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TCA 11 - Anaemia > Haemolytic anaemias > Flashcards

Haemolytic anaemias Flashcards

1
Q

What is haemolytic anaemia?

A

Anaemia due to the destruction of premature RBCs before their normal lifespan of 120 days

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2
Q

Where can haemolysis occur?

A

Intravascular -> in the circulation
Extravascular -> in the reticuloendothelial system
Macrophages, liver, spleen and bone marrow

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3
Q

What are signs of increased red cell breakdown?

A
  • MCV normal or increased
  • Increased bilirubin
  • Increased urobilinogen
  • Increased serum LDH (lactate dehydrogenase)
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4
Q

What are signs of increased red cell production?

A

Increased reticulocytes (large, immature RBCs)

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5
Q

What suggests extravascular haemolysis?

A

Splenomegaly

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6
Q

What suggests intravascular haemolysis?

A
  • Increased free plasma Hb released from RBCs
  • Methalbuminaemia
  • Decreased plasma haptoglobinuria
  • Haemoglobinuria
  • Haemosiderinuria
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7
Q

What investigations would you order of haemolytic anaemia?

A 
•	FBC
•	Reticulocytes
•	Bilirubin
•	LDH
•	Haptoglobin
•	Urinary urobilinogen
•	Blood film 
•	Specific
      Coomb’s test
      EMA-binding
      Glucose-6-phosphate dehydrogenase level
      Haemoglobin identification (HPLC)
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8
Q

What are congenital causes of haemolytic anaemia?

A

o RBC membrane (hereditary elliptocytosis, hereditary spherocytosis, hereditary stomatocytosis)
o RBC enzyme deficiencies (G6PD, pyruvate kinase)
o RBC haemoglobin disorders (thalassaemia, sickle cell disease)

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9
Q

What are the acquired causes of haemolytic anaemia?

A

o Autoimmune haemolysis (AIHA)
o Microangiopathic haemolytic anaemia (HUS, TTP, DIC)
o Drugs, infections, toxins
o Copper deficiency (Wilson’s disease)

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10
Q

What is elliptocytosis?

A

Autosomal dominant

Red cells are elliptocytic in shape

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11
Q

What is hereditary spherocytosis?

A

Autosomal dominant

inherited abnormalities of red cell membrane proteins

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12
Q

What does hereditary spherocytosis often present with?

A
  • Neonatal jaundice

- Gallstones -> cholecystectomy and splenectomy

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13
Q

How do you diagnose hereditary spherocytosis?

A
  • Family Hx present in 75% of cases
  • FBC
  • Reticulocyte count
  • Blood film
    Micro-spherocytes and polychromatic macrocytes

If there are none of the above:
- EMA-binding
Weak fluorescence

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14
Q

What is hereditary stomatocytosis?

A
  • Autosomal dominant
  • Many red cells have mouth-like slits of central pallor
  • Abnormality with sodium pump
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15
Q

What is glucose-6-phosphate dehydrogenate (G6PD) deficiency?

A
  • X-linked

- ‘Bite’ cells

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16
Q

What are the symptoms of glucose-6-phosphate dehydrogenate (G6PD) deficiency?

A

Sudden onset of:
o Feeling unwell and lack energy
o Become pale and yellow in colour have a backache
o Passing dark coloured urine (Hb that has leaked through glomerulus)

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17
Q

What must patients avoid in glucose-6-phosphate dehydrogenate (G6PD) deficiency?

A

Food

  • Fava beans
  • Broad beans

Drugs

  • Many anti-malarial drugs
  • Aspirin (large doses)
  • Chloramphenicol
  • Dapsone
  • Phenylhydrazine
  • Nalidixic acid
  • Nitrofurantoin
  • Vitamin K

Precipitants
-Henna

18
Q

What is pyruvate kinase deficiency?

A
  • Autosomal recessive

- ‘Sputnik cells’ with protruding spikes

19
Q

What is sickle cell disease?

