GI Flashcards
What is gastro-enteritis?
Diarrhoea that occurs when intestinal fluid output overwhelms the absorptive capacity of the GI tract
Why does diarrhoea happen?
(1) Damage to the villous brush border of the intestine, causing malabsorption of intestinal contents and leading to an osmotic diarrhoea (CF, lactose intolerance, IBD, coeliac)
(2) The release of toxins that bind to specific enterocyte receptors and cause the release of chloride ions into the intestinal lumen, leading to secretory diarrhoea (infection, post-antibiotics)
What is oral rehydration therapy
1:1 ratio of sodium and glucose
Difference between watery stools, blood/mucus and steatorrhoea
Frequent, watery stools are more consistent with viral gastroenteritis, while stools with blood or mucous are indicative of a bacterial, steatorrhoea in coeliac, CF
Does the time scale of diarrhoea give a clue to its pathology?
Yes
A long duration of diarrhoea (>14 days) is more consistent with a parasitic or noninfectious cause of diarrhoea
Causes of vomiting in children?
GI: GORD, gastro-enteritis, constipation, overfeeding
Allergy/intolerance
Toxic ingestion
Obstructive: pyloric stenosis, intussessption, intestinal malrotation
Vestibular: Migraine/motion sick/labyrinthitis
CNS: Concussion, meningitis, raised ICP
Metabolic: DKA, Addison’s, CAH
Behavioural: Bulemia nervosa
Differential to gastro-enteritis
Hepatitis, IBD, appendicitis, DKA, lactose intolerance, pancreatitis, pyelonephritis, UTI, intussusception, pyloric stenosis, septic shock, toxic ingestion, overflow constipation
Common bacterial causes of gastro-enteritis
Enterotoxic E. Coli, Campylobacter, Salmonella, C. diff, Shigella
Common viral causes of gastro-enteritis
Rotavirus, noroviruses, enteric adenovirus
Common parasitic causes of gastro-enteritis
Giardia, cryptosporidium
When would you send a stool sample in suspected gastro-enteritis
If:
C. diff is suspected
Blood in stool
Parasites likely
Difference between reflux and GORD disease?
Reflux is relaxation of the lower oesophageal sphincter
GORD disease is reflux oesophagitis • Barrett’s oesophagus • Respiratory complications • Failure to thrive
Symptoms of GORD
- Vomiting
- Irritability
- Coughing after feeds.
- Sandhifer syndrome
- Failure to thrive
- Refusal to feed
What is Sandhifer syndrome?
- Reflux causes baby to extend and spasm until acid returns to stomach (spasmodic torsional dystonia)
- Accurate Hx needed to distinguish this from infantile spasms
Treatment of infant GORD?
Tilting bed and not lying infant down after feeds
Thickening the milk
Adding gaviscon into the milk which thickens and decreases acidity
Decrease volume and increase freq of feeds Omeprazole
Red flags of GORD
Forceful and frequent <2months old Bile stained Haematemesis Onset >6 months or persists >1yr Blood in stool Abdominal distension/mass/tenderness, Systemic unwell Faltering growth or weight loss
How do you test for a food allergy?
Response to elimination for 3-4 weeks AND reintroduction
Symptoms of a food allergy in infants
GORD Loose /frequent stools Blood/mucous in stools Abdominal pain Infantile colic Food refusal/aversion Constipation (straining on a soft stool) Perianal redness Pallor and tiredness Faltering growth Eczema -> if CHRONIC
What is lactose intolerance
Inability to digest lactose into its constituents, glucose and galactose, secondary to low levels of lactase enzyme in the brush border of the duodenum
Symptoms of lactose intolerance
Loose stools, abdominal bloating and pain, flatulence, nausea, and borborygmi (stomach rumbles)
Cause of symptoms in lactose intolerance
The combined increase in faecal water, intestinal transit, and generated hydrogen gas accounts for the wide range of gastrointestinal symptoms
What is secondary lactose intolerance?
