Brainscape's Knowledge GenomeTM

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


See full index

Medicine Finals > Haematology > Flashcards

Haematology Flashcards

1
Q

Basics of haematology:

Characteristics of red blood cells (erythrocytes)?

A
  • Life span = 120 days
  • No nucleus or cell organelles
  • Biconcave shape
  • Contains haemoglobin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Basics of haematology:

Functions of red blood cells?

A
  • Transport O₂ to tissues
  • Transport CO₂ to the lungs for elimination
  • Involved in acid-base homeostasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Basics of haematology:

Types of white blood cells?

A
  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Basics of haematology:

Neutrophil characteristics and functions?

A

Characteristics:

  • Around 60% of total WCC
  • Polymorphic lobulated nucleus
  • Have specific protease-containing granules

Function:

  • Acute inflammatory response
  • Phagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Basics of haematology:

Lymphocyte characteristics?

A
  • Around 25-33% of total WCC
  • Mononuclear cell with round, densely staining nucleus
  • Small, pale cytoplasm
  • Includes T cells (∼80%), B cells (∼15%), and natural killer cells (∼5%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Basics of haematology:

Lymphocyte functions?

A 
T cells:
- Adaptive (cellular) immune response
Differentiate into:
- Cytotoxic T cells (CD8+)
- Helper T cells (CD4+)
- Regulatory T cells

B cells:

  • Adaptive (humoral) immune response
  • Differentiate into plasma cells → antibody production
  • Can act as antigen-presenting cells

NK cells:
- Innate immune response

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

Basics of haematology:

Monocyte characteristics and functions?

A

Characteristics:

  • Around 5% of total WCC
  • Kidney-shaped nucleus
  • Mononuclear cell

Functions:

  • Differentiates into macrophage
  • Phagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Basics of haematology:

Eosinophil characteristics and functions?

A

Characteristics:

  • Around 1-3% of total WCC
  • Bilobate nucleus
  • Large eosinophilic granules

Functions:

  • Defence against parasitic infections
  • Production of enzymes and proteins e.g. histaminase
  • Phagocytosis of immune complexes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Basics of haematology:

Basophil characteristics and functions?

A

Characteristics:

  • Around 0-0.75% of total WCC
  • Dense, basophilic granules of heparin and histamine

Functions:

  • Mediates allergic reaction
  • Synthesis and release of leukotrienes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Basics of haematology:

What are macrophages?

A
  • Phagocytic cells located in peripheral tissues (e.g. Kupffer cells in the liver)

Functions:

  • Phagocytosis of pathogens, old RBCs, and cellular debris
  • Antigen-presentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Basics of haematology:

What are mast cells?

A
  • Differentiate from basophils
  • Contain heparin and histamine
  • IgE binds to cell membrane → degranulation → allergic reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Basics of haematology:

What are dendritic cells?

A
  • Phagocytic white cells that differentiate from either lymphoid or myeloid precursors

Functions:

  • Phagocytosis
  • Antigen-presentation
  • Links innate and adaptive immune response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Basics of haematology:

Where is erythropoietin produced?

A

Endothelial cells in the peritubular capillaries of the kidneys

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

Basics of haematology:

Stages of red blood cell development?

A
  1. Haematopoietic stem cell
  2. Proerythroblast
  3. Erythroblast
  4. Normoblast
  5. Reticulocyte

When reticulocytes enter the bloodstream they begin to mature into erythrocytes over 1-2 days.

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

Basics of haematology:

What factors affect the number of reticulocytes seen on a blood film?

A
  • Increased reticulocytes indicates increased erythropoiesis (e.g. due to haemolysis)
  • Decreased reticulocytes indicate decreased erythropoiesis (e.g. due to aplastic anaemia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Basics of haematology:

What are the two white cell lineages?

A
  • Myeloid line

- Lymphoid line

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

Basics of haematology:

Stages of lymphocyte production?

A
  • Lymphopoiesis in the bone marry
  • T lymphocytes mature in the thymus
  • B lymphocytes mature in the bone marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Basics of haematology:

Stages of thrombopoiesis?

