Haematology

Question 1

What is the management for Von Willebrands?

Answer 1

Tranexamic acid for mild bleeding
desmopressin (DDAVP): raises levels of vWF by inducing release of vWF from Weibel-Palade bodies in endothelial cells
factor VIII concentrate

Question 2

What are the haemoglobin values of a neonate until 12 years?

Answer 2

Neonate <140g/L
1-12 months <100 g/L
1-12 years <110 g//L

Question 3

What is the most common form of nutritional deficiency and why?

Answer 3

Iron deficiency anaemia, because iron forms haemoglobin and therefore if there is not enough iron there is reduced haemoglobin causing anaemia.

Question 4

What are the RF for iron deficiency anaemia?

Answer 4

Preterm, low birth weight infants & multiple births, excessive breast feeding (>6 months), delayed introduction to solids, excessive cows milk (low iron content and poorly absorbed). Adolescent females are at risk of IDA due to growth spurt and menstruation and low iron diets (vegan, poverty, fad diets).

Question 5

What are the MCV values for a normocytic, micro and macrocytic anaemia?

Answer 5

Normo -80-100 MCV.
Micro<80 MCV,
Macro >100 MCV

Question 6

Name different types of microcytic anaemia?

Answer 6

IDA, anaemia of chronic disease and the thalassaemias (all smaller)

Question 7

Name the different types of macrocytic anaemia?

Answer 7

Folate deficiency, pernicious anaemia (B12), alcoholism, drugs such as methotrexate and zidovudine.

Question 8

Name the different types of normocytic anaemia?

Answer 8

Acute blood loss, anaemia of chronic disease and haemolytic anaemias (sickle cell).

Question 9

What does MCV mean?

Answer 9

The volume of the average red blood cell in a given blood sample that is found by multiplying the hematocrit by 10 and dividing by the estimated number of red blood cells

Question 10

What are the three types of anaemia?

Answer 10

That due to blood loss, due to less RBC production, or due to more RBC breakdown. (just to clarify)

Question 11

What is the most common cause of IDA?

Answer 11

Inadequate intake, prolonged and excessive consumption of cow’s/breast milk- low iron containing (formula contains supplemented iron & is therefore ok!!), late introduction to iron containing solids.

Question 12

What are the other causes of IDA?

Answer 12

Malabsorption- coeliac disease/IBD. Also blood loss!

Question 13

What are the rare blood loss causes of IDA?

Answer 13

Meckel’s diverticulum, oesophagitis, secondary to NSAIDs, tumours, cysts, intestinal parasites eg hookworm.

Question 14

Recap: what is meckels diverticulum?

Answer 14

Symptomatic lesions usually present before two years of age. It is often referred to by the rule of 2’s; 2% of the population, within 2 feet of the ileocecal valve, 2 inches in length, tow types of heterotopic Mucosa, and presentation before the age of two.

Question 15

What are the clinical features of IDA (may be nonspecific as children can adapt to low Hbs).

Answer 15

Pallor, lethargy, breathlessness, poor/slow feeding, some may develop pica….

Question 16

What is pica?

Answer 16

Pica is characterized by an appetite for substances that are largely non-nutritive. Eg. eating pencils, soil etc in order to gain more iron.

Question 17

What is seen on the blood film in IDA?

Answer 17

Low MCV <80, (high number of abnormally small RBCs), microcytic anaemia (small RBCs), hypo chromic RBCs (pale and colourless) and decreased ferritin (meaning low iron stores).

Question 18

What is the management for IDA?

Answer 18

Give 5mg/kg of elemental iron/day. eye sytron or niferex (these do not stain teeth like other iron preparations)

Question 19

When should haem levels be checked when supplementation started?

Answer 19

After 5-10 days, and if normal continue treatment for 3 months in order to replenish iron stores.

Question 20

If Hb levels do not improve following supplementation, what should be screened for?

Answer 20

Thalassaemia trait

Question 21

Which foods should you avoid in toddlers due to inhibition of iron uptake and absorption?

Answer 21

Cow’s milk, tea (tannin inhibits iron uptake), high-fibre foods (phyate inhibits iron absorption- if you just pooh everything out iron can’t be absorbed).

Question 22

What is haemophilia? (genetically)

Answer 22

X-linked autosomal recessive clotting disorder

Question 23

Which factor is deficient in haemophilia A and B?

Answer 23

Factor 8 & 9 respectively.

Question 24

Because haemophilia is an X-linked disorder, what does this mean?

Answer 24

It primarily affects males

Question 25

What are the clinical features of haemophilia?

Answer 25

Rare to present in neonates, most cases present after infant begins to mobilise, causing intracranial bleeds etc. May present with prolonged bleeding after circumcision!. Other features are easy bruising, bleeding into joints, IM bleeds (may lead to compartment syndrome, nerve compression, ischaemic contracture. Also Intracranial bleeds following minor head trauma.

Question 26

What are the investigations for haemophilia?

Answer 26

Increased APTT, decreased factor 8 or 9 (duh)

Question 27

How do you manage haemophilia?

Answer 27

You can give prophylaxis of IV factors (through portacath) or you can treat with recombinant factors following a major bleed.

Question 28

What is the prognosis for haemophilia?

Answer 28

Excellent prognosis, normal life expectancy.

Question 29

What is HSP? What triad of symptoms does it cause?

Answer 29

SMALL vessel vasculitis associated with IgA complexes. it causes arthritis, colicky abdo pain & palpable, papular purpuric rash. Also most common vasculitis in childhood and normally in prepubescent males. (also it may have been preceded by a viral or bacterial infection of throat, airways etc)

Question 30

Just to confirm, what type of rash is seen in HSP?

