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
Hypophosphataemia seen in refeeding syndrome leads to what symptoms?
- Cardiac Dysfunction: Impair myocardial contractility, leading to heart failure. It may also cause arrhythmias due to its role in maintaining normal cellular electrophysiology.
- Respiratory Failure: Phosphate is essential for ATP production, necessary for respiratory muscle function. Severe hypophosphatemia can lead to muscle weakness, including the diaphragm and intercostal muscles, potentially resulting in acute respiratory failure.
- Neurological Complications: Confusion and seizures to coma, attributable to disturbed ATP metabolism in the central nervous system.
- Haematological Effects: Reduced 2,3-diphosphoglycerate levels in erythrocytes affect oxygen release from haemoglobin, leading to tissue hypoxia. Hypophosphatemia can also result in hemolysis.
- Rhabdomyolysis: Phosphate depletion impairs ATP production in muscles, which can lead to muscle breakdown and rhabdomyolysis.
ECG findings in hyperkalaemia?
- Peaked or ‘tall-tented’ T waves (occurs first)
- Loss of P waves
- Broad QRS complexes
- Sinusoidal wave pattern
- Ventricular fibrillation
Mx for hepatorenal syndrome?
Terlipressin, they work by causing vasoconstriction of the splanchnic circulation.
Double duct sign on CT scan?
Pancreatic Cancer.
High-resolution CT scanning is the investigation of choice if the diagnosis is suspected
imaging may demonstrate the ‘double duct’ sign - the presence of simultaneous dilatation of the common bile and pancreatic ducts.
Features of Whipple’s disease?
Whipple’s disease is a rare multi-system disorder caused by Tropheryma whippelii infection. It is more common in those who are HLA-B27 positive and in middle-aged men.
- Malabsorption: diarrhoea, weight loss
- Large-joint arthralgia
- Lymphadenopathy
- Skin: hyperpigmentation and photosensitivity
- Pleurisy, pericarditis
- Neurological symptoms (rare): ophthalmoplegia, dementia, seizures, ataxia, myoclonus
Barium swallow demonstrates a corkscrew appearance in what condition?
Diffuse Oesophageal Spasm.
Mx for Barrett’s oesophagus?
- High-dose proton pump inhibitor
whilst this is commonly used in patients with Barrett’s the evidence base that this reduces the change of progression to dysplasia or induces regression of the lesion is limited. - Endoscopic surveillance with biopsies for patients with metaplasia (but not dysplasia) endoscopy is recommended every 3-5 years.
- If dysplasia of any grade is identified endoscopic intervention is offered. Options include:
- Radiofrequency ablation: preferred first-line treatment, particularly for low-grade dysplasia
- Endoscopic mucosal resection
Triad of Budd Chiari syndrome?
Budd-Chiari syndrome, or hepatic vein thrombosis, is usually seen in the context of underlying haematological disease or another procoagulant condition.
Causes:
- Polycythaemia rubra vera
- Thrombophilia: activated protein C resistance, antithrombin III deficiency, protein C & S deficiencies
- Pregnancy
- Combined oral contraceptive pill: accounts for around 20% of cases
- Abdominal pain: sudden onset, severe
- Ascites → abdominal distension
- Tender hepatomegaly
Kantor string sign is seen in which condition?
Crohn’s disease.
Double target sign on CT scan?
‘double target sign’, which consists of a central low attenuation lesion surrounded by a high attenuation inner rim and a low attenuation outer ring. This sign suggests a hepatic abscess.
Ix for Whipple’s disease?
Whipple’s disease is a rare multi-system disorder caused by Tropheryma whippelii infection.
Investigation:
Jejunal biopsy shows deposition of macrophages containing Periodic acid-Schiff (PAS) granules.
Abx prophylaxis for patients with SBP and Ascites?
Offer prophylactic oral ciprofloxacin or norfloxacin for people with cirrhosis and ascites with an ascitic protein of 15 g/litre or less until the ascites has resolved.
Gold standard investigation for Achalasia?
- Oesophageal manometry is the correct answer. It is the gold standard investigation to diagnose achalasia because it has the highest sensitivity. Manometry will show a high resting lower oesophageal pressure.
- Barium swallow:
it has a lower sensitivity than oesophageal manometry. A barium swallow would show a dilated oesophagus that tapers smoothly to a beak-like narrowing at the gastro-oesophageal junction. ‘Bird beak appearance’.
Mx for Achalasia?
- Pneumatic (balloon) dilation is increasingly the preferred first-line option. Less invasive and quicker recovery time than surgery,
patients should be a low surgical risk as surgery may be required if complications occur. - Surgical intervention with a Heller cardiomyotomy should be considered if recurrent or persistent symptoms.
- Intra-sphincteric injection of botulinum toxin is sometimes used in patients who are a high surgical risk.
- Drug therapy (e.g. nitrates, calcium channel blockers) has a role but is limited by side-effects
Ix for PBC?
Immunology:
- Anti-mitochondrial antibodies (AMA) M2 subtype are present in 98% of patients and are highly specific.
