Gastroenterology Flashcards
Features of Wilson’s disease?
Low caeruplasmin and deranged LFTs
KF rings
Older children may have neuropsychiatric symptoms
Features of NAFLD
Most common cause of liver disease in children
Associated with obseity
Hepatomegaly may be present (but difficult to note in obese children)
Definitive diagnosis can only be made with biopsy but rarely needed, elevated LFTs and suggestive USS are usually enough
Thin projection of the right lower lobe of the liver, easily palpable within the lateral right abdomen
Riedel lobe
Tissue absent in aganglionic segments of bowel, diagnostic of Hirschsprung’s disease
Meissner’s plexus
Tissue usually extending from caecum to RUQ, that cross the duodenum
Ladd bands
Fascia of the anterior abdominal wall, just superficial to the external oblique muscle
Scarpas fascia
Ligamentum teres
The remnant umbilical vein
Uncinate process
Hook shaped process, found in the pancreas, the ethmoid bone and ribs
Liver segment 2
The superior lateral segment of the left lobe of the liver
Vermiform appendix
Narros, worm-shaped structure that extends from the posteromedial surface of the caecum
First condition to exclude in a neonate with bilious vomiting?
Malrotation and midgut volvulus until proven otherwise
- upper and lower contrast study (often missed on XR)
- bilious gastric aspirates/emesis suggest obstruction distal to the ampulla of Vater
What do fat globules in the stool indicate?
Intraluminal problem e.g. failure of enzyme process or bile to suspend fats, i.e. maldigestion
What do fatty acid crystals in the stool indicate?
Mucosal/brush border problem (fatty acid not absorbed), i.e. malabsorption
Relevance of chymotrypsin?
Chymotrypsin and elastase-1 are enzymatic products of pancreatic secretion that remain relatively stable during transport through the GIT
Sensitivity of 85% for advanced pancreatic exocrine insufficiency, but only 49% for mild and moderate (it may be diluted in the presence of concomitant diarrhoea. Exogenous enzymes interfere with the test)
Overview of primary intestinal lymphangiectasia
Characterised by diffuse or localised ectasia of enteric lymphatics. Obstruction of the intestinal lymphatics impairs lymph flow and increases pressure in the intestinal lymphatics. This leads to leakage of lymph into the intestinal lumen, reduced recirculation of intestinal lymphocytes into the peripheral circulation, and decreased absorption of fat-soluble vitamins.
Is a protein-losing enteropathy, you would expect low protein and albumin in the LFTs
Overview of Meckel’s diverticulum
Common cause of significant GI bleeding, with 60% presenting before 2 years
Due to erosion of intestinal mucosa from ectopic gastric mucosa, found within the MD in 25% of cases
The ectopic mucosa can be detected by Technecium-99m scan (“Meckel’s scan”)
Age of presentation of food protein induced colitis?
Usually presents by 18 months
The most common triggers are milk and soy proteins
Overview of juvenile polyps
Juvenile polys are one of the most common causes of significant PR bleeding, with peak presentation at 3-4 years of age
Most often pedunculate hamartomas, which can be both diagnosed and removed during colonoscopy
Presentation of very early onset IBD in young children (<6 years)?
Usually accompanied by growth failure and systemic symptoms
Strong genetic component, often linked to messengers involved in immune regulation (such as IL-10), and associated immunodeficiencies occur in 25% of cases
Causes of PR bleeding in children
Meckel’s, colitis (inflammatory/infective), juvenile polyps, IBD, anal fissures, intussusception, HSP, lymphonodular hyperplasia, rectal ulcer syndrome
Oesophagus muscle types?
Upper 1/3 - striated, innervated by spinal accessory nerves, allows for voluntary initiation of swallowing
Middle 1/3 - mixed, innervated by dorsal motor nerve of vagus
Distal 1/3 - smooth muscle, innervated by dorsal motor nerve of vagus
Orophrayngeal dysphagia
Refers to inability to transfer food to the oesophagus
Neurological causes of oropharyngeal dysphagia?
Cortical - pseudo bulbar palsy (UMN lesion) due to bilateral stroke
Bulbar - ischaemia, tumour (LMN)
Peripheral - polio, ALS
Muscular causes of oropharyngeal dysphagia?
Muscular dystrophy
Cricopharyngeal incoordination - failure of UES to relax with swallowing
Zenker’s diverticulum
Types of dysphagia?
Oropharyngeal
Oesophageal (mechanical or non-mechanical)
Difference between dysphagia and dysmotility?
Dysphagia to solids before liquids (can manifest when solids introduced to diet)
Dysmotility - liquids are affected as early as (or earlier) than solids
Embryologic origin of oesophagus?
Post pharyngeal foregut, distinguished from the stomach by 4 weeks
Investigations for oesophageal obstruction?
