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Essential Haematology > 5. Haemolytic Anemias: Membranopathies And Enzymopathies > Flashcards

5. Haemolytic Anemias: Membranopathies And Enzymopathies Flashcards

1
Q

List two types of Hereditary Hemolytic anemia that are caused by membrane defects

A

Hereditary spherocytosis HS

Hereditary elliptocytosis

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2
Q

What is the most common hereditary hemolytic anemia in Northern Europeans

A

Hereditary spherocytosis HS

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3
Q

List seven steps for the pathogenesis of Hereditary spherocytosis

A 
Deficient or defective membrane proteins
Membrane instability
Lack of deformability
Mature erythrocytes become spherocytic
Splenic trapping and phagocytosis
Extravascular hemolysis
Splenomegaly (Due to this virus it takes shape of these red blood cells they are unable to pass through microvascular spleen vessels and they die prematurely there)
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4
Q

What is the most common inheritance pattern of hereditary spherocytosis

A

Autosomal dominant

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5
Q

Anemia due to the hereditary spherocytosis presents at which age

A

At any age from infancy to old age

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6
Q

What are the three main clinical presentations of hereditary spherocytosis

A

Autosomal dominant inheritance
Splenomegaly
Anemia
Jaundice

(Some presents with pigment call stones)

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7
Q

List five laboratory features of hereditary spherocytosis including relative Reticulocyte, MCV and MCHC values

A 
Variable anemia (severity of anemia is usually similar within families)
MCV normal or decreased
MCHC normal
Blood film shows microspherocytes
Reticulocytes I usually 5 to 20%
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8
Q

Read this case and diagnose the patient

A nine year old female jaundiced for several years Is admitted to the hospital at age 18 months and was transfused. Mother has no history of jaundice, father not available. Elder sister died at age 14 after operation for gallstones.

Physical examination shows peel mucosa, moderate jaundice, probable spleen 5 cm below left coastal margin

Results//
Hemoglobin 7.5 g/dL
MCV 71.0 FL
MCHC 36 g/dL
Direct Coombes test negative
Osmotic fragility increased
A

Hereditary spherocytosis

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9
Q

What is the osmotic fragility test

A

It is a test used to measure erythrocyte resistance to hemolysis while being exposed to different levels of dilution of a saline solution

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10
Q

What is the purpose of Osmotic Fragility in testing for Hereditary Spherocytosis

A

Confirms the presence of HS

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11
Q

What does the Osmotic Fragility test for Hereditary Spherocytosis show

A

Increased

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12
Q

What is the principle form of treatment for hereditary spherocytosis

A

Splenectomy (avoided before age 4)

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13
Q

Splenectomy is required for hereditary spherocytosis treatment list three immunizations necessary for this treatment to take place

A

Haemophilus influenza
Streptococcus pneumoniae
Neisseria meningitidis

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14
Q

True or false most hereditary elliptoCytosis patients are clinically silent

A

True

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15
Q

What causes hereditary elliptocytosis

A

Abnormal spectrin

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16
Q

Which enzyme deficiency leads to defective red cell metabolism

A

Glucose-6-phosphate dehydrogenase deficiency G6PD

17
Q

What is the function of G6PD

A

Reduces NADP the while oxidizing Glucose 6 Phosphate

NADP is needed to reduce glutathione (which maintains RBCs cell structure)

18
Q

What is the result of Glutathione deficiency

A

Renders the red cell susceptible to oxidant stress

19
Q

What is the inheritance of Glucose-6-phospate dehydrogenase deficiency

A

Sex linked, affecting males

And carried by females

20
Q

Female carriers of G6PD deficiency show what amount of G6PD

A

1/2

21
Q

Female G6PD deficiency heterozygotes have an advantage of resistance to which disease

A

Falciparum Malaria

22
Q

What are the main races affected by G6PD deficiency

A

West Africa
Mediterranean
Middle East
South East Asia

23
Q

What are the clinical features of G6PD deficiency

A

Usually asymptotic

Acute heamolytic anemia in response to oxidant stress

Neonatal Jaundice

Congenital Non-spherocytic haemolytic anemia (rare)

24
Q

What are some conditions for ocidant stress that induce Acute Haemolytic Anemia in G6PD deficient patients

A

Drugs
Fava beans
Infections

25
Q

What causes acute anemia in G6PD deficient patients

A

Rapidly developing intravascular haemolysis with haemoglobinuria

26
Q

What is the blood count of the G6PD deficient patient between crises

A

Normal

27
Q

What tests are performed to diagnose G6PD deficiency

A

Direct enzyme assay on RBCs

28
Q

What is the presentation of the RBCs of a G6PD deficient patient on a blood film

A

Contracted or Fragmented cells
‘Bite’ cells/ ‘blister’ cells

((Which have heinz bodies removed by the spleen)

((Heinz bodies are oxidized, denatured Haemoglobein))

29
Q

What are Heinz Bodies

A

Heinz bodies are oxidized, denatured Haemoglobein

30
Q

What is the treatment for G6PD deficiency

A
  • the offending drug (drug/source of oxidant stress)
  • ## underlying infection treated

Essential Haematology (14 decks)

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