Brainscape's Knowledge GenomeTM

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


See full index

Case 11: Anaemia > Haemolytic anaemia > Flashcards

Haemolytic anaemia Flashcards

1
Q

What is haemolytic anaemia?

A

A number of conditions that result in the premature destruction of RBCs.
Presents with acute or subacute development of fatigue or jaundice, and may include orthostasis and mild splenomegaly.
NB: Usually macrocytic anaemia, with↑reticulocyte count and jaundice with unconjugated hyperbilirubinaemia

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

What indicated haemolytic anaemia?

A

Anaemia, reticulocytosis, low haptoglobin, high LDH and high indirect bilirubin suggest haemolysis.

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

What does Coomb’s test do?

A

Differentiates immune from non-immune aetiologies.

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

Causes of haemolytic anaemia?

A

Hereditary-
Inherited RBCs defects (membrane)- hereditary spherocytosis, elliptocytosis (pyropoikilocytosis)
Enzyme deficiencies- G6PD deficiency, Pyruvate kinase deficiency.
Abnormal Hb production- sickle cell anaemia, thalassaemia
Acquired-
Immune- Autoimmune (warm or cold reacting antibodies, drug-induced, autoimmune)
Non-immune- infection, trauma (like malignant HTN), HELLP syndrome in pregnancy, mechanical prosthetic heart valves, march haemolysis, thermal injury and osmotic lysis, hypersplenism and liver disease.

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

Signs & symptoms of haemolytic anaemia?

A 
Pallor 
Jaundice 
Fatigue 
Shortness of breath 
Dizziness 
Splenomegaly 
Active infections 
Episodic dark urine 
Triggered by exposure to cold
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Risk factors of haemolytic anaemia

A 
Autoimmune disorders 
Lymphoproliferative disorders 
Prosthetic heart valve 
Family origin in the Mediterranean 
Middle East 
Sub-Saharan Africa
Southeast Asia 
FHx of haemoglobinopathy or RBC membrane defects 
Paroxysmal nocturnal haemoglobinuria
Thermal injury
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tests and investigations of haemolytic anaemia

A 
FBC (low Hb) 
MCHC (increased) 
Reticulocyte count 
Peripheral smear 
Unconjugated bilirubin 
LDH 
Haptoglobin 
Urinalysis 
Direct antiglobulin test (DAT or Coombs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Coombs test?

A

It tests for antibodies to RBCs.

There’s indirect and direct Coombs test.

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

What is the Indirect Coombs test?

A

This is the test used to cross match blood for suitability for transfusion.
A positive test means the tested donor red cells are incompatible and should not be given as a transfusion.
Blood sample from donor and recipient’s serum (containing antibodies), are obtained and mixed together.
Antihuman antibodies (Coombs reagent) are added to the mixture.
If RBCs agglutinate, the test is positive.

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

When is indirect Coombs test used?

A

Prenatal testing for pregnant women.

Testing blood prior to a transfusion.

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

What is the direct Coombs test?

A

This test is done much less often and detects
antibody to patient’s own serum causing an autoimmune haemolytic anaemia.
Blood sample from patient with immune-mediated haemolytic anaemia is washed to
extract RBCs.
RBCs incubated with antihuman antibodies (Coomb’s reagent).
If RBCs agglutinate, the test is positive

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

When is direct Coombs test used?

A

Used to identify haemolytic anaemia.

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

Differentials of haemolytic anaemia?

A

Anaemia due to blood loss
Underproduction anaemia
Transfusion reaction.

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

Management of haemolytic anaemia?

A

Once the diagnosis of haemolytic anaemia has been determined, a haematological
consultation is warranted.

All aetiologies of haemolytic anaemia require some degree of supportive care- supportive care includes transfusions and folate supplementation.

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

What is hereditary spherocytosis?

A

autosomal dominant, commonest inherited RBC disorder in northern Europeans.
RBCs are less deformable and get trapped in the spleen, causing extravascular haemolysis and splenomegaly.
Blood film shows micro-spherocytes and polychromatic macrocytes
(reticulocytes), with no areas of central pallor

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

Diagnosis of hereditary spherocytosis?

A

EMA-binding test is gold standard but if family history + blood film + FBC results correlate, it is not required.

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

Complications of hereditary spherocytosis

A

Neonatal and adult jaundice
Chronic haemolysis
Increased risk of gallstones from increased bilirubin

18
Q

Management of hereditary spherocytosis?

A

Regular folic acid supplementation, often splenectomy required.

19
Q

What is hereditary elliptocytosis?

A

Hereditary elliptocytosis
(pyropoikilocytosis) –autosomal dominant,
1:2000
incidence. Not clinically significant except in homozygotes
Also known as ovalocytosis.
In most cases treatment is not necessary.
In the most severe variants, folic acid, red cell transfusion and splenectomy (after the age of 5) may be required. Patients should be monitored during events known to precipitate haemolysis.

20
Q

Pathophysiology of hereditary elliptocytosis?

A

a group of disorders of the red blood cell (RBC) membrane that are characterized by elliptical-shaped erythrocytes (elliptocytes) and shortened RBC survival.
Unlike normal RBCs, which repeatedly and momentarily assume an elliptical shape to negotiate through capillaries but then regain their biconcave discoid shape after they pass through the microcirculation, the RBCs in HE lack the elastic recoil necessary for returning to the discoid shape and eventually assume the fixed characteristic morphology of elliptocytes, with a decreased surface-to-volume ratio.
These elliptocytes are not as deformable as normal RBCs and are eventually trapped and removed by the spleen; this manifests as haemolytic anaemia.