A
  • Occurs in bone marrow
  • Myeloid precursor cell → megakaryoblasts → megakaryocytes → platelets

About 1/3 of the body’s platelets are stored in the spleen

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

Basics of haematology:

Platelet characteristics and function?

A
  • Lifespan 8-10 days

- Contain dense granules (serotonin, histamine) and alpha granules (vWF, fibrinogen, fibronectin, platelet factor IV)

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

Erythrocyte morphology and haemoglobin:

What are the two types of erythrocyte dysmorphia

A
  • Anisocytosis (RBCs of varying size)

- Poikilocytosis (RBCs of varying shape)

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

Erythrocyte morphology and haemoglobin:

What are dacryocytes? What are they seen in?

A
  • Teardrop-shaped RBCs
  • Seen in some conditions where there is bone marrow infiltration, primarily 𝗺𝘆𝗲𝗹𝗼𝗳𝗶𝗯𝗿𝗼𝘀𝗶𝘀
  • Also seen in 𝘁𝗵𝗮𝗹𝗮𝘀𝘀𝗮𝗲𝗺𝗶𝗮

Da𝗖𝗥𝗬ocytes = tear-shaped

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

Erythrocyte morphology and haemoglobin:

What factors contribute to sickle cell formation?

A
  • Sickle cell anaemia gene mutations

- Hypoxia and conditions related to hypoxia worsen sickling (e.g. acidosis, high altitude)

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

Erythrocyte morphology and haemoglobin:

What are schistocytes? What are they seen in?

A
  • Fragmented red blood cells
  • Seen in microangiopathic haemolytic anaemia (e.g. haemolytic uraemic syndrome, DIC, TTP)
  • Also seen when there’s mechanical damage to RBCs (e.g. artificial valves, extracorporeal circulation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Erythrocyte morphology and haemoglobin:

What are macrocytes? What are they seen in?

A
  • Large, spherical RBCs

- Seen in megaloblastic anaemia (e.g. B₁₂ deficiency, folate deficiency)

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

Erythrocyte morphology and haemoglobin:

What are spherocytes? What are they seen in?

A
  • Small, spherical RBCs - no central pallor as no concavity
  • Seen in haemolytic anaemias (e.g. 𝗵𝗲𝗿𝗲𝗱𝗶𝘁𝗮𝗿𝘆 𝘀𝗽𝗵𝗲𝗿𝗼𝗰𝘆𝘁𝗼𝘀𝗶𝘀, autoimmune haemolytic anaemia, haemolytic transfusion reaction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Erythrocyte morphology and haemoglobin:

What are target cells? What are they seen in?

A
  • Cells with a bullseye appearance (dark outer ring, pale ring inside that with a dark centre; normally there’s only the two ‘rings’)
  • Seen in haemoglobinopathies e.g. thalassaemia
  • Seen post-splenectomy
  • Sometimes seen in liver disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Erythrocyte morphology and haemoglobin:

What are Heinz bodies? What are they seen in?

A
  • Inclusion bodies of iron-containing, denatured DNA

- Classically seen in glucose-6-phosphate dehydrogenase (G6PD) deficiency anaemia

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

Erythrocyte morphology and haemoglobin:

What are ringed sideroblasts? What are they seen in?

A
  • Perinuclear ring of iron in the mitochondria of erythroblasts. Detected in a bone marrow film.
  • Seen in sideroblastic anaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Erythrocyte morphology and haemoglobin:

What are Howell-Jolly bodies? What are they seen in?

A
  • DNA inclusions that 𝗱𝗼 𝗻𝗼𝘁 contain iron

- Seen in asplenism (normally they are detected and destroyed in the spleen; in asplenism, they can accumulate)

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

Erythrocyte morphology and haemoglobin:

What is the normal composition of a haemoglobin molecule in an adult?

A
  • HbA1 (the main adult haemoglobin): ααββ (95-98%)

- HbA1c: glycosylated Hb (seen in diabetes mellitus)

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

Erythrocyte morphology and haemoglobin:

What is the composition of fetal haemoglobin? What is physiologically different compared with adult Hb?