Damage of the brush border
Usually after acute illness (eg. giardiasis, gastroenteritis, Crohn’s, HIV enteropathy, Chemo)
What are risk factors for constipation?
LAC (looked after children), physical disability, toddlers, Down’s and autism
Red flags in constipation
- Constipation from birth (hischsprung? congenital defect in GI system)
- Previously unknown leg weakness/delayed gross motor (spinal cord?)
- Abdominal distension with vomiting (bowel obstruction?)
- Faltering growth (CF, coeliac)
- Non responsive to treatment within 3 months
What is hirschsprung disease?
- Functional obstruction of the gut due to lack of innervation and ganglia in the distal colon
- -> increased smooth muscle tone and intrinsic enteric relaxing impulses are lost
- Developmental disorder, usually diagnosed in newborn period if there is a failure of passage of meconium in the first 24-48hrs after birth & distended abdomen.
How do you diagnose hischsprung disease?
Diagnosed with contrast enema and full thickness rectal biopsy
How do you treat hischsprung disease?
Removal of aganglionic bowel using intestinal pull through (Soave)
Signs of a congenital pyloric stenosis?
- Presents in 1st 3-4 weeks of life with projectile, non bilious vomiting after feeds
- Baby is malnourished and always hungry
- Pyloric mass felt in RUQ in test feed
Treatment of pyloric stenosis
Correct alkalosis
Stabilise ions
Hydrate
Pyloromyotomy
What is intussusception? What happens if untreated?
Small bowel telescopes (swallowing itself by invagination)
Untreated-> necrotic bowel
Signs and symptoms of intussusception?
- Presents at any age (esp 5-12months)
- Intermittent inconsolable crying with drawing of legs up +- bilious vomiting
- May have ‘redcurrant jam’ blood in nappy
- Sausage shaped abdominal mass may be felt
What is seen on USS in intussusception?
Target sign
Treatment of intussusception
Reduction by air enema/balloon catheter under USS
Fluid resuscitation
Analgesia
Antibiotics
Risk factors for intussusception?
More common in CF, HSP, lymphoma
What happens in midgut malrotation? Signs and symptoms?
- If gut is malrotated during embryonic development it is prone to undergo volvulus upon the mesentery. Superior mesenteric artery completely cut off.
- Usually in neonatal period: green bilious vomit, distension, rectal bleeding
What is coeliac disease?
• IgA autoimmune systemic disorder of genetically susceptible individuals (eg HLA-DQ2-8)
• Triggered and maintained by gluten
1/100 children
Signs of coeliac disease?
Largely distended abdomen, Weight loss/skeletal appearance after weening Flat buttocks Failure to thrive Abnormal stools
How is coeliac diagnosed?
Diagnosis by serology (IgA, EMA, TransGlutaminase) and histology (flattening of cilia, inflammation)
Must be eating at least 2 portions a day of gluten for 4 months for these features to be seen.
Diagnosis can also be a really high IgA and genetic testing.
Treatment of coeliac?
Gluten free diet for life
(Wheat, rye, barley)
Dietetic support
What is associated with coeliac disease?
