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Medicine (Year 5) > Gastroenterology (Tests and signs) > Flashcards

Gastroenterology (Tests and signs) Flashcards

1
Q

Rapid urease test/urea breath test

A

The urea breath test can be used to identify the presence of Helicobacter pylori (H. pylori). It works on the ability of H. pylori to convert urea into ammonia and carbon dioxide (CO2). Patients swallow carbon-13 (13C) enriched urea which is converted into ammonia and 13C CO2, which is exhaled. After 30 minutes, the patient exhales into a glass tube and mass spectrometry is used to calculate the amount of 13C CO2 present.

Anti-acid drugs such as proton pump inhibitors should be stopped for at least 2 weeks and antibiotics should be stopped for at least 4 weeks before testing, as these can lead to false negatives.

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2
Q

Oesophagogastroduodenoscopy (OGD)

A

an endoscopic procedure that visualises the upper GI tract down to the duodenum. It involves passing a narrow flexible tube (gastroscope) down the oesophagus. As well as viewing the GI tract, OGDs can take samples of tissue for biopsy and can be used for therapeutic purposes (e.g. endoscopic band ligation in varices).

Some patients may be offered topical lidocaine to numb the throat or may be offered sedatives (e.g. midazolam) in patients who are anxious or agitated.

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3
Q

Barium swallow

A

A barium swallow is used to visualise the oesophagus and stomach using a series of x-rays after a patient swallows barium sulfate. Barium sulfate is an insoluble compound and is radiopaque, therefore when consumed, it coats the GI tract which then appears white on an x-ray film.

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4
Q

Colonoscopy

A

A colonoscopy is an endoscopic technique which visualises the large bowel and distal small bowel. It involves passing a flexible tube through the anus. Like other endoscopic techniques in the GI tract, it not only visualises tissues but can also be used to take biopsies and be therapeutic.

Around 2 days before a colonoscopy, patients should eat plain foods. 1 day before the colonoscopy, patients are instructed to drink sachets of laxatives to empty their bowels for the test. During the procedure, analgesia and sedation may be offered

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5
Q

Sigmoidoscopy

A

Unlike a colonoscopy which can visualise the entire colon, a sigmoidoscopy visualises the sigmoid colon. It may be useful over a colonoscopy, for example, in severe ulcerative colitis where a risk of bowel perforation is present, as sigmoidoscopies carry a lower risk of perforation.

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6
Q

Barium enema

A

Like a barium swallow, barium sulfate is used in barium enemas as it is insoluble and radiopaque. Patients are given laxatives the day before the barium enema to empty their bowels. Serial x-rays are performed and the bowels appear white as they are coated with barium sulfate.

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7
Q

liver function tests

A

LFTs often include:

  • Bilirubin
  • Alkaline phosphatase (ALP)
  • Alanine transaminase (ALT)
  • Aspartate transaminase (AST)
  • Gamma-glutamyltransferase (GGT)

Actual measures of liver function:

  • Albumin
  • International normalised ratio (INR)

Other tests that may be considered are:

  • Viral serology
  • Autoantibodies (e.g. antinuclear, antimitochondrial, and anti-smooth muscle antibodies)
  • Alpha-fetoprotein (AFP) – for hepatocellular carcinoma
  • Ferritin and transferrin saturation – for haemochromatosis
  • Caeruloplasmin – for Wilson’s disease
  • Alpha-1 antitrypsin (A1AT)
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8
Q

Bilirubin

A

Bilirubin is the resulting product of haem breakdown:

  • Total bilirubin measures both conjugated (direct) and unconjugated indirect) bilirubin
  • Conjugated and unconjugated bilirubin can help to identify where the problem is if there is hyperbilirubinaemia.
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9
Q

The ratio of AST: ALT can help with identifying the cause:

A
  • Chronic liver disease: ALT > AST
  • Once cirrhosis occurs: AST > ALT
  • AST: ALT ratio >2 suggests alcoholic liver disease
  • AST:ALT ratio <1 suggests non-alcoholic liver disease
  • Alcoholic liver disease is unlikely to cause an AST >1000 IU/L
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10
Q

Gamma-glutamyltransferase (GGT)

A

Gamma-glutamyltransferase (GGT) is found in hepatocytes, biliary epithelial cells, the kidneys, and intestines. Key points are:

  • All liver diseases may show increased GGT levels
  • Like ALP, increased GGT levels suggest cholestasis
  • GGT can confirm that a raised ALP is due to liver damage and not another cause
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11
Q

Alkaline phosphatase (ALP)

A

Alkaline phosphatase (ALP) is an enzyme found in cells lining the bile ducts but also in bone. It is involved in the calcification of bones. Key points are:

  • An elevated ALP (often with elevated GGT) suggests cholestasis
  • A high ALP with normal GGT suggests bone disease
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12
Q

Albumin

A

Albumin is a marker of liver function with high sensitivity, as it is made specifically in the liver. Since it has a long half-life, it is not as useful in acute disease. Reduced levels of albumin can cause oedema.

Key points are:

  • Albumin levels can be decreased in chronic liver disease (e.g. cirrhosis)
  • Albumin can also be decreased in nephrotic syndrome, as it is lost through the urine
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13
Q

Isolated increase in bilirubin

A

Determining whether the bilirubin is conjugated or unconjugated can help with identifying the underlying cause. The causes of an isolated increase in unconjugated bilirubin are:

  • Hereditary and acquired causes of haemolytic anaemia:
  • Gilbert’s syndrome – impaired bilirubin conjugation
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14
Q

Increased ALT and AST

A

A rise in AST and ALT greater than ALP and GGT suggests a hepatitic picture. Causes may be:

Toxic:

  • Alcohol
  • Paracetamol
  • Infectious:
  • Hepatitis A, B, C, D, and E
  • HIV infection
  • Plasmodium falciparum malaria
  • Entamoeba haemolytica
  • Leptospirosis

Autoimmune:

  • Autoimmune hepatitis
  • Primary biliary cirrhosis
  • Primary sclerosing cholangitis

Other:

  • Non-alcoholic fatty liver disease
  • Wilson’s disease
  • Hereditary haemochromatosis
  • Alpha-1 antitrypsin deficiency
  • Hepatocellular carcinoma
  • Liver metastases
  • Lymphoma
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15
Q

gallbladder and bileduct tests

A

Endoscopic retrograde cholangiopancreatography (ERCP)

Magnetic resonance cholangiopancreatography (MRCP)

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16
Q

Endoscopic retrograde cholangiopancreatography (ERCP)

A

An ERCP is used to diagnose and treat disorders of the bile ducts, gallbladder, pancreas, and liver. Patients may be given local anaesthetic spray to numb the throat and sedatives before the procedure. An endoscope is passed down the oesophagus, through the stomach and pylorus into the duodenum through to the ampulla of Vater (where the common bile duct and pancreatic duct meet).

During an ERCP, a contrast medium may endoscopically be injected into the biliary tree and pancreas, allowing for cholangiopancreatography (x-ray imaging of the bile ducts and pancreas).

An ERCP is both diagnostic and therapeutic. It may be used for gallstone extraction and stent insertion through the ampulla of Vater to allow bile drainage (may be performed in pancreatic cancer for palliation).

An ERCP can carry risks of infection and pancreatitis.

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17
Q

Magnetic resonance cholangiopancreatography (MRCP)

A

An MRCP is a relatively safer and non-invasive alternative to an ERCP and uses magnetic resonance imaging (MRI) to produce images of the liver, bile ducts, gallbladder, and pancreas. It is safer than an ERCP as it is non-invasive and does not require ionising radiation.

Due to the non-invasive nature of MRCP, it does not permit interventions to be performed, such as stone extraction, stent insertion, or biopsy.

