Anaemia and Sickle Cell Disease Flashcards

1
Q

Define anemia

A

This is defined as a low haemoglobin concentration and may be due to either a low red cell mass or increased plasma volume

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2
Q

What is considered low HB concentration in females ?

A

<11.5g/dL

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3
Q

What is considered low Hb concentration in males?

A

<13.5g/dL

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4
Q

What are 6 symptoms of anaemia

A

Fatigue
Dizziness
Tinnitus
Dyspneoa
Palpitations
Chest pain (with pre existing CAD)

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5
Q

What Hb concentration is considered severe anaemia?

A

<8.0g/dL

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6
Q

List a few signs of severe anaemia that can be observed in the Cardiovascular Clinical Examination

A

Hyperdynamic Circulation signs
- Tachycardia
- Flow murmurs
- cardiac enlargement

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7
Q

List 4 types of anaemia in relation to the Mean Cell Volume

A

Low MCV- microcytic anemia
Normal MCV (normocytic anaemia)
High MCV (macrocytic anemia)
Haemolytic Anemias

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8
Q

What is the normal mean rbc cell volume

A

84-96fl

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9
Q

FUN QUESTION

How many fl make a litre

A

10 to the power of 15
1 000 000 000 000 000

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10
Q

Low MCV corresponds with a mean cell Hb (MCH) of what value?

A

<27pg

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11
Q

List 3 causes of Low MCV anaemia

A

Iron-deficiency anaemia
Thalassaemia
Sideroblast anaemia

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12
Q

List 6 causes of Normal MCV anaemia

A

Acute Blood Loss
Anaemia of chronic disease
Bone marrow failure
Renal Failure (low erythropoietin production)
Pregnancy
Hypothyroidism

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13
Q

What will serum iron, ferritin and total iron-binding capacity show in Thalassemia and Sideroblastic Anaemia

A

Iron increase
Ferritin increase
TIBC decrease

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14
Q

List 4 causes of high MCV (macrocytic anaemia)

A

B12 or folate deficiency
Alcohol excess/Liver disease
Reticulocytosis
Marrow infiltration

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15
Q

Define sickle-cell anaemia

A

This is an autosomal recessive disorder causing production of abnormal B globin chains.

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16
Q

What is the amino acid substitution in the gene coding for B chain in Sickle Cell Anaemia?

A

Glutamate is substituted by Valine at position 6 on chromosome 11

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17
Q

The substitution of glutamate on the B chain with valine at postion 6 results in the production of what type of Haemoglobin ?

A

HBS

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18
Q

What is the genotype for a sickle cell anaemia

A

HbSS

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19
Q

What is the genotype for sickle cell trait

A

HbAS

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20
Q

What is the phenotype for HbSS

A

Sickle cell disease

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21
Q

What is the phenotype for HbAS

A

Sickle-cell trait

22
Q

Under which conditions would a person with Sickle -cell trait cause symptoms/disabilty

A

Hypoxia: anaesthesia, high altitude

23
Q

Describe in one sentence the pathogenesis of HbS

A

HbS polymerizes when deoxygenated, causing RBCs to deform, producing sickle cells, which are fragile and haemolyse, and also block small vessels.

24
Q

What is the prevalence of Sickle Cell anaemia in African heritage

A

1:700

25
Q

Which tests are done to diagnose Sickle Cell disease

A

CBC : Hb = 6.0-9.0g/dL
inc. reticulocytes
U and E : inc. bilirubin
Sickle Solubility Test
Hb Electrophoresis: Gold standard

26
Q

what is the Gold standard for detecting sickle cell disease and why?

A

Hb Electropheresis

Confirms the diagnosis and distinguishes HbSS and HbAS states

27
Q

What is the disadvantage of the Sickle Solubility Test in diagnosing Sickle Cell Disease?

A

It does not distinguish between HbSS and HbAS

28
Q

List 3 crisis that can occur in Sickle Cell Disease

A

Vaso-occlusive crisis
Aplastic Crisis
Sequestration Crisis

29
Q

What triggers Vaso-occlusive crisis in anaemia

A

Cold
dehydration
infection
hypoxia

30
Q

Vaso-occlusive crisis often affects where in the body causing severe pain?

A

Marrow

31
Q

If <3yrs and hands are affected by the vaso-occlusive crisis, what is the result

A

Dactylitis

32
Q

CNS infarcts occur in 10% of children and can lead to

A

Stroke
seizures
cognitive defects

33
Q

In vaso-occlusive crisis what can be used to asses the risk of impending stroke

A

Doppler Ultrasonography

34
Q

What therapy/treatment can be done to prevent stroke in children with vaso-occlusive disease?

A

Transfusion, as the HbS is reduced

35
Q

What microb causes aplastic crisis in sickle cell disease persons ?

A

Parvovirus B19

36
Q

What is the effect of parvovirus B19 in perons with sickle celll disease?

A

Decreased marrow production, especially RBCs
(aplastic crisis)

37
Q

What is sequestration crisis?

A

Pooling of blood in the spleen +/- liver , with organomegaly, severe anaemia and hypovolemic shock.

38
Q

What is the management for patients with sequestration crisis?

A

Blood transfusion needed

39
Q

List 7 complications of sickle cell disease

A

Splenic infarct
Poor growth
Chronic Renal Failure
Gallstones
Retinal Disease
Iron Overload
Lung Damage

40
Q

At what age do splenic infarcts occur in children with sickle cell disease ?

A

<2yrs

41
Q

What is the main complication of splenic infarct in children with sickle cell disease

A

inc. susceptibility to infection

42
Q

How does Sickle Cell Disease lead to lung damage?

A

Hypoxia>fibrosis>pulmonary hypertension

43
Q

Lung damage secondary to sickle cell disease can be partially prevented by what therapy?

A

Incentive Spirometry

44
Q

What is the drug management for a person with frequent crisis in sickle cell disease?

A

Hydroxyurea/
Hydroxycarbamide (Siklos)

45
Q

What class of drug is Hydroxyurea?

A

Anti metabolites

46
Q

How does hydroxyurea assist in Sickle Cell Disease Crisis?

A

Hydroxyurea raises the amount of fetal
haemoglobin in red blood cells, thereby reducing
sickling.

47
Q

What are the 7 steps in management of sickle cell crises?

A

1)Analgesia eg. IV opiates

2)Crossmatch blood. CBC, reticulocytes, blood cx, mid stream urine.

3)Rehydrate with IV fluids and keep warm.

4) O2 by mask if SPO2 <95%

5)Broad spectrum antibiotics if Temp. >38oC

6)Measure PCV, reticulocytes, liver, and spleen bd

7) Give blood transfusion if HB or reticulocytes fall sharply

48
Q

What is Acute Chest Syndrome in sickle Cell Crises?

A

Entails pulmonary infiltrates involving complete lung segments, causing pain, fever, tachypnoea, wheeze, and cough.

49
Q

What are the chief causes of infiltrates in Acute Chest Syndrome in Sickle Cell Crisis?

A

Fat Embolism (from bone marrow)
Infection (with Chlamydia, Mycoplasma)

50
Q

What is the treatment of acute Chest Syndrome ?

A

O2
analgesia
broad spec. antibiotics
bronchodilators (salbutamol)

51
Q

What is sideroblastic anemia

A

If you have sideroblastic anemia, you have anemia from lack of red blood cells and too much iron in your system because your body’s not making use of iron in your red blood cells

52
Q

What is thalassemia

A

Thalassemia is an inherited (i.e., passed from parents to children through genes) blood disorder caused when the body doesn’t make enough of a protein called hemoglobin