Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DTMH Block 4 > Tropical haematology > Flashcards

Tropical haematology Flashcards

1
Q

What is haemolytic anaemia?

A

Anemia due to shortened RBC survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is haemolytic anemia classified?

A

Intra vs extravascular
Inherited vs acquired

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the clinical presentation of haemolytic anemia?

A

Pallor
Jaundice
Gallstones
Splenomegaly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can haemolysis be confirmed with laboratory markers?

A

Elevated
- indirect bili
- LDH
- reticulocyte count
Decreased
- haptoglobin
Urine haemosiderin *intravascular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the differences in the mechanism of intravascular vs extravascular haemolysis?

A

Intravascular = mechanical or complement mediated
Extravascular = immune mediated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the differences in the causes of intravascular vs extravascular haemolysis?

A

Intravascular = microangiopathies (DIC, TTP, HUS) vs macroangiopathies (mechanical heart valve)
Extravascular = autoimmune disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the differences in the hemolysis of intravascular vs extravascular haemolysis?

A

Intravascular = hemolysis in plasma
Extravascular = RBCs removed by RES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the differences in the haptoglobin level of intravascular vs extravascular haemolysis?

A

Intravascular = low haptoglobin
Extravascular = normal haptoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the differences in the RBC shape of intravascular vs extravascular haemolysis?

A

Intravascular = non-spherocytic
Extravascular = spherocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the differences in the iron loss of intravascular vs extravascular haemolysis?

A

Intravascular = iron loss via haemosiderin excretion via kidneys
Extravascular = no iron loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name examples of genetic haematological disorders

A

Thalassemias
Sickle cell
G6PD
Haemoglobinopathies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain what haemoglobin is

A

Iron-containing oxygen transporting metalloprotein in RBC
Heme - iron at centre with hydrophobic pocket
Globin - 4 chains (2 alpha 2 non-alpha) stabilised by hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many alpha genes are on chromosome 16?

A

4 alpha genes (2 per chromosome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many beta globin genes are on chromosome 11?

A

5 functional genes
2 pseudogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the globin chain composition of haemoglobin A?

A

Alpha
Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the globin chain composition of haemoglobin A2?

A

Alpha
Delta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the globin chain composition of haemoglobin F?

A

Alpha
Gamma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the normal ratio of haemoglobin in an adult?

A

HbA >95%
HbA2 2-3%
HbF <1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the difference in a thalassemia vs a haemoglobinopathy?

A

Thalassemia = decreased production of normal globin chain
Haemoglobinopathy = production of abnormal globin chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which thalassemia is rare in Africa?

A

Beta thalassemia (except Liberia and parts of North Africa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Discuss the clinical features of a thalassemia

A

Hypochromic microcytic anemia
Tissue hypoxia
Skull deformities (frequent ear and sinus infections)
Pathological fractures
Stunted growth
HSM (causes secondary thrombocytopenia and leucopenia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the difference in point mutations in beta thalassemia?

A

Beta - = absence of beta chain production from locus
Beta positive = partial deficiency of beta chain production from locus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What will the difference be in homozygous vs heterozygous beta thalassemia?

A

Homo - severe anemia
Hetero - mild anemia, elevated HbA2 on electrophoresis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which ratio is highly suggestive of a thalassemia trait?

A

MCV/RCC <12

25
Q

Discuss the genetics of alpha thalassemia

A

Normal genotype = aa/aa
1. 1 gene deletion (aa/-a) silent carrier
2. 2 gene deletion (a-/a- OR –/aa) mild anemia
3. 3 gene deletion (–/a-) Hb H disease
4. 4 gene deletion (–/–) Hb Barts hydrops fetalis = lethal

26
Q

Why is 3 gene deletion called Hb H disease?

A

RBCs contain unstable beta 4 chains
Beta 4 = Hb H

27
Q

What is the difference in time of presentation for beta thalassemia vs alpha thalassemia?

A

Alpha - neonate
Beta - 3 to 6m

28
Q

Discuss the management of alpha thalassemia HbH disease

A

Folic acid supplement
Avoid oxidant drugs
Low iron diet +/- iron chelation therapy
Splenectomy if severe
Monitor closely in pregnancy

29
Q

What is the mechanism of sickle cell disease?

A

Change of glutamine to valine (B chain, 6th aa) -> in deoxygenated form, Hb starts to polymerise and precipitate -> becomes rigid -> removed by spleen -> can clump in spleen, fingers, bone

30
Q

How high is the heterozygote frequency of sickle cell in Africa?

