Gastroenterology Flashcards
Investigation for autoimmune pancreatitis?
Antinuclear antibodies and IgG4 levels are raised in autoimmune pancreatitis and are commonly used in conjunction with radiographic imaging (such as a CT abdomen and pelvis) to confirm the diagnosis. Radiographic features of autoimmune pancreatitis include diffuse enlargement, giving the appearance of a ‘sausage-shaped’ pancreas.
Liver function in Alcoholic Liver Disease?
- Gamma-GT is characteristically elevated
- Ratio of AST:ALT is normally > 2, a ratio of > 3 is strongly suggestive of acute alcoholic hepatitis
Pharmacological Mx for NAFLD?
The mainstay of treatment is lifestyle changes (particularly weight loss) and monitoring.
There is ongoing research into the role of gastric banding and insulin-sensitising drugs (e.g. metformin, pioglitazone).
anti-smooth muscle antibodies?
Autoimmune hepattis.
PBC Antibody?
- Anti-mitochondrial antibodies (AMA) M2 subtype are present in 98% of patients and are highly specific.
- smooth muscle antibodies in 30% of patients
- raised serum IgM
Mx for PBC?
- First-line: ursodeoxycholic acid
slows disease progression and improves symptoms. - Pruritus: cholestyramine
- Fat-soluble vitamin supplementation.
- Liver transplantation
e.g. if bilirubin > 100 (PBC is a major indication)
recurrence in graft can occur but is not usually a problem
Ix for small bowel bacterial overgrowth syndrome?
- Hydrogen breath test.
- Small bowel aspiration and culture: this is used less often as invasive and results are often difficult to reproduce.
- Clinicians may sometimes give a course of antibiotics as a diagnostic trial.
A combination of low vitamin B12 and high folate levels favours small bowel bacterial overgrowth.
This is because bacteria in the bowel absorb vitamin B12 and convert it to its inactive analogue, which then competes for normal B12 absorption in the gut, resulting in low levels. Conversely, bacteria are able to synthesise folate, resulting in normal or elevated levels.
Mx for SBBOS?
Antibiotic therapy: Rifaximin is now the treatment of choice due to relatively low resistance.
Co-amoxiclav or metronidazole are also effective in the majority of patients.
Mx of oesophageal varices?
No varices: Rescope 2-3 years
Grade 1 varices: Rescope 1 year
Grade 2 or 3 varices or signs of bleeding: Non-cardio selective beta blocker
Mx for Bowel obstruction secondary to metastatic cancer?
Dexamethasone.
Ix of choice for bile acid malabsorption?
The test of choice is SeHCAT.
Nuclear medicine test using a gamma-emitting selenium molecule in selenium homocholic acid taurine or tauroselcholic acid (SeHCAT).
SeHCAT is bile acid analogue which can be detected by a nuclear medicine scan. The SeHCAT test involves a baseline scan, and then a 7 day scan. A 7-day SeHCAT retention value of less than 15% is generally considered indicative of bile salt malabsorption.
Causes for bile acid malabsorption?
Bile-acid malabsorption is a cause of chronic diarrhoea. This may be primary, due to excessive production of bile acid, or secondary to an underlying gastrointestinal disorder causing reduced bile acid absorption. It can lead to steatorrhoea and vitamin A, D, E, K malabsorption.
Secondary causes are often seen in patients with ileal disease, such as with Crohn’s.
Other secondary causes include:
- Cholecystectomy
- Coeliac disease
- Small intestinal bacterial overgrowth
Mx for bile acid malabsorption?
Bile acid sequestrants e.g. Cholestyramine.
Ix for Coeliac disease?
- Tissue transglutaminase (TTG) antibodies (IgA) are first-choice according to NICE.
- Endomyseal antibody (IgA)
needed to look for selective IgA deficiency, which would give a false negative coeliac result.
- Anti-gliadin antibody (IgA or IgG) tests are not recommended by NICE
anti-casein antibodies are also found in some patients.
Endoscopic intestinal biopsy
the ‘gold standard’ for diagnosis - this should be performed in all patients with suspected coeliac disease to confirm or exclude the diagnosis.
Traditionally done in the duodenum.
Findings:
- Villous atrophy
- Crypt hyperplasia
- Increase in intraepithelial lymphocytes
- Lamina propria infiltration with lymphocytes
Mx for C.Diff infection?
First episode of C. difficile infection:
1. First-line therapy is oral Vancomycin for 10 days
2. Second-line therapy: oral Fidaxomicin
3. Third-line therapy: oral vancomycin +/- IV metronidazole
Life-threatening C. difficile infection:
- Oral vancomycin AND IV metronidazole
Risk factors for Small Bowel Bacterial Overgrowth Syndrome?
(SBBOS) is a disorder characterised by excessive amounts of bacteria in the small bowel resulting in gastrointestinal symptoms.
- chronic diarrhoea
- bloating, flatulence
- abdominal pain
Risk factors for SBBOS (things that affect motility):
- neonates with congenital gastrointestinal abnormalities
- Scleroderma
- Diabetes mellitus
Signet ring cells seen in which condition?
Signet ring cells may be seen in gastric cancer. They contain a large vacuole of mucin which displaces the nucleus to one side. Higher numbers of signet ring cells are associated with a worse prognosis.
Eradication for H.Pylori?
Eradication may be achieved with a 7-day course of:
- PPI + Amoxicillin + (Clarithromycin OR Metronidazole)
If penicillin-allergic: PPI + Metronidazole + Clarithromycin
Mx for diarrhoea following bowel resection in Crohn’s disease?
n patients who have had the ileum removed, bile acid malabsorption is a major cause of diarrhoea as most bile acids are reabsorbed in the ileum. This condition can be treated with Cholestyramine.
Ix for Carcinoid syndrome?
24h urinary 5-HIAA.
Constipation predominant IBS if patients not responding to laxatives, next pharmacological option?
For patients with constipation who are not responding to conventional laxatives Linaclotide may be considered, if:
- optimal or maximum tolerated doses of previous laxatives from different classes have not helped and
they have had constipation for at least 12 months
Second-line pharmacological treatment:
low-dose tricyclic antidepressants are used in preference to SSRIs.
Lactulose is not recommended in IBS as can worsen bloating!
Which IBD drugs can cause pancreatitis?
Both mesalazine and sulfasalazine can cause drug induced pancreatitis, however the risk is much higher with mesalazine.
Pancreatitis is 7 times more common in patients taking mesalazine than sulfasalazine.
Ix for hereditary haemochromatosis?
Transferrin saturation is considered the most useful marker.
- Ferritin should also be measured but is not usually abnormal in the early stages of iron accumulation
Testing family members:
genetic testing for HFE mutation
Iron profile in hereditary haemochromatosis?
Typical iron study profile in patient with haemochromatosis:
- Transferrin saturation > 55% in men or > 50% in women
- Raised ferritin (e.g. > 500 ug/l) and iron
- Low TIBC