Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCD 2- Diagnostics > Diagnostics > Flashcards

Diagnostics Flashcards

1
Q

What are the likely causes of fever, rash and lymphadenopathy with D&V and red patches on lower leg with weight loss?

A

Viral illness- HIV (BILLY CASE STUDY)

NB. first few symptoms could be glandular fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the likely causes of diarrhoea?

A

Virus
Bacteria
Parasites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What tests would a GP do if a patient presented with fever, rash, lymphadenopathy and diarrhoea?

A 
FBC, ESR, CRP
LFTs
U&Es
Blood glucose
Ix of viral illness
Stool culture - bacteriology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are LFTs?

A

Liver function tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are U&Es?

A

Urea and electrolytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What stages are necessary before collecting blood?

A

Check it’s correct patient
Label CORRECT tube (colour lid is important)
Check if urgent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the main difference between different blood collection tubes?

A

Contain different anticoagulants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q 
What anticoagulants are found in blood collection tubes with the following colours?
Red
Yellow
Purple
Grey
Blue
Green
A 
Red= none
Yellow= gel to speed up clotting
Purple= potassium EDTA
Grey= fluoride oxalate (poison)
Blue= citrate
Green= heparin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the purpose of potassium EDTA in purple topped blood tubes?

A

Stops blood from clotting and preserves cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the purpose of fluoride oxalate in grey topped blood tubes?

A

Poison
Red cells will use up glucoses (because they’re living)
So have to poison them to measure glucose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What blood collection tube is used for U&E?

A

Serum in yellow/red top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What blood collection tube is used for glucose?

A

Plasma in grey top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What blood collection tube is used for HBA1c? What is the purpose of HBA1c?

A

Plasma in purple top

Can measure glucose in the blood over last 3 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What blood collection tube is used for TFT?

A

Serum in yellow/red top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What blood collection tube is used for liver function tests?

A

Yellow/red top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the difference between serum and plasma?

A

Plasma is the blood fluid that carries blood clotting agents

Serum is the water fluid from blood without the clotting factors (appears yellow, at top of centrifuged sample)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If you want to collect serum (in U&E), why do you used a yellow/red topped collecting tube?

A

Blood clots (no anticoagulant in yellow/red)
Clot can be removed
Leaves serum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens if blood is treated EDTA or heparin?

A

Clotting factors are unused
Blood can’t clot
Blood can be separated into red cells and plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In centrifuged blood, describe the layers that would appear

A

TOP-> BOTTOM
Plasma (yellow)
Lymphocyte and monocyte band (white-ish, opaque)
Density gradient fluid (colourless, clear)
Gel barrier
Erythrocytes and neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is found in the blue topped blood tube? What does it do?

A

Citrate chelates calcium
Need to be careful- need correct quantities= must fill exactly to 4ml
Normally should clot 14 secs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How can glucose from the blood be measured?

A

Red cells consume glucose (anaerobic glycolysis)
Longer blood is left out-> lower glucose may read
To avoid this, need to treat with fluoride oxalate (poison) which prevents red cells using glucose (so glucose levels stabilise)

GREY-TOPPED TUBE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why are liver enzymes important to study diagnostically?

A

Clues from a pattern of enzymes

Extra enzymes leak into blood if liver is damaged-> may cause disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What liver enzymes (and related substances) are commonly measured?

A

Alkaline phosphatase
Aspartate amino-transferase (AST)
Alanine amino-transferase (ALT)
Gamma glutamyl transferase (GGT)

Albumin= synthesised in liver
Bilirubin= waste product
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What hormones are often studied diagnostically in hormone assays?

A

Thyroxine
TSH
Cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

When is a chemical pathologist contacted?

A

When you want the sample to be rapidly centrifuged out of hours
When you want to measure labile hormones such as insulin
When you urgently need CSF glucose and protein to be measured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

If sodium is slightly below the reference range what does this mean?

A

Often OK
May be due to large volume of water (will affect Na in short term but after passing urine will probably be back to normal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What could low Na and high K indicated?

A

Dehydration (e.g. from diarrhoea)

Could also be due to adrenal failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are urea and creatine used as a marker of? What does it mean if they are inconsistent?

A

Renal failure (urea and creatinine concentration rise)

Creatine can cope for a few days, urea struggles
Creatine probably indicates permanent damage to GFR

Could have high urea with normal creatine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why do you need to be aware of haemolysis in a blood sample? How can you know if blood has been haemolysed?

