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Phase 2 GI Care > GI Investigations > Flashcards

GI Investigations Flashcards

1
Q

Name 8 routine lab blood tests done in GI investigations

A
  1. FBC/CBC
  2. LFT
  3. Albumin
  4. PT
  5. Amylase
  6. Coeliac serology
  7. Lactose intolerance congenital test
  8. Pancreatic enzyme tests
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2
Q

Which test should be done on patients prior to CT//MRI scans?

A

because contrast can damage kidneys from scans

Plain Ct is done without contrast but contrast is needed to look at bowel.

You need an eGFR>90, if below 60, then indicates CKD

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3
Q

How can CT damage kidneys?

What is done to avoid this?

A

Can get contrast-related nephropathy

if eGFR is less, flow through kidneys and filtration is less–> decreasing eGFR increases your chance of crystallisation of contrast, which can cause tubular damage–> renal failure

Bowels require the most contrast in CT therefore to avoid nephropathy, give patient IV fluids ( saline) to increase eGFR+ give acetylcysteine to avoid nephropathy

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4
Q

Give 2 purposes of LFT’s

A
  1. Confirm a clinical suspicion of potential liver damage
  2. To distinguish between hepatocellular injury ( hepatitis/ hepatic jaundice) and cholestasis ( post-hepatic ie obstructive jaundice)
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5
Q

Which 4 enzymes produced by the liver are part of LFT’s?

A
  1. ALT
  2. AST
  3. ALP
  4. GGT
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6
Q

When is ALT increased?

What is the normal range of ALT?

A

Alanine Transaminase

increased in hepatocellular injury (viral, alcoholic. drug-induced)

found in high concentrations within hepatocytes and enters blood following hepatocellular injury

3-40iu/L

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7
Q

When is AST raised? Is it more or less specific than ALT?

What is its normal range?

A

AST is less specific than ALT; also produced in muscle cells, produced post-MI

higher than ALT, in alcohol-related liver disease

Normal range= 3-30iu/L

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8
Q

Where is ALP produced?

When is it raised?

A

Alkaline Phosphatase; range= 30-100umol/L

produced in bile ducts, intestine, kidneys, placenta and bones

rasied din liver pathology due to increased synthesis in response to cholestasis

useful indirect marker of cholestasis

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9
Q

What does an isolated raise in ALP indicate?

Name 6 possible causes

A

a non-hepatobiliary pathology

  1. Vitamin D deficiency
  2. Pregnancy
  3. Bony metastases or a primary bone tumour e..g Sarcoma
  4. Recent bone fracture
  5. Renal osteodystrophy
  6. Salivary gland malfunction
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10
Q

What defines clinically apparent ie visible jaundice?

How can we differentiate between conjugated and unconjugate hyperbilirubinaemia

A

Raised bilirubin >60umol/L

Unconjugated bilirubin is not water-insoluble and, therefore, doesn’t affect the colour of the patient’s urine. Conjugated bilirubin, however, can pass into the urine as urobilinogen, causing the urine to become darker.

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11
Q

Give the clinical picture of stool and urine colour of:

1) Pre-hepatic jaundice
2) Hepatic jaundice
3) Post-hepatic jaundice

A
  1. Normal urine + normal stools = pre-hepatic cause
  2. Dark urine + normal stools = hepatic cause
  3. Dark urine + pale stools = post-hepatic cause (obstructive)
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12
Q

Give 3 causes of unconjugated hyperbilirubinaemia

A
  1. Haemolysis ( haemolytic anaemia)
  2. Impaired hepatic uptake ( congestive heart failure, drugs)
  3. Impaired conjugation ( Gilbert’s syndrome)
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13
Q

Give 2 causes of conjugated hyperbilirubinaemia

A
  1. Hepatocellular injury
  2. Cholestasis
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14
Q

What is the AST:ALT ratio like normally? When is it raised?

A

usually AST:ALT ratio<1

BUT it is raised, ie higher than 1 in alcohol-related liver disease

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15
Q

What is GGT raised and when is it raised?

A

Gamma Glutamyl Transpeptidase

can indicate biliary epithelial damage and bile flow obstruction
also raised in response to alcohol and drugs e.g. phenytoin

Raised GGT and ALP indicate cholestasis

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16
Q

How do we compare the rise in ALT and ALP?

A

A greater than 10 fold rise in ALT and a less than 3-fold increase in ALP suggests a predominantly hepatocellular injury

A less than 10 fold rise in ALT and a more than 3-fold increase in ALP suggests cholestasis

can have a mixed picture involving both hepatocellular injury and cholestasis

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17
Q

Name 3 acute phase reactants and when raised, what do they indicate?

A
  • Ferritin
  • Platelets
  • ESR

When raised, all indicate inflammation

18
Q

What tests do we do do if we suspect haemolysis/ haemolytic anaemia?