A
  • Autosomal recessive
  • Beta globin variant
    HbAS -> carriers/sickle cell trait
    HbSS -> Homozygous
20
Q

Which groups is sickle cell disease most common in?

A

African patients

21
Q

How is sickle cell anaemia diagnosed?

A
  • Normal MCV

- Normocytic RBCs with sickle cells

22
Q

Why are blood transfusions not required in sickle cell anaemia?

A

Oxygen dissociation curve if sickle Hb is shifted to the tight and oxygen is more readily released into tissues

23
Q

What is a sickle cell crisis?

A

Small blood vessels are occluded by sickle shaped cells which cause infarction of the tissues.

24
Q

What is a vaso-occlusive (painful) sickle crisis?

A

Small blood vessel are occluded:

  • Bone marrow
  • Kidney
  • Brain (stroke)
  • Spleen
25
Q

What is an aplastic sickle crisis and how do you treat it?

A

Due to parvovirus B19 with sudden reduction in marrow production

  • Blood transfusion
  • Self-limiting
26
Q

What is a sequestration sickle crisis and how do you treat it?

A

Blood pooling in the spleen +/- liver with organomegaly, severe anaemia and shock

  • Blood transfusion
  • Splenectomy
27
Q

What is acute chest syndrome in sickle cell crisis and what causes it?

A

Fever/ respiratory symptoms with new infiltrates on X-ray

Causes:

  • Vaso-occlusion
  • Infection
28
Q

How can repeated cases of acute chest syndrome lead to pulmonary HTN?

A

Hypoxia -> fibrosis -> pulmonary HTN

29
Q

How do you manage chronic sickle cell disease?

A
  • Hydroxycarbamide
  • Pneumococcal vaccine
  • Prophylactic penicillin V/erythromycin
  • Folic acid
  • Stem cell transplantation
30
Q

What does Hydroxycarbamide do?

A

Stimulates HbF which prevents crises

31
Q

How do you manage crises?

A
  • IV analgesics (opiates) within 30 mins of arriving at hospital
  • Crossmatch blood
  • Septic screen
  • IV fluids
  • Keep warm
32
Q

How do you manage beta thalassaemia major?

A
  • Blood transfusion
  • Iron chelation (remove access iron from the body)

Cure -> stem cell transplantation

33
Q

When would you start iron chelation?

A

When ferritin >1000ug/L to avoid neuro and skeletal toxicity

34
Q

What can you use for iron chelation?

A

Deferoxamine

  • IV
  • > 12 hours of subcutaneous infusions up to 5X per week
  • Painful
  • Poor compliance

Desferasirox

  • Oral
  • Once daily dose
35
Q

What are the types of autoimmune haemolytic anaemia (AIHA)?

A
  • Warm

- Cold

36
Q

What does a blood film look like with warm autoimmune haemolytic anaemia (AIHA)?

A

Micro-spherocytes and polychromatic macrocytes

37
Q

How do you diagnose autoimmune haemolytic anaemia (AIHA)?

A

Coombs
- DAT
The DAT is positive for IgG in warm AIHA and for complement in cold AIHA

38
Q

What does the blood slide look with cold autoimmune haemolytic anaemia (AIHA)?

A

Clumps of red cells agglutinated by the presence of cold agglutins

39
Q

What causes warm autoimmune haemolytic anaemia (AIHA)?

A 
o	Rheumatoid diseases e.g., SLE
o	Lymphoma
o	Chronic lymphatic leukaemia
o	Drugs (cephalosporins)
o	Ovarian teratoma
40
Q

How do you treat warm autoimmune haemolytic anaemia (AIHA)?

A

Steroids

41
Q

What causes cold autoimmune haemolytic anaemia (AIHA)?

A

o EBV
o Mycoplasma pneumonia
o Ulcerative colitis

TCA 11 - Anaemia (5 decks)

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