A

Red cells lyse and this releases the Ca inside red cells
High K often due to haemolysed sample

So when centrifuged-> haemolysed blood serum appears pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

If the potassium is raised, what does the lab need to check?

A

If the blood is haemolysed (pink serum)

High K often due to haemolysed sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How does creatinine show renal function?

A

Marker of GFR (normal creatinine means normal GFR)

Very little is absorbed or secreted by the tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How does urea show renal function?

A

Levels rise when a patient is dehydrated

GFR stays the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

When studying liver enzymes, what else can be useful to measure?

A

Measure AST and GGT in a patient with jaundice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What cardiac enzymes are studied in diagnostic tests by the GP?

A 
Troponins (rapid test for abnormal cardiac function)
Creatine kinase (CK)
Aspartate amino transferase (AST)
Lactate Dehydrogenase (LDH)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are cardiac enzymes? What do they indicate?

A

During a heart attack, heart muscle is damaged
Enzymes leak into blood in large amounts
Indicate if someone has had a heart attack

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What types of laboratory tests are used in diagnostic virology?

A

Non-specific

Virological

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Outline what is seen on a patient with measles virus?

A

Blotchy wine stain rash

Red all over

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Outline what is seen on a patient with shingles virus?

A

Dermatomal distribution

Red blotches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What features/components of a virus can be detected? (With e.g.s)

A

Infectious virus (virus isolation and EM)

Protein components (antigens) of the virus (p24 antigen in HIV, surface antigen in HBV etc.)

Genetic components of the virus (DNA or RNA)

Host response (e.g. antibody or cell response)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are the main diagnostic methods for viruses?

A

Cell culture

Electron microscopy

Antibody detection (serology - EIA)

Antigen detection (Immunofluorescence - IF enzyme immunoassay - EIA)

Genome detection (PCR)

Quantification of antibody/antigens

Serotyping (e.g. HIV)

Quantification of genomes (viral load)

Genome sequencing (genotyping, antiviral resistance testing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the limitations of lab tests?

A

Give rise to false negative and false positive results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is sensitivity?

A

Test’s ability to correctly id positive samples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is specificity?

A

Test’s ability to correctly id negative samples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is quantification of genomes essential for?

A

Quantification of genomes-> identifies viral load

Essential for diagnosis and monitoring of HIV, HBV and HCV, and also for CMV and EBV in the immunocompromised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What samples are usually used in virus investigations?

A

Throat swab, Nasopharyngeal aspirate (NPA), bronchoalveolar lavage (BAL), ET secretions

Stools

Urine

CSF

Blood (clotted or EDTA)

Saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

When are throat swaps used in viral detection?

A

Detection of respiratory viruses (IF or EIA) = PCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

When are stools used in viral detection?

A

For rotavirus, adenovirus and norovirus antigen detection (EIA)
PCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

When is urine used in viral detection?

A

For BK virus and adenovirus

PCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

When is CSF used in viral detection?

A

For herpes viruses and enteroviruses

PCR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

When is clotted blood used in viral detection?

A

For serology (ab detection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

When is blood (with EDTA) used in viral detection?

A

For PCR

Viral load testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

When is saliva used in viral detection?

A

For serology and/or PCR (e.g. measles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Compare IgM and IgG (relating to viral diagnostics)

A

IgM= lower specificity (see more false positives)
Found in acute phase of disease
Duration= 3 months

IgG= higher specificity
Found in acute phase of disease
Duration= lifelong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What can avidity tests distinguish between?

A

Acute, recurrent or past infection by avidity of marker-specific IgG

For rubella, CMV, HIV, hepatitis viruses, EBV etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What can 4th generation EIAs of HIV detect? Why is this useful?

A

Ab + p24 Ag

Allows us to identify infection at an earlier level
Before abs have time to work in the blood

56
Q

Why do all reaction samples from an HIV EIA undergo confirmatory testing in a second assay? What happens to confirmed positives next?

A

To exclude non-specific reactivity (false positives)

Confirmed positives undergo typing (HIV 1 vs 2)

Repeat blood sample and EDTA blood for HIV viral load from all new positives

57
Q

What is point-of-care testing?

