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Anemia Case > Case 14 flashcards > Flashcards

Case 14 flashcards

1
Q

What are thehistology and electrophoresis characteristics of beta thalassaemia trait?

A

Asymptomatic hypochromic microcytic anaemia with high RCC, target cells on blood smear, and elevated HbA2.

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2
Q

What is the most common form of beta thalassaemia trait?

A

Beta thalassaemia trait.

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3
Q

What are the symptoms of beta thalassaemia trait?

A

Mild anaemia, target cells on blood smear, and elevated HbA2.

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4
Q

How is beta thalassaemia trait diagnosed?

A

By Hb electrophoresis/HPLC showing elevated HbA2.

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5
Q

What is the treatment for beta thalassaemia trait?

A

It does not require treatment.

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6
Q

What is thalassaemia intermedia?

A

It is a moderate severity form of thalassaemia that is less transfusion dependent.

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7
Q

What are the complications of thalassaemia intermedia?

A

Bone deformities and iron overload.

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8
Q

What is sickle cell trait?

A

It is the heterozygote form of sickle cell anaemia with normal life expectancy.

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9
Q

What causes sickle cell disease?

A

Homozygosity for the HbSS mutation in the β globin gene.

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10
Q

What happens to deoxygenated HbS?

A

It polymerises and forms insoluble aggregates that distort RBC shape.

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11
Q

Describe what is a sickle cell disease?

A

Transfusion dependent anaemia, painful crises, and infarctive episodes.

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12
Q

How is sickle cell anaemia diagnosed?

A

By FBC and PB smear showing sickle cells and Hb electrophoresis/HPLC.

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13
Q

What are the complications of sickle cell anaemia?

A

Painful episodes, infections, neurological complications, pulmonary problems, gallstones, leg ulcers, glomerular injury, aplastic crises, and splenic sequestration.

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14
Q

What is the treatment for sickle cell anaemia?

A

Immunisation, prophylactic antibiotics, folate supplementation, urgent treatment of infections, and transfusion as needed.

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15
Q

What does RBC metabolism require energy for?

A

Cationic balance, RBC shape, membrane integrity, maintaining functional Hb, and 2,3 DPG formation.

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16
Q

What is the main source of energy for RBC metabolism?

A

Anaerobic glycolysis.

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17
Q

What is the role of the Rapoport Luebering shunt?

A

To form 2,3 DPG/BPG from glucose 6 phosphate.

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18
Q

What is the most common hereditary RBC enzymopathy?

A

Glucose 6 Phosphate Dehydrogenase deficiency (G6PD deficiency).

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19
Q

What is the inheritance pattern of G6PD deficiency?

A

X-linked recessive.

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20
Q

What is the clinical manifestation of G6PD deficiency?

A

Oxidative injury to RBC membrane and contents resulting in haemolysis.

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21
Q

What is the significance of G6PD deficiency?

A

It results in decreased NADPH synthesis and inability to maintain GSH.

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22
Q

What causes acute haemolytic episodes in G6PD deficiency?

A

Infection, fava bean exposure, and oxidant drugs.

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23
Q

How is G6PD deficiency diagnosed?

A

By measuring enzyme activity (not during acute haemolytic episode).

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24
Q

How is G6PD deficiency treated?

A

By avoiding oxidant drugs and promptly managing infections.

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25
Q

What are the protein defects that result in hereditary spherocytosis?

A

Defects affecting vertical interactions between the membrane skeleton and lipid bilayer.

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26
Q

What is the most common non-immune haemolytic anaemia in Caucasians?

A

Hereditary spherocytosis.

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27
Q

What causes the spherical shape of RBCs in hereditary spherocytosis?

A

Reduced deformability due to defective interaction with membrane.

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28
Q

What is the treatment for hereditary spherocytosis?

A

Folate supplementation and splenectomy if severe.

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29
Q

What are the reasons for splenomegaly in some anaemias?

A

Congestion, infiltration, and hypertrophy/increased work.

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30
Q

What can cause splenomegaly due to congestion?

A

Portal hypertension due to any cause.

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31
Q

What can cause splenomegaly due to infiltration?

A

Haematological malignancy, such as myeloproliferative disorders and acute leukaemia.

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32
Q

What can cause splenomegaly due to hypertrophy/increased work?

A

Haemolysis.

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33
Q

What is the main function of mitochondria in erythroid cells?

A

To be used in the formation of haem.

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34
Q

What happens to apo transferrin after the formation of haem?

A

It is released.

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35
Q

Is there a known mechanism for iron excretion?

A

Apart from the sloughing of epithelial cells, there is no known mechanism for iron excretion.

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36
Q

Where does most of the circulating iron come from?

A

Most circulating iron is derived from iron already within the system.

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37
Q

How is iron mainly recovered from senescent red blood cells?

A

Old and damaged RBCs are phagocytosed by macrophages, mainly in the spleen, and are lysed, the haem catabolized (haemoxygenase) and the iron released.

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38
Q

What happens to some of the iron in macrophages after the phagocytosis of RBCs?

A

Some of the iron remains in the macrophage as ferritin.

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39
Q

How is most of the iron released after the phagocytosis of RBCs?

A

Most of the iron is released via ferroportin into circulation, where it is immediately oxidised by caeruloplasmin and picked up by transferrin.

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40
Q

How much iron is turned over by RBCs every day?

A

1% of RBCs turn over every day (= 25mg iron).

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41
Q

What is ferritin?

A

Ferritin is the storage form of iron. It is an iron (Fe3+) complexed with apoferritin.

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42
Q

How are ferritin levels regulated?

A

Ferritin levels are regulated by iron. When body levels of iron are low, ferritin levels are proportionally low.

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43
Q

What instances can increases ferritin levels?

A

Ferritin levels increase with inflammation and in liver disease, released from damaged hepatocytes.

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44
Q

What is haemosiderin?

A

Haemosiderin is a water-insoluble form of iron, poorly understood. It is a complex of ferritin, denatured ferritin, and other material.

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45
Q

Where is haemosiderin commonly found?

A

Haemosiderin is most commonly found in macrophages in tissues.

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46
Q

What is the main function of hepcidin?

A

Hepcidin is the regulator of iron status. It prevents the uptake of iron via the GIT and also prevents the release of iron from storage.

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47
Q

What stimulates the secretion of hepcidin?

A

Hepcidin is secreted in response to increased iron stores and inflammation (IL-6).

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48
Q

What suppresses hepcidin secretion?

A

Hypoxia and increased RBC production (erythropoiesis) suppress hepcidin secretion.

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49
Q

What happens when hepcidin binds to ferroportin?

A

It causes internalization and proteosomal degradation of the transporters, preventing the release of iron into the circulation.

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50
Q

Where is iron lost when hepcidin inhibits ferroportin?

A

Iron is lost into the stool during epithelial cell shedding, resulting in decreased uptake in the GIT.

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51
Q

Where is iron stored when hepcidin inhibits ferroportin?

A

Iron is stored in macrophages and hepatocytes.

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52
Q

What are the stimuli for hepcidin synthesis?

A

Iron overload and inflammation (IL-6) stimulate hepcidin synthesis.

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53
Q

What inhibits hepcidin synthesis?

A

Hypoxia, iron deficiency, and erythropoiesis inhibit hepcidin synthesis.

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54
Q

What are the consequences of decreased hepcidin?

A

Increased uptake of iron (GIT) and increased release from RES, leading to increased iron availability and chronically to iron overload (haemochromatosis).

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55
Q

What are the consequences of increased hepcidin?

A

Decreased uptake from GIT, decreased iron release, decreased iron availability, and chronically leads to decreased availability for erythropoiesis (anaemia of chronic disease).

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56
Q

What is the gold standard for investigating iron status?

A

The gold standard is bone marrow.

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57
Q

Which stain is used to identify iron in the bone marrow?