A
  • FBC; looking for low Hb, low haematocrit, ,MCV
  • Reticulocyte count ( young blood cells); high in haemolysis as bone marrow is trying hard to replace RBC’s which are being destroyed
  • Haptoglobin; low haptoglobin indicates haemolytic anemia
19
Q

Describe the lab results seen in alcoholic hepatitis

A

AST and ALT raised

AST raised to 250/300

markedly increase in GGT and IgA and ferritin

20
Q

Describe the 4 synthetic functions of the liver

A
  • Conjugation and elimination of bilirubin
  • Synthesis of albumin
  • Synthesis of clotting factors
  • Gluconeogenesis
21
Q

Give the function of albumin

GIve 5 causes of reduced albumin

A

helps to bind water, cations, fatty acids and bilirubin. maintains oncotic pressure of the blood

Reduced in:

  1. Sepsis
  2. Nephrotic syndrome
  3. Protein-losing enteropathies
  4. Cirrhosis
  5. Protein deficiencies; Kwashiokor, Marasmus
22
Q

When is globulin raised?

A

Cirrhosis

Autoimmune disease; autoimmune hepatitis, chronic inflammatory disease; SLE, Rheumatoid arthritis

23
Q

Why does platelet count fall in cirrhosis?

Describe the Hypersplenism Triad

A

Falls due to hypersplenism because of increased splenic pooling

TRIAD OF:

  1. Splenomegaly
  2. Compensatory bone marrow proliferation
  3. CYTOPENIA; anaemia, leucopenia, thrombocytopenia
24
Q

What immunoglobulins and antibodies are raised in autoimmune hepatitis?

A
  • raised IgG
  • raised SMA
  • raised IgA
25
Q

What does raised IgM indicate?

A

PRIMARY BILIARY CHOLANGITIS/ CIRRHOSIS

26
Q

Which 2 hep strains are transmitted via:

1) Faeco-oral route?
2) Parental route?

A

A and E

B and D

27
Q

Which tumour marker is raised in pancreatic cancer?

A

CA 19-9

28
Q

What is WILSON’S disease and what lab value would be decreased?

Describe its clinical presentation

A

autosomal recessive metabolic; impaired copper excretion causes accumulation of copper in the body

  • Ceruloplasmin is DECREASED ie less serum copper<20-4 mg/dL
  • raised urinary copper
  • can get Kayser-Fleischer rings
    *
29
Q

Decribe the extra-pyramidal symptoms of Wilson’s disease

A

extracellular deposits of copper

affects CNS and causes a movement disorder

can get HYPERKINESIS; tremor and dystonia

rigidity

Parkinsonism is common

30
Q

How does Campylobacter cause GBS?

A

Infection can cause a de-myelination of neurones antigens C. jejunilipopolysaccharide resembles GMi ganglioside on peripheral nerve myelin.

therefore causes demyelination–> causing exposed neurones–> infection of nerves–> ascending paralysis

31
Q

When examining the stool, what are you looking for?

A
  • changes in colour
  • consistency
  • pH
  • presence of mucus/blood
  • WBC
  • bile
  • fat, sugars
32
Q

What would increased fat content in stool indicate?

What would high pH indicate in stool?

A

Increased fat in coeliac disease, pancreatitis

High pH indicates inflammation and cancer

33
Q

What diseases do enzyme immunoassays detect viral and bacterial Ag?

A

C difficile

H. pylori

34
Q

What is FOB and what is it used for?

A

Faecal occult blood test

  • detection of blood in the faeces which is not visually apparent
  • conc of human Hb detectable in faeces increases in colorectal cancer
  • done to guide referral for suspected colorectal cancer
35
Q

Who should be tested for FOB?

What to do if FOB is positive?

A

1) If <60 yrs old with iron deficiency anaemia/ bowel habit changes
2) If older than or 50 yrs old with unexplained weight loss and abdominal pain
3) If older than or 60 yrs old; anaemia in the absence of an iron defiency

if FOB is positive, urgent 2 week referral for colorectal cancer

36
Q

How should false negatives/ positives be avoided when patients are doing FOB tests?

A
  • meat-free diet
  • avoid horse-radish, iron and abscorbic acid
  • patients should not be bleeding from another source ie menstruation
37
Q

What is faecal calprotectin and which two diseases does it distinguish between?

A

protein released by neutrophils, which are increased in IBD; therefore normally unlikely to be shed in stools

  • raised in intestinal inflammation; distiguishes between IBD and IBS ( non-inflammatory)
  • Tested if watery or bloody diarrhoea
38
Q

Why is calprotectin raised in IBD ?

A

Calprotectin is released by neutrophils and more likely to be elevated because of breakdown or shedding of neutrophils in stools

normal calprotectin is less than 50

39
Q

What causes a false positive calprotectin ?

A

raised in invasive infections e.g. Diverticulitis

Medications e.g. NSAIDS e.g. naproxen, PPI

40
Q

WHAT IF you had normal calprotectin but still had symptoms of IBD?

A

this can be a flair up

therefore calprotectin is good at helping to check if a patient is responding to treatment or in remission

41
Q

Name 3 causes of infective diarrhoea for:

1) Viruses (3)
2) Bacteria (4)
3) Protozoa (1)

A

1) Rotavirus ( norovirus), adenovirus, enterovirus
2) Campylobacter jejuni, Enterococcus, Salmonella, C diff
3) Giardia lamblia,

42
Q

Which disease should also be considered in a patient with suspected coeliac disease?

A

Infection with GIARDIA LAMBLIA

  • because they both cause villous atrophy on small intestine atrophy

Phase 2 GI Care (3 decks)

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