Fluoroscopy - may include video evaluation of swallowing, often first line test
Endoscopy - if intrinsic lesion is suspected
Manometry - if dysmotility is suspected
Oesophageal duplication cysts
Occur from foregut duplication, affect distal oesophagus on the right side
Commonly present with respiratory distress due to airway compression
Dysphagia more common in older children
Upper GI bleeding can occur due to acid from gastric mucosa
Neuroenteric cysts
May contain glial elements and are associated with vertebral anomalies
Diagnosed using barium swallow, chest CT and MRI
Surgical excision
Most common masses which compress the oesophagus and produce obstructive symptoms?
Mediastinal lymph nodes: infective (TB, histoplasmosis), neoplasm (lymphoma)
Most common cause for oesophageal obstruction symptoms?
Eosinophilic oesophagitis
Cricopharyngeal achalasia
Failure of complete relaxation of the upper oesophageal sphincter
Cricopharyngeal incoordination
Full relaxation of the UES but incoordination of the relaxation with the pharyngeal contraction
Systemic causes of swallowing dysfunction?
Many - CP, Arnold-Chiari malformation, bulbar palsy or cranial nerve defects, transient pharyngeal muscle dysfunction, SMA, muscular dystrophy, MS etc
Differentiating muscle types in motility disorders
Upper oesophageal and upper oesophageal sphincter dysmotility = striated muscle
Lower oesophageal and lower oesophageal sphincter dysmotility = smooth muscle
Overview of achalasia
Primary oesophageal motor disorder characterised by loss of LES relaxation (resting pressure >30mmHg) and loss of oesophageal peristalsis
Damage to smooth muscle innervation: loss of myenteric ganglion cells
Triple A syndrome
Achalasia, ACTH insensitivity (low BSL), alacrima
Associated with 12q13 deletion
Clinical features of achalasia
Regurgitation and dysphagia with solids and liquids
May have malnutrition or chronic cough
Retained oesophageal foot can produce oesophagitis
Gold standard investigation for achalasia
Manometry/motility study
- peristalsis in distal oesophagus, incomplete or absent LES relaxation = diagnostic
Treatment of achalasia
Goals: relieve symptoms, improve emptying, prevent megaoesophagus
Medical = CCB (nifedipine), PDE inhibitors, nitrates
Endoscopy = injection of botulinum toxin, pneumatic dilatation
Surgical = Heller myotomy (reflux is complication)
Complications of achalasia
Respiratory - aspiration, bronchiectasis, lung abscess
GIT - malnutrition, increased risk of oesophageal cancer (secondary to chronic inflammation)
Diffuse oesophageal spasm
= normal peristalsis with abnormal high pressure waves
Present with chest pain
Barium oesophagogram: corkscrew pattern
No treatment, can try CCB or anticholinergics or nitrates
Classification of hiatal hernia
Type 1 = sliding: gastroesophageal junction slides into thorax, often associated with reflux
Type 2 = paraoesophagheal: fungus insinuated next to oesophagus, fullness after eating/upper abdominal pain are common symptoms
Type 3 = combination
Investigation/treatment of hiatal hernia
Upper GI series and upper GI endoscopy
Treatment involves managing reflux, surgical correction with fundoplication only if reflux not well controlled
Causes of ‘pill oesophagitis’?
Tetracycline
KCl
Ferrous sulphate
NSAIDs
Alendronate
Causes of oesophagitis?
= histological diagnosis of inflammation
GORD
Eosinophilic oesophagitis
Infectious oesophagitis
Pill oesophagitis
Caustic ingestion
Radiation
Sclerotherapy
Mechanisms of GORD
Hiatus hernia
Increased frequency of LOS relaxation
Decreased LOS pressure
Decreased oesophageal motility
Gastric emptying time altered
Definition of GORD
Reflux PLUS one of:
1. histopathological changes of oesophageal epithelial lining
2. symptoms of reflux (FTT, oesophagitis, episodes of aspiration pneumonia)
Natural history of reflux in infants
Becomes evident in the first few months of life, peaks at 4 months and resolves in 90% by 12 months
Clinical manifestations of infantile reflux
Regurgitation and vomiting
Oesophagitis features - pronounced irritability with arching, refusal to feed, weight loss, haematemesis
Respiratory features - chronic cough and wheeze, obstructive apnoea, stridor
Sandifer syndrome
Food refusal and neck contortions, presenting in older children as signs of reflux
Normal values of distal oesophageal acid exposure (on pH monitoring)?
Normal values of distal oesophageal acid exposure (pH<4) are <5-8% of the total monitored time
Indications for fundoplication in GORD?
Neurological disease
Not responding to medical therapy
Complications - peptic strictures, Barrett’s oesophagus
Gastrostomy feeds
Respiratory disease
Overview of eosinophilic oesophagitis
= chronic oesophageal disorder characterised by infiltration of the oesophageal epithelium with eosinophils
Most patients male, mean age at diagnosis 7 years
More common in those with atopy
Clinical manifestations of eosinophilic oesophagitis?
Infants = vomiting, feeding problems and poor weight gain
Older children and adolescents = food dysphagia with occasional food impactions or strictures, and may complain of chest or epigastric pain, slow eating
Pathogenesis of eosinophilic oesophagitis?
T helper type 2 cytokine mediated pathways leading to production of a potent eosinophil chemoattractant, eotaxin-3, by oesophageal epithelium
Diagnostic criteria for eosinophilic oesophagitis
> 15 eosinoophils/hpf on biopsy
Persistence of eosinophilia after a PPI trial
Secondary causes excluded
Dietary management of eosinophilic oesophagitis?
Successful in 60-80% of children
Target elimination diet = remove foods known to be allergic for patient
Six food elimination diet = eliminate foods commonly associated with allergy (milk and wheat most frequently impacted, also eggs, soy, nuts, seafood)
Elemental diet = all food intake changed to liquids (not practical)
Treatment of eosinophilic oesophagitis?
PPI = 40-50% of patients respond
Topical steroids = fluticasone and budesonide (swallowed inhaled corticosteroids)
Biological agents = anti-IL5 antibodies (mepolizumab, relizumab)
Complications of eosinophilic oesophagitis?
Stricture
Oesophageal perforation
No long term risk of cancers identified
Risk factors for infectious oesophagitis?
Diabetes
Alcohol
Glucocorticoids
Immunosuppressants
Broad spectrum antibiotics
Pathogens in infectious oesophagitis?
Candida albicans (most common)
Viral - HSV, CMV
Bacterial - uncommon (trypanosoma cruzie, cryptosporidium)
Clinical features of infectious oesophagitis?
Odynophagia +++ (pain on swallowing)
Dysphagia (solids and liquids)
Fevers and bleeding (but uncommon)
Four points of anatomic narrowing of the oesophagus which are at risk for FB?
Cricopharyngeus (upper oesophageal sphincter)
Aortic arch
Left main stem bronchus
Diaphragmatic hiatus
Medication used for treatment in oesophageal obstruction?
Glucagon 1mg IV - relaxes LES enough to allow passage of food in 50% of patients, affects only smooth muscles (so not helpful for proximal obstructions or strictures)
Boerhaave syndrome
Spontaneous oesophageal perforation associated with sudden increase in intra-oesophageal pressure (vomiting, coughing, straining)
Location of oesophageal perforations?
Perforation in proximal thoracic oesophagus - pneumothorax, effusions LEFT side of chest
Signs of more distal tears manifest on the RIGHT
Foregut/midgut/hindgut
Foregut: upper GI tract to the level of the bile duct insertion
Midgut: rest of small bowel and large bowel to the midtransverse colon
Hindgut: colon and upper anal canal
Common inhibitory factors for the stomach
- Reverse enterogastric reflex (presence of acid/protein in small intestine/small bowel distension)
- Secretin
- Gastric inhibitory peptide
- VIP
- Somastatin
Parietal cell functions?
Secrete HCl acid
Intrinsic factor for B12 absorption
Overview of omeprazole
Blocks acid secretion in response to all stimuli
Dose dependent irreversible inhibition with increasing effect over days (max effect by day 5)
>20mg inhibit all intragastric acidity in most individuals
Binds to hepatic CYP450 - inhibits oxidative metabolism of some drugs (e.g. phenytoin)
Most common cause of duodenal ulcers?
H pylori
Clinical features of duodenal ulcer?
Abdominal pain - worst before a meal, relieved by a meal
Clinical features of gastric ulcer?
Abdominal pain (epigastric usually)
Usually worse 2-4 hours after meal
Often pain at 2-3am (Hal secretion highest)
Relieved by antacids
First line treatment for H. pylori eradication?
Amoxicillin + clarithromycin + omeprazole for 10-14 days
Overview of Zollinger-Ellison syndrome
= rare syndrome characterised by severe PUD
Neuroendocrine tumour -> gastrin -> autonomous gastric acid secretion
Usually also have diarrhoea
98% of patients have elevated gastrin levels
Associated with MEN-1 and rare with NF and TS
Risk factors for H. pylori
SES most important predictor
Household crowding
Ethnicity
Migration from high prevalence areas
Infected parent (especially mum)
Contaminated water
Transmission: faecal-oral, oral-oral or gastric-oral
Which immunoglobulin in breastmilk is the most immunoprotective?
IgA - in breastmilk is secretory IgA, and is important as infant intestinal IgA production does not begin until several months of age
What are the pathways via which calcium is absorbed?
The paracellular pathway or the transcellular route
Paracellular is the primary pathway: passive absorption when the luminal concentration of calcium is high, enhanced by 1, 25-dihydroxyvitamin D which makes the junction more permeable to calcium
Which vitamins are likely to be deficient in short bowel syndrome?
Fat soluble vitamins: Vitamin A, D, E, K
Trace element deficiencies (iron, zinc, selenium) due to increased faecal losses
Vitamin B12 (as is absorbed in the ileum)
Magnesium
Where is vitamin C absorbed?
Passively in the proximal small bowel
Which organism is likely to cause diarrhoea and malabsorption in patients with CVID?
Giardia lambila (treat with metronidazole)
Which omentum attaches the stomach and duodenum to the liver?
Lesser omentum
Which omentum attaches the stomach to the transverse colon?
Greater omentum
Overview of Behcet disease?
Diagnosis: ulcers (oral or genital) occurring 3 times per year, plus 2 of the following: pathergy, uveitis and erythema nodosum
Pathergy = pustular reaction 24-48 hours after sterile needle puncture
Frequency of ulcers in PFAPA syndrome?
2-4 weekly, associated with fevers
PFAPA = Periodic fever, aphthous stomatitis, pharyngitis, adenitis
Features of splenic sequestration?
Vaso-occlusion in the spleen, and RBC pool in spleen. Causes marked drop in Hb, a persistent reticulocytosis and a rapidly enlarging spleen. There is a risk of hypovolaemic shock, and an associated mortality rate of 10-15%
Overview of aplastic crisis
Transient arrest of erythropoiesis and a sudden reduction in Hb concentration and RBC precursors in the bone marrow. This most often follows parvovirus B19 infection
Risk of parvovirus in sickle cell disease?
Limits reticulocyte production
Infliximab mechanism of action?
Binds to tumour necrosis factor
Infliximab is a monoclonal antibody
TNF-a is thought to be directly related to the pathogenesis of IBD, and blocking this can stop the inflammatory process
Overview of gastroschisis?
Protruding intestines with no covering membrane, usually to the right of the umbilicus
The protruding intestines are often thickened, fibrous and poorly functioning
Requires immediate surgery, complications include midgut volvulus, NEC and short bowel syndrome
Overview of omphalocele
Midline defect in the umbilical region which is >4cm
Often contained both solid organs and intestines
50-75% of neonates with omphalocele have another congenital anomaly
Overview of diastasis recti?
A vertical bulge noted when intra-abdominal pressure is raised, due to weakness of the fascia between the rectus abdominal muscles
= normal finding in neonates
Overview of umbilical hernia
<4cm, midline at the umbilicus, contains only intestines
Rarely cause incarceration and often self-resolve, although some require surgical closure
Elevated tissue transglutaminase (tTG) with normal IgA?
Coeliac disease
Diagnostic test for hereditary spherocytosis?
Osmotic fragility test - spherocytes have a reduced SA:V ratio therefore increased susceptibility to osmotic lysis in hypotonic solutions.
The osmotic fragility test detects haemolysis by measuring the fraction of total Hb released from red cells at progressively more dilute salt concentrations
GI problems associated with autosomal recessive polycystic kidney disease?
Biliary issues, as the protein fibrocystic is found in the epithelial cells of the hepatic bile duct (as well as in the kidneys). Most patients with ARPKD are born with some evidence of fibrosis on biopsy.
Hepatomegaly and portal hypertension develop over time in most patients.
Carol disease occurs in later stages
Cut off dose for investigation of paracetamol overdose?
> 10g or >200mg/kg
- would start NAC regardless if presenting >8 hours after ingestion
Conditions with increased risk of developing coeliac disease?
T1DM
Selective IgA deficiency
First degree relative with coeliac
Turner syndrome
Williams syndrome
Down syndrome
Autoimmune thyroiditis
Possible diagnosis for hypoalbuminaemia, oedema, pleural/pericardial effusions?
Think of protein-losing enteropathies - particularly with no evidence of liver or renal disease
Can test with A1AT clearance, as this protein is a similar molecular weight as albumin and not actively secreted, absorbed or digested.
Supplementation with what micronutrient is most effective in treating chronic diarrhoea in malnourished children?
Zinc
Which nutrients are absorbed in the duodenum/proximal jejunum?
Calcium, magnesium, phosphate, iron, folic acid
Which nutrients are absorbed in the distal ileum?
Vitamin B12, bile acids
Rates of absorption of calcium at different locations?
The duodenum is the region of most efficient absorption (active transport), however most calcium is likely absorbed in the ileum (passive transport)
Key feature of diencephalic syndrome
Significant absence of subcutaneous adipose tissue
Diencephalic syndrome occurs when benign astrocytomas affect the hypothalamus and thalamus, causing failure to thrive in a happy patient with preserved appetite and grossly normal development
Most common dietary factor associated with iron deficiency in infancy?
Introduction of unmodified cow’s milk prior to eight months