A

Prussian Blue staining is used to identify iron in the bone marrow.

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58
Q

What is the formula for calculating MCH?

A

MCH = Hb / RBC

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59
Q

What is the formula for calculating MCHC?

A

MCHC = Hb / Hct

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60
Q

What does RDW indicate?

A

RDW is an indicator of the distribution of individual RBC sizes in a sample

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61
Q

How is the RBC uniquely adapted for its function?

A

The RBC is anucleate and specialized for facilitating gaseous exchange and transporting O2, CO2, and NO

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62
Q

What is the size of a normocytic RBC compared to a lymphocyte nucleus?

A

The whole normocytic RBC is smaller than the nucleus of a lymphocyte

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63
Q

What are some acquired causes of anemia?

A

Acquired causes of anemia can include iron deficiency, blood loss with replacement of plasma volume, and red cell defects

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64
Q

What are some primary or inherited red cell defects that can lead to anemia?

A

Membrane or cytoskeleton defects, abnormalities of red cell metabolism, and abnormal hemoglobin synthesis can lead to anemia

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65
Q

What is the role of the Embden-Meyerhoff pathway in red cells?

A

The Embden-Meyerhoff pathway is an anaerobic glycolytic pathway that provides energy for maintenance of red cell volume, shape, and flexibility

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66
Q

What is the key enzyme involved in the Embden-Meyerhoff pathway?

A

The key enzyme is pyruvate kinase

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67
Q

What is the role of the hexose monophosphate shunt in red cells?

A

The hexose monophosphate shunt produces NADPH and reduces glutathione to protect RBC against oxidative stress

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68
Q

What is the key enzyme involved in the hexose monophosphate shunt?

A

The key enzyme is G6PD

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69
Q

What is the function of hemoglobin in RBCs?

A

Hemoglobin is a specialized iron-containing protein integral for O2 transport in RBCs

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70
Q

What are some requirements for effective hemoglobin synthesis?

A

Effective hemoglobin synthesis requires iron, folate, and Vitamin B12

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71
Q

How many O2 molecules can each heme group in hemoglobin bind?

A

Each heme group can bind a single O2 molecule, totaling four O2 molecules per hemoglobin molecule

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72
Q

What causes ineffective hemoglobin production?

A

Mutations in relevant genes can cause reduced or absent globin chain synthesis, leading to ineffective hemoglobin production

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73
Q

What are thalassemias and sickle cell anemia examples of?

A

Thalassemias are quantitative abnormalities of globin chain synthesis, while sickle cell anemia is a qualitative abnormality of hemoglobin

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74
Q

What is the major regulator of the O2 affinity of hemoglobin?

A

2,3-DPG (2,3-diphosphoglycerate) is the major regulator of the O2 affinity of hemoglobin

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75
Q

What is the P50 in the context of the dissociation curve of hemoglobin?

A

P50 is the partial pressure at which hemoglobin is 50% saturated with O2 (26.6mmHg for normal blood)

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76
Q

What can cause a left shift or right shift of the dissociation curve of hemoglobin?

A

Certain conditions and hemoglobins can cause a left shift (increased O2 affinity) or right shift (decreased O2 affinity) of the dissociation curve

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77
Q

What does anaemia indicate?

A

Anemia indicates low hemoglobin and insufficient RBC mass to adequately deliver O2 to peripheral tissues

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78
Q

What must be considered during FBC to determine anaemia?

A

During FBC, WBC, Hb, and platelets must be considered instead of RBCs themselves

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79
Q

Is anaemia itself a disease?

A

No, anaemia is a feature of an underlying disease and must be treated by identifying and addressing the underlying cause

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80
Q

What are the factors that increase polymerization of HbS molecules?

A

Deoxygenation, higher HbS concentration, acidosis

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81
Q

What are the factors that decrease polymerization of HbS molecules?

A

Decrease in 2,3 BPG, increase in HbF and HbA2; alpha thal, hydration

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82
Q

What are the causes of sickle cell disease/anaemia/trait?

A

RBC membrane damage, haemolysis - intra and extra vascular, veno-occlusion, hypercoagulable state

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83
Q

What are the different sub-phenotypes of sickle cell disease?

A

Vaso-occlusive, haemolysis and vasculopathy, high HbF, pain

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84
Q

What are the clinical investigations for sickle cell disease?

A

FBC: normocytic anaemia, peripheral smear: sickle cells, nucleated RBCs, target cells, Howell-Jolly bodies, HbS on electrophoresis, low HbA2

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85
Q

What are the treatment options for sickle cell disease?

A

Prevention of complications (education, routine health management, nutrition, antibiotics & vaccinations), blood transfusions, disease modifying therapies, symptomatic treatment (pain, antibiotics, transfusions, rehydration), curative (stem cell transplantation, gene therapies)

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86
Q

What is the life expectancy for individuals with sickle cell disease in different regions?

A

UK median survival is 67 years, Tanzania median survival is 33 years, Sub-Saharan Africa U5MR for children with SCD is 50 - 90%

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87
Q

What are the components of counselling for sickle cell disease?

A

Information of the condition, psycho-social support, recurrence risk, familial implications, genetic testing, carrier screening, prenatal testing

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88
Q

What is thalassemia?

A

Thalassemias are hereditary abnormalities of haemoglobin production characterized by a quantitative deficiency of alpha or beta globin gene

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89
Q

What are the common geographical regions where thalassemia is prevalent?

A

Mediterranean, SE Asia, Africa in malaria areas

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90
Q

What are the pathogenic mechanisms of thalassemia?

A

Oxidative injury, membrane damage, abnormal hydration, reduced deformability

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91
Q

What are the genetics of alpha thalassemia?

A

Each chromosome 16 has 2 alpha genes, involving 1-4 of the genes, autosomal recessive, phenotype dependent on mutations

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92
Q

What are the clinical features of thalassemia?

A

Anaemia, complications of haemolysis (jaundice, hepatosplenomegaly), complications of extramedullary haematopoiesis (skeletal changes, growth deficiency), complications of iron overload (endocrine, cardiovascular), leg ulcer, thrombosis

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93
Q

What are the treatment options for thalassemia?

A

Manage anaemia (transfusion, dietary care, supplements), assessment of iron stores and chelation therapy, splenectomy, monitor/ manage complications, stem cell transplant or gene therapy (mainly beta thalassemia)

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94
Q

What is the genotype and phenotype of alpha thalassaemia for Africa (equator)?

A

Genotype: alpha-/alphaalpha, Phenotype: silent carrier, normal

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95
Q

What is the genotype and phenotype of alpha thalassaemia for SE Asia?

A

Genotype: alpha-/alpha-, Phenotype: thalassemia (asymptomatic, mild microcytic anaemia)

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96
Q

What is the genotype and phenotype of alpha thalassaemia for the Mediterranean trait?

A

Genotype: alpha-/alpha-, Phenotype: HbH (mild to moderate microcytic anaemia)

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97
Q

What is the genotype and phenotype of alpha thalassaemia when there are no alpha globin genes?

A

Genotype: –/–, Phenotype: Hb Barts (Hydrops fetalis)

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98
Q

What are the blood tests used to investigate iron deficiency?

A

Serum iron, serum transferrin, % saturation transferrin, serum soluble transferrin receptors, serum ferritin, serum hepcidin

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99
Q

What is the normal range for serum iron?

A

9 - 30 umol/L

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100
Q

How is serum iron affected by diet?

A

It is affected by diet

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101
Q

What happens to serum iron in iron deficiency?

A

It is decreased

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102
Q

What happens to serum iron in iron overload?

A

It is increased

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103
Q

What is the transferrin concentration in iron deficiency?

A

It is increased

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104
Q

What is the transferrin concentration in iron overload?

A

It is decreased

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105
Q

What is the % saturation of transferrin in iron deficiency?

