Flashcards in GI IV Deck (29):
Gilbert's syndrome is associated with an isolated elevation of unconjugated bilirubin due to mild deficiency of glucuronyl transferase, with normal liver architecture and consequently no elevation in urobilinogen.
Alkaline phosphatase is normal. Bilirubin concentrations are variable, and jaundice can be precipitated by drugs and infection.
It is the commonest form of familial non-haemolytic hyperbilirubinaemia affecting 2-5% of the population, and is now thought to be inherited in an autosomally recessive manner, although other abnormalities may contribute to phenotype.
Budd-Chiari syndrome: Cause of splenomegaly
Hepatic vein thrombosis/Budd-Chiari results in portal hypertension and splenomegaly.
Colonic carcinoma is not associated with splenomegaly.
Other causes include infections such as
Splenomegaly is not a feature of congestive cardiac failure.
AXR useful for....
Up to 30% of patients with end-stage chronic pancreatitis will have diffuse calcification within the pancreas gland, best visualised by an oblique abdominal view.
Caecal carcinoma is only reliably demonstrated on double-contrast barium enema or colonoscopy. The 'parrot's beak' sign is the characteristic appearance on plain films with the distended sigmoid loop arising out of the pelvis.
Cholesterol stones are typically radiolucent. Only 10% of all gallstones are radio-opaque (c.f. 90% of renal stones).
Black pigment stones are more commonly calcified and therefore visible on the AXR. The plain AXR is perhaps the most useful investigation in fulminant colitis. Serial AXRs will demonstrate toxic dilatation of the colon (>6 cm diameter, usually the transverse colon), which is an indication for surgery.
Pharmacological causes of pancreatitis
Drugs associated with pancreatitis include
The most notable precipitant is alcohol.
Chemotherapy with cisplatin/vinca alkaloids may produce acute pancreatitis but radiotherapy is not associated with acute but is associated with chronic pancreatitis.
Which does not predispose to gastro-oesophageal reflux disease (GORD)?
Predisposing factors include
Antral disorders and disorders of emptying (Pyloric stenosis)
Previous vagal surgery
yet there does not appear to be an association with H. pylori, in fact data would suggest an increase in GORD associated with H pylori eradication.
The characteristic radiological feature is the 'string sign', which comprises a thin contracted pyloric canal, containing a central streak of barium.
The clinical symptoms commonly appear in this time frame.
The vomiting is not bile stained but consists of large volumes of curdled milk. Appetite and feeding are normal or increased.
The characteristic metabolic abnormality is hypochloraemic hypokalaemic alkalosis.
Achalasia cardia is a neuromuscular failure of relaxation at the lower end of the oesophagus due to loss of ganglia from the Auerbach's plexus (absence of ganglion cells in the neural plexus of the intestinal wall leads to Hirschsprung's disease).
It is more common in females (3:2) and is frequently seen during the third decade of life.
There is progressive dysphagia to solids and liquids, chest pain and regurgitation of old food from the dilated oesophageal sac.
x Ray reveals a dilated oesophagus with a tapering lower oesophageal segment, likened to a bird's beak, which fails to relax.
There is absence of gastric air bubbles because the dilated oesophagus never completely empties and therefore swallowed air cannot pass into the stomach.
Chest x ray shows air or fluid level behind the heart and the expanded oesophagus gives the appearance of a 'double right heart border'.
Coeliac disease and HLA B8
Haemochromatosis and HLA A3
Primary sclerosing cholangitis and HLA B8
Ulcerative colitis and HLA B27
HLA B8 is also associated with polymyalgia rheumatica.
Haemochromatosis is also associated with HLA B14.
Primary biliary cirrhosis is associated with HLA DR8.
Malabsorption may be associated with numerous disorders but typically occurs with:
Pancreatic exocrine deficiency
Coeliac disease: dermatitis herpetiformis is an association that responds to dapsone.
Inflammatory bowel disease.
Diverticular disease may be associated with bacterial overgrowth and malabsorption.
Helicobacter is associated with peptic ulceration not malabsorption.
Mesenteric ischaemia is associated with malabsorption but pain after eating is the main feature. Patients lose weight because eating is painful and from an element of malabsorption.
