Haematology Flashcards
1
Q
How long is the lifespan of a RBC?
A
120 days
2
Q
Why is this long life of red blood cells advantageous to us, in terms of tests?
A
It allows for calculation of HbA1c to show diabetic control over 2-3 months
3
Q
What is HbA1c?
A
Glycosolated haemoglobin
4
Q
How does HbA1c work? Why is this good?
A
Concentration of glucose bound to Hb is proportionate to the blood glucose levels at the time the cell was made, so HbA1c gives the avergae amount of glucose bound over 3 months, not just at that moment in time (cap blood glucose).
5
Q
Who is HbA1c not accurate in?
A
Haemolytic patients due to shorter lifespan of RBCs.
6
Q
What is the lifespan of a platelet? Why is this clinically relevant?
A
10 days - this is why pts on aspirin/clopidogrel etc need to come off it a week prior to surgery
7
Q
What is the lifespan of a neutrophil?
A
2-4 days
8
Q
What is the lifespan of a lymphocyte?
A
Very variable - days or years depending on the subtype/function of that lymphocyte
9
Q
Where are the 2 areas that haematopoiesis occur in early gestation?
A
- Weeks 1-6 of gestation in the yolk sac
- Week 6 to month 6 of gestation in the liver and spleen
10
Q
Where does haematopoiesis occur from month 6 of gestation throughout life?
A
Bone marrow
11
Q
Which bones in children contribute to haematopoiesis?
A
All of them!
12
Q
Which bones in adults contribute to haematopoiesis?
A
Pelvis Sternum Skull Ribs Vertebrae
13
Q
Due to the areas that contribute to haematopoiesis in adults, where are most bone marrow aspirations/biopsies performed?
A
Anterior iliac crest
14
Q
When do you get haematopoiesis occuring outside the bone marrow?
A
In haemoglobinopathies and myeloproliferative disorders.
15
Q
What group of hormones drives haematopoiesis?
A
Cytokines
16
Q
Which cytokines drive haematopoiesis?
A
Erythropoietin Thrombopoietin G-CSF GMCSF Interleukin 6 Others also
17
Q
What does Erythropoietin stimulate?
A
Red blood cell production
18
Q
Where is Erythropoietin made?
A
Kidneys
19
Q
What does thrombopoietin stimulate?
A
Platelet production (via megakaryocytes)
20
Q
Where is thrombopoietin made?
A
Liver and kidney
21
Q
What does G-CSF stimulate?
A
Production of granulocytes and stem cells (Granulocyte colony stimulating factor)
22
Q
What is GMCSF and what does it stimulate?
A
Granulocyte-macrophage colony stimulating factor.
Stimulates neutrophil, eosinophil, and basophil production
23
Q
What causes the kidney to release erythropoietin?
A
Hypoxia/anaemia
24
Q
What does erythropoietin act on in the bone marrow?
A
E-progenitor cells
25
How is iron concentration in the body regulated?
By absorption from the gut
26
Where does iron come from, and how do we lose it?
Diet
Loss of blood, sloughing of mucosal epithelial cells, and pregnancy
27
Can we have too much iron?
Yeep
28
What happens in iron overload?
Fe2+ produces hydroxyl and lipid radicals -> damage lipid membranes, nucleic acids and proteins.
29
How are thalassaemias and myelodysplasias treated?
Regular transfusions
30
Other than iatrogenic, how else can a pt become iron overloaded?
Hereditary haemochromatosis
31
Tell me about hereditary haemochromatosis...
Autosomal recessive
Increased gut absorption
Iron deposited in liver, heart, pancreas, testicles, and skin.
32
What does iron deposition in these organs cause?
```
Cirrhosis
DM
Cardiomyopathy
Arthritis
Hypogonadism
```
33
How is hereditary haemochromatosis treated?
Desferal or regular venesection
34
How is iatrogenic iron overload caused and treated?
Regular transfusions
Iron chelating agents given e.g. desferal/desferrioxamine
35
What process are vit B12 and folate needed for?
DNA synthesis
36
Why are RBCs macrocytic in b12 or folate deficiency?
They can't leave G2 stage of replication, so mitosis doesn't occur, and cell growth continues without division.
37
What are the clinical signs of b12/folate deficiency?
Glossitis
Angular cheilosis/stomatitis
Jaundice
38
What kind of anaemia results from b12 deficiency?
Pernicious anaemia
39
Where is B12 absorbed from, and therefore who is at risk of developing pernicious aneamia?
Terminal ileum
Pts who have had ileal resection, Crohns pts, coeliacs, UC pts (backwash ileitis)
40
What is folate deficiency caused by?
