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Haematology > Red Cells and Congenital Anaemia > Flashcards

Red Cells and Congenital Anaemia Flashcards

1
Q

What is anaemia and Sx

A

The reduction in red cells or their haemoglobin content

Sx 
Pallor
Fatigue
SOB
Chest pain
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2
Q

What can cause anaemia

A

Blood loss
Increased destruction of red cells
Lack of production or defective production

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3
Q

What substances are required for definite red cell production

A

Iron
B12
Folic acid
Erythropoeitin

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4
Q

What are substances are needed for red cell production

A 
Copper
Cobalt 
Manganese
Thiamine
Vit B,C,E 
A 
GM-CSF
Androgens 
Thyroxine
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5
Q

Where are red cells broken down

A

In the reticuloendothelial system extravacular
Can be done intravascular if damaged
Spleen = majority
Liver / LN / lungs

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6
Q

What are red cells (haem + globe) broken down into

A

Globin -> AA
Haem -> bilirubin (bound to albumin in plasma)
Iron is reutilised and binds to transferrin
Stored as ferritin in the liver

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7
Q

Is bilirubin conjugated or unconjugated

A

Unconjugated as not passed through liver

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8
Q

What are congenital causes of anaemia

A 
Defects in 
Red cell membrane 
Metabolic enzymes and pathways
Haemoglobin production (haemoglobinopathy) 
Leads to haemolysis
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9
Q

What pathways are involved in RBC formation and what enzymes are affected

A

Glycolysis to produce energy
Pentose phosphate shunt to prevent oxidative damage
G-6PD enzyme + pyruvate kinase

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10
Q

What diseases are associated with red cell membrane issues

A

Hereditary spherocytosis
Hereditary elliptocysos
Heriditary pyropoikilocytosis

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11
Q

What is hereditary spherocytosis

A

Autosomal dominant defects in structural proteins so removed faster by the spleen

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12
Q

What proteins are affected

A

Ankyrin / Band 3

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13
Q

What is the presentation of hereditary spherocytosis

What would cause abdominal pain

A

Variable
FTT
Anaemia
Jaundice + pigment gallstones due to increased bilirubin
- Can present with abdominal pain due to gall stone / splenic rupture
Splenomegaly
Chronic Sx but can have crisis e.g. in infection / parvovirus
If aplastic crisis = no increase in reticulocyte count

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14
Q

How do you Dx

A

Typical Hx, FH + spherocytes on film = Dx
Osmotic fragilited= +Ve
Raised unconjugated bilirubin
Reticulocytes + blurbing will be high
Electrophoresis / EMA binding test if atypical

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15
Q

How do you treat hereditary spherocytosis / follow up

A

Body compensates with lower Hb
Folic acid - higher requirement due to turnover
Transfusion if haemolysis increased in intercurrent illness
Splenectomy as main site of destruction

Follow up

  • FBC, SBR
  • Spleen size
  • USS gall bladder
  • general health
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16
Q

What does G6PD deficiency lead too

A

G6PD protects haemoglobin from oxidative damage so Increased oxidative damage
Protection against malaria

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17
Q

What type of inheritance of G6PD deficiency

A

X-linked

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18
Q

How do you diagnose G6PD

A

FBC
G6PD assay
Blood film - blister and bite cells / Heinz bodies

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19
Q

How does G6PD deficiency present

A

Intravascular haemolysis as structural damage in circulation
Anaemia
Jaundice + gallstones
Splenomehaly

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20
Q

Wha will intravascular haemolysis lead too

A

Haemoglobinuria which can damage kidneys

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21
Q

What are triggers to haemolysis in G6PD deficiency

A 
Infection
Acute illness e.g. DKA
Broad beans
Anti-malarial drug - check G6PD level 
Other drugs - sulphonamide / ciprofloxacin / trimethoprim / nitrofurantoin
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22
Q

What other enzyme deficiency is there and what does it cause

A

Pyruvate kinase
Leads to reduced ATP and increased 2,3-DPH
Anaemia / jaundice / gall stones

23
Q

What is haemoglobin made up of

A

Haemo = carries o2
Globin chains = determine type of Hb
2 alpha chains - 4 alpha genes so if mutation in one can still make good chain
2 beta chains - 2 beta genes so if mutation can’t make beta
Delta / gamma chains can take over if genes missing

