Upper GIT disorders

Question 1

Zollinger-Ellison syndrome

Answer 1

Excessive levels of gastrin, usually from a gastrin secreting tumour (usually duodenum or pancreas)

MEN1 in 1/3
Ch 11q13

Clinical:

• multiple gastroduodenal ulcers
• diarrhoea
• malabsorption

Diagnosis:

• fasting gastrin >1000
• Gatate PET-CET (new standard)
• secretin stimulation test
• genetic test available (90%)

Question 2

Hypergastrinaemia

Answer 2

Prolonged acid inhibition as most common cause of this (PPI, H2RA)

DDx:

• atrophic gastritis (pernicious anaeia, H pylori)
• vagotomy/SB resection
• rare: gastrin-secreting tumours (ZE syndrome), renal failure, hypercalcaemia, hyperlipidaemia (artefactual)

Question 3

Coeliac disease - genetics

Answer 3

Genes: HLA DQ2, HLA DQ8 (common in caucasians)

NPV: 994%
Not causative

Question 4

Coeliac disease - histo

Answer 4

Flat (loss of villi)
Inc crypts, inflammatory cells
Inc intraepithelial lymphocytes

Question 5

Coeliac disease - antibodies

Answer 5

Anti-gliadin Ab (IgA, IgG)
Chr 6

Tissue transglutaminase (IgA) [most accurate]

Endomysial Ab (IgA)

Deamidated gliadin peptide (IgG) [useful in IgA deficiency, less sensitive than TTG)

Question 6

Hereditary pancreatitis

Answer 6

Autosomal dominant

80% penetrance

Trypsinogen gene (PRSS 1)
Substitution
Chromosome 7

Question 7

Pancreatitis - other genetic associations

Answer 7

SPINK1 mutation
= serine protease inhibitor Kazal-type 1
= tumour-associated trypsin inhibitor (TATI)
= pancreatic secretory trypsin inhibitor (PSTI)

Normal trypsinogen activity
Usually missions mutation codon 34

Other:

• CFTR mutation
• variant common chymotrypsin C (cofactor only, need to have other risks)