Haematology Flashcards
1
Q
causes of microcytic anaemia
A
- iron deficiency
- thalassemias - alpha and beta
2
Q
causes of normocytic anaemias
A
- acute bleeding
- chronic disease
- renal disease
- mixed picture = mix of big and small RBCs → normal mean size.
3
Q
causes of Macrocytic anaemias
A
- folate deficiency
- B12 deficiency
- haemolysis
- bone marrow disorders
4
Q
what are hypo chromic cells
A
pale RBCs due to reduced amounts of Hb - iron deficiency
5
Q
what factors lead to decreased RBC production
A
6
Q
what factors lead to increased increased RBC loss
A
- Acute bleeding
- Haemolysis
7
Q
define anaemia
A
- haemoglobin below lower limit of normal
- (sex adjusted Female normal 110-147g/l, male 131 – 166g/l)
8
Q
what other factors would you check in a pt with low Hb
A
- platelet count
- WBC level
9
Q
define MCV
A
- Mean Corpuscular [cell] Volume
- average cell size of RBCs = 80-98fl
10
Q
define MCH
A
- Mean Cell Hb
- amount of Hb in each cell
- hypochromic, normochromic
11
Q
T/F
reticulocyte count is part of a routine FBC
A
False
has to be requested specially
12
Q
what is a reticulocyte count
A
- count of the number of young RBCs
- measures the rate of RBC production
13
Q
causes of macrocytosis
A
NOTE: not necessarily always caused by anaemias.
- Folate deficiency
- B12 deficiency
- Reticulocytosis
- Raised immunoglobulins
- Hypothyroidism
- Alcohol
- Bone marrow failure, especially myelodysplastic neoplasms
- Drugs, e.g. methotrexate,
14
Q
when is reticulocyte count a useful investigation
A
- in pts with symptoms of anaemia with a normocytic MCV
- increased of decreased reticulocyte count can help narrow down the cause of anaemia
15
Q
what are the 2 main classes of normocytic anaemia
AND
what causes them
A
- normocytic anaemia with increased reticulocyte count - therefore there is bone marrow response
- acute bleed
- haemolytic anaemias e.g. sickle cell. G6pd deficiency.
- normocytic anaemia with decreased reticulocyte count - thus there is bone marrow failure
- aplastic anaemia - bone marrow disorder
- chronic diseases - esp. CKD
16
Q
recommended iron/ day intake
amount of iron absorbed daily
function of iron
A
- 15mg/ day
- 1mg absorbed/day
- used for Hb synthesis
17
Q
causes of iron deficiency
A
- blood loss - GI, menstrual
- pregnancy - a quarter of iron is transferred to foetus
- impaired absorption - gastrectomy, coeliac disease
- dietary deficiency - elderly and vegans
- hookworm - blood loss @ site of attachment
18
Q
where is iron absorbed
A
SI: duodenum + jejunum
19
Q
T/F ferritin is a good diagnostic tool for iron deficiency anaemia
A
True BUT:
- Ferritin is used to store iron in the RBCs, so the amount of ferritin in the blood gives an indication of how much iron in the blood.
- BUT ferritin is an acute phase protein so could go up in an infection even if the pt is anaemic
- so normal or high ferritin doesn’t rule out Fe-deficient anaemia
20
Q
what is transferrin and how is it used
A
- A protein that binds iron.
- transferrin saturation is used as a diagnostic tool: reduced saturation = Fe anaemia
- transferrin synthesis is increased in Fe deficiency → reduced saturation as less is occupied by iron.
