GI: Pyloric Stenosis, Gastroenteritis & Coeliac Disease Flashcards
What is the pyloric sphincter?
A ring of smooth muscle that forms the canal between the stomach and the duodenum.
What is pyloric stenosis?
Hypertrophy of circular and longitudinal muscle layers in the pylorus.
This leads to narrowing of the pylorus - results in gastric outlet obstruction.
What is the classic presenting feature of pyloric stenosis?
Postprandial projectile non-bilious vomiting
Risk factors for pyloric stenosis?
There are no strongly associated risk factors of pyloric stenosis.
Some may include:
- Male
- First born
- FH
- Maternal smoking
Is the vomiting in pyloric stenosis bilious or non-bilious?
Non-bilious
What causes projectile vomiting in pyloric stenosis?
After feeding, there is increasingly powerful peristalsis in the stomach as it tries to push food into the duodenum.
Eventually it becomes so powerful that it ejects the food into the oesophagus, out of the mouth and across the room. This is called “projectile vomiting”.
When does pyloric stenosis typically present?
In the first few weeks of life.
When does the vomiting in pyloric stenosis typically occur?
Immediately following a feed, and the child is often extremely hungry and irritable after the episode.
Clinical features of pyloric stenosis?
1) Increasingly forceful and ultimately projectile non-bilious vomiting
2) Haematemesis (10%)
3) Weight loss or inadequate weight gain, failure to thrive
4) Dehydration
5) Stool changes; often small and hard, sometimes the child passes little to no stool
6) Visible peristalsis (may become more prominent following a feed)
What are some signs of dehydration in infants?
- sunken fontanelles
- sunken eyes
- dry mucous membranes
- poor skin turgor
- decreased tearing
- lethargy
- tachycardia
- prolonged CRT
- decreased urine output
What metabolic changes can vomiting in pyloric stenosis result in?
- severe hypochloraemia
- hypokalaemic dehydration with metabolic alkalosis
What may be felt in the abdomen in pyloric stenosis?
Firm, non-tender 1-2cm mass in the right upper quadrant of the abdomen.
This is a result of the thickening of the pylorus muscles, often described as an ‘olive’.
Classic triad in pyloric stenosis?
1) palpable pyloric mass
2) visible peristalsis
3) projectile vomiting
Relevant investigations in pyloric stenosis?
1) Test feed with dextrose water
2) ABG
3) U&Es
4) Abdo US
One bedside investigation in pyloric stenosis is a test feed with dextrose water.
What does this involve?
This causes the pylorus to contract, making an epigastric mass more obvious on examination. This may also result in projectile vomiting.
If the pylorus was palpable from this test feed, no further imaging is required, and the diagnosis can be confirmed.
If the test is inconclusive, an ultrasound will be required.
What will an ABG show in pyloric stenosis?
Hypochloraemic hypokalaemic metabolic alkalosis caused by the loss of fluid, hydrogen and chloride through excessive vomiting.
What are the requirements for diagnosing pyloric stenosis on an abdo US?
1) Pyloric stenosis must be >4mm in thickness and;
2) Pyloric muscle length must be >18mm
3) There must be an obstruction preventing the passage of fluid beyond the pylorus, despite gastric peristalsis.
What sign is often described on US in pyloric stenosis?
A ‘target sign’ - this is due to hypertrophied hypoechoic muscle surrounding echogenic mucosa
What is the management of pyloric stenosis?
1) NG tube insertion
2) Preoperative rehydration and correction of electrolyte abnormalities
3) Ramstedt’s pyloromyotomy - definitive surgical management
What is the definitive management of pyloric stenosis?
Ramstedt’s pyloromyotomy
What is the role of NG tube insertion in pyloric stenosis?
This decompresses the stomach and allows accurate recording & replacement of gastric losses.
What is Ramstedt’s pyloromyotomy?
Involves longitudinally incising the muscle fibres of the hypertrophic pyloric muscle. This defect is left open, allowing the pyloric mucosa to bulge through the incision and providing a wider passage between the pylorus and the duodenum.
What are the 2 key pre-op complications of pyloric stenosis?
