L21-22 - White Cell Disorders and Their Investigations Flashcards

1
Q

Compare the changes in the haematopoeitic system under reactive or malignant change.

A

Reactive = Mainly quantitative changes** in normal cell types, Qualitative changes possible, e.g. atypical lymphocytosis

Malignant = Primary abnormality of haemopoietic system. Usually both quantitative and qualitative changes

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2
Q

List the 5 lab investigations of WBC disorders.

A
  • Complete blood count
  • Morphology, including: PBS, BM aspirate, trephine biopsy, cytochemistry
  • Immunophenotype, including: Flow cytometry, immunohistochemistry
  • Cytogenetics: Karyotyping, FISH
  • Molecular genetics: PCR-based
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3
Q

Limitation of machine differential CBC?

A

Not good for blasts; good if only neutrophil, lymphocyte, monocyte, eosinophil, basophil

Always verify with manual count if in doubt

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4
Q

Function of Peripheral blood smear?

A

 Confirm nature of cytopenia / increased white cell count

 Detect abnormal cell types / abnormal morphology

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5
Q

Advantages and disadvantages of BM aspirate for white cell disorder?

A

Adv: Good cytological detail:

  • Determine cellularity
  • Detect dysplastic morphology
  • Assess haemopoiesis of diff. lineages

Disadv:
- Architecture not preserved

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6
Q

Advantages and disadvantaged of Trephine biopsy for white cell disorder?

A

Adv:

  • Preserves bone marrow architecture: assess marrow cellularity, pattern of abnormality, structure
  • Allows immunophenotyping by immunohistochemistry

Disadv:

  • Less sensitive than aspirate for cytological detail
  • More invasive
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7
Q

Compare the technique for cytochemistry of myeloid lineage vs lymphoid?

A

Myeloid =  Myeloperoxidase (MPO: in neutrophils)  Sudan Black B (SBB)

Lymphoid = immunophenotyping to classify (no good cytochemistry)

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8
Q

Compare what is investigated in cytochemistry vs immunophenotyping?

A

Cytochemistry = Uses microscopy to detect dye / reaction product*** in the cells of interest

Immunophenotyping: Detects antigens* on cells of interest = determines cell lineage*

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9
Q

List the antigens used to differentiate myeloid vs lymphoid lineages in immunophenotyping? exam

A

Myeloid lineage:
 Myeloperoxidase (MPO) (exam)
 CD117, CD13, CD33

Lymphoid lineage:
 B-ALL: CD19 (exam), CD79a, CD22
 T-ALL: CD3 (exam)

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10
Q

Define whats investigated by flow cytometry?

A

investigate co-expression of antigens on a single cell

peripheral blood or marrow aspirate

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11
Q

What tissues are assessed in flow cytometry vs immunohistochemistry vs cytochemistry?

A

Cytochemistry = peripheral blood / bone marrow aspirate

Immunohistochemistry = trephine biopsy

Flow cytometry = peripheral blood / bone marrow aspirate

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12
Q

Immunohistochemistry is a good technique for investigating co-expression of Ag on single cell. T or F?

A

False

Flow cytometry used instead for finding co-expression of Ag

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13
Q

Karyotyping asseses cells in which phase of cell cycle?

A

study of chromosomes at metaphase stage*** of Mitosis when chromatin is highly condensed

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14
Q

Principle of FISH?

A

Single-stranded DNA probes attached with fluorophores/fluorochromes

> > form hybrid double-stranded complexes with their complementary genomic DNA sequences in cell

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15
Q

What is investigated by FISH?

A

Fluorescence in-situ hybridisation

Investigate:
 Increase / decrease in copy number of target genes
 Whether there is fusion of target genes

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16
Q

What is the most common cause of leucocytosis? exam

A

Quantitative WBC disorder = mostly reactive causes

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17
Q

List some causes of neutrophilia?

A

· Infections: Bacterial, esp. pyogenic

· Inflammation

· Malignancy
o Solid tumours
o Haematological: Myeloproliferative neoplasms, esp. CML, MF

· Drugs 
o Steroid (demargination of neutrophils), growth factors etc.
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18
Q

List some P/E or clinical presentation signs of neutrophilia caused by Infection? Investigation?

A
 Fever 
 Cough 
 Sputum  
 Diarrhea 
 Dysuria

Microbioloical investigations (i.e. sputum culture, AFB smear, culture)

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19
Q

List some P/E or clinical presentation signs of neutrophilia caused by Inflammation? Investigation?

A

Symptoms/signs:  Skin rash  Photosensitivity  Joint pain etc.

Inflammatory markers:
o Erythrocyte sedimentation rate (ESR)
o C-reactive protein (CRP)
Autoimmune markers

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20
Q

List some P/E or clinical presentation signs of neutrophilia caused by Malignancy? Investigation?

A

 Cachexia / weight loss
 Masses
 Lymphadenopathy
 Blood-stained sputum

  • PBS +/- Marrow exam
  • Cytogenics
  • Molecular genetics
  • Tumour markers
  • Radiological scans
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21
Q

Types of malignancies that cause neutrophilia?

