Gastroenterology

Question 1

Absorption

Answer 1

DUODENUM: Iron, Ca, Mg, PO4, fat soluble vitamins (D, E, A, K), folic acid
JEJUNUM: most minerals/nutrients, vitamins, folic acid
SMALL BOWEL: carbohydrates, protein, water soluble vitamins (B, C), fatty acids, monoglycerides, medium chain TG
TERMINAL ILEUM: vit B12, bile salts
LARGE INTESTINE: water, electrolytes (Na/K/Cl)

Question 2

Carbohydrates

Answer 2

GLUCOSE: Glut 1 in, Glut 2 out
GALACTOSE: Glut 1 in, Glut 2 out
FRUCTOSE: Glut 5 in, Glut 2 out (Fructose Five)
SUCROSE = GLUCOSE + FRUCTOSE (sucrase/isomaltase)
LACTOSE = GLUCOSE + GALACTOSE (lactase)
MALTOSE = GLUCOSE + GLUCOSE (maltase/sucrase)

Glut 1: Brain, RBC
Glut 2: beta islet, liver, kidney, small intestine
Glut 3: brain, placenta
Glut 5: spermatocytes, GIT

1kcal = 4.8kJ
Breast milk 100mL = term formula 100mL = 280kJ = 67 calories

Question 3

Absorption and digestion

Answer 3

Carbohydrate malabsorption: low pH, reducing substances, hydrogen breath test e.g. lactose intolerance, coeliac

Fat maldiGestion: fat Globules e.g. CF, pancreatitis, Scwachmann Diamond

Fat malAbsorption: fatty Acid crystals e.g. coeliac, CMPI

Protein maldigestion: alpha 1 antitrypsin e.g. coeliac, IBD

Pancreatic insufficiency: faecal elastase, tryptic acid e.g. CF

Faecal calprotectin - neutrophils

Question 4

Diarrhoea

Answer 4

Osmotic:
- Acidic pH <5
- HIGH osmol gap
- LOW stool Na <60
- Reducing substances
- Small volumes
- Stops when intake stops
E.g. lactose intolerance, post viral gastro, coeliac, IBD, lactase deficiency, gluc/galactose malabsorption, sucrose is maltose deficiency

Secretory:
- Basic pH >6
- LOW osmol gap
- HIGH stool Na >100
- NO reducing substances
- Large volumes
- Continmues when intake stops
E.g. Bacterial (E. Coli, salmonella, crypto), electrolyte disturbance

Question 5

Vitamin Deficiencies

Answer 5

Vitamin B1 (thiamine): wet beri beri CCF, dry beri beri CNS
Vitamin B6 (pyridoxine): neonatal seizures
Vitamin B12 (Cobalamin): peripheral neuropathy, hypertonia
Vitamin E: ataxia, loss of reflexes
Vitamin A: loss of night vision, blindness

Question 6

Coeliac disease

Answer 6

1:100, 5-10% family history
Complications: eosinophilic oesophagi’s, lymphoma, GOT cancer, dermatitis herpetiformis
Associated: T1DM, autoimmune thyroid, T21, Turners, Williams
HLDQ2, HLADQ8 0 if negative rules out CD. Also + in T1DM and others
Anti TTG Ig A - most sensitive
Anti endomysial IgA - most specific (IgA def can given false result)
<2 y TTG reduced sensitivity - deaminated gliadin better
Small bowel biopsy gold standard
Stool - osmotic diarrhoea, fatty acid crystals

Question 7

Biliary atresia

Answer 7

Unconjugated hyperbilirubinemia
HIDA scan
Kasai procedure
Complication Vit E deficiency

Question 8

Pyloric stenosis

Answer 8

Hypokalaemia
Hypochloraemia
Metabolic alkalosis
H+ in urine

Question 9

Crohns

Answer 9

10% first degree relative
Patchy, skin lesions, transmural, cobble stone
Non-caeseating granuloma
Complications: arthralgia, erythema nodosum, uveitis, perianal disease, orofacial granulomatosis
Enteral nutrition - 70% mucosal healing

Question 10

Ulcerative colitis

Answer 10

Large bowel/continuous
Mucosal, diffuse, inflammatory infiltrates
Complications: pyoderma gangrenous, PSC, toxic megacolin, cholestatic liver disease

Question 11

Hepatitis

Answer 11

Surface - outside
- Antigen - have virus - chronic, current, carrier
- Antibody - have had virus - immunised, past infection
Envelope - one layer in
- Antigen - have virus - chronic, current
- Antibody - have had virus - chronic, carrier, resolved
Core - inside the envelope
- IgG - have had virus - current, chronic, resolved
- IgM - current infection
DNA
- Inside the core - positive - current, chronic infection