A
  • HbF (fetal haemoglobin): ααγγ

- Has a higher affinity for O₂ so it can extract it from the maternal circulation

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

Erythrocyte morphology and haemoglobin:

What changes to haemoglobin structure occur as people get older?

A
  • 𝗔lpha is 𝗔lways there

- 𝗚amma 𝗚oes, and 𝗕ecomes 𝗕eta

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

Erythrocyte morphology and haemoglobin:

What does a shift to the right on the oxygen-haemoglobin dissociation curve mean?

A
  • Lower affinity for O₂ → ↑dissociation of O₂ from Hb → ↑tissue oxygenation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Erythrocyte morphology and haemoglobin:

Causes of a shift to the right on the oxygen dissociation curve?

A
  • ↑ PCO₂
  • Fever
  • High altitude
  • Exercise
  • Acidaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Erythrocyte morphology and haemoglobin:

What does a shift to the left on the oxygen-haemoglobin dissociation curve mean?

A
  • Higher affinity for O₂ → ↓dissociation of O₂ from Hb → ↓tissue oxygenation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Erythrocyte morphology and haemoglobin:

Causes of a shift to the left on the oxygen dissociation curve?

A
  • ↑ CO
  • ↑ Methemoglobin
  • ↑ Fetal haemoglobin (HbF)
  • ↑ pH
  • ↓ PCO₂
  • ↓ Body temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Anaemia:

Causes of microcytic anaemia?

A
  • Iron deficiency anaemia
  • Lead poisoning
  • Late-stage anaemia of chronic disease
  • Sideroblastic anaemia
  • Thalassaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Anaemia:

Causes of normocytic anaemia?

A
  • Haemolytic anaemia
  • Acute blood loss
  • Aplastic anaemia
  • Anaemia of chronic disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Anaemia:

Causes of macrocytic anaemia?

A
  • Vitamin B₁₂ deficiency
  • Folate deficiency
  • Phenytoin
  • Liver disease
  • Alcohol use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Anaemia:
Clinical features?
(General features)

A
  • Pallor
  • Fatigue
  • Exertional dyspnoea
  • Pica (craving for ice, dirt)
  • Worsening of angina pectoris

Features of a hyperdynamic state:

  • Bounding pulse
  • Tachycardia/palpitations
  • Flow murmur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Anaemia:

Investigation of microcytic anaemia?

A

Iron studies:

  • ↓ Ferritin OR normal/↑ ferritin and ↑ TIBC: iron deficiency anaemia
  • Normal/↑ ferritin and ↓ TIBC: anaemia of chronic disease

Peripheral blood smear:

  • Reticulocyte count is important
  • Other dysmorphic red cells (e.g. spherocytes)

Bone marrow biopsy if sideroblastic is anaemia suspected

In older patients, IDA warrants colonoscopy/gastroscopy to investigate for GI malignancy

42
Q

Anaemia:

Investigation of macrocytic anaemia?

A

Peripheral blood smear:
- Hypersegmented neutrophils = megaloblastic anaemia (B₁₂/folate)

  • Serum B₁₂
  • Serum folate
43
Q

Anaemia:

What is aplastic anaemia?

A

Pancytopenia caused by bone marrow insufficiency

44
Q

Anaemia:

Causes of aplastic anaemia?

A
  • Idiopathic in 50%
  • Drugs (e.g. chemotherapy, carbamazepine)
  • Radiation
  • Viruses (e.g. parvovirus B19, HBV)
  • Fanconi anaemia (autosomal recessive disorder causing bone marrow failure, 50% develop AML or MDS)
45
Q

Anaemia:

Causes of iron deficiency anaemia?

A
  • Excessive blood loss: menorrhagia, GI bleeding
  • Inadequate dietary intake: vegans/vegetarians higher risk
  • Poor intestinal absorption: e.g. coeliac disease
  • Increased iron requirements: e.g. growth spurts, pregnancy
46
Q

Anaemia:

Features of iron deficiency anaemia?