21
Q
T/F
serum iron is a useful investigative tool for Fe anaemia
A
FALSE
serum iron is useless as there are day to day fluctuations and circadian variation
22
Q
management of Fe deficient anaemia
A
- stop bleeding if there is bleeding
- iron replacement - oral is preferred
- Hb should rise 20mg every 3-4 weeks
- oral and IV are equivalent so no benefit to IV
- IV requires hospitalisation + there’s risk of extravasation → permanent skin discolouration
- once Hb and MCV levels are normal continue replacement for a further 3 months to ensure bone marrow stores are replenished
23
Q
what are the results of iron studies in Fe deficient anaemia
A
- ↓ ferritin
- ↓ transferrin saturation
- ↑total iron binding capacity
- ↓ serum iron [not reliable]
24
Q
where is B12 absorbed in the gut
A
the terminal ileum
25
what is the first stem cell for blood cells that → further cells
multipotent haematopoietic stem cell
26
what cells are produced from the multipotent haematopoietic stem cell
* myeloid stem cells
* lymphoid stemcells
27
what cells are derived from myeloblast cells
* monocyte → macrophage
* eosinophil
* neutrophil
* basophil
28
what cells are derived from common myeloid progenitor cells
* myeloblast
* erythroblast
* megakaryocytic
* mast cells
29
what cell are platelets derived from
megakaryocyte
30
what cells are derived from lymphoid progenitor cells
* B cells
* T cells
* Natural killer cells
31
what is a reticulocyte
AND
what is it derived from
* an immature RBC
* derived from erythroblasts
32
what cells are antigen presenting cells and which is the ‘professional’
* professional = dendritic cell
* APCs
* macrophages, B cells + dendritic cells present using MHC2
* all epithelial cells can present using MHC1.
33
what is the most common inherited bleeding disorder
Von Willerbrand Disease
34
what are the types of von willerbrand disease AND which is the most severe
* type 1,2 and 3
* type 3 is the most severe
35
what is the cause of Von Willerbrand disease
* an autosomal dominant genetic disease that → deficient, absent or malfunctioning Von Willerbrand Factor.
* VWF = a glycoprotein needed for formation of the platelet plug
36
what is Von Willerbrand Factor
a glycoprotein needed for platelet adhesion for the formation of the platelet plug.
37
how does VWD present
* pts present with unusually easy, heavy or prolonged bleeding:
* Bleeding gums with brushing
* Nose bleeds (***epistaxis***)
* Heavy menstrual bleeding (***menorrhagia***)
* Heavy bleeding during surgical operations
* severe post-natal bleeding
38
how is VWD diagnosed
* no single diagnostic test, a combo of:
* abnormal bleeding
* family hx
* bleeding assessment tools such as PT, APTT, FBC
39
how is VWD managed
* not managed on a day to day basis only in preparation for an operation or in response to major bleeding.
* **Desmopressin** can be used to stimulates the release of VWF
* **VWF** can be infused
* **Factor VIII** is often infused along with plasma-derived VWF
40
what are the main causes of bleeding disorders
* over anticoagulation
* heparin, aspirin, clopidogrel, heparins, thrombolytics
* genetic conditions
* VWD
* haemophilia: A +B
* DIC: Disseminated Intravascular Coagulopathy
41
what causes haemophilia
* A
* B
* haemophilia is an X-linked recessive disorder - men only need 1 and women need 2 X Genes.
* haemophilia A is caused by a deficiency in factor 8
* haemophilia B is caused by a deficiency in factor 9
42
who is mostly affected by haemophilia
* men as it is an X-Linked recessive condition.
* women are rarely affected as 2 X-genes are needed
43
symptoms of haemophilia
* excessive bleeding in response to minor trauma
* spontaneous haemorrhage without any trauma
* easy bruising
* epistaxis
44
investigations for diagnosis of haemophilia
* APTT: prolonged
* **plasma factor 8 + 9: decreased or absent = diagnostic**
45
signs of haemophilia
* **haemarthrosis**: bleeding in joints: knees, ankles + elbows especially.
* **Prolonged bleeding following heel prick:** common presentation in neonates
* **Cutaneous purpura:** often first presentation of acquired haemophilia
46
symptoms of haemophilia
* spontaneous bleeding into joints
* excessive bleeding
* easy bruising
* fatigue
47
management of haemophilia
* IV infusion factor 8 or 9 +
* desmopressin
* desmopressin stimulates release of VWF
* tranexamic acid = antifibrinolytic
* reduces bleeding
48
what is disseminated intravascular coagulation
* an acquired syndrome → over-activation of the coagulation cascade → formation of intravascular thrombi + depletion of clotting factors and platelets.
49
what can trigger DIC
* severe infection e.g. sepsis
* major trauma
* malignancy
* major vascular disorder
* immunological reactions
* multiple organ failure
* obstetric complication
50
signs of DIC
in the context of severe systemic illness
- excessive bleeding
- petechiae
- bruising
- hypotension
- fever
- confusion
- coma
51
investigations for DIC
* PT: prolonged
* platelet count: decreased
* fibrinogen: decreased
* imaging for sites of thrombosis