- Smooth muscle antibodies in 30% of patients.
Imaging:
required before diagnosis to exclude an extrahepatic biliary obstruction (Ultrasound or MRCP).
NOT liver biopsy unless diagnostic uncertainty.
Ix results seen in Wilson’s disease?
- Slit lamp examination for Kayser-Fleischer rings.
- Reduced serum caeruloplasmin
- Reduced total serum copper (counter-intuitive, but 95% of plasma copper is carried by ceruloplasmin)
- Free (non-ceruloplasmin-bound) serum copper is increased
- Increased 24hr urinary copper excretion
- The diagnosis is confirmed by genetic analysis of the ATP7B gene
Mx for eosinophilic oesophagitis?
Eosinophilic oesophagitis is characterised by an allergic inflammation of the oesophagus. An oesophageal biopsy will show dense infiltrate of eosinophils in the epithelium.
Thought to be caused by an allergic reaction to ingested food.
Risk Factors:
- Allergies/ asthma: suffering from food/ environmental allergies or atopic dermatitis and asthma increases the risk of diagnosis
- Family history of eosinophilic oesophagitis or allergies
- Coexisting autoimmune disease e.g. coeliac disease
Adults often experience dysphagia, strictures/ fibrosis (56%), food impaction (55%), regurgitation/ vomiting, anorexia.
Endoscopy: diagnosis can only be made on the histological analysis of an oesophageal biopsy. There must be more than 15 eosinophils per high power microscopy field to diagnose the condition. Other findings on endoscopy include reduced vasculature, thick mucosa, mucosal furrows, strictures and laryngeal oedema. Histologically, the diagnosis is made more likely in the presence of epithelial desquamation, eosinophilic microabscesses, and abnormally long papillae.
Mx:
- Dietary modification
- Topical steroids e.g. fluticasone and budesonide are options when dietary modification fails. This requires the patient to swallow solutions of the steroid to line the oesophagus. This should be done for eight weeks before being reassessed.
- Oesophageal dilatation: 56% of patients require this at some point in their treatment to reduce the symptoms associated with oesophageal strictures
Mx for Whipple’s disease?
Oral co-trimoxazole for a year is thought to have the lowest relapse rate, sometimes preceded by a course of IV penicillin.
Risk factors and features of microscopic colitis?
Risk factors:
1. smoking
2. Drugs: NSAIDs, PPIs and SSRIs
Mx: need to stop the offending drug
- watery diarrhoea: usually insidious but more acute presentations are seen
- faecal urgency and incontinence is a frequent feature
- abdominal pain
- constitutional symptoms such as weight loss, lethargy and arthralgia may be present
- non-specific investigation findings include mild anaemia and raised inflammatory markers.
Histology: Lymphocytic infiltrate within the intestinal villi.
Features of hydatid cyst?
Hydatid cysts are endemic in Mediterranean and Middle Eastern countries. They are caused by the tapeworm parasite Echinococcus granulosus.
CONTAINS MULTIPLE SMALL DAUGHTER CYSTS.
- Up to 90% of cysts occur in the liver and lungs
- Morbidity caused by cyst bursting, infection and organ dysfunction (biliary, bronchial, renal and cerebrospinal fluid outflow obstruction)
- Recurrent episodes of urticaria are likely to be secondary to the contents of the cyst leaking. Much of the morbidity related to hydatid cysts is caused by anaphylactic reactions.
Imaging:
1. Ultrasound if often used first-line
2. CT is the best investigation to differentiate hydatid cysts from amoebic and pyogenic cysts
Echinococcus granulosuscan serology is USEFUL in investigation of suspected hydatid cysts.
Ultrasound shows ‘sand sign’, debris within the cyst moving freely and the CT scan suggests sister cysts. Both of these findings are characteristic of hydatid disease.
Surgery is the mainstay of treatment (the cyst walls must not be ruptured during removal)!!
How to calculate serum-ascites albumin gradient (SAAG)?
Serum Ascites Albumin Gradient SAAG accurately identifies the presence of portal hypertension
SAAG = Serum albumin value - ascitic fluid albumin
SAAG > 11g/L
(indicates portal hypertension)
Liver disorders are most common cause:
- Cirrhosis/alcoholic liver disease
- Acute liver failure
- Liver metastases
- Right heart failure
- Budd-Chiari syndrome
- Portal vein thrombosis
- Veno-occlusive disease
- Myxoedema
SAAG <11g/L
Hypoalbuminaemia:
- Nephrotic syndrome
- Severe malnutrition (e.g. Kwashiorkor)
- Malignancy
- Peritoneal carcinomatosis
- Tuberculous peritonitis
- Pancreatitis
- Bowel obstruction
- Biliary ascites
- Postoperative lymphatic leak
- Serositis in connective tissue diseases
Symptoms of vitamin C deficiency?
Scurvy leads to impaired collagen synthesis and disordered connective tissue as ascorbic acid is a cofactor for enzymes used in the production of proline and lysine. It is associated with severe malnutrition as well as drug and alcohol abuse, and those living in poverty with limited access to fruits and vegetables.
- Follicular hyperkeratosis and perifollicular haemorrhage
- Ecchymosis, easy bruising
- Poor wound healing
- Gingivitis with bleeding and receding gums
Sjogren’s syndrome
Arthralgia
Oedema - Impaired wound healing
- Generalised symptoms such as weakness, malaise, anorexia and depression
Triad of Budd Chiari syndrome?
Budd-Chiari syndrome or hepatic vein thrombosis is usually seen in the context of underlying haematological disease or another procoagulant condition.
Causes:
- Polycythaemia rubra vera
- Thrombophilia: activated protein C resistance, antithrombin III deficiency, protein C & S deficiencies
- Pregnancy
- COCP
Triad of:
1. Abdominal pain: sudden onset, severe
2. Ascites → abdominal distension
3. Tender hepatomegaly
Budd Chiari syndrome vs Portal Vein thrombosis?
Budd Chiari Syndrome is posthepatic obstruction while Portal Vein Thrombosis is prehepatic obstruction.
Portal vein thrombosis does not cause liver failure because its pre-hepatic blood flow from the gut so it only causes symptoms secondary to portal hypertension whereas Budd-chiari causes liver failure because blocking the blood flow out of the liver causes hepatic congestion.
Biopsy findings?
WHIPPLE’S DISEASE small intestinal biopsy: macrophages containing Periodic acid-Schiff (PAS) granules infiltrating into the lamina propria.
SARCOIDOSIS biopsy: non-caseating granulomas.
TB biopsy: caseating granuloma.
ULCERATIVE COLITIS biopsy: acute & chronic inflammation of the mucosa leading to crypt abscess formation.
CROHN’S DISEASE biopsy: full-thickness inflammation w non-caseating granuloma & lymphoid aggregate formation & skip regions.
COELIAC DISEASE biopsy: lymphocyte infiltration, villous atrophy & crypt hyperplasia.
GASTRIC MALT LYMPHOMA biopsy:
large number of lymphocytes that have irregular nuclear contours w abundant cytoplasm.
GASTRIC CA biopsy: signet ring cells may be seen. They contain a large vacuole of mucin which displaces the nucleus to one side.
Management for Gastric MALT Lymphoma?
- Associated with H. pylori infection in 95% of cases.
- Good prognosis
- If low grade then 80% respond to H. pylori eradication.
MALT lymphoma (or MALToma) which is a form of lymphoma invading the mucosa-associated lymphoid tissue. Because there is a causal relationship between Helicobacter Pylori infection and MALT lymphoma, it is vital to identify the presence of H. pylori and treat it. 50-90% of cases achieve complete response with H. pylori treatment and eradication.
In severe flare of Crohn’s if does not respond to IV steroids next step in management?
Biologic therapy is considered in treatment of an acute flare of Crohn’s disease when symptoms don’t improve after 5 days of IV hydrocortisone.
The next step in management should be considered, which would be anti-TNFα agents e.g. Infliximab or Adalimumab.
Most important blood test in diagnosing haemochromatosis?
TRANSFERRIN SATURATION is considered the most useful marker
Which medication should not be used with Allopurinol?
Azathioprine.
Allopurinol enhances the effects and increases the toxicity of azathioprine.
Lung carcinoid can sometimes release what?
Lung carcinoid may results in Cushing’s syndrome secondary to ACTH release.
What is Gardner’s syndrome?
A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma and epidermoid cysts on the skin.
- Adenomatous intestinal polyposis, which can present with changes in bowel habit and rectal bleeding, osteomas and fibromas. 50% of patients with Gardener’s syndrome have colon cancer by the age of 39.
Lead pipe sign colon is seen in what condition?
Ulcerative colitis.
Features of Plummer-Vinson syndrome?
Triad of:
1. Dysphagia (secondary to oesophageal webs!!)
2. Glossitis
3. Iron-deficiency anaemia
Treatment includes iron supplementation and dilation of the webs
Mx for acute mesenteric ischaemia?
Acute mesenteric ischaemia is typically caused by an embolism resulting in occlusion of an artery which supplies the small bowel, for example the superior mesenteric artery. Classically patients have a history of atrial fibrillation.
Immediate laparotomy is usually required, particularly if signs of advanced ischemia e.g. peritonitis or sepsis.
Features of Zollinger Ellison syndrome?
Zollinger-Ellison syndrome is a condition characterised by excessive levels of gastrin secondary to a gastrin-secreting tumour. The majority of these tumours are found in the first part of the duodenum, with the second most common location being the pancreas.
Around 30% of gastrinomas occur as part of MEN type I syndrome.
- Multiple gastroduodenal ulcers
- Diarrhoea
- Malabsorption
Diagnosis
1. Fasting gastrin levels: the single best screen test
2. Secretin stimulation test
Which condition is associated with Anti-liver/kidney microsomal type 1 antibodies (LKM1)?
Type 2 autoimmune hepatitis occurs in children and is associated with Anti LKM1 antibody.