A

40% (protective from falciparum malaria)

31
Q

Which sickle cell patients are susceptible to falciparum malaria?

A

Homozygous

32
Q

Discuss the clinical presentation of sickle cell disease

A

Children - pain, infection
Adults - chronic organ damage
3 types of crisis
- vaso-occlusive crisis
- aplastic crisis
- sequestration crisis
Acute chest syndrome
Recurrent strokes
Leg ulcers
Bone infarctions, OM
Haematuria
Priapism
Cholestasis
HSM
Delayed puberty
Retinal neovascularisation

33
Q

What is vast-occlusive crisis?

A

Hypoxia
Infection anywhere in body
Painful

34
Q

What is aplastic crisis?

A

Dramatic fall in Hb
Parvovirus B19
Folate deficiency (pregnancy)

35
Q

What is sequestration crisis?

A

Sudden, massive blood pooling in enlarged spleen -> hypotension
Occurs in children

36
Q

How is sickle cell disease diagnosed?

A

Hb 5-11
Normochromic normocytic anemia
Sickle and target cell morphology
Increased WCC
Increased plt
Electrophoresis (HbS present , HbF increased, HbA2 increased)

37
Q

To which organisms are you predisposed to infection in sickle cell disease?

A

Encapsulated (s.pneumo, h.influenza, n. meningitidis)
Salmonella (OM)
If iron overloaded -> yersinia

38
Q

Name precipitating factors for sickle cell disease symptoms

A

High altitudes
Hypoxia (infarction)
Low temperature (vasoconstriction)
Low pH (acidosis)
Infections (dehydration, acidosis, hypoxia)

39
Q

What is sickle cell trait?

A

Less than half the Hb in each RBC is HbS - asymptomatic and only sickle if severe hypoxia or hyperosmolarity

40
Q

Discuss management of sickle cell disease

A

Keep extremities warm
Folate
Hydroxyurea in patients with >3 crises per year
Vaccinations
Penicillin prophylaxis <6yo
Stem cell transplant

41
Q

Which biomarker must be monitored with hydroxyurea use?

A

White cell count

42
Q

Discuss the management of acute vase-occlusive crisis

A

Hydration
Analgesia (avoid pethidine)
Oxygen
Consider transfusion if severe sx anemia

43
Q

Discuss the management of acute chest syndrome

A

Antibiotics
Incentive spirometry
Maintenance hydration only

44
Q

Discuss the management of strokes

A

Exchange transfusion

45
Q

What is HbC?

A

2 normal alpha chains and 2 variant beta chains
Lysine replaces glutamic acid -> unstable Hb -> precipitates in RBCs and forms crystals -> decreased deformability and increased blood viscosity

46
Q

What is HbE?

A

Point mutation in beta chain
Change of glutamic acid to lysine
Mild haemolytic with microcytosis and target cells

47
Q

How is G6PD diagnosed?

A

Fluorescent spot test
Spectrometry

48
Q

Discuss classic TTP

A

Deficiency of von Willebrand factor cleaving protease -> circulating von Willebrand multimers and platelet microthrombi -> red cells fragment on micro thrombi -> microangiopathic hemolytic anemia

49
Q

What is the pentad of TTP?

A

Fever
Fragments
Low plt
Renal dysfunction
Neurological symptoms

50
Q

Discuss management of TTP

A

Exchange transfusion/plasmaphoresis
Avoid giving plt
Treat until LDH normalises

51
Q

Which malignancies are associated with EBV?

A

Burkitt lymphoma
Hodgkin lymphoma
Primary CNS
Primary effusion

52
Q

Which diseases are associated with HTLV-1?

A

Adult T cell leukemia/lymphoma
HTLV1 associated myelopathy
Uveitis
Myositis
Dermatitis

53
Q

What are the features of babesios?

A

Fever
Mild HSM
Haemolytic anemia

54
Q

Discuss babesios

A

Disease of animals
Confused with malaria (no pigment production or RBC changes)
Thrombocytopenia
Normal to low WCC

55
Q

Discuss trypansosomiasis

A

African sleeping sickness
Tsetse fly

56
Q

Discuss the haematological abnormalities seen in trypanosomiasis

A

Dilutional anemia
Leucocytosis
Thrombocytopenia

57
Q

Discuss leishmaniasis

A

Transmitted by phlebotamine sandfly

58
Q

Discuss the haematological abnormalities seen in leishmaniasis

A

Normocytic normochromic anemia
Pancytopenia (hypersplenism)
Thrombocytopenia

59
Q
A

DTMH Block 4 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions