prescribed agents in medical practice:
- Adsorbents e.g. kaolin, smectite
- Anti-motility agents e.g. loperamide
No high-level evidence available for benefit of anti-diarrhoeals —> ***NOT recommended
Potentially serious adverse SE:
- increase in intestinal transit time **reduce clearance of pathogens / toxins
- abdominal distension
- **ileus
- drowsiness in loperamide
