Gastro Flashcards
Physiology
What’s the difference in the myenteric and meissners plexus
Myenteric- peristalsis
Meissners- controls mucous glands
Where is the majority of iron absorbed?
Duodenum
Carb physiology
What are the 2 major forms of starch and how do they differ
What else can make up starch
Amylose- has 1,4 bonds only
Amylopectin has 1,4 and 1,6 bonds
Glycogen
Outline the major steps in CHO digestion
Chewed in the mouth. Some amylase action- partial hydrolysis
Nothing but churning in the stomach
Most happens in the small intestine-pancreatic amylase causes hydrolysis
Brush border enzymes break into glucose
What do the following enzymes break down
Maltase
Sucrase
Lactase
Maltase= Maltose- 2xglucose Sucrase= Sucrose- glucose and fructose Lactase= Lactose- glucose and galactose
What happens in glucose galactose malabsorption
Where is the defect
Glucosuria and reducing substances in the urine on breast milk introduction
Na glucose channel
What causes fructose malabsorption
What causes hereditary fructose intolerance
Glut 2 and 5 transporter defects
AR defect of adalase B
Protein absorption
What are proteins made up of
What are the 2 ends
Chains of amino acids
Carboxy end and nh3 end
Proteins
Outline metabolism
What stomach enzymes induce and inhibit this
Chewed in the mouth
Pepsinogen goes to pepsin in the stomach and breaks peptide bonds
Pancreatic enzymes induced by enterokinase
Trypsinogen to trypsin which allows all other enzymes to work within the duodenum
Gastrin and secretin. Somatostatin inhibits
How can amino acids be absorbed
As single amino acids
Broker down within luminal cells via peptidases
What are examples of monosaccharides
What are examples of polysaccharides
Glucose, galactose and fructose
Sucrose and lactulose
Lymphangiectasia
What two syndromes is it associated with
What is it
What two other things will be low
Turners and noonans
Protein and fat malabsorption
Immunoglobulins and lymphocytes
Abetalipoproteinaemia What is it? What is a common complication What eye disorder is seen What nero signs are there What is seen on blood film
Severe fat deficiency- can’t make chylomicrons Vitamin E deficiency Retinitis pigmentiosa Peripheral neuropathy Acanthocytes
When we eat fats what form are they normally in?
Triglycerides
Outline fat digestion
Emulsified in the stomach
Broken down by pancreatic lipases in small intestine to free fatty acids
Combine with bile salts to form mixed micelles
Outline fat absorption
Free fatty acids enter cells
Back to triglycerides
Form a chylomicron
Go to the lymphatic system then to the blood via thoracic duct
What is the difference between saturated and unsaturated fats
Saturated=single bonds only
Unsaturated= double bonds
What is different in neonates regarding fat digestion
Have stomach and linguine lipase that can work in the stomach and break down short and medium fas which is more common in milk
What is different about medium fatty acid metabolism and why is this useful?
Can be absorbed directly into the portal venous system
Useful for malabsorption or chylothoracies
Biliary atresia What will syndromic BA have? Does it normally associate with IUGR? What is seen on ultrasound? What is seen on biopsy?
Congenital heart disease and poly/asplenia
No!
Contracted bile duct. Dilated ports hepatis
Black pigment and reversal of hepatic artery to vein ratio
Biliary atresia
What surgical procedure is performed
When is it best preformed
What is the ultimate treatment
Kasai
Before 12 weeks
Liver transplant
Alagille syndrome
What are the 2 common genetic forms
What phenotypically is seen
JAG 1, NOTCH2
Normal if Notch 2, otherwise triangle face, broad forehead, posterior embryotoxin, butterfly vertebrae, peripheral pulmonary stenosis
What is is seen on biopsy of alagille syndrome
Bile duct paucity
Bile duct disease
What is an example of a bile acid transporter disease
Persistent familial intrahepatic cholestasis
Paracetamol overdose
What are 3 examples of potentially toxic ingestions
When after ingestion should the level be taken
When should NAC be started?
What is the toxic metabolite that builds up?
What does NAC do?
>10g, >200mg/kg, staggered subtheraputic overdoses 4 hrs Before 8 hrs NAPQI Restores glutathione
What are carbohydrates stored as in the liver
Glycogen
Alpha 1 AT DEF
What is the inheritance
What is the gene
AR
Serpin1a
Alpha 1 AT def
What is the normal function of the protein
What is the severe form called- what happens
When does lung disease typically present
How should family members be screened
To prevent lung damage against neutrophil elastase
ZZ disease- hepatocytes cant secrete the protein
Adolescence or adulthood
Screen alpha 1 AT Levels
Jaundice
Other than haemolysis, what else can cause unconjugated hyperbili
Enzyme defects- Gilbert’s and crigler Najjar
UDP Glucuronyl transferase
What are genetic causes of conjugated hyperbili
What test will help differentiate the two?