Regarding the rectum
The rectum lies in the posterior part of the pelvic cavity.
It is continuous with the sigmoid colon at the rectosigmoid junction where there is often an acute angulation (not constriction) in the intestine which may hamper the passage of the colonoscope.
When the rectum pierces the pelvic floor it turns abruptly downwards and backwards, and terminates at the anorectal junction where it is continuous with the anal canal.
Unlike the colon, the rectum is devoid of appendices epiploicae and has no taeniae, the longitudinal muscle being distributed uniformly around its circumference.
The upper third of the rectum is covered anteriorly and on both sides by peritoneum while the middle third, lying behind the rectouterine or rectovesical pouch, has peritoneum only on its anterior surface.
The arterial supply of the rectum is derived principally from the superior rectal artery, the continuation of the inferior mesenteric artery. This supply may be supplemented by middle rectal branches from the internal iliac arteries.
Intra-abdominal sepsis should be considered in all patients with MODS of unknown cause.
Bacteraemia caused by laparotomy initially worsens MODS causing a temporary (occasionally permanent) deterioration in the patient's condition.
Septic patients are safer in theatre than in the radiology department and CT gives little information which will not be obtained at laparotomy.
Coagulopathy will be exacerbated by surgery and blood transfusion and will result in poor haemostasis or worse, no haemostasis.
Leaving the abdomen open initially allows for re-inspection of the wound, the abdomen should be closed when the patient's condition has improved.
Abdominal drains inserted when...
Drains should be used prudently and not prophylactically. A wound should not be closed until adequate haemostasis has been achieved, with excessive / uncontrollable bleeding the abdomen should be packed with gauze. Adequate peritoneal lavage should be performed with soiling. Anastomotic breakdown is diagnosed clinically, drain outputs can be misleading. A drain in the gallbladder bed may cause a bile leak. The common bile duct is repaired around a T-tube, most surgeons place a drain close to the repair.
H2 receptors mediate gastric acid secretion and are also present in human heart, blood vessels, uterus and the brain although their exact function is not clearly defined.
The H2 receptors in the stomach are situated on the basolateral aspect of the parietal cell.
The receptor complex spans the cell membrane and contains an adenylcyclase enzyme (without the need for a linked transmembrane protein). When the receptor is activated by histamine (not gastrin) the net result is an increase in intracellular cAMP which stimulates acid secretion and release from the parietal cell.
Omeprazole is a proton pump inhibitor and as the name suggests specifically inhibits the proton pump.
in ascites complicating cirrhosis
It should be remembered that a patient with ascites complicating cirrhosis will have hyperaldosteronism, i.e. sodium retention with consequent potassium loss.
Decreased vascular resistance,
Increased plasma volume, and
Low serum sodium.
Free fatty acids
Free fatty acid (such as alpha ketoglutarate and 3OH butyrate) release in starvation (and diabetic ketoacidosis) is responsible for ketosis.
Insulin inhibits the release of free fatty acids.
FFA stimulates hepatic gluconeogenesis and inhibits metabolism via the hexose monophosphate shunt and anaerobic glycolysis.
Spontaneous bacterial peritonitis
With spontaneous bacterial peritonitis the mortality rate is less than 50%. Being spontaneous it does not imply intestinal perforation.
Spontaneous bacterial peritonitis is a diagnosis of exclusion and is confirmed when the results of blood cultures and peritoneal tap become available. A laparotomy should be performed if in any doubt.
Only when a peritoneal tap reveals a non-enteric organism can antibiotic therapy be instituted with caution.
Ascitic fluid provides an excellent medium for blood borne bacteria. Haemolytic Streptococci, Escherichia coli and Klebsiella are most frequently cultured.
renal blood flow
The Fick principle can be used to estimate RBF through clearance.
Renal blood flow is approximately 25% of cardiac output.
RBF should be increased in response to hypoxia.
RBF is higher in the cortex than medulla as one might expect with the increasing glomeruli in this region.
Sympathetic stimuli produce vasoconstriction.
Common features of pheochromocytoma include:
Palpitations and tachycardia
Bradycardia is rather unusual, as is hypotension.