24
Q

What does the haem in our blood look like

A

HbA (aaBB) = 97%
HbA2 (aaDD) = 2% - make if lose beta chains
HbF (aaYY) = <1% (high in fetal)
Should have NO sickle (aaSS)

25
Q

What leads to haem binding more oxygen

A

Exercise
Acidosis
Hyperthermia
Hypercapnia

26
Q

What has highest affinity fro oxygen

A

HbF as need to take oxygen from mother’s blood

27
Q

What is the function of haemoglobin

A

Delivery 02 to tissue and co2 to the lungs

28
Q

What are the haemoglobinopathies and how do you Dx

A

Autosomal RECESSIVE disorders of haemoglobin
Absent or reduced chain production but normal structure - thalassaemia
- Beta absent or reduced
- Alpha absent or reduced
Structutrally abnormal chains due to point mutation - sickle cell

Dx = electrophoresis

29
Q

What is sickle cell disease and what types can you get

A

Beta gene of HbA has sickle cell mutation leading to abnormal protein - HbS
Homosygotes have sickle cell disease
Heterozygoutes have trait (protective against malaria) which is why more common in Africa has selective advantage - asymptomatic unless at high altitude etc.

Hb in blood

  • HbA = 0%
  • HbA2 = 2%
  • HbF = 20%
  • HbS = 8-90%

Homozygous - HbSS

  • Inherited two abnormal copy of sickle
  • Classic sickle

Compound heterozygous - HbSc

  • Inherited one abnormal sickle but also another mutated recessive
  • Less severe

Combined thalassaemia

  • Inherited sickle gene (HbS) but also have beta-thalassaemia
  • Abnormal structure and reduced production
30
Q

What happens in sickle cell

A

When deoxygenated fully / placed under stress, sickle cell RBC polymerises and forms aggregated and keep sickle shape
Increased risk of haemolyis = haemolytic anaemia
Broken parts of RBC can get stuck in vessel = occlusion
RBC removed by spleen much faster - 20 instead of 120
Damage to blood vessel due to RBC breakdown and blockage

31
Q

What is the sickle cell crisis

A 
Endothelial activation 
Inflammation
Coagulation acitvated
Vasodilators - NO
Vaso-occlusion / blockage of small blood vessel
32
Q

Wha does sickle cell crisis cause and long term

Major = vaso-occlusion + haemolytic

A

Vaso-occlusive painful crisis causing ishchaemia (pain / fever = main Sx)

  • Bone - AVN
  • Hand and feet if <3 = dactylitis
  • CNS - STROKE IN CHILDREN etc (can be ischaemic or haemorrhage due to damaged vessel)
  • Priaprism
  • Acute chest syndrome
  • Renal infarction

Severe anaemia - normocytic normochromic
- Jaundice / fatigue

Severe infections

Sequestrian

  • Sickling when spleen / lungs cause pooling of blood
  • Can lead to hypovolaemic shock / abdominal pain / splenomegaly but as get older more likely atrophy
  • Enlarged liver and spleen as blood pools

Aplastic crisis - parovirus (Sudden fall in Hb)

Haemolytic crisis (rare)

Long term

  • Chronic multi-organ damage due to occlusion / damage
  • Chronic haemolytic normocytic anaemia
  • Splenic infarction and atrophy in early childhood so don’t get splenomegaly
  • Increased risk of infection / sepsis
  • Growth
  • Chronic renal failure
  • Gall stones
  • Lung damage
  • Stroke due to damage
  • Retinopathy
  • Pulmonary hypertension due to microvascular damage
33
Q

What does acute chest syndrome present with

A 
Either due to infection or vase-occlusive crisis 
Pulmonary infiltrates on CXR
Dyspnoea
Low sats
Fever 
Chest pain
34
Q

What causes increased infection and what type

A

Hyposplenism
Usually encapsulated organisms
Salmonella = typical but rare in real life

35
Q

What can precipitate crisis

A 
Hypoxia 
Infection
Dehydration
Cold exposure 
Pregnancy can stress more 
Can be well in between
36
Q