Dublin Johnson
Rotor
Urinary coproporphyrin- increased in DJ, reduced in rotor
Wilson disease Which chromosome and gene Signs Characteristic blood test What happens to serum copper Diagnostic test
13 ATP7B Neuropsychiatric- early Parkinson’s, liver failure, KF rings AST:ALT ratio 4:1 Raised or decreased Caeruloplasmin- low
Wilson’s
First line chelation therapy
Other useful treatments
Penicillamine
Zinc EDTA
Types of autoantibodies-
Autoimmune hepatitis 1
Autoimmune hepatitis 2
Which type is more common in kids?
Smooth muscle and ANA
Liver kidney
2
Does hepatitis A normally cause liver failure?
How should you be treated if post exposure
No
Vaccine plus IG
Hepatitis B What antibodies/antigens are seen: - vaccinated - active infection - active replication - past infection
Anti HepB s
Hep b S
Hep b E
Anti s and c
What rash is found in kids with active hep b. What does it look like?
Granotti crosti
Salmon pink papules to face and buttocks
Hepatitis B
What phase is treatment normally targeted
What meds are given
How do you manage an infant with a mum with active infection
What other infection can occur simultaneously
Clearance phase- chronic active hepatitis
Interferon alpha and nucleoside analogues- combination therapy
Give vaccine and IG
Hep D
Hepatitis C
What are the main complications
Is breast feeding safe?
Cirrhosis and HCC
YES
Early onset IBD
Which IL is commonly associated?
What else is commonly seen
IL10
Immunodeficiencies
What is the general pattern of inflammation in Crohn’s disease
What might the first signs of disease be?
Are systemic features and extra intestinal disease more or less likely than UC
What gene defect is seen most commonly
Patchy anywhere from mouth to anus, glanulomas, transmural, strictures and fistulae.
Spares rectum
Can have perianal disease
Growth faltering
More!
NOD 2
What is the general pattern of inflammation in UC
Which ANCA is likely to be positive
Pancolitis
Patchy, mucosal, no granulomas
P ANCA
What 2 rashes are commonly seen in Crohn’s disease
Erythema nodosum
Pyoderma gangrenosum
What is faecal calprotectin a marker of?
What does it correlate severity of
Neutrophil derived inflammation
UC not CD
Azathioprine
How does it work
Why do metabolites need to be monitored
How is it monitored and what does the results indicate
What can be given to help
What should be checked prior to starting and what indicates not to start it
What is the risk of lymphoma
Direct action of T cells
Changed in the liver to 6MCP. Can cause BM Suppression
6TG levels- low= possible poor compliance. High= toxicity possible
Allopurinol
TMPT status- if heterozygous or homozygous don’t give
4x general ppn
What is the main cause of intestinal damage in coeliac disease
Unchecked activation of T lymphocytes
How do infilximab and adalimumab compare and differ
Both anti TNF alpha
Inflix is IV, Ada is SC
Ada is humanised
What test has the best negative predictive value in coeliac disease- HLA or anti TTG
How is diagnosis in diabetes different?
Do you need symptoms to make a diagnosis
Do you need a biopsy of positive HLA and antibodies x2
HLA d2 and 8
All need a biopsy
No
No
Coeliac disease
What might you seen in the stool
Fatty acid crystals and raised reducing substances (general malabsorption)
What 3 syndrome last does coeliac disease associate with
Downs turners and Williams
What rash is associated with coeliac disease ?
If found alone is it diagnostic?
Dermatitis herpeteformis
Yes
Other than coeliac disease what can cause villlous atrophy
Giardia and rotavirus Whipples Soy milk and protein intolerance Eosinophilic gastritis Lymphoma GVHD
What is the most common type of oesophageal atresia
OA with distal TOF
Where are iron magnesium and calcium mainly absorbed
Duodenum and jejunum
What is the main physiological cause of reflux?
Transient lower eosophageal sphincter relaxation
What is the most likely causative agent in EOE
How many eosinophils are needed to be seed on microscopy
Milk
>20 per high powered field
How do PPIs work?
Bind to the HKATPase pump
Swallowed coins, how do you tell if they’re in the trachea or oesophagus?
Side on=tracheal
End on=oesophageal
What do the fore mid and hindgut make up?
When does the primatove gut start to develop
From 4 weeks
Fore- until the cbd insertion at the duodenum
Mid- until mid transverse colon
Hind- until anal canal
Where is intrinsic factor secreted from?
Parietal cells of the body of the stomach
What are the three hormones the stomach secretes? What do they do
Gastric- increased acid secretion and motility.
Somatostatin- inhibits gastrin and insulin
Pepsinogen- cleaved to pepsin and useful
Digestive hormone
Pyloric stenosis
What factors make it more likely
What medication can cause it
B and O blood groups
Son of a mum who had it
Erythromycin
H pylori
What type of bacteria is it?
What three things does it cause?
Gram neg bacillus
Gastritis, peptic ulcers (mostly duodenal) and cancer- mostly lymphoma or adenocarcinoma
H pylori How does it usually present in kids What is the best diagnostic test? What is used to monitor treatment effect? What is the treatment?