A
  • Solid tumours: WBC reaction or paraneoplastic causing neutrophilia
  • Haematological: Myeloproliferative neoplasms***: esp. CML and Myelofibrosis
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22
Q

What are the expected cytogenetic and molecular genetic results of CML?

A

Cytogenetics: t(9;22) Translocation = Philadelphia chromosome

Molecular genetics (e.g. PCR): BCR-ABL1 fusion transcript (defining mutation of CML)

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23
Q

Most common cause of Basophilia? 2 Less common causes?

A

myeloproliferative neoplasms** (especially chronic myeloid leukemia (CML))

Less common:
 Autoimmune diseases, IBD  Acute hypersensitivity

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24
Q

3 causes of Monocytosis?

A

 Infections (especially tuberculosis, bacterial infections)

 Autoimmune diseases

 Chronic myelomonocytic leukaemia (CMML)

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25
Q

List some DDx of spenlomegaly?

A
  • Portal hypertension
  • Infection: esp. infective endocarditis, infectious mononucleosis, malaria, schistosomiasis
  • Autoimmune diseases
  • Storage diseases (in paediatrics)
  • Haematological diseases causing sequestration (e.g. sickle cell anaemia)
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26
Q

What haematological diseases can cause splenomegaly?

A

Myeloproliferative neoplasm (can be massive in CML & MF),

lymphomas and leukaemias

Thalassaemia intermedia or major

Haemolytic anaemia

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27
Q

List important causes of thrombocytosis?

A
  • Reactive to bleeding, inflammation, autoimmune diseases
  • Hyposlenism ( most commonly post-splenectomy)
  • Malignant: solid or Myeloproliferative neoplasms
28
Q

Expected bone marrow and PBS histology in CML?

A

Bone marrow: Increased myeloid cells and megakaryocytes (with abnormal morphology)

Marked leucocytosis: Prominent Bimodal distribution of myelocytes and neutrophils + marked eosinophilia and Basophilia

29
Q

Most common cause of Eosinophilia in HK?

A

Drug reaction

usually has concurrent deranged liver functions

30
Q

List causes of eosinophilia? (think about what eosinophils do)

A
  • Drug reaction**
  • Hypersensitivity reaction
  • Infections: esp. parasitic/ helminthic/ exotic infections from travel
  • Autoimmune diseases
  • Malignancies: solid or haemo.
31
Q

List some malignancies that causes eosinophilia?

A

 Lymphomas (T-cell lymphoma, Hodgkin lymphoma)

 Myeloproliferative neoplasms (MPN), e.g. CML

 Solid malignancies (e.g. lung cancer)

32
Q

What investigations for eosinophilia caused by malignancies?

A
  • PBS to ascertain eosinophilia
    : e.g. dysplastic features, high blast count, abnormal lymphoid cells
  • CXR for suspected solid tumour: e.g. lung, mediastinum
  • BM exam for suspected haemic malignancy: further cytogenetics, molecular tests
  • LN biopsy if suspected lymphoma/ lymphadenopathy
33
Q

What type of Mibi test to do for eosinophilia?

A

Test for parasitic infections:

Stool for culture of ova and cyst

34
Q

What are the first line investigation for bleeding tendencies e.g. after tooth extraction?

A

Complete blood count, PT/APTT

35
Q

List some causes of pancytopenia? (think about different ways to cause myelosuppression)

A
  • Infections causing myelosuppression
  • Drug induced: e.g. chemotherapy-caused myelosuppression
  • Dietary deficiencies
  • Autoimmune induced myelosuppression
  • Infiltrative marrow malignancies
  • Splenomegaly

Rare:

  • Inherited
  • Paroxysmal nocturnal haemoglobinuria
36
Q

What are the marrow malignancies that cause pancytopenia?

A

– Marrow infiltration
– Acute Leukaemia
– Aplastic anaemia
– Myelodysplastic syndrome (MDS)

37
Q

Investigations for megaloblastic anaemia?

A

Diet history
Complete blood count (CBC)
Peripheral blood (PB) smear
Vitamin B12 / folate level

38
Q

Define acute leukemia.

A

≥20% blasts in the peripheral blood / bone marrow

39
Q

2 histological features of acute myeloid leukemia? (AML, APL?)

A

Auer rod = pathognomonic feature of myeloid neoplasms (e.g. AML, MDS)

Faggot cell (many Auer rods) = acute promyelocytic leukemia (APL))

40
Q

Expected Clinical features, blood count, clotting profile in acute promyelocytic leukaemia (APL)?

A

 Clinical features: anaemic symptoms, bleeding tendencies + bruising, Fever and infection related to leukopenia.

 Blood count: pancytopenia (classical)

 Clotting profile: disseminated intravascular coagulation (DIC) ***: Increase PT, APTT, D-dimer

41
Q

Define the characteristic morphology of myeloid cells in APL?

A

Faggot cells

42
Q

Molecular genetic and cytogenetic feature of APL?