A

POCT is laboratorytestingor analyses performed in the clinical setting by non-laboratory healthcare professionals

Performed close to the patient so the results are available more quickly than when samples are sent off

58
Q

What is the benefit of RSV point of care testing?

A

Positive reaction-> infection control protocols can be put into place before patient enters ward
E.g. isolation

59
Q

Why is virus isolation in cell culture rarely used? What is it still useful for?

A

Reference lab only
Slow, time consuming (hence expensive)
Still useful for phenotypic antiviral susceptibility testing (HSV)

60
Q

Why is microscopy of viruses rarely used? When can it be used?

A

Viruses are too small to be seen by light microscopy
They can be visualised DIRECTLY using an electron microscope
Sample types: stool and vesicle fluids

61
Q

How does an infant usually present with respiratory synctial virus (RSV)?

A

with respiratory distress in winter
Hyperinflation of chest
Bronchilitis (probably caused by respiratory syncytial virus (RSV)

62
Q

What is immunofluorescence (IF) used for in virus detection? What are the limitations?

A

Useful for the direct detection of viral antigens in clinical samples (DIF)
(e.g. respiratory viruses)
Can be used for typing and cell culture confirmation

Rapid and inexpensive but subjective and very dependent on the skill of the technician and the quality of the sample

63
Q

What kind of samples can be used for respiratory tract infections?

A 
Throat swab +/- nose swab
Nasopharyngeal swab
Nasopharyngeal aspirate (NPA)
Bronchoalveolar lavage (BAL)
Endotracheal tube (ET) secretions

-> for respiratory virus PCR

64
Q

What is multiplex PCR?

A

Test for >1 virus per tube

Quicker and more cost effective than normal pCR

Technical reasons- limited to 3 (maybe 4) viruses

65
Q

List examples of respiratory tract infections caused by viruses

A 
Influenza
Parainfluenza
RSV
Rhinovirus
Human metapneumovirus (HMPV) 
Adenovirus
Bocavirus
Coronavirus
66
Q

Give two examples of viruses affecting the CNS?

A

Meningitis

Encephalitis

67
Q

How can CNS viruses be detected?

A

CSF for PCR (HSV, VZV, enterovirus)

Stools and throat swab for enterovirus detection (i.e. by PCR)

Blood for serology and/or PCR for West Nile and/or Japanese Encephalitis virus infection and other arboviruses

68
Q

In the clinical history below, what CNS viral disease tests would be considered?

Meningitis or encephalitis

Young child with febrile fits

Immunocompromised

Recent travel to endemic region

In context of an outbreak

SSPE

A

Meningitis or encephalitis: HSV, VZV and enterovirus

Young child with febrile fits: add HHV-6 and parechovirus

Immunocompromised (eg HIV): add CMV, EBV and JC virus

Recent travel to endemic region: consider Japanese Encephalitis, West Nile virus, equine encephalitides, tick borne encephalitis

In context of an outbreak: e.g. mumps

SSPE: measles antibody index

69
Q

When a patient has diarrhoea and vomiting, what is used to diagnose a viral cause?

A

Stool (preferred)
Vomit- lower yield
PCR multiplex or antigen detection assays (EIA)

70
Q

What viruses commonly cause D&V?

A 
Norovirus
Rotavirus
Adenovirus,
Sapovirus
Astrovirus
71
Q

What is PCR?

A

Polymerase chain reaction
Method for amplifying specific RNA (RT-PCR) or DNA sequences
Cycle ( x 30)

Denature
Primer annealing
Chain elongation (with Taq polymerase)
… cyclical with dsDNA

72
Q

What is dsDNA?

A

Double stranded DNA
Made from RNA with reverse transcriptase
Need to make copy of virus you’re looking for

73
Q

What types of serological tests are used in viral diagnosis?

A

IgM vs IgG

Antibody avidity

74
Q

What types of PCR are used in viral diagnosis?

A 
Reverse transcription PCR
Real Time PCR
Multiplex PCR
Viral load testing
Sequencing (antiviral drug resistance testing)
75
Q

What does it mean if a patient is CMV IgG positive but IgM negative?

A

They had CMV in the past but not currently

76
Q

What does enlarged glands mean? What does enlarged lymph nodes mean?

A

Glands being up= mumps

Enlarged lymph node=cervical lymph adenopathy

77
Q

What are the main parts of sequencing applications for viral diagnosis?

