alimentary Flashcards
what are the different phases of vomiting
pre-ejection phase
ejection phase
post-ejection phase
what are the clinical features of each phase
pre ejection: pallor, nausea, tachycardia
ejection: retch, vomit
post ejection: weakness, shivering, lethargy
what causes vomiting?
stimulation of vomiting centre in medulla triggered by:
- enteric pathogens
- infection
- visual/olfactory stimuli - fear
- head injury/raised ICP
- inner ear stimuli
- metabolic derangements/chemotherapy
what are the different types of vomiting?
- vomiting with retching
- projectile vomiting
- bilious vomiting
- effortless vomiting
- haemetemesis
what are the causes of vomiting?
infants: GOR, cow’s milk allergy, infection, intestinal obstruction
children: gastroenteritis, infection, appendicitis, intestinal obstruction, raised ICP, coeliac disease
young adults: gastroenteritis, infection (H. Pylori), appendicitis, raised ICP, DKA, cyclical vomiting syndrome, bulimia
describe presentation of pyloric stenosis
babies 4 - 12 weeks boys > girls projectile non-bilious vomiting weight loss dehydration +/- shock electrolyte disturbance: metabolic alkalosis (↑pH), hypochloraemia (↓Cl), hypokalaemia (↓K)
what are the investigations for pyloric stenosis
- test feed
- blood gases: hypokalemic, hypocholermic metabolic alkalosis after prolonged vomiting
what is the management for pyloric stenosis
fluid resuscitation
refer to surgeons if obstruction
describe effortless vomiting
due to gastro-oesophageal reflux
self-limting
symptoms:
- vomiting, haematemesis
- nutritional: feeding problems, failure to thrive
- respiratory: apnoea, cough, wheeze, chest infections
- neurological: sandifer’s syndrome
what are the investigations for effortless vomiting
history and examination
oesophageal pH study/impedance monitoring
endoscopy
imaging: video fluoroscopy, barium swallow
what is the management for effortless vomiting
feeding advice: thickeners, feeding position & volumes
nutritional support: calories supplements, exclusion diet, nasogastric tube, gastrostomy
medical treatment (rare): prokinetic drugs, acid suppressing drugs, H2 receptor blockers, proton pump inhibitors
surgery (rare): nissen fundoplication
what should bilous vomiting always be presumed to be due to?
intestinal obstruction until proved otherwise
ALWAYS ring alarm bells
what are the causes of bilious vomiting
intestinal atresia (in newborn babies only) malrotation intussusception ileus crohn’s disease with strictures
what are the investigations for bilious vomiting
abdominal x-rays
consider contrast meal
surgical opinion regarding laparotomy
what is the fluid balance of the GI system?
9L fluid enters duodenum
1.5L gets to colon
<200ml lost in faeces
how is the surface area of the small intestine increased?
mucosal folds
villi
What is there increased risk of in untreated coeliac disease?
Small bowel lymphoma
what is the definition of chronic diarrhoea?
4 or more stools per day for more than 4 weeks
- <1 week: acute diarrhoea
- 2 - 4 weeks: persistent diarrhoea
- > 4 weeks: chronic diarrhoea
what can cause diarrhoea?
motility disturbance: toddler diarrhoea, irritable bowel syndrome
active secretion: acute infective diarrhoea, inflammatory bowel disease
malabsorption of nutrients: food allergy, coeliac disease, cystic fibrosis
what types of diarrhoea are there?
osmotic
- movement of water into bowel to equilibrate osmotic gradient
- usually a feature of malabsorption (enzymatic defect or transport defect)
- mechanism of action of lactulose/movicol
secretory
- classically associated with toxin production from vibrio cholerae and enterotoxigenic Escherichia coli
- intestinal fluid secretion predominantly driven by active Cl- secretion via CFTR
what drives intestinal fluid secretion in secretory diarrhoea?
intestinal fluid secretion predominantly driven by active Cl- secretion via CFTR
what is the clinical approach to chronic diarrhoea?
history: age, abrupt/gradual onset, family/travel history
growth and weight gain of child
faeces analysis: appearance, stool culture, determination of secretory vs osmotic
what types of disease does fat malabsorption occur in?
pancreatic disease
- lack of lipase and resultuant steatorrhoea; clasically cystic fibrosis
hepatobiliary disease
- cholestasis; clasically chronic liver disease
how does coeliac disease present in children?
- abdominal bloatedness
- diarrhoea
- failure to thrive
- short stature
- constipation
- tiredness
- dermatitis herpatiformis