How do you Rx painful thrombotic crisis

A 
ADMIT 
Analgesia - often use high strength 
Bloods 
- FBC + relic, U+E, LFT
- X-match
- Sepsis screen / culture 
ECG + CXR + ABG 
Fluid 
Oxygen to stop polymerisation process 
Consider Ax or try to treat precipitant

Blood transfusion if Hb or reticulocyte fall sharply - guided by haematologist
Exchange transfusion if neuro complications

37
Q

How do you Rx chest crisis

A 
Resp support
O2 
Ax - macrolide and cephalosporin 
IV fluid
Analgesia
May need ventilation 
May need exchange transfusion

If someone comes in want to know

  • Sickle % and baseline Hb
  • Any recent complication / admission
  • Any disease modifying / exchange transfusion
38
Q

What is given as life long prophylaxis

A

Vaccinations as hyposplenism
Penicillin prophylaxis
Pneumococcal vaccine 5 yearly
Folic acid

39
Q

How do you Dx sickle cell

A

Most Dx at new-born screen

Hb electrophoresis
- Indirct to look for sickled Hb

Can do direct sequence of beta global gene to look for mutation

40
Q

What is general management

A

Avoid trigger
Ensure vaccines up to date
Ax prophylaxis
Blood transfusion
Disease modifying drug - hydroxycarbamiade / hydroxyurea - increases HbF which cannot sickle as no BB and improve RBC life-space
ALLOGRAFT bone marrow transplant can be indicated in young patient with specific complication e.g. stroke
Gene therapy
Have a low threshold for admission as hyposplenism can led to severe infections
- Temp >38
- Child with mild to mod pain
- Chest Sx

41
Q

What is thalassaemia

A

Reduced or absent global chain production due to mutations or deletions in alpha or B genes
Thalassaemia minor or trait if one or 2 chains missing
Major if 3 or all chains missing
Leads to chronic haemolytic and microcytic anaemia

Hb in blood

  • HbA = 0%
  • HbA2 = 2%
  • HbF = 95%
42
Q

What are 4 types of thalassaemia

A

Homozygous alpha zero if mutation in all 4 alpha gene
Beta thalassaemia major (homozygous betA) if mutation in both beta genes
Non transfusion depedent
Beta thalassaemia trait / minor if mutation in one

Major = no chain produced
Minor = reduced amount
43
Q

How does homozygous alpha zero present

A

Hydrops fettles Incompatible with life as no alpha chains

44
Q

What is Beta thalassaemia major

A

Absence of beta chain as not inherited
Still have alpha which can joint with delta or gamma to make foetal haemoglobin
Most severe

45
Q

When do you become transfusion dependent / symptomatic

A

When fatal Hb drops and gamma exchanged for beta at around 4 months

46
Q

How does it present

A 
Microcytic anaemia with symptoms quite severe
FTT
Expansion of ineffective marrow to compensate for chronic anaemia leading to 
- Bone deformities
- Fractures
- Skull and facial bossing  
HSM as spleen deals with RBC's
Jaundice
Gall stones
Can cause heart failure
47
Q

How do you Dx

A

Screen in pregnancy
FBC, MCV, film
Film = target cell
Reticulocyte = raised but not enough to be normocytic
Hb electrophoresis - low HbA or HbF = DIAGNOSTIC
Ferritin levels normal

48
Q

How do you Rx

A

Monitor FBC / complications
Chronic transfusion 4-6 weeks
Splenectomy
Bone marrow transplant = curative

49
Q

What is risk of transfusion and how do you monitor

A

Iron overload - present like haemochromatosis
Cause heart / liver / endocrine failure
Monitor with ferritin levels

50
Q

How do you Rx

A

Iron chelation - deferoxamine

51
Q

What is beta thalassaemia minor / trait

A

Carrier state- AR
Usually no symptoms
Microcytic anaemia with mild Sx

52
Q

What is seen on film

A

Hypochromic Microcytic

53
Q

What are all congenital anaemia’s

A

Haemolytic so increased reticulocyte count

Sickle cell RBC lifespan can be as small as 5 days

54
Q

If have splenectomy what is needed

A

Flu and pneumococcal immunisation
Penicillin
Alert

Haematology (13 decks)

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