A

It is decreased

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106
Q

What is the % saturation of transferrin in iron overload?

A

It is increased

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107
Q

What is the normal amount of transferrin that can bind to iron?

A

Up to 60 umol/L

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108
Q

What is the normal range for % saturation of transferrin?

A

20 - 45%

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109
Q

What is the serum ferritin concentration in iron deficiency?

A

It is decreased

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110
Q

What is the serum ferritin concentration in iron overload?

A

It is increased

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111
Q

What happens to serum ferritin concentration in inflammation?

A

It is increased

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112
Q

What happens to soluble transferrin receptors in iron deficiency?

A

They are increased

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113
Q

What happens to soluble transferrin receptors in iron overload?

A

They are decreased

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114
Q

What happens to soluble transferrin receptors in inflammation?

A

They remain unchanged

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115
Q

What are the diagnostic indicators for simple iron deficiency anemia?

A

Low serum iron, microcytic hypochromic anemia, low ferritin, low % saturation of transferrin, high soluble transferrin receptors

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116
Q

What are the common causes of iron deficiency anemia?

A

Blood loss, frequent pregnancies, malabsorption

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117
Q

What is the cause of anemia of chronic disease?

A

Inadequate erythropoietin production, inhibition of erythroid proliferation, and sequestration of iron into the RES

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118
Q

What causes the sequestration of iron in anemia of chronic disease?

A

Stimulation of hepcidin secretion by IL-6

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119
Q

What are the biochemical results of anemia of chronic disease?

A

Low plasma iron, normal or increased ferritin, normal or low transferrin, and normal % saturation of transferrin

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120
Q

What is the challenge in diagnosing anemia of chronic disease?

A

Identifying patients with concomitant iron deficiency

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121
Q

What is a good indicator of inflammation?

A

C-Reactive Protein (CRP) level

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122
Q

What is the recommended assessment for functional vs real iron deficiency with and without acute phase response?

A

Combined measurements of CHr, sTfR, and Ferritin with calculation of a sTfR/log Ferritin ratio

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123
Q

What can cause cardiac arrhythmias if cold blood is rapidly infused?

A

Infusing cold blood rapidly can cause cardiac arrhythmias.

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124
Q

How are platelets stored and why can they be transfused quickly?

A

Platelets are stored at room temperature and can be transfused quickly because of this.

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125
Q

How are plasma products prepared before transfusion and why?

A

Plasma products are frozen and thawed to body temperature before use, allowing for quick transfusion.

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126
Q

What vital signs should be recorded before starting a blood transfusion?

A

The vital signs of the patient should be recorded before beginning the transfusion.

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127
Q

How long should the patient be monitored after starting a transfusion?

A

The patient should be carefully monitored for the first 30 minutes of the transfusion.

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128
Q

What should be watched for during the first 30 minutes of a transfusion?

A

Any adverse symptoms suggestive of a transfusion reaction should be watched for.

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129
Q

What are dietary sources of Folic acid?

A

Leafy vegetables, legumes, and egg yolks are dietary sources of Folic acid.

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130
Q

What is the biological role of folate?

A

The biological role of folate is to carry 1-carbon (methyl) fragments for DNA/RNA synthesis and methylation reactions.

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131
Q

Which cells are affected first by folate deficiency?

A

Rapidly dividing cells, such as blood cell precursors in the bone marrow, are affected first by folate deficiency.

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132
Q

What are the manifestations of folate deficiency?

A

Manifestations include macrocytic anemia with megaloblastic marrow, malabsorption in intestinal mucosal cells, and neural tube malformation in growing fetuses.

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133
Q

Who is at risk of folate deficiency?

A

People with intestinal disease, malabsorption syndromes, and folate-poor diets are at risk of folate deficiency.

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134
Q

What is the role of folate in the production of nuclear bases?

A

Folate is needed for the synthesis of nuclear bases for DNA/RNA, but its deficiency can cause megaloblastic anemia and cell division to stop.

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135
Q

What happens when B12 deficiency occurs?

A

In B12 deficiency, available folate gets trapped as 5-methyl-THF, leading to megaloblastic anemia and potential neurological damage.

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136
Q

Why does B12 deficiency cause megaloblastic anemia?

A

B12 deficiency causes megaloblastic anemia because folate becomes trapped as methyl-THF, resulting in the inability to make nuclear bases for cell division.

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137
Q

What happens when SAM levels are low?

A

When SAM levels are low, MTHFR is disinhibited and available folate is diverted to MTHF, leading to megaloblastic anemia if folate levels are already low.

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138
Q

What is the priority in B12 deficiency?

A

Cycle 2, which prevents neurological degeneration, is prioritized in B12 deficiency.

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139
Q

What occurs in B12 deficiency even with adequate folate levels?

A

In B12 deficiency, folate essentially becomes trapped as methyl-THF, causing ‘functional’ folate deficiency and megaloblastic anemia.

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140
Q

What is the result of B12 deficiency when SAM production decreases?

A

When SAM production decreases due to B12 deficiency, methionine cannot be regenerated, leading to neurological disease.

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141
Q

What is targeted in the treatment of certain diseases?

A

Folate pathways in bacteria, protozoa, and humans are targeted in the treatment of certain diseases.

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142
Q

What are some examples of organisms that synthesize their own folate?

A

Plants, bacteria, and parasitic organisms like malaria and toxoplasmosis synthesize their own folate.

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143
Q

What is the role of methionine in the CNS?

A

Methionine is an essential methyl donor in the CNS for the synthesis of neurotransmitters and phospholipids used to make myelin.

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144
Q

What happens in B12 deficiency even with adequate folate levels?

A

In B12 deficiency, folate becomes trapped as methyl-THF, causing ‘functional’ folate deficiency and potentially leading to megaloblastic anemia.

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145
Q

What is the effect of low methionine synthase activity?

A

Low methionine synthase activity can lead to reduced SAM production, impacting essential methylation reactions in the CNS.

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146
Q

What are the earliest symptoms of dorsal column involvement?

A

The earliest symptoms are paresthesia, observed in the form of tingling, burning, and sensory loss of the distal extremities.

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147
Q

How does loss of proprioception usually present?

A

Loss of proprioception usually presents as a difficulty in maintaining balance in the absence of visual cues.

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148
Q

What are the symptoms of lateral corticospinal tract dysfunction?

A

The symptoms include muscle weakness, hyperreflexia, and spasticity.

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149
Q

What are the other signs of upper motor neuron damage?

A

Other signs include Babinski sign, spasticity, and possible progression to paraplegia or quadriplegia.

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150
Q

What causes gait abnormalities in the form of sensory ataxia?

A

Spinocerebellar tract degeneration causes gait abnormalities in the form of sensory ataxia.

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151
Q

What are the late signs in diagnosing B12 deficiency?

A

Measuring B12 in plasma, checking for megaloblastic anemia, and increased LDH 1 isoenzymes.

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152
Q

What are the early biochemical manifestations of B12 deficiency?

A

Elevated total homocysteine and elevated urinary and plasma methyl-malonic acid.

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153
Q

What is the recommended method when measuring Red Cell Folate and B12 levels?

A

Always measure Red Cell Folate AND B12 together.

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154
Q

What are some possible causes for B12 deficiency?

A

Possible causes include diet, gastric mucosal integrity, Pernicious Anemia, distal Ileum investigation, and celiac disease screening.

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155
Q

What is the Schilling test used for in B12 deficiency diagnosis?

A

The Schilling test is used to determine the cause of B12 deficiency by assessing absorption and factors like PA or bacterial overgrowth.

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156
Q

What are the indicators of intravascular hemolysis?

A

Unconjugated bilirubin elevation, increased urobilinogen on urine dipstick, elevated LDH 1 and AST in plasma, decreased haptoglobin levels, visible schistocytes, and potential hemoglobinuria.