Unconjugated hyperbilirubinaemia results when the liver is unable to cope with the breakdown of red blood cells as occurs in sickle cell, hereditary spherocytosis and Gilbert's.
Carcinoma of the head of the pancreas results in conjugated hyperbilirubinaemia.
Biliary atresia is also associated with a conjugated jaundice.
On the other hand, haemolysis is associated with unconjugated hyperbilirubinaemia as is Gilbert's disease.
Precipitants of acute pancreatitis include
Gallstones and alcohol as the commonest
Type V hyperlipidaemia (hypertriglyceridaemia)
as well as infections such as mumps, coxsackie, EBV or the hepatits viruses.
Hypocalcaemia may be caused by pancreatitis
Regarding jejunal biosy
A. Electron microscopy is necessary to confirm the presence of villousatrophy
B. It is contraindicated over the age of 70 years
C. In tropical countries apparently healthy people have a mucosalstructure which would be regarded as abnormal in Europe
D. It can be used to diagnose Whipple's disease
E. Sub-total villous atrophy is diagnostic of gluten-sensitiveenteropathy and is not found in other conditions
A. The villus atrophy may be seen with a magnifying glass.
B. There is a group of patients who present with coeliac disease in older age - sometimes in their 90s. They present with iron deficiency anaemia, osteoporosis or weight loss.
C. They would not be 'healthy'.
E. Sub-total villus atrophy is seen in a number of conditions other than coeliac disease (for instance,
Severe tropical sprue
Cow's milk / soya sensitivity in children
Cancer of the oesophagus is a recognised complication of Barrett's oesophagus. It is also recognised in association with coeliac disease.
Chest discomfort is frequently an early symptom.
From top to bottom the commonest site distribution is 15, 50, 35%.
Ninety per cent are squamous carcinomas, 8% adenocarcinomas.
The overall five year survival is poor at around 20% and late presentation means that about 50% are suitable for surgical intervention.
Regarding meckels diverticulum
Two per cent of the population have Meckel's, which is an ileal remnant of vitello-intestinal duct.
It contains ectopic gastric mucosa/pancreatic tissue. It is usually asymptomatic. Severe bleeding (acute) or obstruction and abdominal pain can occur.
A technetium scan shows increased uptake in 70%.
H2 breath test is for bacteria which split marker molecules releasing gas in the breath (for example, hydrogen 14/O2). It is not used for the diagnosis of Meckel's where bacterial overgrowth is not a problem.
Littre described a Meckel's diverticulum in a hernial sac in 1700, 81 years before Meckel was born.
Oesophageal spasm can be particularly difficult to distinguish from angina pectoris.
Reflux often presents with oesophageal spasm and pain.
Also spasm may be relieved by GTN making the differential diagnosis more difficult.
It usually is substernal to the throat but may radiate to the back
Not erythema marginatum
Crohn's disease is associated with a relative risk of four to six times with smoking but smoking is protective in ulcerative colitis (UC).
Skin manifestations include erythema nodosum and pyoderma gangrenosum.
Also there is slightly increased risk of bowel carcinoma though less than UC.
Characeterisitc of right sided colon cancer
Iron deficiency anaemia is a common feature of colonic neoplasia particularly caecal lesions which may be clinically apparent as a mass in the right iliac fossa.
PR bleeding is more suggestive of left sided lesions, as is obstruction.
Weight loss is another presenting feature.
metabolic acidosis causes
Metabolic acidosis may arise as a consequence of lactic acidosis (sepsis, MI, cirrhosis) or may accompany bicarbonate losses with hydrogen ion retention (renal tubular acidosis [RTA]).
Laxatives cause a metabolic alkalosis with excessive chloride loss.
Hepatic encephalopathy results in hyponatraemia due to water retention, hypoglycaemia due to depleted hepatic glycogen store, hypokalaemia, hypophosphataemia and metabolic alkalosis.
Dermatitis herpetiformis is associated with coeliac disease.
There is an association with increased fracture rate due to the increased incidence of osteoporosis secondary to steroid treatment.
Sclerosing cholangitis is more common in ulcerative colitis (UC) than Crohn's disease.
The severity of the uveitis is related to disease activity; this is not the case for sacroiliitis.