Reduced absorption or increased utilisation
41
What diseases cause less folate absorption?
Crohn's disease
| Coeliac disease
42
What drugs can decrease folate levels?
Methotrexate
Trimethoprim
(Some others, used less frequently)
43
What can folate deficiency cause in pregnancy?
Neural tube defects
44
What clinical signs can B12 deficiency cause?
Peripheral neuropathy
Optic atrophy
Confusion
Reduced cognition
45
Name 2 haemoglobin abnormalities.
Thalassaemia
| Sickle cell disease
46
What is a thalassaemia?
A reduced rate of synthesis of either alpha or beta globin chains so the ratio is no longer 1:1
47
What does thalassaemia cause?
Ineffective haematopoiesis and haemolysis ->
Anaemia, jaundice, splenomegaly
48
How does sickle cell disease occur?
Autosomal recessive point mutation -> Beta chain abnormality that changes the shape of the haemoglobin
49
What does the sickle cell mutation change in the protein coding?
Glutamic acid -> valine
50
What is sickle cell trait?
Carrier of the sickle cell gene causing sickles cell changes in some blood cells
51
What does full blown sickling lead to?
Chronic haemolysis and episodic tissue infarction
Chronic anaemia
Jaundice
52
Why are the symtpoms of anaemia in sickle cell patients milder than you would expect?
The adjusted shape of the sickle cell causes a sift in the oxygen dissociation curve to the right
53
What is a sickle cell crisis?
Sickling causes microcirculation infarction -> tissue ischaemia
Can cause various crises throughout the body
54
What can trigger sickle cell crisis?
```
Hypoxia
Infection
Cold
Dehydration
Stress
```
55
What is an aplastic crisis?
Temporary cessation of red cell production. Because of the markedly shortened red cell survival time in patients with sickle cell disease, a precipitous drop in hemoglobin occurs in the absence of adequate reticulocytosis -> sever anaemia.
56
What is a sequestration crisis?
Pooling of blood in the liver or spleen -> organomegaly, anaemia, and hypotensive shock
57
What complication to do with the spleen can sickle cell lead to?
Hyposplenism -> asplenia.
Repeated insult to spleen leaves it unable to function
58
What infections are pts with hyposplenia more susceptible to?
All of them, but especially from encapsulated bacteria
59
What are the encapsultaed bacteria that asplenic patients need to look out for?
Gram negatives mostly, such as E. coli, Salmonella, Neisseria meningitidis, and Klebsiella pneumonias.
Some gram positives also such as strep pneumoniae, strep pyogenes, and staph epidermidis.
60
Other than infection and hyposplenism, what other complications can develop due to sickle cell disease?
```
Pulmonary hypertension
Renal Impairment
Ulcers and poor wound healing
Priapism
Pigment gallstones
Osteomyelitis and AVN
```
61
How do we manage sickle cell disease?
Avoid triggers for crises
Give vaccinations and prophylactic abx
Give folic acid
62
How do we manage a sickle cell crisis?
The usual, treat the ABCDE as it comes. Analgesia, rest, fluids, warmth, LMWH, O2, ?transfusion, treat the cause.
63
With a thalassaemia, if i said alpha thalassaemia does that mean an alpha or beta gene copy/copies is missing?
Alpha copy is missing in alpha thalassaemia
64
How does a thalassaemia get more serious?
The more genes are missing, the worse it gets.
65
Who has alpha thalassaemia trait?
Anyone with one or 2 inactive alpha chain genes
66
If you have alpha thalassaemia trait, what will I see on your blood work?
Lowered MCV and Mean cell Hb
67
Can you live with 3 or 4 missing alpha chain genes?
Yes to 3, no to 4.
68
Tell me about only having 1 alpha chain.
Compatable with life, causes Haemoglobin H disease where Hb=70-110, decreased MCV and MCH, hypersplenism.
69
Tell me about only having no alpha chains.
Fatal in early life as an alpha chain is essential. Called Hydrops fetalis.
70
How many copies are there of the beta Hb chain gene?
2
71
When one beta chain gene is missing, what does the pt have?
Beta thalassaemia trait
72
When both beta chain genes are missing, what does the pt have?
Beta thalassaemia major
73
What are the features of beta thalassaemia major?
Severe anaemia for first 6 months of life.
Hepatosplenomegal
Bone marrow hyperplasia
Osteoporosis
74
Aside from regular blood transfusions, how do we treat thalassaemias?
```
Iron chelating agents so we don't cause iatrogenic iron overload
Folic acid suppliments
Splenectomy
Immunisation and prophylaxis
Treat any resulting endocrine disorders
```
75
Do we need to treat thalassaemia trait?