Associated with other autoimmune disease (T1DM, thyroid disease)
Secondary lactose intolerance
Inflammatory bowel disease signs and symptoms
Abdo pain, poor growth, delayed puberty, diarrhoea, rectal bleeding, pyoderma gangrenosum
Crohn’s signs and symptoms
Oral ulcers, anorexia, anal fissures/fistulae, weight loss:
transmural
Ulcerative colitis signs and symptoms
Passage of mucus, urgency, bloody diarrhoea
Diffuse mucosal, uniform, continuous inflammation
Complications of Crohn’s disease
Intestinal strictures
Abscesses in the wall of the intestine or adjacent structures
Fistulae
Anaemia
Malnutrition
Colorectal and small bowel cancers
Growth failure and delayed puberty in children
Extra-intestinal manifestations of Crohn’s
Arthritis and abnormalities of the joints, eyes, liver and skin
Secondary osteoporosis
Treatment of Crohn’s
To induce remission:
Oral steroids/budesonide
Aminosalicylates (sulfasalazine and mesalazine) are less effective
Azathioprine or mercaptopurine can be added
MAB: adalimumab and infliximab if severe
Maintenance:
Azathioprine or mercaptopurine
Loperamide hydrochloride or codeine phosphate for diarrhoea
Ulcerative colitis treatment
Chronic diarrhoea:
loperamide hydrochloride or codeine phosphate
Rectal aminosalicylate (mesalazine or sulfasalazine
Add oral prednisolone if not improved
MABs if not improved
Acute severe:
IV ciclosporin/infliximab
IV hydrocortisone
Treatment of C.diff colitis
Metronidazole
Vancomycin
First line treatment in mod/severe constipation
Macrogol (eg laxido) osmotic laxative
What is the diagnosis of tinkling bowel sounds, swelling in testicle, cannot get above, doesn’t transilluminate
An incarcerated inguinal hernia
Due to processus vaginalis (outpouching of peritoneum)
What are the 2 main types of malabsorption?
Due to lack of enzymes for breakdown of food (eg pancreatic insufficiency)
Due to disruption of luminal border of gut
What can go wrong in the luminal phase to cause malabsorption?
Cofactor deficiency (eg pernicious anaemia) Lipid solubilisation (bile salt synthesis/cholestasis/bile salt loss) Defective nutrient hydrolysis (pancreatic enzymes, lipase activation, rapid transit of food)
Signs of malabsorption
- Weight loss/Failure to thrive
- Abnormal diarrhoea/steatorrhoea/flatulence
- Nutritional deficiency
Risk factors for malnutrition
Delayed or problematic progression of solids
Early feeding difficulties (GORD, tube feeding)
Poor appetite
Dental problems
Parents cultural attitude
Behavioural difficulties /rigid parenting skills
Parental (eg post-natal depression)
What can go wrong in the mucosal phase to cause malabsorption?
Extensive mucosal loss (resection/infarction)
Diffuse mucosal disease (coeliac, Crohn’s)
Disease of enterocytes
What can go wrong in the transport phase to cause malabsorption?
Vascular (vasculitis, atheroma)
Lymphatic drainage
Most common cause of gastroenteritis in UK
Rotavirus
What metabolic issue can cause constipation?
Hypothyroidism
Name 4 pathogens that can cause bloody diarrhoea
Shigella, E.coli, salmonella, campylobacter
Name 4 signs of chronic liver disease in children
Bruising
Clubbing
Splenomegaly
Encephalopathy
Difference between infant and adult inguinal hernias
Infant (always indirect, due to patent processus vaginalis)
Adult (indirect or direct, due to weakness in muscle of inguinal canal
Definition of hernia
Protrusion of a viscus or part of a viscus through the walls of its containing cavity into an abnormal position
Describe formation of congenital hernia
Patent processus vaginalis
Processus vaginalis should obliterate following descent of the testes.
If it stays patent it may fill with
- Fluid → hydrocele
- Bowel/omentum → indirect inguinal hernia
Describe an indirect inguinal hernia
Emerge through deep ring, inguinal canal and superficial ring
Intestinal loop within spermatic cord
Same 3 coverings as cord and descend into the scrotum
Can strangulate
Herniating bowel passes lateral to inferior epigastric vessels
Above and medial to pubic tubercle
Describe direct inguinal hernia
Acquired, older people
Emerge through Hesselbach’s triangle, defect in posterior wall of inguinal canal (peritoneum and transversalis fascia)
Herniating bowel passes medial to inferior epigastric vessels
Rarely descend into scrotum
Rarely strangulate
Above and medial to pubic tubercle
Borders of hesselbach triangle
Inguinal ligament (inferiorly) Inferior epigastric vessels (superio-laterally) Rectus abdominis muscle (medially)
Where are femoral hernias?
Below inguinal ligament
In femoral canal
Below and lateral to pubic tubercle
Medial to sartorius and femoral nerve and artery