A

Genotyping
Antiviral resistance testing
Phylogenetic analysis

78
Q

What microbiological diseases can cause diarrhoea and vomiting?

A 
Infectious Diarrhoea
Endocarditis (SBE)
Syphilis 
Toxoplasma
Tuberculosis
Brucellosis 
Melliodosis
79
Q

What are the common diagnostic techniques in bateriology?

A

Culture (sterile sites= blood/CSF or non-sterile sites)

Serology

Molecular techniques

Antimicrobial susceptibility testing

80
Q

What microbiological disease can’t be cultured? How can it be diagnosed?

A

Syphilis can’t be cultured

Rely on serology to diagnose

81
Q

Is the skin a sterile site?

A

No

Approx 50 mil bacteria on average square cm of human skin

82
Q

What are the non-sterile sites in the body? What does this mean?

A 
Nasopharynx
Skin
Upper bowel
Lower bowel
Vagina

Organisms may not be affecting them
Presence of organism isn’t diagnostic

83
Q

What does a positive blood culture show?

A

Indicator (change in colour) says blood culture is positive

Use non-selective medium (designed to grow any/as many as possible because shouldn’t be any bacteria in blood)

Don’t have growth suppressors etc.

84
Q

Why should blood/pus be taken before giving antibiotics? When shouldn’t you wait?

A

If there is small growth on agar, antibiotic could hide it-> false negative

Shouldn’t wait if you suspect meningitis (very septic)

85
Q

What can gram stain cultures show?

A

Show type of cell (based on cell wall)

+VE= deep purple colour stain

  • Thick peptidoglycan layer
  • 1 membrane (cytoplasmic)
  • VE= pinky colour stain
  • Thin peptidoglycan layer
  • 2 membranes (cytoplasmic and outer)
86
Q

What is coagulase? What is it used for?

A

Coagulaseis a protein enzyme produced by several microorganisms that enables the conversion of fibrinogen to fibrin

Used to distinguish between different types of Staphylococcus isolates

87
Q

What are the types of staphylococci? What do they cause?

A

Bacteria

  1. S. aureas= e.g. MRSA
    - > severe infections e.g. skin/soft tissue, endocarditis, osteomyelitis
  2. Coagulase negative staphylococci
    - > skin commensals of low pathogenic potential
    - > can infect prosthetic material causing pacemaker infections and endocarditis
88
Q

What is an alpha result in haemolytic streptococci?

A

Alpha is incomplete haemolysis

E.g. pneumococcus and group of viridile streptococci

89
Q

What is a beta result in haemolytic streptococci?

A

Beta is complete haemolysis

E.g.
Strep group A= streptococcus pyogenes
Strep group B

Meningitis and sepsis

90
Q

What can cause diarrhoea?

A

Bacteria e.g. salmonella, shigella, campylobacter, e coli, c diff, cholera

Parasites e.g. amoeba, giardia, cryptosporidium

Viruses

91
Q

What are the 3 most common causes of food poisoning?

A

Salmonella (inc S. typhi )
Shigella
Campylobacter

92
Q

Where are giardia and cryptosporidium parasites more common?

A

Rural areas

Giardia= unclean water
Cryptosporidium= contact with animals, spread by soil, water, food or surfaces contaminated by infected faeces
93
Q

What investigations from stool samples are there for bacterial diseases?

A

Culture on agar plates

Only Salmonella, Shigella and Campylobacter
looked for routinely

Different pathogens have different culture
requirements

Clostridium difficile- toxin detection or PCR for
toxin gene

94
Q

What investigations from stool samples are there for parasites?

A

Concentration, special stains

Look for ova sometimes

95
Q

Why are different kinds of agar used in bacteriology?

A

Suppress commensural bacteria (particularly important for non-sterile sites)

e.g. XLD= selects for salmonella
TCBS= vibrio cholerae
One type selects for campylobacter and can be incubated at hotter temp (campylobater can survive)

96
Q

What is MIC?

A

Minimum Inhibitory Concentrations

Lowest conc of an drug that will inhibit the visible growth of a microorganism aftantimicrobial er overnight incubation

97
Q

What can you tell from gradient MIC studies?

A

See diameter of bacterial resistance

Large= sensitive
Small= resistant
98
Q

What can you tell from disc diffusion studies of MIC?

A

Approximate MIC
If certain size= sensitive

Cheaper than other MIC studies

99
Q

How long can infectious diarrhoea persist?