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157
Q

What are the common causes of intravascular hemolysis?

A

Causes include autoimmune factors, mechanical stress on red cells, infectious agents like malaria, inherited red cell fragility disorders, and osmotic factors.

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158
Q

What are the common causes of extravascular hemolysis?

A

Hypersplenism, large hematomas, and acute pancreatitis are common causes of extravascular hemolysis.

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159
Q

What are the clinical signs and consequences of hemolysis?

A

Clinical signs include pallor, mild jaundice, red urine in cases of intravascular hemolysis, and the potential for Acute Renal Failure.

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160
Q

What is ex vivo hemolysis and what causes it?

A

Ex vivo hemolysis is red cell lysis during blood draw, often caused by poor phlebotomy technique.

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161
Q

How is intravascular hemolysis differentiated from ex vivo hemolysis?

A

Intravascular hemolysis causes specific indicators like increased bilirubin, urobilinogen, LDH 1, decreased haptoglobin, schistocytes, and potential hemoglobinuria.

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162
Q

What are some extremities that can be affected by certain conditions?

A

Fingers, noses, and ears

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163
Q

What are some conditions associated with extremities?

A

Acrocyanosis, Raynaud’s phenomenon, Livido reticularis, severe pain on eating/drinking cold things, cutaneous necrosis/ulcers

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164
Q

What antibodies are classically associated with syphilis?

A

Donath-Landsteiner antibodies

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165
Q

In what conditions can Donath-Landsteiner antibodies arise?

A

Other conditions like chickenpox

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166
Q

How do Donath-Landsteiner antibodies behave under different temperatures?

A

They bind to the P-group antigen at cold temperatures but do not dissociate at higher temperatures

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167
Q

What is the primary immunoglobulin class of the antibodies?

A

IgG

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168
Q

What is the consequence of Donath-Landsteiner antibodies fixing complement in the circulation?

A

They cause intravascular haemolysis

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169
Q

What are some clinical presentations of paroxysmal cold hemoglobinuria?

A

Dark urine, back or leg pain, abdominal cramping, weakness, malaise, nausea, vomiting, fever or chills, subsequent pallor and/or jaundice in severe cases

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170
Q

What investigations are helpful in diagnosing autoimmune hemolytic anemia?

A

Clinical history and examination, full blood count, smear, haemolytic screen, Coombs test/Direct Antiglobulin Test

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171
Q

What are some findings in a full blood count of autoimmune hemolytic anemia?

A

Decreased Hb, increased red cell distribution width, increased numbers of nucleated RBCs

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172
Q

What are some findings in a smear of autoimmune hemolytic anemia?

A

Spherocytes, fragments

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173
Q

What are some markers in the haemolytic screen for autoimmune hemolytic anemia?

A

Increased lactate dehydrogenase, increased bilirubin, decreased haptoglobin, increased reticulocyte count

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174
Q

What does the Coombs test/Direct Antiglobulin Test detect in autoimmune hemolytic anemia?

A

IgG antibodies and bound complement

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175
Q

What type of cold agglutinin disease is generally C3d positive?

A

Cold agglutinin disease

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176
Q

What type of warm autoimmune hemolytic anemia is generally IgG positive?

A

Warm AIHA

177
Q

What condition is generally positive for both IgG antibodies and bound complement?

A

Paroxysmal cold hemoglobinuria

178
Q

What are some possible secondary causes of AIHA?

A

Infections (EBV, atypical bacteria, syphilis), autoimmune conditions (SLE), malignancies (B-cell clonal disorders)

179
Q

What is the treatment for most cold agglutinin diseases and paroxysmal cold hemoglobinuria?

A

Supportive treatment until underlying condition resolves, nutrients supplementation (e.g. folate, iron), warm temperature maintenance

180
Q

What specific treatments can be used for warm AIHA?

A

Corticosteroid therapy, Rituximab, complement inhibition, immunosuppression, splenectomy in severe/refractory cases

181
Q

What are the characteristics of malaria?

A

Endemic in many parts of sub-Saharan Africa, South and South-East Asia, Central and South America, affecting about 3.4 billion people

182
Q

What were the estimated malaria cases and deaths in 2018?

A

228 million cases worldwide, 405,000 deaths worldwide

183
Q

Which regions have the highest risk of malaria?

A

Africa and South/South-East Asia

184
Q

What is the process of haematopoiesis in the yolk sac?

A

Haematopoiesis in the yolk sac involves the generation of microglia and production of erythro-myeloid progenitors (EMPs) and lympho-myeloid progenitors (LMPs).

185
Q

What is the role of the pro-definitive wave in haematopoiesis?

A

The pro-definitive wave generates erythro-myeloid progenitors (EMPs) and lympho-myeloid progenitors (LMPs) in the yolk sac or embryo.

186
Q

What is the function of the definitive wave in haematopoiesis?

A

The definitive wave generates pre-HSCs, which mature into HSCs capable of self-renewal.

187
Q

Where do the pro-definitive and definitive wave progenitors travel to?

A

The pro-definitive and definitive wave progenitors travel to the liver.

188
Q

What types of cells are produced in the liver during haematopoiesis?

A

Erythrocytes, megakaryocytes, granulocytes, T and B cells, and monocyte-derived macrophages are produced in the liver.

189
Q

What is the source of tissue-resident macrophages at birth?

A

EMP-derived macrophages colonize the embryo and constitute the majority of tissue-resident macrophages at birth.

190
Q

Where does primitive haematopoiesis take place?

A

Primitive haematopoiesis takes place in the blood islands along the wall of the yolk sac.

191
Q

What are the characteristics of progenitors in the yolk sac?

A

Progenitors in the yolk sac cannot fulfil the functions of adult-type HSC when transplanted to older individuals.

192
Q

What types of cells are produced during primitive haematopoiesis?

A

Large, nucleated erythrocytes are produced during primitive haematopoiesis.

193
Q

Where does definitive intraembryonic haematopoiesis begin?

A

Definitive intraembryonic haematopoiesis begins in small clusters of cells in the splanchnopleuric mesoderm associated with the ventral wall of the dorsal aorta and AGM region.

194
Q

What are hemogenic endothelial cells and where are they located?

A

Hemogenic endothelial cells are found within the ventral half of the paired dorsal aortae, which are clusters of hematopoietic stem cells.

195
Q

What is the shift in haematopoiesis from the liver to the bone marrow controlled by?

A

The shift in haematopoiesis from the liver to the bone marrow is controlled by cortisol secreted by the foetal adrenal cortex.

196
Q

Which organs serve as minor sites of blood cell production?

A

The spleen, kidney, thymus, and lymph nodes serve as minor sites of blood cell production.

197
Q

Which cell type is retained in the brain during haematopoiesis?

A

Microglia, of primitive macrophage origin, are retained in the brain as a stable and self-renewing population.

198
Q

Which cells replace those produced during the primitive wave for WBCs?

A

Monocyte-derived macrophages gradually replace those produced during the primitive wave for WBCs.

199
Q

What is the role of EMPs in haematopoiesis?

A

EMPs generate granulocytes, a cell type not produced during primitive haematopoiesis.

200
Q

Where do angioblasts initially form small cell clusters?

A

Angioblasts initially form small cell clusters (blood islands) within the embryonic and extraembryonic mesoderm.

201
Q

What are the causes of secondary iron overload?

A

Another disorder or treatment such as thalassaemia or blood transfusions.

202
Q

What are the biochemical features of iron overload?

A

Increased serum iron, low transferrin, high % transferrin saturation, increased ferritin, and low hepcidin.

203
Q

How does chronic iron overload differ from acute iron overdose?

A

In chronic overload, transferrin and ferritin have had time to respond.

204
Q

What are the common causes of elevated ferritin?

A

Chronic inflammation, chronic alcohol consumption, liver disease, renal failure, metabolic syndrome, or malignancy.