A
  • Fatigue, SOBOE
  • Palpitations
  • Pallor
  • Koilonychia (spoon-shaped nails)
  • Hair loss
  • Atrophic glossitis
  • Angular stomatitis
47
Q

Anaemia:

Investigation of iron deficiency anaemia?

A

History:

  • Changes in bowel habit
  • Menstrual history
  • Dietary changes
  • Medication history
  • FBC
  • Iron profile (ferritin, TIBC, transferrin saturation)
  • Blood film - ?poikilocytosis/anisocytosis
  • Endoscopy - ?malignancy (all males or post-menopausal women with unexplained IDA should get 2ww)
48
Q

Anaemia:

Management of iron deficiency anaemia?

A
  • Treat underlying cause if appropriate
  • Encourage iron-rich diet (meat, green leafy vegetables)
  • Oral ferrous sulfate - should continue for 3 months after iron profile normalises to replenish iron stores
  • May require parenteral iron in malabsorption or if oral iron is not tolerated
49
Q

Thalassaemia:

What is thalassaemia?

A
  • A group of hereditary haemoglobin disorders causing mutations in the α- or β-globin chains (alpha or beta thalassaemia)
  • It is further classified based on the number of alleles affected (α-globin is coded by four alleles, β-globin is coded by two alleles) - the number of deficient alleles directly correlates to the severity of the disease (minor/intermedia/major)
50
Q

Thalassaemia:

Epidemiology?

A
  • β-thalassaemia more common in Mediterraneans

- 𝗔lpha thalassaemia commoner in 𝗔sians and 𝗔fricans

51
Q

Thalassaemia:

Clinical features of beta thalassaemia?

A 
Minor variant (1/2 defective allele):
- Unremarkable symptoms (low risk of haemolysis or splenomegaly)

Major variant (2/2 defective alleles):

  • Severe haemolytic anaemia requiring frequent transfusions
  • Growth retardation
  • Hepatosplenomegaly
  • Skeletal deformities (high forehead, prominent zygomata and maxillae)
  • Infection with parvovirus B19 → aplastic crisis
52
Q

Thalassaemia:

Clinical features of alpha thalassaemia?

A 
Silent carrier (1/4 defective allele):
- Asymptomatic

Alpha thalassaemia trait (2/4 defective alleles):
- Mild haemolytic anaemia with normal RBC

Haemoglobin H disease (3/4 defective alleles):

  • Jaundice and anaemia at birth
  • Chronic haemolytic anaemia that may require transfusion
  • Hepatosplenomegaly
  • Symptoms generally less severe than beta thalassaemia major

Hb Bart’s → hydrops fetalis (4/4 defective alleles):

  • Intrauterine ascites and hydrops fetalis (fetal heart failure)
  • Incompatible with life (die in-utero or shortly after birth)
53
Q

Thalassaemia:

Diagnosis?

A
  • FBC
  • Peripheral blood smear (PBS; shows teardrop and target cells)
  • Haemoglobin electrophoresis (identifies which chains are present)
  • Diagnosis confirmed with genetic testing
54
Q

B₁₂ deficiency:

Causes?

A

Malabsorption:

  • ↓intrinsic factor
  • Reduced uptake of B₁₂-IF complex e.g. due to chronic alcoholism, coeliac disease, Crohn’s

Inadequate intake:

  • Anorexia nervosa
  • Vegan diet (occurs after years of inadequate intake)

Increased demand:

  • Pregnancy
  • Breastfeeding
  • Tapeworm infection
55
Q

B₁₂ deficiency:

Pathophysiology?

A
  • B₁₂ is an important co-enzyme in DNA synthesis

- Low B₁₂ → impaired DNA synthesis → immature, large, nucleated RBC formation (megaloblasts)

56
Q

B₁₂ deficiency:

What is pernicious anaemia?

A
  • Type of B₁₂ deficiency caused by autoantibodies against intrinsic factor/gastric parietal cells
  • Results in impaired B₁₂ absorption in the terminal ileum
  • Associated with other autoimmune disorders
  • Increased risk of gastric cancer
57
Q

B₁₂ deficiency:

Symptoms?

A
  • General signs and symptoms of anaemia

Neurological disturbances (usually symmetrical):

  • 𝗣𝗲𝗿𝗶𝗽𝗵𝗲𝗿𝗮𝗹 𝗻𝗲𝘂𝗿𝗼𝗽𝗮𝘁𝗵𝘆: glove and stocking symptoms
  • B₁₂ maintains myelin so deficiency → subacute combined degeneration of the spinal cord; affects 𝗱𝗼𝗿𝘀𝗮𝗹 𝗰𝗼𝗹𝘂𝗺𝗻𝘀 (paraesthesia, impaired proprioception, loss of vibration sense), 𝗹𝗮𝘁𝗲𝗿𝗮𝗹 𝗰𝗼𝗿𝘁𝗶𝗰𝗼𝘀𝗽𝗶𝗻𝗮𝗹 𝘁𝗿𝗮𝗰𝘁 (spastic paresis) and spinocerebellar tracts (ataxia)
  • Reversible dementia

N.B: neurological manifestations of B₁₂ deficiency are hard to localise; the trio of peripheral neuropathy, and dorsal column and lateral CST involvement should prompt suspicion.
𝗦ubacute 𝗖ombined 𝗗egeneration = 𝗦pinocerebellar tract, 𝗖orticospinal tract, and 𝗗orsal column

58
Q

B₁₂ deficiency:

Investigations?

A
  • anti-IF antibodies
  • anti-parietal cell antibodies
  • MRI if subacute combined degeneration suspected
59
Q

B₁₂ deficiency:

Management?

A

Primary care:

  • Encourage dietary intake
  • IM hydroxocobalamin (frequency depends on features)
60
Q

Folate deficiency:

Causes?

A
  • Poor intake
  • Poor absorption
  • Increased demands
  • Drugs (e.g. phenytoin, trimethoprim)
61
Q

Folate deficiency:

Symptoms?

A
  • Anaemia
  • Glossitis
  • Maternal deficiency → fetal neural tube defects

Does not cause neurological symptoms

62
Q

Folate deficiency:

Investigation?

A
  • FBC
  • ↑homocysteine
  • If folate deficiency is suspected, ALWAYS rule-out B₁₂ deficiency
63
Q

Folate deficiency:

Management?

A
  • Folate supplementation (at risk women should start supplementation pre-conception)
  • Always treat any coexisting B12 deficiency BEFORE folate (treat deficiencies in alphabetical order), otherwise it can cause subacute combined degeneration
64
Q

Haemolytic anaemia:

What are the two types?

A
  • Intrinsic haemolytic anaemia: increased destruction of RBCs due to a defect within the RBC
  • Extrinsic haemolytic anaemia: increased destruction of normal RBCs
65
Q

Haemolytic anaemia:

Causes of intrinsic haemolytic anaemia?

A
  • Thalassaemia
  • Sickle-cell anaemia
  • G6PD deficiency
  • Hereditary spherocytosis
66
Q

Haemolytic anaemia:

Causes of extrinsic haemolytic anaemia?

A
  • HELLP syndrome
  • Malaria
  • Hypersplenism
  • Chronic lymphocytic leukaemia
  • ABO/Rh incompatibility
67
Q

Haemolytic anaemia:

What is the direct Coombs test (DAT; direct antiglobulin test)? What does a positive result indicate?

A
  • A laboratory investigation that tests for the presence of antibodies and/or complement proteins bound to the surface of RBCS
  • A positive result indicates that the patient’s RBCs have autoantibodies/complement proteins adhered to them which are causing haemolysis (e.g. autoimmune haemolytic anaemia)

𝗗𝗶𝗿𝗲𝗰𝘁 Coombs test = antibodies 𝗱𝗶𝗿𝗲𝗰𝘁ly bound to RBCs

68
Q

Haemolytic anaemia:

What is the indirect Coombs test? What does a positive result indicate?