A

Usually short term

100
Q

What do histopathologists study?

A

Tissues

From: 
Biopsies (mostly) 
Resection specimens
Frozen sections (can be very quick)
Post-mortems
101
Q

What do cytopathologists study?

A

Cells

From:
Smears (cervical screening)
Fine need aspirations

102
Q

What are the main questions to ask when studying a histopathological biopsy?

A

Is it normal?

Is it inflamed? (If so, what is the cause?)

Is it cancer? (If so, what type is it?)

103
Q

What are the main questions to ask when studying a histopathological resection specimen?

A

How far has the cancer spread? (Is this affecting drainage)

Is it all out? (Judge by margins)

104
Q

What are the main questions to ask when studying a histopathological frozen section?

A

Is it cancer?

Is it all out?

RAPID- can use quickly in middle of surgery

105
Q

What post-mortems are more common; hospital or coroner?

A

Coroner’s

106
Q

Why are coroner’s post-mortems used? Why are they more common than hospital post-mortems?

A

When they don’t know or other factors e.g. poisoning, self-harm, industrial
Don’t need consent- they are legal post mortem

NB. Can’t take any tissue

107
Q

How are sections obtained for histopathology?

A

Specimen must be properly labelled
Fix in formalin
Embed in paraffin wax
Cut sections

108
Q

What processes can happen to histopathological sections?

A

Stain e.g. gram

ID specific antigens using antibodies (immunohistochemistry)

Carry out molecular tests

109
Q

How long does a histopathology result take to reach the clinician for the following processes?
Frozen section
Biopsies
Resection specimens

A

Frozen section= 30 mins
Biopsies= 2-3 days
Resection specimens= 5-7 days

110
Q

What does Kaposi’s sarcoma indicate?

A

HIV AIDs

111
Q

What test would you use to visualise a vascular tumour infiltrating collagen bundle?

A

Immunocytochemistry for CD31

112
Q

What does it mean if fine needle aspiration of one of the enlarged nodes reveals a mixed cell population?

A

Reactive lymphadenopathy

113
Q

Describe an antibody (structure)

A

Y shaped molecule

Has an antigen binding region at end of tips of Y (have variable regions)

Hinge region in middle

114
Q

Why are antibodies used as the basis of many diagnostic tests?

A

Specificity of abs for their target ags

Antibodies can be raised against almost any antigen (including immunoglobulins for other species= anti-antibodies)

115
Q

What is indirect labelling using an anti-antibody?

A 
Antigen binds to antibody
Reporter used (on antibody)
116
Q

When are antibodies produced by the patient?

A

In autoimmune disease

For defence against infection

117
Q

List manufactured antibodies

A

Antisera from immunised animals (polyclonal)
Monoclonal antibodies
“Genetically engineered” antibodies

118
Q

How are monoclonal antibodies generated?

A

Mouse challenged with antigen

Spleen cells (limited cell division, produce Ab, HGPRT +ve) 
Myeloma cells (immortal, no ab production, HPRT -ve)

SPLEEN CELLS AND MYELOMA CELLS FUSE

Hybridomas

Culture in HAT medium select for positive cells (immortal, produce Ab, HGPRT +ve)

Clone by limiting dilution

Harvest monoclonal antibodies

119
Q

How are antibodies produced using recombinant DNA technology?

A

Isolate population of genes encoding ab variable regions

Construct fusion protein at V region with a bacteriophage coat protein

–

Clone random population of variable regions gives rise to a mixture of bacteriophages (phage-display library)

Select phage with desired V regions by specific binding to antigen

120
Q

What are the therapeutic uses of manufactured antibodies?

A

Prophylactic protection against microbial infection
E.g. IVIG, synagis (anti-RSV)

Anti-cancer therapy
E.g. anti-HER2

Removal of T-cells from bone marrow grafts
E.g. Anti-CD3

Block cytokine activity
E.g. Anti-TNFa

121
Q

Outline the nomenclature for therapeutic monoclonal antibodies

  • omab
  • imab
  • umab
A

-OMAB
Mouse monoclonal e.g. anti-CD3 muronomab

-IMAB
Chimeric or partly humanised e.g. anti-TNFa infliximab

-UMAB
Human e.g. anti-RSV palivizumab

122
Q

What are the diagnostic uses of manufactured antibodies?