1) Electrolyte abnormalities
2) Dehydration
Is gastroenteritis more commonly bacterial or viral?
Viral
What is the most common cause of infantile gastroenteritis?
Rotavirus
What are the 3 most common viruses causing infantile gastroenteritis?
1) Rotavirus
2) Norovirus
3) Adenovirus
When is the rotavirus vaccination given?
At 8 and 12 weeks
Is rotavirus part of the national vaccination programme in the UK?
Yes
How is rotavirus spread?
By the faecal oral route or by environmental contamination, incidence peaks over the winter months.
What is the ommonest cause of gastroenteritis in ALL age groups in the UK?
Norovirus
What is the most commonly reported bacterial cause of gastroenteritis in the UK?
Campylobacter
Give 2 key bacterial causes of gastroenteritis
1) Campylobacter
2) E. coli
What are some key conditions to think about in young patients with loose stools?
- Infection (gastroenteritis)
- Inflammatory bowel disease
- Lactose intolerance
- Coeliac disease
- Cystic fibrosis
- Toddler’s diarrhoea
- Irritable bowel syndrome
- Medications (e.g. antibiotics)
Which E. coli strain can lead to haemolytic uraemic syndrome (HUS)?
E. coli 0157 –> produces the Shiga toxin
Presentation of infection with E. coli 0157 strain?
- abdo cramps
- bloody diarrhoea
- vomiting
- HUS (as Shiga toxin destroys RBCs)
What increases the risk of haemolytic uraemic syndrome?
Antibiotics !
Antibiotics should be avoided if E. coli gastroenteritis is considered.
What is the most common bacterial cause of gastroenteritis worldwide?
Campylobacter Jejuni
Clinical features of gastroenteritis?
- Sudden onset of loose/watery stool with or without vomiting
- Abdominal pain/cramps
- Mild fever
- Recent contact with someone with diarrhoea or vomiting.
What is a key complication of gastroenteritis?
Dehydration
Which children with gastroenteritis are at particularly risk of dehydration?
1) Young children (especially under 6months).
2) Children who have passed >5 diarrhoeal stools in the last 24 hours.
3) Children who have vomited >2x in the last 24 hours.
4) Children who have stopped breast feeding during the illness.
What are some signs of clinical dehydration?
- Appears to be unwell or deteriorating
- Altered responsiveness (for example, irritable, lethargic)
- Decreased urine output
- Sunken eyes
- Dry mucous membranes (except for ‘mouth breather’)
- Tachycardia
- Tachypnoea
- Reduced skin turgor
When should a stool sample should be sent in suspected infantile gastroenteritis?
1) Septicaemia is suspected or
2) blood and/or mucus is present in the stool or
3) the child is immunocompromised
Management of infantile gastroenteritis if the child is not clinically dehydrated?
1) Continue breast feeding/other milk feeds
2) Encourage fluid intake
3) Discourage fruit juices and carbonated drinks especially if the child is at risk of dehydration.
4) Offer oral rehydration salt solution (ORS) as supplemental fluid to those at risk of dehydration.
Management of infantile gastroenteritis if the child is clinically dehydrated?
Oral therapy for all children unless they have the indications for IV therapy:
1) Give ORS solution: 50 ml/kg over 4 hours to replace the defecit plus maintenance fluid.
2) Give the ORS solution frequently in small amounts e.g. 5ml every 5 minutes and consider supplementation with their usual fluids.
3) If the child is refusing the oral fluid then consider a NG tube.
When is IV therapy indicated in infantile gastroenteritis?
1) Shock is suspected
2) In a child with any red flag symptoms
3) If there is evidence of dehydration despite use of oral rehydration therapy
4) If the child persistently vomits when ORS solution is given either orally or via NG tube.
What is the fluid requirement for 24 hours in children weighing:
a) 0-10kg
b) 10-20kg
c) >20kg
a) 100ml/kg/day
b) Requirement for the 1st 10kg (i.e. 1000ml)+ 50ml/kg/day
c) Requirement for the 1st 20kg (i.e.1500ml) + 20ml/kg/day