A
  • A laboratory investigation that tests for the presence of free autoantibodies circulating in the patient’s serum
  • Used to screen for rhesus sensitisation
  • Positive result indicates freely circulating anti-RBC antibodies that may be responsible for neonatal haemolysis or a transfusion reaction
69
Q

Glucose-6-phosphate dehydrogenase deficiency:

Pathophysiology?

A
  • G6PD is an enzyme involved in synthesising glutathione, an important antioxidant
  • In G6PD deficiency there is an impairment of this process, resulting in an increased susceptibility to oxidative damage
  • As a result, increased levels of oxidative free radicals can trigger haemolytic crises
70
Q

Glucose-6-phosphate dehydrogenase deficiency:

Triggers of haemolytic crisis?

A
  • 𝗙𝗮𝘃𝗮 𝗯𝗲𝗮𝗻𝘀 (commonly tested)
  • 𝗔𝗻𝘁𝗶𝗺𝗮𝗹𝗮𝗿𝗶𝗮𝗹 𝗱𝗿𝘂𝗴𝘀
  • Bacterial and viral 𝗶𝗻𝗳𝗲𝗰𝘁𝗶𝗼𝗻𝘀 (most common)
71
Q

Glucose-6-phosphate dehydrogenase deficiency:

Inheritance pattern?

A
  • X-linked recessive

- Commoner in African and Mediterranean people

72
Q

Glucose-6-phosphate dehydrogenase deficiency:

Diagnosis?

A

Blood smear:
- 𝗛𝗲𝗶𝗻𝘇 𝗯𝗼𝗱𝗶𝗲𝘀 (inclusion bodies of denatured DNA)

Direct measuring of G6PD activity is diagnostic

73
Q

Glucose-6-phosphate dehydrogenase deficiency:

Management?

A

Educate patient and avoid triggers

74
Q

Hereditary spherocytosis:

What is it?

A
  • Autosomal dominant defect of red blood cell cytoskeleton
  • Commonest hereditary haemolytic anaemia in Northern Europeans
  • Normal biconcave shape of RBC replaced by spherical-shaped RBC
  • Red blood cell survival decreased as destroyed by spleen
75
Q

Hereditary spherocytosis:

Clinical features?

A
  • Anaemia
  • Jaundice
  • Splenomegaly (sphere shaped cells get trapped in capillaries)
  • Gallstones
  • Raised mean corpuscular haemoglobin concentration (MCHC)
76
Q

Hereditary spherocytosis:

Diagnosis?

A
  • Patients with family history, typical clinical features, and typical laboratory findings (spherocytes, raised MCHC) don’t require further investigation.
  • If the diagnosis is equivocal, EMA binding test is used
77
Q

Hereditary spherocytosis:

Management?

A

Acute haemolysis:

  • Supportive care
  • Transfusion if necessary

Chronic management:

  • Folate supplements
  • Splenectomy is definitive management
  • Before splenectomy, vaccinate against S. pneumoniae, N. meningitidis, H. influenzae type B.
78
Q

Hereditary spherocytosis:

Complications?

A
  • Haemolytic crisis (usually after viral infection)

- Aplastic crisis (after 𝗽𝗮𝗿𝘃𝗼𝘃𝗶𝗿𝘂𝘀 𝗕𝟭𝟵 infection; shows low reticulocyte count)

79
Q

Sickle cell anaemia:

What is it?

A
  • Autosomal recessive mutation on chromosome 11 resulting in the formation of an abnormal haemoglobin chain (HbS)
  • Provides some degree of protection against malaria
80
Q

Sickle cell anaemia:

Genetics?

A
  • Heterozygous (HbSA): one sickle cell allele and one normal → sickle cell trait
  • Homozygous (HbSS): two sickle cell alleles → sickle cell disease
81
Q

Sickle cell anaemia:

Clinical features of sickle cell trait (heterozygous)?

A

Painless gross haematuria due to renal necrosis often the only feature

82
Q

Sickle cell anaemia:

Clinical features of sickle cell disease (homozygous)?

A
  • Acute haemolytic crisis (e.g. splenic sequestration crisis, aplastic crisis)
  • Increased risk of infection (e.g. osteomyelitis)
  • Painful vaso-occlusive events (e.g. priapism, acute chest syndrome)
83
Q

Sickle cell anaemia:

Diagnosis?