205
Q

How can iron overload be excluded clinically?

A

By conducting initial tests such as FBC, liver and renal function, and inflammatory markers.

206
Q

What serum ferritin values indicate further investigation?

A

Unexplained values > 1000 uG/L.

207
Q

How can hereditary haemochromatosis be screened?

A

By considering HFE mutation and checking for elevated ferritin and transferrin saturation (>45%).

208
Q

What is the most common form of primary iron overload?

A

Haemochromatosis type 1.

209
Q

What mutation is associated with haemochromatosis type 1?

A

Mutation in HFE protein, specifically C28Y and H63D.

210
Q

How can primary iron overload be definitively diagnosed?

A

By liver biopsy with hepatic iron index/MRI quantitation and genetic screening.

211
Q

What are the features of primary African iron overload?

A

Increased iron absorption from diet, accumulation of iron in RES and hepatocytes, and increased risk of liver disease and infections.

212
Q

What are the causes of secondary iron overload?

A

Conditions requiring repeat blood transfusions or ineffective erythropoiesis (thalassaemia).

213
Q

How is acute iron toxicity caused?

A

By acute ingestion of iron salts and organ damage due to iron-mediated oxygen free radicals.

214
Q

What are the biochemical markers of acute iron toxicity?

A

Increased serum iron, normal transferrin, 100% transferrin saturation, and normal ferritin.

215
Q

What is the treatment for acute iron toxicity?

A

Resuscitation and chelation with desferrioxamine.

216
Q

What is the percentage composition of HbA, HbA2, and HbF?

A

HbA = 97%, HbA2 = 2%, HbF = 1%.

217
Q

What are the two types of haemoglobinopathies?

A

Qualitative (sickle cell anaemia) and quantitative (thalassaemia’s).

218
Q

What are the characteristics of sickle cell disease?

A

Incidence in African population, carrier frequency, pathogenesis, and heterozygote advantage.

219
Q

What is the shape and lifespan of normal RBC?

A

Disc-shaped, soft, easily flows through small blood vessels, and a lifespan of 120 days.

220
Q

What is the shape of sickle RBC?

A

Sickle shape, rigid, often gets stuck in small blood vessels.

221
Q

Where does absorption of iron take place?

A

Absorption of iron takes place in the proximal duodenum.

222
Q

What are the two forms in which iron is taken up in the diet?

A

Iron is taken up in the diet in its inorganic form (Fe3+) and as myoglobin and haemoglobin.

223
Q

How is haem iron taken up?

A

Haem iron is taken up via a haem-specific transporter and the Fe released from the haem inside the cell.

224
Q

What happens to Fe3+ iron before it is taken up by the divalent metal transporter (DMT1)?

A

Fe3+ iron is first reduced to its Fe2+ form before it is taken up by the DMT1.

225
Q

Which substances help convert Fe3+ to Fe2+?

A

Gastric acid and reducing agents (especially vitamin C and the protein DCytb) help convert Fe3+ to Fe2+.

226
Q

Where does iron go once inside the epithelial cell of the proximal duodenum?

A

Once inside the epithelial cell of the proximal duodenum, iron can either be stored as ferritin or transported out of the cell via Ferroportin.

227
Q

How is iron transported out of the cell?

A

Iron is transported out of the cell via a basolateral transporter called Ferroportin.

228
Q

What happens to iron inside the cell?

A

Once inside the cell, iron is stored as ferritin or transported out of the cell.

229
Q

In what form is iron transported in circulation?

A

Iron is transported in its ferric (Fe3+) form in circulation.

230
Q

What happens to iron once it is in circulation?

A

Once in circulation, iron is oxidized to its ferric (Fe3+) form via hephaestin or caeruloplasmin.

231
Q

What does transferrin do with iron?

A

Transferrin solubilizes iron, and also dampens its reactivity.

232
Q

How much of iron binding sites on transferrin does iron occupy in normal human beings?

A

In normal human beings, iron occupies approximately 30% of iron binding sites on transferrin in plasma.

233
Q

How do cells take up iron?

A

Cells take up iron by expressing transferrin receptors on their surfaces.

234
Q

What happens when transferrin receptors bind with transferrin?

A

Transferrin laden with two ferric irons binds transferrin receptors and is endocytosed.

235
Q

Where does iron go once it is inside the endosome?

A

Once endocytosed, iron is reduced and then transported out of the endosome via DMT1 into the cytoplasm.

236
Q

What are the two options for iron once it is in the cytoplasm?

A

Iron is either stored as ferritin (non-erythroid cells) or taken up into cells.

237
Q

What does Rh positive refer to?

A

Presence of the D antigen

238
Q

What does Rh negative refer to?

A

Absence of the D antigen

239
Q

Can other Rh antigens be present on red cells regardless of the D status?

A

Yes

240
Q

Which genes determine Rh expression?

A

RhD and RhCE

241
Q

What antigens does RhCE confer?

A

C, c, E and e antigens

242
Q

When are Rh antibodies formed in Rh-negative individuals?

A

Following an incompatible blood transfusion or transplacental passage of blood during pregnancy

243
Q

Why is Rh antibody formation a concern in Rh-negative pregnant women?

A

Because it can harm the fetus

244
Q

Can Rh-positive people receive Rh-negative blood?

A

Yes

245
Q

Can Rh-negative women of childbearing age receive Rh-positive blood?

A

No

246
Q

Which antibodies can occasionally cause transfusion reactions and HDFN?

A

Antibodies to C, c, E and e antigens

247
Q

What is the cause of Haemolytic disease of the fetus and newborn (HDFN)?

A

Maternal IgG antibodies crossing the placenta and binding to fetal red cells with corresponding antigens

248
Q

What are the most frequent cause of HDFN?

A

Anti ABO antibodies

249
Q

Which type of antibodies are usually associated with the most severe cases of HDFN?

A

Anti Rh (specifically anti D) antibodies

250
Q

Which antibodies can also be IgG and cross the placenta to affect the fetus?

A

Anti A and anti B antibodies

251
Q

Which antibodies are most commonly seen in Group O pregnant women?

A

IgG anti A and B antibodies

252
Q

What is the main aim of managing Rh HDN?

A

To prevent Rh D antibody formation in Rh-negative pregnant women

253
Q

When can Anti D antibody be administered to Rh-negative women?

A

At 28 weeks, during any potentially sensitizing events (e.g., amniocentesis, abortion), and 72 hours after birth if the baby is Rh positive

254
Q

What are the risks associated with blood product transfusions?

A

Incompatible blood transfusions and transmission of infection from donor to patient

255
Q

What is the most frequent cause of incompatible blood transfusions?

A

Human error

256
Q

What is the window period risk associated with transfusion of blood products?

A

Transmission of infection from a donor to a patient during a period where the infection is not yet detectable

257
Q

How should a blood product be ordered?

A

Using a blood ordering request form and providing a blood sample in a crossmatch tube

258
Q

In what type of sets are blood and products given?

A

Specialized IV sets containing filters

259
Q

Can fluids or drugs be added to the blood product?

A

No

260
Q

What should be compared before starting a blood transfusion?

A

The details on the product with the order form and patient folder at the bedside

261
Q

What information should be checked before starting a blood transfusion?

A

Patient name & hospital number, unit serial number & blood type, expiration date

262
Q

What must the patient do before receiving a transfusion?

A

Sign informed consent for the transfusion

263
Q

How quickly should red cell units be transfused?

A

Very slowly over 1 - 2 hours

264
Q

When can blood be transfused rapidly?

A

For rapid red cell transfusions

265
Q

What are the possible causes of intrinsic hereditary haemolytic anaemia?

A

Abnormal RBC membrane, abnormal RBC metabolism, haemoglobin abnormalities

266
Q

What are the possible causes of acquired haemolytic anaemia?