18
Q

An ascitic tap may be used to:

A
  • Determine the aetiology and nature of ascites (e.g. if it is a transudate or exudate)
  • Detect malignant cells
  • Diagnose and identify the underlying cause of spontaneous bacterial peritonitis
19
Q

jaundice as a sign

A

Jaundice becomes apparent when the serum bilirubin levels are over 35 μmol/L. The presence of jaundice can suggest problems with the

  • liver
  • biliary tract
  • blood (e.g. haemolytic anaemia).
20
Q

production of bilirubin

A
  1. In the reticuloendothelial cells, haem (found in haemoglobin) is converted to biliverdin and then converted to bilirubin.
  2. In the liver, bilirubin is converted into conjugated (direct) bilirubin, making it soluble and easier to excrete.
  3. Some bilirubin can escape the process and remain as unconjugated (indirect) bilirubin, which is insoluble.
  4. Conjugated bilirubin is excreted into the duodenum in bile. Once it reaches the colon, bacteria deconjugate the bilirubin and convert it into urobilinogen.
  5. 80% of this urobilinogen is eventually converted into stercobilin, giving faeces their colour.
  6. The remaining 20% is reabsorbed into the blood, which is processed in the liver for bile production.
  7. Some of the remaining 20% reaches the kidneys where it is oxidised into urobilin and excreted in the urine.
21
Q

Pre-hepatic (haemolytic) jaundice

A

This form of jaundice is most commonly caused by a pathologically increased rate of red blood cell haemolysis.

MOA Haemolysis releases high levels of unconjugated bilirubin, which overwhelms the liver, leading to the deposition of unconjugated bilirubin in tissues.

Causes:

  • Hereditary and acquired causes of haemolytic anaemia
  • Gilbert’s syndrome – impaired bilirubin conjugation

Since the bilirubin is unconjugated, it cannot be excreted into the intestines, leading to dark stools and urine that darkens when left to stand, as urobilin forms as more time progresses.

22
Q

Hepatic (hepatocellular) jaundice

A

This form of jaundice is due to damage to the hepatocytes, leading to an inability of the liver to conjugate bilirubin. Both unconjugated and conjugated bilirubin levels increase

Causes:

Toxic:

  • Alcohol
  • Paracetamol

Infectious:

  • Hepatitis A, B, C, D, and E
  • HIV infection
  • Plasmodium falciparum malaria
  • Entamoeba haemolytica
  • Leptospirosis

Autoimmune:

  • Autoimmune hepatitis
  • Primary biliary cirrhosis
  • Primary sclerosing cholangitis

Other:

  • Non-alcoholic fatty liver disease
  • Wilson’s disease
  • Hereditary haemochromatosis
  • Alpha-1 antitrypsin deficiency
  • Hepatocellular carcinoma
  • Liver metastases
  • Lymphoma
23
Q

Post-hepatic (cholestatic) jaundice

A

This form of jaundice is due to a blockage of the bile ducts that transport bile and conjugated bilirubin out of the liver. The liver can conjugate the bilirubin, but cannot excrete it, leading to high amounts of conjugated bilirubin. Causes may be:

  • Gallstones (choledocholithiasis)
  • Iatrogenic injury
  • Ascending cholangitis
  • Pancreatic cancer
  • Cholangiocarcinoma
  • Biliary atresia
  • Primary biliary cirrhosis
  • Cystic fibrosis
  • Lymphoma
  • Pregnancy

Since less conjugated bilirubin is excreted into the intestinal tract, less urobilinogen is produced. This results in less stercobilin, leading to pale stools. Although there is less urobilin (due to the lack of urobilinogen), the excess conjugated bilirubin is excreted in the urine, giving dark urine.

24
Q

typical findings for jaundice depending on location

A
25
Q

Boas’ sign

A

Boas’ sign describes hyperaesthesia in the right lower scapular region or right upper quadrant of the abdomen. It is associated with acute cholecystitis.

26
Q

Courvoisier’s law

A

Courvoisier’s law states that a painless palpable mass in the right upper quadrant along with jaundice is unlikely to be due to gallstones. This sign suggests the presence of pancreatic cancer or cholangiocarcinoma.