A

Blood group serology

Immunoassays

  • Hormones
  • Antibodies
  • Antigens

Immunodiagnosis

  • Infectious diseases
  • Autoimmunity
  • Allergy (IgE)
  • Malignancy (myeloma)
123
Q

What is ELISA?

A

Enzyme linked immunosorbent assay

Add anti-A ab covalently linked to enzyme (to 2 samples, one with antigen A and one with antigen B)

Wash away unbound antibody

Enzyme makes coloured products from added colourless substrate

Measure absorbance of light by coloured product

(Sample with ag A= coloured)

124
Q

What is lateral flow assay architecture?

A

Rapid testing

Simple devices intended to detect the presence (or absence) of a target analyte in sample (matrix) without the need for specialized and costly equipment

125
Q

Where could serum antibodies against HIV be from?

A

Mother

126
Q

What immunological conditions can cause the following?

Vague aches and pains
Loss of appetite and weight loss
“Glands” up in his neck (lymph adenopathy)
Fever, rash, small red patches, some lumpy

A

Vague aches and pains= immune complexes

Loss of appetite and weight loss= poor nutrition (effect on bone marrow cells)

“Glands” up in his neck (lymph adenopathy)= immune activation

Fever, rash, small red patches, some lumpy= acute phase, activation, immune complexes

127
Q

What does it mean if you are concerned about immune complexes?

A

Concerned about:

Inflammation / complement activation
Serum sickness (immune complexes in circulation)
Immune complex glomerulonephritis
Immune complex deposition at other sites (skin, joints, lungs)

128
Q

What is immunodeficiency?

A

State in which the immune system’s ability to fight infectious disease and cancer is compromised or entirely absent

Most are acquired (“secondary”) due to extrinsic factors that affect the patient’s immune system

129
Q

How can immunodeficiency be studied?

A

Serum immunoglobulin levels (serum electrophoresis, ELISA, nephelometry)

Specific antibodies (ELISA)

Lymphocyte subsets (flow cytometry)

130
Q

What is serum electrophoresis used for?

A

Measures specific proteins in the blood to help ID some diseases

I.e. Monoclonal expansion of B cells
? B cell malignancy
Investigate for myeloma

If there is an active immune response-> not immunodeficient

131
Q

What are lymphocyte subpopulations (ID’d by flow cytometry)

A 
CD3+= T cells- pan T cell marker
CD4+= T cells- T helper/cells
CD8+= T cells- cytotoxic T cells
CD19+= B cells
CD56+= Natural Killer (NK) cells
132
Q

What do you need for flow cytometry?

A

Continuous power supplies
Complex IT systems
Standardised sampling
High cost, highly specialised precision equipment
Advanced, reliable infrastructure
Mixture of cells is labeled with fluorescent antibody

133
Q

What is the natural history of HIV infection?

A

0-6 weeks
Primary infection leads to decrease CD4+ T lymphocyte count (1050->500)

3-9 weeks
Acute HIV syndrome
Wide dissemination of virus
Seeding of lymphoid organs
Increase and then decrease of HIV RNA copies per ml plasma

Clinical latency (until approx 8/10 years)
Gradual increase in HIV RNA copies per ml plasma
Gradual decrease in CD4+ count

Around 8 years
Constitutional symptoms
(Trajectory continues for HIV RNA copies per ml plasma
and CD4+ count)

Around 10 years
Opportunistic diseases and death
Steep increase in HIV RNA copies per ml plasma
CD4+ count around 0

134
Q

How is a patient treated and monitored for HIV?

A

Patient tested for abs to HIV

If HIV+ perform CD4 count-> low CD4 count
If HIV+ perform viral load-> high viral load

Commence ART (1st line therapy)

Monitor CD4 count and viral load (every 3 months)

If CD4 count decreases and/or viral load increases then try ART (2nd line therapy)

135
Q

What defines the extent of immune damage and predicts short term outlook in ART naive HIV-1 patients?

A

CD4 T cell count

136
Q

As CD4 declines, what symptoms of HIV appear?

A 
700= Lymphadenopathy and thrombocytopenia
500= bacterial skin infection, herpes simplex, zoster, oral, skin fungal infections
400= Kaposi's sarcoma
300= Hairy leukoplakia and TB
200= PCP, cryptococcis, toxoplasmosis
100= CMV, lymphoma

MCD 2- Diagnostics (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions