Gastroenterology

Question 1

Investigation for AGE***

Answer 1

> Blood

• FBC: leukocytosis
• ABG: metabolic acidosis
• BUSE/Cr: dehydration and electrolyte imbalance
• Serum bicarbonate: low in metabolic acidosis

> Stool

• Stool for rotavirus antigen
• Stool for ova and cyst

Question 2

Management for AGE***

Answer 2

• Assess the degree of dehydration using WHO chart

> Plan A: treat at home

• Give extra fluid: 50-100ml (<=2 y/o)/ 100-200ml (>2y/o) after each loose stool
• Continue feeding
• Know when to return to clinic

> Plan B: treat with ORS

• First 4 hours: weight (in kg) x 75
• After 4 hours: reassess and treat accordingly

> Plan C: treat immediately

• Assess ABC
• IV fluid immediately: 20ml/kg NS rapid bolus, repeat if necessary
• Reassess frequently (1-2 hourly) and adjust infusion as necessary

Question 3

Complication of AGE***

Answer 3

> Renal

• Hypovolemic shock
• Electrolyte imbalance
• Metabolic acidosis
• Renal venous thrombosis
• Hemolytic uremic syndrome

> CNS
- Convulsion

> GIT
- Prolonged diarrhea (>14 days)

Question 4

Content of ORS**

Answer 4

• Glucose
• Sodium chloride
• Potassium chloride
• Sodium citrate

Question 5

Definition of hemolytic uremic syndrome

Answer 5

• Simultaneous occurrence of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury

Question 6

Type of electrolyte imbalance in AGE

Answer 6

• Acidosis: tachypnoea (Kussmaul breathing)
• Potassium depletion: hypotonia, weakness
• Hypocalcemia: neuromuscular instability (eg: muscle spasms)
• Hypoglycemia: lethargy, come, convulsion

Question 7

Clinical feature of intussusception

Answer 7

• Abdominal pain
  ® Sudden onset
  ® Intermittent, severe, crampy, progressive abdominal pain
• Vomiting
• No abdominal tenderness, or only focal tenderness
• Abdominal mass
  ® Sausage-shaped
• Bloody stool: Jelly like; mixture of mucus and blood

Question 8

Function of glucose in ORS*

Answer 8

• ORS works because of the Sodium Glucose Co-Transport System
• The jejunum contains SGLT-1 transporter proteins
• If 2:1 ratio of Na+ and glucose is consumed, SGLT-1 actively transports both across epithelial wall
• Osmotic imbalance is created, water is immediately pulled into vascular system

Question 9

Classification of dehydration

Answer 9

○ Degree of body weight loss
	§ Mild (<5%)
	§ Moderate (5-10%)
	§ Severe (>10%)
○ Osmolality
	§ Hypotonic (<275 mOsm/kg)
	§ Isotonic (275-295 mOsm/kg)
	§ Hypertonic (>295 mOsm/kg)
○ Blood level of sodium
	§ Hyponatremic (<130 mmol/L)
	§ Isonatremic (130-150 mmol/L)
	§ Hyperosmolar (>150 mmol/L)

Question 10

Classification severity of diarrhea

Answer 10

• Severe: more than 10 loose, watery stools in 24 hours
• Moderate: having more than a few but not more than 10 diarrhea tools in 24 hours
• Mild: having a few diarrhea stools in 24 hours

Question 11

Causes of AGE***

Answer 11

• Virus
  § Rotavirus (most common)
• Bacteria
  § Campylobacter jejuni (commonest, Enteroinvasive, bloody diarrhea)
  § Shigella, Salmonella (bloody)
  § Vibrio cholerae (Enterotoxigenic, watery diarrhea)
  § E. coli (bloody for enterohemorrhagic/ enteroinvasive varient)
• Parasite
  § Entamoeba histolytica(bloody)

Question 12

Management of hypernatremic dehydration***

Answer 12

• If in shock, give resuscitation with 0.9% normal saline as required with bolus
• Avoid rapid correction (may cause cerebral edema, convulsion and death)
• Aim for deficit correction over 48-72 hours and [Na] fall not >0.5 mmol/L/hr
• Repeat BUSE every 6 hours until stable
• Slower rate if chronic hypernatremia (>5 days)
• Aware of hypocalcemia and hyperglycemia

Question 13

Pharmacological agent for AGE**

Answer 13

• Antimicrobial (not routinely, only in children with bloody diarrhea)
• Antidiarrheal medication - diosmectite (Smecta)
• Probiotic (reduce duration)
• Zinc supplement (reduce the duration and severity)

Question 14

Management of hyponatremic dehydration***

Answer 14

• For acute symptomatic, 2ml/kg bolus (max 100ml) of 3% Sodium Chloride over 10-15 minutes
• A future bolus if symptoms are still present after the initial bolus
• If symptoms still present after the 2nd bolus, check plasma sodium level and consider a third bolus
• Measure the plasma sodium concentration at least hourly
• Rate of increase of plasma sodium should not exceed 12 mmol/l in a 24-hour period (prevent osmotic demyelination syndrome)
• For asymptomatic hyponatremia - 0.9% sodium chloride
• In hyponatremia with normal/ raised volume, fluid restriction is necessary

Question 15

How to assess dehydration clinically*

Answer 15

> 4 important WHO

• General appearance (alert, irritable)
• Tissue elasticity
• Eyes
• Thirst

> Others

• Extremities
• Anterior fontanelle
• Mucous membrane
• Heart rate
• Breathing
• Peripheral pulse
• CRT
• Skin turgor
• Urine output

Question 16

Mechanism of metabolic acidosis in AGE

Answer 16

• Most likely to be due to bicarbonate losses in diarrheic stools
• In shock, can lead to lactic acidosis
• Can present with tachypnea