27
Q

Charcot’s triad

A

Charcot’s triad describes jaundice, fever, and right upper quadrant pain, which suggest the presence of acute cholangitis.

28
Q

Reynold’s pentad

A

Reynold’s pentad describes Charcot’s triad (jaundice, fever, and right upper quadrant pain), along with shock (hypotension with or without tachycardia), and an altered mental status. It suggests serious acute cholangitis.

29
Q

Murphy’s sign

A

Murphy’s sign describes the arrest of inspiration on palpation of the right upper quadrant. It is tested by asking the patient to breathe out, palpating the right upper quadrant, and asking the patient to breathe in. During inspiration, the abdominal organs move down as the lungs expand and the diaphragm moves down. As the gallbladder moves down and comes into contact with the examiner’s hand, the patient stops breathing in due to pain.

30
Q

Abdominal guarding

A

Abdominal guarding describes the voluntary contraction of abdominal wall muscles in anticipation of pain when the abdomen is palpated to ‘guard’ the underlying inflamed tissue.

31
Q

Abdominal rigidity

A

Abdominal rigidity differs from guarding as it describes the involuntary increased tension of abdominal muscles due to underlying inflammation. Rigidity tends to occur over the inflamed area, whereas guarding tends to be generalised over the entire abdomen. Abdominal rigidity suggests peritoneal inflammation.

32
Q

Rebound tenderness

A

Rebound tenderness describes pain upon removal of pressure to the abdomen. It suggests the presence of parietal peritoneum inflammation due to stretching.

33
Q

Rovsing’s sign

A

Rovsing’s sign describes pain felt in the right lower quadrant when palpating the left lower quadrant. It is associated with appendicitis. Abdominal viscera pain nerves do not localise well and elicit generalised pain. Once the inflammation irritates the peritoneum, the pain becomes localised. Palpation of the left lower quadrant stretches the peritoneum, eliciting pain on the right side when inflamed.

34
Q

Hepatomegaly

A

Hepatomegaly describes an enlarged liver and may occur due to infection, malignancy, cirrhosis, or right heart failure.

35
Q

Splenomegaly

A

Splenomegaly describes an enlarged spleen which can result from infection (such as infectious mononucleosis), portal hypertension (e.g. secondary to cirrhosis), and haematological disorders including myeloproliferative disorders, malignancy, and haemoglobinopathy.

36
Q

Hepatosplenomegaly

A

Hepatosplenomegaly describes the enlargement of both the liver and spleen. Its cases include, but are not restricted to, liver cirrhosis, right-sided heart failure, infection, and haematological disorders including myeloproliferative disorders, malignancy, and haemoglobinopathy.

37
Q

Sister Mary Joseph nodule

A

The Sister Mary Joseph nodule describes a periumbilical nodule. Its presence may suggest the presence of gastrointestinal malignancy, including gastric cancer and pancreatic cancer.

38
Q

Virchow’s nodes

A

The left supraclavicular lymph nodes are known as Virchow’s nodes. If a palpable mass is felt in this region, it may suggest gastric cancer metastasis, as this is one of the first sites it metastasises to.

39
Q

Shifting dullness

A

Shifting dullness is a sign that looks for the presence of ascites. It is done with the patient initially lying flat and percussing the midline of the abdomen. This should give a resonant sound due to the fluid settling to the bottom and gas being present. Percussion then moves away from the examiner until it becomes dull, suggesting the presence of fluid. The examiner’s finger is left at the first point of dullness and the patient rolls onto the other side. Around 10-30 seconds later, this point is percussed again back to the centre. If this point is now resonant, ascites is likely to be present and shift due to gravity.

40
Q

Cullen’s sign

A

Cullen’s sign describes periumbilical discolouration due to oedema and bruising. It occurs due to intra-abdominal bleeding and is seen in acute pancreatitis and abdominal trauma.

41
Q

Grey Turner’s sign

A

Grey Turner’s sign describes flank discolouration due to bruising secondary to retroperitoneal haemorrhage. It is associated with acute pancreatitis.

Medicine (Year 5) (34 decks)

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