A

Immune mechanisms, fragmentation syndromes, macrovascular haemolysis, toxins

267
Q

What are the features of increased RBC production in haemolytic anaemia?

A

Reticulocytosis, nucleated red blood cells on blood film, bone marrow erythroid hyperplasia, haemoglobinuria/haemosiderinuria

268
Q

What are the features of increased red cell breakdown in haemolytic anaemia?

A

Unconjugated hyperbilirubinaemia, increased urinary urobilinogen, decreased or absent serum haptoglobin

269
Q

What are the possible damaged red cell characteristics in haemolytic anaemia?

A

Morphology, raised LDH

270
Q

What is the significance of peripheral blood smear in investigating haemolytic anaemia?

A

RBC morphology is critical, polychromasia and nucleated red cells suggest a bone marrow response, spherocytes indicate loss of central area of pallor, burr cells are seen in renal failure

271
Q

How can the precise diagnosis of haemolytic anaemia be determined?

A

Distinguishing between inherited and acquired causes, conducting tests such as G6PD screen, Hb electrophoresis/HPLC, Coombs test, flow cytometric immunophenotyping

272
Q

What are the characteristics of warm autoimmune haemolytic anaemia?

A

Idiopathic or secondary to an underlying systemic condition, usually IgG autoantibodies, extravascular haemolysis, presence of polychromasia, spherocytosis, and nucleated red blood cells

273
Q

What are the characteristics of alloimmune haemolytic anaemia?

A

Results from antibodies to RBC antigens produced by another individual, can occur in haemolytic transfusion reactions or haemolytic disease of the newborn

274
Q

What are the characteristics of cold autoimmune haemolytic anaemia?

A

Less common than warm AIHA, spontaneous agglutination of RBCs, may be secondary to lymphoproliferative disorders or infections, can result in cold haemagglutinin disease with mild anaemia, jaundice, and acrocyanosis

275
Q

What activates the system in response to pattern recognition receptors?

A

Pattern recognition receptors activate the system.

276
Q

What is the role of cellular and humoral responses in malaria?

A

Both cellular and humoral responses are important in malaria.

277
Q

Which forms are targeted by cytotoxic responses in malaria?

A

Cytotoxic responses target the hepatic and merozoite forms in malaria.

278
Q

What do antibodies target in malaria?

A

Antibodies target the merozoites and erythrocyte stages in malaria.

279
Q

What is the significance of malaria vaccines in the fight against malaria?

A

Malaria vaccines represent a key development in the fight against malaria.

280
Q

Which malaria vaccine has been approved by WHO in 2021?

A

The RTS, S vaccine has been approved by WHO in 2021.

281
Q

What is anaemia?

A

Anaemia is a condition associated with reduced red cell mass and haemoglobin levels.

282
Q

How is anaemia diagnosed?

A

Anaemia can only be diagnosed with a lab test.

283
Q

What causes autoimmune haemolytic anaemia (AIHA)?

A

AIHA is caused by immune-mediated destruction or lysis of red blood cells.

284
Q

What are the mechanisms of haemolysis?

A

Mechanical, infections (such as malaria), venoms, and copper/zinc toxicity can cause haemolysis.

285
Q

Where does haemolysis occur in autoimmune haemolytic anaemias?

A

Haemolysis can occur intravascularly or extravascularly.

286
Q

Under what conditions does warm AIHA occur?

A

Warm AIHA occurs at body temperature.

287
Q

Under what conditions does cold AIHA occur?

A

Cold AIHA occurs in extremities and below body temperature.

288
Q

What is the role of the spleen in haemolysis?

A

The spleen is the major effector organ of extravascular haemolysis.

289
Q

What are the clinical presentations of warm AIHA?

A

Warm AIHA presents with anaemia, pallor, tiredness/weakness, and potentially jaundice and splenomegaly.

290
Q

What is cold agglutinin disease?

A

Cold agglutinin disease is characterized by antibodies targeting the I system antigens.

291
Q

Which infections can lead to the development of cold agglutinin disease?

A

Epstein-Barr virus infection, Mycoplasma spp infections, and certain autoimmune diseases can lead to the development of cold agglutinin disease.

292
Q

What does the I antigen bind weakly to?

A

The I antigen binds weakly to antibodies.

293
Q

What is the most severe form of malaria?

A

P. falciparum

294
Q

What causes all the clinical symptoms associated with malaria?

A

Rupture of infected erythrocytes, host cytokine response to infection, cytoadherence of infected erythrocytes to vascular epithelium

295
Q

What is tropical splenomegaly syndrome?

A

Chronic untreated non-falciparum malaria in people who live in areas of high intensity transmission

296
Q

What are the signs and symptoms of malaria?

A

Fever, headache, confusion, dizziness, weakness, nausea, vomiting, diarrhoea, loss of appetite, poor feeding in children, muscle/joint aches, cough in children, classical febrile paroxysms with chills, fevers, and sweats

297
Q

Who are the risk groups for complicated malaria?

A

Pregnant and post-partum women, children under 5, splenectomised people, elderly under 65, immunocompromised including HIV+

298
Q

What is the gold standard technique for laboratory confirmation of malaria?

A

Blood smear stained with Giemsa stain

299
Q

What is the recommended treatment for uncomplicated malaria in adults?

A

Artemether-lumefantrine or quinine plus doxycycline

300
Q

What is the recommended treatment for uncomplicated malaria in children under 5 and pregnant patients?

A

Artemether-lumefantrine or quinine plus clindamycin

301
Q

What is the recommended treatment for complicated malaria in adults and children?

A

IV artesunate followed by oral artemether-lumefantrine or IV quinine followed by artemether-lumefantrine or quinine plus doxycycline/clindamycin

302
Q

What is the most common non-falciparum malaria in South Africa?

A

P. ovale

303
Q

What is the recommended treatment for non-falciparum malaria?

A

Artemether-lumefantrine for extra-hepatic phases, primaquine for hepatic stage and radical cure; treat mixed infections as P. falciparum and add a course of primaquine if P. vivax or P. ovale is identified

304
Q

What is the laboratory diagnosis for malaria?

A

Blood smear (thick smear to make the diagnosis, thin smear to identify species), rapid diagnostic test detecting parasite antigen

305
Q

What are the four basic functions of antibodies?

A

Opsonisation, Complement fixation, Antibody dependent cellular cytoxicity, Neutralisation

306
Q

Which cells are responsible for phagocytosing parasites and infected red cells?

A

Dendritic cells and macrophages

307
Q

What is the role of Th1 CD4+ T cells?

A

Activating the cell-mediated wing of the immune system and activating antigen presenting cells

308
Q

How do T-cells kill infected cells?

A

By secreting perforin and granzyme

309
Q

What is the function of antibodies in P. falciparum?

A

Disrupting all stages of the lifecycle, promoting the clearance of infected red blood cells

310
Q

What are some factors that can inhibit dendritic cells?

A

Certain factors, especially haemozoin

311
Q

What is the role of CD4+ T cells in immunity to malaria?

A

Critical to immunity, potentiating the activity of cytotoxic CD8+ T cells

312
Q

What is the RTS,S vaccine targeting?

A

The sporozoite to prevent hepatocyte infection

313
Q

How is herd immunity achieved against malaria?

A

Stimulating the production of antibodies in the host to block parasite proliferation in mosquitoes

314
Q

What are the three distinct stages of Plasmodium falciparum in humans?

A

Pre-erythrocyte or hepatic stage, Erythroid asexual stage, Sexual stage

315
Q

What is the efficacy of the RTS,S vaccine in preventing severe disease?

A

About 29%

316
Q

What is the relationship between malaria immunity and individuals living in malaria-endemic areas?

A

These individuals develop semi-immunity to malaria, experiencing less severe infection compared to those living outside these areas

317
Q

How do mosquitoes and malaria parasites counteract control measures?

A

Mosquitoes become resistant to pesticides, parasites become resistant to anti-malarial drugs

318
Q

What is the potential problem with CD4+ T cells and the red blood cell?

A

The red blood cell does not express high levels of MHC 1, making it ‘invisible’

319
Q

What is the best way to elicit a potent immune response in controlled malaria infection?

A

By irradiating mosquitoes and allowing them to bite the individual

320
Q

What are the complications of severe malaria?

A

Overwhelming stimulation of pattern receptors, increased vascular permeability, disseminated coagulopathy, systemic organ dysfunction

321
Q

What are some types of abuse that migrants may face?

A

Murder, rape, sexual violence, extortion, kidnapping, degrading body searches, torture, and muggings.

322
Q

What are some risks associated with imprisonment and detention for migrants?

A

Risk of tuberculosis (TB) and reported cases of multi-drug resistant TB (MDR-TB) in detention centers.

323
Q

What are some mental health issues that migrants may experience?

A

Stress, depression, and trauma.

324
Q

How does mobility affect vulnerability to high-risk sexual behavior among migrants?

A

Mobility per se can make people vulnerable to high-risk sexual behavior, especially among migrant communities with high infection rates of HIV/AIDS.

325
Q

Why is it challenging to reach and provide interventions for migrant populations?

A

Mobility makes people more difficult to reach through classic interventions, and there is a lack of harmonized treatment regimes and protocols between different countries.

326
Q

What attitudes should health professionals have when working with migrant patients?

A

Courtesy, respect for human dignity, patience, empathy, and tolerance (as per the patient rights charter).

327
Q

What are some practical examples of adapting consultations and care for migrant patients?

A

Using translators or visual aids if no translator is available, tailoring treatment plans, providing detailed referrals, and managing patient expectations.

328
Q

What rights do refugees and asylum seekers have regarding healthcare?

A

Access to healthcare, choice of health services, confidentiality, informed consent, continuity of care, healthy and safe environment, participation in decision-making, treated by a named healthcare provider, refusal of treatment, a second opinion, and the right to complain about health services.

329
Q

What are some key barriers for migrants in accessing healthcare?

A

Structural/health system-related barriers, contextual barriers (cultural and communication), and behavioral/patient-related barriers (poor health-seeking behaviors, socio-economic factors, lack of orientation/induction to the healthcare system).

330
Q

What are the two populations of cells that exist within the blood islands?

A

Peripheral cells (endothelial cells) and core cells (haemocytoblasts)

331
Q

What is the thymus responsible for?

A

Maturation of T lymphocytes into immunocompetent T cells

332
Q

What role does thymosin play in the thymus?

A

Thymosin plays a role in the maturation process of T lymphocytes

333
Q

What are the two areas that make up the structure of the thymus?

A

Outer area (cortex) and inner area (medulla)

334
Q

Where does haematopoiesis begin in the embryo?

A

In the yolk sac of the embryo

335
Q

What is the chief site of blood cell production in the human embryo?

A

Foetal liver

336
Q

Which organs serve as minor sites of blood cell production?

A

Spleen, kidney, thymus, and lymph nodes

337
Q

What is the primary site of haematopoiesis throughout life?

A

Bone marrow

338
Q

What are the major blood components?

A

Erythrocytes, leukocytes, platelets, and plasma

339
Q

What does FBC stand for?

A

Full blood count

340
Q

What are the normal reference ranges for RBC count in men and women?

A

Men: 4.3-5.6 X10^12/L, Women: 3.9-4.9 X10^12/L

341
Q

What is anaemia?

A

Reduced circulating haemoglobin per unit volume of blood compared to the reference range

342
Q

How is haemoglobin measured in the FBC?

A

Converted to stable form (hemiglobincyanide) and measured using light transmittance

343
Q

Why is anaemia important?

A

It is a common global healthcare problem with significant morbidity and can indicate underlying diseases/disorders

344
Q

What is the formula for Hct (haematocrit)?

A

Hct = VolumeRBC/VolumeTOTAL

345
Q

What is MCV (mean cell volume)?

A

MCV is the ratio of Hct to RBC count

346
Q

What are the common causes of macrocytic anaemia?

A

Many causes

347
Q

What is the characteristic feature of megaloblastic anaemia?

A

Oval macrocytes

348
Q

What are the blood film findings associated with megaloblastic anaemia?

A

Nucleated RBCs, hypersegmented neutrophils

349
Q

Which vitamin deficiencies can cause megaloblastic anaemia?

A

Vitamin B12 or folate deficiency

350
Q

What is the shape of RBCs in sickle cell anaemia?

A

Sickle cell shape

351
Q

What problems can be caused by abnormal RBCs in sickle cell anaemia?

A

Tissue hypoxia due to obstruction of small vessels

352
Q

What are the characteristics of autoimmune haemolytic anaemia on a blood film?

A

Spherocytes, increased reticulocytes

353
Q

Which condition is associated with spherocytes and Coombs test negative?

A

Hereditary spherocytosis

354
Q

What is the most important condition associated with circulating fragments and anaemia?

A

Thrombotic thrombocytopenic purpura

355
Q

Which patient populations have unique reasons for anaemia?

A

Premature neonates, pregnant women, chronic renal failure patients, HIV patients, patients with severe hepatosplenomegaly

356
Q

What is the reticulocyte count percentage?

A

The percentage of all RBCs that are reticulocytes

357
Q

How can the reticulocyte count be corrected for the degree of anaemia?

A

Multiply by the patient’s hematocrit divided by a normal hematocrit

358
Q

What is the reticulocyte production index?

A

A correction for reticulocyte lifespan

359
Q

What is haemolytic anaemia?

A

A group of anaemias resulting from reduced RBC survival

360
Q

What are the causes of haemolysis?

A

Intrinsic RBC defects, loss of structural integrity of RBCs, external factors

361
Q

Where does extravascular haemolysis occur?

A

In the reticuloendothelial system, mainly spleen

362
Q

What is the site of haemolysis in intravascular haemolysis?

A

In the blood vessels

363
Q

How can haemolytic anaemias be classified?

A

Hereditary haemolytic

364
Q

How can mutations in stem cells affect bone marrow activity?

A

Mutations in stem cells can lead to increased bone marrow activity, which may lead to leukemia, lymphoma, myeloproliferative neoplasms, and other cancers.

365
Q

What are the potential outcomes if diseased stem cells can be repaired or replaced?

A

If diseased stem cells can be repaired or replaced, the underlying disease could potentially be cured.

366
Q

What are the components of a whole unit of donated blood?

A

A whole unit of donated blood consists of plasma, a buffy coat containing white blood cells and platelets, and red blood cells.

367
Q

What are the main proteins found in plasma?

A

Plasma contains proteins including clotting factors, immunoglobulins, fibrinogen, and albumin.

368
Q

Why are platelets important in blood?

A

Platelets are important for clotting and prevention of bleeding.

369
Q

What biomolecule is found in red blood cells and binds oxygen?

A

Red blood cells have hemoglobin, an iron-containing biomolecule that binds oxygen.

370
Q

What are antigens and where are they found?

A

Antigens are proteins found on the surface of red blood cells.

371
Q

How do individuals develop naturally occurring ABO antibodies?

A

By 3-6 months of age, the immune system will have been exposed to A and B-like antigens in exogenous sources, leading to the development of antibodies unless these antigens are present on the red cells.

372
Q

What are the four blood groups discovered by Karl Landsteiner?

A

The four blood groups discovered by Karl Landsteiner are A, B, AB, and O.

373
Q

What is the H antigen and its relation to the A and B antigens?

A

The H antigen is a precursor to A and B antigens. ABO genes code for enzymes that affect the outcome of the H antigen.

374
Q

What are the most common Rh antigens?

A

The most common Rh antigens are D, C, c, E, and e.