Not usually, as asymptomatic.
If symptomatic, usually hypochromic and microcytic anaemia that presents like iron deficiency. Don't want to iron overload them!
76
What is MCV important in?
Determining the cause of anaemia
77
What is the haematocrit?
Packed cell volume i.e. volume % of red blood cells in blood
78
Who is a raised haemaocrit often seen in and why?
COPD pateints or those who live at altitude due to chronic hypoxia.
79
What is a reticulocyte?
Young erythrocyte/rbc
80
When are reticulocytes raised?
Anameia
81
When are reticulocytes lowered?
Haematinic deficiency or bone marrow failure
82
What is anisocytosis?
Increased variability in size of RBCs
83
What is dimorphism of RBCs?
2 distinct red cell populations
84
What can spiculated red cells be called?
Echinocytes
Acanthocytes
Keratoncytes
Schistocytes
85
What is a myeloproliferative disorder?
Overproduction of one or several blood elements with dominance of a transformed clone
86
What can a myeloproliferative disorder lead to?
Acute leukaemia
87
What is the difference between lymphoma and leukaemia?
Leukaemia starts in the bone marrow and then spreads to the lymphatic tissues
Lymphoma starts in the lymphatics due to abnormal lymphocytes
88
How do myeloproliferative disorders come about?
Myeloid stem cell becomes damaged so it ignores apoptotic signals, rapidly divides, and produces more myeloid cells
89
What gene is responsible for myeloproliferative disorders?
JAK2 (mutated)
Janus kinase 2
90
What is a myelodysplastic syndrome?
Dysplastic changes in blood cells leading to increased numbers of abnormal precursor cells
91
What is myelofibrosis?
Proliferation of an abnormal cell type leading to damage and fibrosis of bone marrow
92
What is multiple myeloma?
Bone marrow based cancer affecting plasma cells
93
What is pancytopaenia?
Anaemia, thrombocytopaenia and neutropenia combined - global lack of blood cells
94
What are the 2 mechanisms that can lead to pancytopaenia?
Global problem with blood production
Process destroying all blood products
95
What could cause pancytopaenia via bone marrow decreased production of blood cells?
-Aplastic anaemia
-Myelodysplastic syndrone
Myelofibrosis
-Bone marrow failure
-Iatrogenic bone marrow suppression secondary to radiotherapy and chemotherapy
96
What could cause pancytopaenia via increased blood product destruction?
Autoimmune haemolytic anaemia
97
What are the 4 types of leukaemia?
Acute myeloid leukaemia
Chronic myeloid leukaemia
Acute lymphoid leukaemia
Chronic lymphoid leukaemia
98
What is myeloid leukaemia?
Excess granulocyte production
99
What is lymphoid leukaemia?
Excess lymphocyte production
100
What characterises acute leukaemia?
Abundance of blast/progenitor cells in bone marrow and on blood films
101
What characterises chronic leukaemia?
Abundance of fully differentiated cells
102
Who gets acute lymphocitic leukaemia?
Children
103
Who gets chronic lymphocitic leukaemia?
Adults.
M:F 2:1
104
Who gets acute myeloid leukaemia?
Adults
105
Who gets chronic myeloid leukaemia?
People 20-50
Children can get this rarely
106
How does acute myeloid leukaemia present?
Symptomatic anaemia
Mucosal and internal bleeding
Increased susceptibility to infection
107
How does acute lymphoblastic leukaemia present?
```
Symptomatic anaemia
Greater tendency to illness
Bruising and bleeding
Bone or lung pain
Failure to thrive
```
108
How does chronic myeloid leukaemia present?
```
Symptomatic massive splenomegaly
Symptomatic anaemia
Hyperviscousity of blood and clots
Bone pain
Hypermetabolism
```
109
How does chronic lymphocytic leukaemia present?
Asymptomatic or unspecific symptoms
LAD
Hepatosplenomegaly
110
What are the classifications of lymphoma?
Hodgkins
Non Hodgkins
High grade vs low grade
B cell vs T cell
Systemic vs localised
111
Who is Hodgkin lymphoma common in?
Young adults
112
What is Hodgkins lymphoma?
Idk *************
113
Do more on lymphoma
Ok
114
What are non Hodgkins lymphomas?
Any malignant solid tumours of lymphoid tissue not characterised as Hodgkins lymphoma
115
What is multiple myeloma?
Bone marrow based cancer affecting plasma cells
116
What are the most common symptoms of multiple myeloma and how do we remember them?
CRAB
Calcium raised
Renal failure
Anaemia
Bone pain