A

Fusion gene of PML-RARa: targeted and degraded by ATRA/ Arsenic trioxide

Cytogenetics: t(15;17)

43
Q

Which cytochemistry dyes react strongly in APL

A

Strongly positive for myeloperoxidase & Sudan Black B

44
Q

Sequalae and treatment for APL?

A

Fatal intracranial bleeding secondary to thrombocytopenia and DIC

urgent treatment with all-trans retinoic acid or Arsenic trioxide +/- supportive transfusion, esp. platelet, plasma

45
Q

Which subtypes of cytopenia are common manifestations of haemo. malignancies?

A

Usually anaemia and thrombocytopenia

may have Leucopenia, or leukocytosis with neutropenia

46
Q

List some causes of Neutropenia?

A

 Infection, especially viral (e.g. cytomegalovirus (CMV), HIV, EBV, hepatitis, parvovirus)

 Autoimmune

 Drug-induced

 Marrow malignancies

 Inherited (very rare)

47
Q

List some marrow malignancies that cause neutropenia?

A

– Marrow infiltration
– Leukaemia
– Aplastic anaemia
– Myelodysplastic syndrome (MDS)

48
Q

Describe the histological features in BM biopsy in MDS?

A
  • Hypercellular/ hyperplastic marrow
  • Focal prominence of blasts
  • Increased and dysplastic myeloid, erythroid precursors +/- megakaryocytes
49
Q

Expected CBC findings in MDS?

A

– Pancytopenia

– Red cell macrocytosis

50
Q

Expected karyotype findings in MDS?

A

Complex karyotype, including del(5q) and monosomy 7

51
Q

List causes of lymphocytosis?

A

• Reactive
– Lymphocytosis: Infections, autoimmune disease
– Atypical lymphocytosis: Viral infections, autoimmune disease

• Malignant
– Acute: ALL
– Chronic: CLL, leukaemic phase of lymphomas

52
Q

Lymphocytosis returns positive in Myeloperoxidase and Sudan black B in cytochemistry. T or F?

A

False

Myeloperoxidase and Sudan black B are for myeloid lineages

53
Q

Which antigens to look out for when investigating possible lymphocytosis?

A

CD3 (T cell marker)

CD19 (B cell marker)

79a-PE = B cell marker

54
Q

What causes atypical lymphocytosis?

A

Atypical = reactive

viral infections / autoimmune disease

55
Q

Prototype of atypical lymphocytosis? Morphology of cells?

A

Prototype = infectious mononucleosis

lymphocytosis with increased atypical lymphocytes (bigger, irregular nucleus)

56
Q

Expected karyotyping results in paediatric B-ALL?

A

Hyperdiploid karyotype

54,XY,+8,+10,+11,+12,+14,+21,+21,+22

57
Q

Causes of lymphadenopathy?

A
  • Infection: TB, pyogenic, viral
  • Autoimmune/ inflammatory diseases
  • Haemo. malignancies: LYMPHOMA**, possible leukaemia or metastatic carcinoma
58
Q

List the investigations for lymphadenopathy?

A

 CBC
 Peripheral blood smear
 Imaging - HRUS, PET-CT
 Lymph node biopsy

59
Q

List the investigations work-ups for CLL/ lymphoma?

A
  • Morphology: Peripheral blood, bone marrow, lymph node biopsy
  • Immunophenotyping: Diagnostic classification by Flow cytometry
  • Cytogenetics/FISH: Prognostication
60
Q

Difference in the type of cells that cause acute vs chronic haemo. malignancies?

A

Acute = immature cell types, i.e. AML, ALL, Blasts ≥20% in peripheral blood or BM

Chronic = mature cell types: mature B cell lymphoma, mature T cell lymphoma

61
Q

Difference in the rate of advancement between acute and chronic haemo. malignancies?

A

Acute = rapid and fatal if untreated

Chronic = usually slows, but some malig. can progress fast i.e. Burkitt lymphoma, DLBCL

62
Q

How is lymphoma vs leukemia distinguished?

A

Depends on the primary tissue involved or originated from:
– Leukaemia: from blood and/or bone marrow

– Lymphoma: from lymph nodes, spleen, or other tissues (e.g. nasopharynx, GI tract)

63
Q

Explain whether leukaemia and lymphoma overlap?

A

Not mutually exclusive***

> > leukaemias can localise in lymph nodes or tissues (i.e. T lymphoblastic lymphoma in mediastinal LN)

> > Late stage lymphoma can spread from LN to involve blood and BM (i.e. lymphoma in leukaemic phase)

64
Q

How to tell MDS from MPN?

A

• Mutations for Uncontrolled proliferation**
– More towards MPN**

• Mutations for Impaired differentiation**
– More towards MDS**

Depends on mutation pattern and phenotype!

65
Q

Which type of genetic sequencing is commonly used in cancer testing?

A

Targeted sequencing of selection of genes

66
Q

Which type of genetic sequencing is commonly used in rare inherited diseases?

A

Whole EXOME sequencing: All exons of protein-coding genes