375
Q

What happens when IgG or IgM antibodies attach to specific RBC antigens?

A

When IgG or IgM antibodies attach to specific RBC antigens, they can cause agglutination and result in intra vascular or extra vascular hemolysis.

376
Q

What is the main cause of raised potassium levels in the blood?

A

Red cell cytoplasm releasing potassium

377
Q

Name three techniques to prevent raised potassium levels during blood collection.

A

Avoid using tiny needles, high vacuum, and drawing blood rapidly through long thin lines.

378
Q

What is methaemoglobin and why can’t it carry oxygen?

A

Methaemoglobin is oxidized ox Fe2+ to Fe3+ and cannot carry oxygen.

379
Q

What is the purpose of MetHb reductase in red blood cells?

A

To protect RBCs from oxidation.

380
Q

How does cyanide poisoning affect cytochrome oxidase and Met-Hb?

A

Cyanide binds to cytochrome oxidase and Met-Hb, causing methaemoglobin anaemia.

381
Q

Name two drugs that can cause methaemoglobin anaemia.

A

Local anaesthetics and nitrites.

382
Q

What are porphyrias?

A

Inherited defects of haem biosynthesis.

383
Q

What are the two types of precursors that build up in porphyrias?

A

Porphyrinogens and PBG (porphobilinogen) and d-ALA (delta-aminolevulinic acid).

384
Q

What are the symptoms of acute porphyric attacks?

A

Abdominal pain, sensory and motor neuropathy, autonomic neuropathy, CNS dysfunction, and hyponatremia.

385
Q

What should be given during acute porphyric attacks to shut down fatty acid oxidation?

A

Dextrose.

386
Q

What are the key diagnostic tests for acute intermittent porphyrias?

A

Measuring PBG (porphobilinogen) and d-ALA (delta-aminolevulinic acid) in urine.

387
Q

What are the management steps for acute porphyric attacks?

A

Make a diagnosis, stop haem synthesis by giving extra glucose, and correct hyponatremia.

388
Q

What is the process by which blood cells are formed in the body called?

A

Haematopoiesis

389
Q

Name one type of anaemia that may require the removal of damaged cells.

A

Megaloblastic anaemia or Sickle cell anaemia

390
Q

What is the term for an enlargement of the spleen?

A

Splenomegaly

391
Q

Which blood test is the most commonly ordered and provides clues to underlying disease processes?

A

Full Blood Count (FBC)

392
Q

What is the most immature precursor cell that gives rise to the production of blood cells called?

A

Haematopoietic stem cell

393
Q

How many bone marrow stem cells become 500 billion cells per day?

A

1 in 10,000

394
Q

What is the term for the production of red blood cells?

A

Erythropoiesis

395
Q

How long do red blood cells survive in circulation?

A

Approximately 120 days

396
Q

What is the main role of red blood cells?

A

Carrying oxygen in haemoglobin

397
Q

What is the term for the production of platelets?

A

Thrombopoiesis

398
Q

Where are megakaryocytes mainly found in the bone marrow?

A

Around blood vessels (perivascular)

399
Q

What cytokine stimulates the production of megakaryocytes?

A

Thrombopoietin (TPO)

400
Q

What are the three types of granulocytes?

A

Eosinophils, basophils, neutrophils

401
Q

What is the term for the production of lymphocytes?

A

Lymphopoiesis

402
Q

What are the three types of bone marrow failure syndromes mentioned?

A

Aplastic anaemia, myelodysplastic syndromes, and acute leukaemia

403
Q

What can stem cells give rise to?

A

All blood cells in the body

404
Q

What are the symptoms of anaemia?

A

Shortness of breath, weakness, palpitations, headaches, etc.

405
Q

What are the signs of anaemia?

A

Pallor of mucous membranes, tachycardia, splenomegaly, etc.

406
Q

What are the specific symptoms of iron deficiency anaemia?

A

Pica

407
Q

What are the specific symptoms of vitamin B12 deficiency anaemia?

A

Loss of proprioception and vibration sense

408
Q

What are the clinical features of anaemia?

A

Influenced by speed of onset, severity of anaemia, patient age, comorbidities, and factors affecting the O2 dissociation curve

409
Q

What are the classifications of anaemia?

A

According to RBC size and mechanism for reduced Hb

410
Q

What are some causes of microcytic anaemia?

A

Iron deficiency, mixed deficiency, thalassaemia

411
Q

What are some causes of normocytic anaemia?

A

Anemia of chronic disorders, megaloblastic (Vit B12/folate def), blood loss

412
Q

What are some causes of macrocytic anaemia?

A

Vitamin B12 and folate deficiency, myelodysplastic syndrome, hypothyroidism

413
Q

What is the role of reticulocytes in anaemia?

A

Marker for effective erythropoiesis, increased in haemolytic anaemia

414
Q

What are the characteristics of iron deficiency anaemia?

A

Microcytic, hypochromic, presence of pencil cells

415
Q

What is the most common type of microcytic anaemia?

A

Iron deficiency anaemia

416
Q

What are the maternal complications of thalassaemia?

A

Maternal complications are mostly fatal

417
Q

What is the treatment for thalassaemia?

A

Treatment includes blood transfusion or chelation as needed, bone marrow transplants, and monitoring for complications

418
Q

What is the genotype and phenotype of β/β0 thalassaemia?

A

Genotype: β/β0; Phenotype: Beta thalassaemia minor/trait, normal with sometimes mild anemia and microcytosis

419
Q

What are the major species of malaria?

A

The major species of malaria are P. falciparum, P. malariae, P. vivax, P. ovale, and P. knowlesi

420
Q

What is the most prevalent and severe form of malaria?

A

Plasmodium falciparum is the most prevalent form in Africa and is also the most severe form

421
Q

How does malaria disease manifest?

A

Malaria disease manifests with symptoms like headache, muscle pain, and photophobia, followed by paroxysms of chills and high fevers

422
Q

What are the severe complications of malaria?

A

Severe complications include cerebral malaria, placental malaria, and malaria-associated renal impairment and blackwater fever

423
Q

What is the role of the innate immune system in malaria?

A

The innate immune system recognizes non-mammalian molecular patterns in malaria and stimulates an inflammatory response

424
Q

What is the process of inflammation in malaria?

A

Inflammation in malaria involves activation of pathways that promote increased vessel permeability, pyrexia, pain, and swelling

425
Q

What percentage of malaria cases in 2020 were accounted for by Africa?

A

96%

426
Q

Which country in sub-Saharan Africa is an exception to malaria transmission?

A

Lesotho

427
Q

Which areas in South Africa have high malaria risk?

A

North-eastern Kwa-Zulu Natal, low altitude areas of Mpumalanga and Limpopo

428
Q

During which months does malaria transmission typically occur in South Africa?

A

September and May

429
Q

What is the term for accidentally transported mosquitoes to non-endemic areas transmitting malaria?

A

Odyssean malaria

430
Q

Which species of mosquito is the vector for malaria?

A

Female mosquito of the genus Anopheles

431
Q

What is the most important species of malaria in Africa?

A

P. falciparum

432
Q

What type of host are humans in the life cycle of malaria?

A

Intermediate host

433
Q

During which stage of the life cycle do merozoites infect new red blood cells?

A

Schizont stage

434
Q

Which species of malaria has the widest distribution in temperate and subtropical areas?

A

P. vivax

435
Q

What is the incubation period of P. falciparum?

A

10-21 days

436
Q

Which species of malaria can persist in hepatocytes as hypnozoites for months to years?

A

P. ovale

437
Q

Which species of malaria generally causes the mildest disease?

A

P. malariae

438
Q

What is the serious complication of P. malariae infection?

A

Nephrotic syndrome

439
Q

Which monkey malaria parasite can infect humans?

A

P. knowlesi

Anemia Case (1 decks)

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