A

Haemoglobin electrophoresis

84
Q

Sickle cell anaemia:

Crisis management?

A
  • Supportive care (opiates, IV fluids, oxygen)
  • Consider antibiotics
  • Blood transfusion if needed
85
Q

Sickle cell anaemia:

Chronic management?

A
  • Hydroxyurea (prevents painful episodes)

- Pneumococcal vaccine every 5 years

86
Q

Polycythaemia:

Causes of primary polycythaemia?

A

Polycythaemia rubra vera

87
Q

Polycythaemia:

Causes of secondary polycythaemia?

A
  • COPD
  • High altitude (e.g. altitude training)
  • Obstructive sleep apnoea
  • Renal cell carcinoma → EPO secretion
88
Q

Polycythaemia:

Genetics of polycythaemia rubra vera?

A
  • JAK2 gene mutation (95% of cases)
  • ↑ tyrosine kinase activity
  • Causes myeloid proliferation (without need for EPO)
89
Q

Polycythaemia:

Clinical features of polycythaemia rubra vera?

A
  • Hyperviscosity → VTE
  • Plethora
  • Pruritus (worse in warm water)
  • Hypertension
  • Splenomegaly
90
Q

Polycythaemia:

Investigation of suspected polycythaemia?

A
  • FBC
  • Blood film
  • JAK2 mutation
  • Serum ferritin
  • Renal and liver function tests
91
Q

Polycythaemia:

Diagnosis of polycythaemia rubra vera?

A

WHO, 2016:
All major criteria or 2/3 major and one minor criterion:

Major:

  1. Evidence of increased RBCs
  2. Bone marrow biopsy
  3. JAK2 mutation

Minor:
- Decreased EPO levels

92
Q

Polycythaemia:

Management of polycythaemia rubra vera?

A
  • Aspirin reduces VTE risk
  • Venesection to keep haemoglobin in normal limits
  • Chemotherapy (hydroxyurea)
93
Q

Polycythaemia:

Prognosis of polycythaemia rubra vera?

A
  • Thrombotic events are common cause of death
  • 5-15% of patients progress to myelofibrosis
  • 5-15% of patients progress to acute leukaemia
94
Q

Haemostasis:

What is primary haemostasis?

A

The formation of a platelet plug following vascular injury

  1. Platelets bind to vWF at the site of the injury
  2. Platelets change shape and activate more platelets
  3. Platelet aggregation
95
Q

Haemostasis:

What is secondary haemostasis?

A

The formation of a stable platelet plug by creating a fibrin meshwork (i.e. the coagulation cascade)

96
Q

Haemostasis:

What systems inhibit haemostasis (to prevent hypercoagulability)?

A
  • (activated) protein C and protein S (inhibit factor 5 & 8)

- Antithrombin (degrades thrombin and factors 9 & 10)

97
Q

Von Willebrand Disease:

What is von Willebrand Disease?

A

Autosomal dominant bleeding disorder caused by deficiency or dysfunction of von Willebrand Factor (vWF)

98
Q

Von Willebrand Disease:

Pathophysiology?

A
  • Deficiency or dysfunction of vWF leads to impaired platelet adhesion → impaired primary haemostasis
  • Also factor ↓VIII activity so secondary haemostasis is impaired
99
Q

Von Willebrand Disease:

Clinical features?

A
  • Often asymptomatic
  • Bruising
  • Epistaxis (nosebleeds)
  • Bleeding from gums and gingiva
  • Prolonged bleeding from minor injuries
  • GI bleeding
  • Menorrhagia
100
Q

Von Willebrand Disease:

Diagnosis?

A

↑ bleeding time
↑/- APTT
Normal PT

Clotting factors:
↓ factor VIII
↓ vWF

101
Q

Von Willebrand Disease:

Management?

A
  • Tranexamic acid for mild bleeding
  • Desmopressin (increases vWP release)
  • Factor VIII

Medicine Finals (18 decks)

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