21
Q

What is hereditary stomacytosis?

A

Hereditary stomatocytosis is characterized by excessively water-laden erythrocytes.
The extremely high influx of Na+(sodium) and water from the plasma exceeds the loss of cellular K+ (potassium ion) and the resulting swollen red cells show a unique combination of large size (high mean corpuscular volume [MCV]), low mean corpuscular hemoglobin concentration (MCHC), and osmotic sensitivity in the osmotic fragility test.
No other condition shows this unique combination. Blood smears feature stomatocytes, or a mixture of stomatocytes and spherocytes.

22
Q

What is G6PD deficiency?

A

X-linked recessive disease.
Blood film shows bite-cells
and blister-cells, after removal of Heinz bodies (denatured Hb) from RBCs.
May also show contracted RBCs.

23
Q

What does G6PD deficiency precipitated by?

A

Precipitated by:
Drugs–aspirin, primaquine, sulphonamides, nitrofurantoin, vitamin K
Exposure – broad beans/favism, moth balls, henna
Infection

24
Q

Diagnosis of G6PD deficiency

A

Enzyme assay for G6PD levels >8 weeks after crisis (as young RBCs may have enough enzyme so results normal)

25
Q

Management of G6PD deficiency?

A

Avoid precipitants and transfuse blood if severe.

26
Q

What is pyruvate kinase deficiency?

A

Autosomal recessive disease.
↓ATP production causes↓RBC survival.
Presents with neonatal jaundice, later chronic haemolysis with splenomegaly ± jaundice.
Blood film shows “Sputnik” cells, with spiky
protrusions.
Diagnosis: Enzyme assay

27
Q

Treatment of pyruvate kinase deficiency?

A

Often not needed, but splenectomy may help.

28
Q

What is autoimmune haemolysis (AIHA)?

A

Mediated by autoantibodies causing extravascular haemolysis and spherocytosis.

29
Q

How many types of AIHA?

A

Warm AIHA

Cold AIHA

30
Q

What is warm AIHA?

A

IgG-mediated binds to RBCs at body temperature (37 deg).
Tx: Steroids or immunosuppressants, ± splenectomy. Prednisolone 1mg/kg OD mane, weaning off slowly. Give omeprazole 20mg OD for gastroprotection.

31
Q

What is cold AIHA?

A

IgM-mediated, binds to RBCs at low temperatures, activating cell surface complement.
Causes chronic anaemia made worse by cold, accompanied by Raynaud’s
phenomenon or acrocyanosis.
Paroxysmal cold haemoglobinuria –
polyclonal anti-P autoantibody binds to RBC surfaces in the cold.
Acute PCH tends to be transient and self-limited; chronic PCH is managed by treating any
underlying infection.
Tx: Keep patient warm. Chlorambucil may help.

32
Q

Causes of AIHA?

A 
Most are idiopathic (primary AIHA)
Secondary causes:
Warm AIHA: lymphoproliferative disease
(chronic lymphocytic leukaemia,
lymphoma), drugs
e.g. cephalosporins, autoimmune disease e.g. SLE, ovarian teratoma
Cold AIHA: May follow infection e.g. EBV, Mycoplasma pneumonia, syphilis.
Ulcerative colitis
33
Q

Tests of AIHA

A

FBC, peripheral smear, serum bilirubin,
LDH, haptoglobin, urine haemoglobin.
-bilirubin,↑urinary urobilinogen,↓plasma haptoglobin,↑LDH,
haemosiderinuria, methemalbumiaemia, spherocytosis, reticulocytosis
-Direct Coombs test (would be positive for both warm and cold)

34
Q

What is haemolytic uraemic syndrome?

A

This is characterised by triad of haemolytic anaemia, acute kidney failure (uraemia) and thrombocytopenia.

35
Q

What is the cause of haemolytic uraemic syndrome?

A

Most common cause of AKI in childhood, usually triggered by infectious dysentery from Shiga toxin-producing E. coli, called STEC-HUS.
The inherited form (resulting in chronic excessive activation of complement) is called atypical
HUS.

36
Q

Treatment of haemolytic uraemic syndrome?

A

Treatment is generally supportive, with dialysis as needed.

Platelet transfusion is contraindicated.

37
Q

What is the thrombotic thrombocytopenic purpura?

A

Autoantibodies inhibit metalloproteinase ADAMTS13, which normally cleaves vWF multimers into smaller units.
The autosomal recessive form is called Upshaw-
Schulman syndrome.

38
Q

Causes of thrombotic thrombocytopenic purpura

A

Idiopathic autoimmunity

Drugs- antivirals, quinine, ciclosporin, tacrolimus, clopidogrel, prasugrel, hormone-altering drugs.

39
Q

Treatment of thrombotic thrombocytopenic purpura

A

Plasmapheresis is first-line, with corticosteroids and other immunosuppresants added

40
Q

What is Warring-Blender syndrome?

A

Caused by defective prosthetic heart valve.
RBCs have been injured due to excess turbulent flow, resulting in a low-grade mechanical haemolytic anaemia.
Blood film shows marked RBC fragmentation with multiple sharp edges, and small fragmented cells

Case 11: Anaemia (6 decks)

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