Non specific abdominal pain
Gastroscopy plus biopsy
Urease breath test
Amox, Clari and ppi for 2 weeks
What usually causes zollinger Ellison syndrome
What is it associated with
How is it diagnosed
Gastrinoma
TS and NF1
Non healing ulcer with high fasting gastrin levels
What might be useful for a plant (phyto) bezoar?
Coca Cola
What is likely to be found in the stools of lactose intolerance
Positive reducing substances, fat and fat crystals
Low stool PH
Are antibiotics recommended with shigella infection
Yes
How might yersinia present
Pseudo appendicitis
What is the genetic association with hirschsprung disease
What is the gold standard investigation.
What syndromes make it more likely
RET
Rectal suction biopsy
Downs. Ondine’s curse
Peutz jeghers syndrome Inheritance Gene Findings When does cancer surveillance start
AD
STK11
Mucocutaneous pigmentation, small intestinal polyps and increased malignancies- breast and reproductive
8 yrs
FAPC
Inheritance
When do polyps start
Screening
AD
Adolescence. Multiple polyps with 100% malignant change
Annual colonoscopy
Secretory and osmotic diarrhoea
How do they differ
Examples of each
Secretory- low osmotic gap, high volume, persists with fasting. CF. Channel pump disorders
Osmotic- high osmotic gap, improves with fasting. Coeliac, lactose intolerance
What can pyloric atresia be associated with
Epidermolysis bullosa
What rash is associated with zinc deficiency
Acrodermatitis enteropathica
What is the usual defect in malrotation
Counterclockwise rotation 270deg around sup mesenteric artery
What are the 3 most common genes associated with pancreatitis in children
What is the difference between swachmann diamond syn and Pearson syn
PRSS 1
SPINK 1
CFTR
SD- BM failure
Pearson- sideroblastic
How successful is EEN at inducing remission in Crohn’s disease
Around 80%
How much calories per gram of:
Fat
Carb
Protein
Fat-9
Protein and carb- 4
Smith lemil opitz syndrome What causes the disease How phenotypically do they present What GI and neuro issues do they have What is the diagnostic test What may be useful to treat
Reduced 7 dehydroxycholesterol resuctase enzyme
Microcephaly with fused fingers and toes
Bowel obstruction and pyloric stenosis
Cataracts seizures and hypotonia
Increased serum DOC
Cholesterol supps and simvastatin
Stool interp
What does alpha 1AT show
What do fatty globules show? Crystals
Intestinal protein loss
Poor digestion- GB or pancreas issue
malabsorption
Stool interp
What is a low stool ph? What does it show? What test should be done next. What level are you looking for
<5.3
Fermentation- CHO malabsorption so monosacchiarides and disaccharides are in the stool
Looking for reducing sugars- >0.5% or 2+
Stool interp How do you calculate stool osmolality What is normal What does high indicate What does low indicate What does high na indicate- what is high What does high cl indicate- what is high
290 -2(na + k)
50-100
Osmotic- can’t absorb
Secretory- secreting too many electrolytes
High na- secretory diarrhoea- above 70
High cl- congenital chloride losing diarrhoea- above 20
Where is b12 absorbed
What does the colon secrete
Terminal ileum
Potassium and bicarb
What structures form from the foregut midgut and hindgut
What is the blood supply
Fore- until duodenum (where bile duct enters) - coeliac artery
Mid- until transverse colon- sup mesenteric artery
Hind- until anus- inf mesenteric artery
Which vascular lesions can cause oesophageal obstruction
Double aortic arches and aberrant right subclavian
How beneficial is EEN at inducing remission in IBD
80%
How is azathioprine metabolised
Why should TMPT test be done before. When should it not be given? When should 50% dose be given instead?
What is the active form called. What do low levels show? High levels?
To 6MP in liver then 6TG
To ensure can break down 6MP. Homozygote- don’t give. Hetero 50% dose
6TG. Low is poor compliance. High- potentially toxic- give allopurinol
What is the triad of swachmann diamond syndrome
Short stature, pancreatic insufficiency and bone marrow failure
What persists to cause a meckels
What is the rule of 2s
Vitelline duct
2% ppn. Men to women 2:1. 2 fr from IC valve and 2 inches long
How do you differentiate between the 3 types of PFICC
What might be seen in the obstetric history
What is the inheritance
1 low GGT and less severe than 2
3 high GGT
Obstetric cholestasis
AR
IPEX syndrome
What gene is abnormal
What is commonly seen
FOXP3 gene
Early diabetes, severe diarrhoea and dermatitis
What is the main cause of liver disease in TPN usage?
What is better soy or fish oil
What medication might be useful in treatment
Lipid content
Omega 3 is kinder
Ursodeoxycolic acid
GLP2 analogues
What are they used for
What do they help? How?
Short bowel syndrome
Reduce TPN requirements. Increase villus height
How does citrulline associate with small bowel mass
Low in short bowel syndrome. Correlates to severity
What is goats milk low in?
Folate
