Paeds - GI Flashcards
where is the pyloric sphincter?
ring of smooth muscle between stomach and duodenum
what is pyloric stenosis?
hypertrophy of the pyloric sphincter causing narrowing which prevents food traveling to duodenum as normal
classical features of pyloric stenosis?
projectile vomiting
usually presents in first few weeks of life
hungry baby
thin, pale and failing to thrive
what causes projectile vomiting in pyloric stenosis?
increasingly powerful peristalsis tries to push food through stenosis
eventually becomes so powerful that is ejects food into the oesophagus and out of the mouth
what might be seen on examination in pyloric stenosis if examined after feeding?
peristalsis might be seen in abdomen
firm round mass might be felt in upper abdomen (feels like big olive) caused by hypertrophied sphincter
blood gases in pyloric stenosis?
metabolic alkalosis (due to vomiting) low chloride
how is pyloric stenosis diagnosed?
abdo US showing thickened sphincter
how is pyloric stenosis managed?
laparoscopic pylorotomy ("ramstedt's operation)
incision made in smooth muscle of pylorus to widen canalwhat is biliary atresia?
congenital condition where section of bile duct is either narrowed or absent
results in cholestasis as bile cant be transported from liver to bowel
what type of bilirubin builds up in biliary atresia?
conjugated (as its obstructed after the liver)
how does biliary atresia present?
presents shortly after birth
jaundice (suspect biliary atresia in babies with persistent jaundice for >14 days or >21 days in premature babies)
initial investigation in biliary atresia?
measure conjugated and unconjugated bilirubin (high conjugated bilirubin suggests obstruction after the liver)
what can cause jaundice in neonate?
many benign causes such as breast milk jaundice
how is biliary atresia managed>
surgery (kasai portoenterostomy)
involves attaching section of small intestine to the opening of the liver where bile duct would normally attach
how successful is surgery in biliary atresia?
somewhat successful
clears jaundice and prolongs survival but often need a full liver transplant at some point
what is hirschsprungs disease?
congenital condition where nerve cells of the myenteric plexus are absent in distal bowel and rectum
what is the myenteric plexus?
forms enteric nervous system (brain of the gut)
AKA auerbachs plexus
runs all the way along the bowel in bowel wall
responsible for peristalsis of large bowel
key pathophysiology of hirschsprungs disease?
absence of parasympathetic ganglion cells in part of myenteric plexus supplying distal colon and rectum
how much of bowel isnt innervated in hirschsprungs?
varies between patients
can range from small area up to entire colon
(called total colonic aganglionosis)
what happens to part of bowel without innervation in hirschsprungs?
section does not relax causing it to become totally constricted
leads to loss of movement of faeces and bowel obstruction
bowel proximal to constriction becomes distended and full
what causes hirschsprungs?
number of associated genes
family history greatly increases risk
hirschsprungs usually occurs in isolation but what other syndromes are associated with hirschsprungs?
downs
neurofibromatosis
waddenburg
MEN2
how does hirschsprungs present?
presentation and age of presentation varies depending on severity
can present with acute bowel obstruction shortly after birth or more gradual symptoms such as
- delayed meconium (>24 hrs)
- chronic constipation since birth
- abdo pain and distension
- vomiting
- poor weight gain and failure to thrive
what complications can occur from hirschsprungs?
hirschsprung-associated enterocolitis (HAEC)