Answer 30

Palpable, papular purpuric (non-blanching) rash.

Question 31

What are the investigations for HSP?

Answer 31

FBC, U&Es, urine dipstick

Question 32

How do you treat HSP?

Answer 32

NSAIDs will help arthritic symptoms, corticosteroids for abdo pain and arthritis may speed up recovery. Also test for nephritis/nephritic syndrome as these have worse prognosis (HTN and decreased renal function). (most will completely resole in 6 weeks).

Question 33

What is sickly cell (genetically)?

Answer 33

Autosomal RECESSIVE haemoglobinopathy caused by inheritance of one or two HbS genes.

Question 34

How does HbS form?

Answer 34

It forms as a result of mutation in chromosome 11, causing an abnormal Beta-globin and in turn an abnormal Hb.

Question 35

What has become the most common genetic abnormality found in children in the UK?

Answer 35

Sickle cell- found in 1 in 2000. Most common in patients who’s parents are black, originating from tropical africa or the caribbean.

Question 36

What is the pathophysiology for sickle cell?

Answer 36

In utero, the fetus contains a different structure of Hb known as fetal Hb (HbF/Hbgamma). This molecule contains 2 alpha and 2 gamma subunits. As the infant reaches the end of their first YEAR of life, their foetal Hb is replaced by adult Hb known as HbA, this has 2 alpha and 2 beta subunits. In sickle cell, the gamma units of HbA are affected.

Question 37

RECAP on sickle cell….

Answer 37

Normally, humans have haemoglobin A, which consists of two alpha and two beta chains, haemoglobin A2, which consists of two alpha and two delta chains, and haemoglobin F, consisting of two alpha and two gamma chains in their bodies. Of these, haemoglobin F dominates until about 6 weeks of age. Afterwards, haemoglobin A dominates throughout life. In people diagnosed with sickle cell disease, at least one of the beta-globin subunits in hemoglobin is replaced with hemoglobin S. In sickle cell anemia, a common form of sickle cell disease, hemoglobin S replaces both beta-globin subunits in hemoglobin.

Question 38

What is the most severe form of sickle cell?

Answer 38

HbSS, these patients are homozygous (2 S’s), meaning virtually all of their haemoglobin is HbS. They have small amounts of HbF but not HbA as both beta subunits are mutated.

Question 39

What is the HbSC disease?

Answer 39

This is when infected children inherit one HbS and one HbC (HbC is a different mutation of beta Hb). This means that these children also have no HbA due to no normal beta gene.

Question 40

What is sickle beta-thalassaemia?

Answer 40

This is when affected children inherit one HBS and one beta-thalasaemia trait from the other. These individuals also do not have a normal beta gene.

Question 41

What is the sickle trait?

Answer 41

These individuals inherit one HbS from one parent and one normal Hb from another meaning approx 40% of their Hb is HbS. Due to this they have an increased resistance to malaria. These people do not have sickle cell but they can pass it to their offspring. This is asymptomatic and only identified after blood tests.

Question 42

How is the ‘sickle shape’ created?

Answer 42

Hb polymerises with RBCs to form rigid, tubular spiral bodies that deform RBCs into a sickle shape. These RBCs have a decreased life span due to their shape and become trapped and occult BVs causing ischaemia in organs or bones -exacerbated by low o2, dehydration & cold.

Question 43

When does sickle cell manifest itself?

Answer 43

Clinical manifestation of sickle cell is delayed until 6 months of age, as this is when most of the Hb gamma (HbF) is replaced by HbA (which contains the abnormal beta-globin)

Question 44

What are the symptoms of SC?

Answer 44

Anaemia from chronic haemolysis (normocytic), increased susceptibility of infection due to hyposplenism and chronic spleen ischaemia due to micro infarction.

Question 45

What are the long-term problems with sickle cell?

Answer 45

Short stature and delayed puberty, stroke and cognitive problems, adenotonsillar hypertrophy (causing sleep apnoea which can cause hyperaemia with faso-occlusive crisis and/or stroke, cardiac enlargement (from CHRONIC ANAEMIA), HF, renal dysfunction (may exacerbate enuresis because of inability to concentrate urine), pigment gallstones, leg ulcers.

Question 46

How do you manage sickle cell?

Answer 46

Children should be immunised and given oral penicillin due to increased risk of infection particularly with strep pneumoniae and HiB to functional asplenia. Also daily folic acid is advised due to increased demand as a result of chronic haemolytic anaemia.

Question 47

What is the prognosis for sickle cell?

Answer 47

It usually causes premature death due to severe complications- around 50% will die before 40. Death is usually due to infection, 3% in childhood.

Question 48

How can screening be carried out for SC?

Answer 48

CVS if parents would like to know, neonatal screening is available in the form of a guthrie test- a heel prick offered to all babies.

Question 49

What is the sickle cell crisis/vaso-occulsive crisis?

Answer 49

Common and painful; sickled RBCs occlude vessels and cause ischaemic injury and pain. Commonly affects limb bones and spine- most serious type of acute chest syndrome leading to severe hypoxia and need for mechanical ventilation and emergency transfusion.

Question 50

How can sickle cell crisis be prevented/minimised?

Answer 50

Reducing exposure to the cold, dehydration and excessive exercise. May also be caused by hypoxic events such as labour and delivery.

Question 51

What is the treatment for sickle cell?

Answer 51

Oral and IV analgesia, infection with antibiotics, exchange transfusion required for acute chest syndrome. Bone marrow transplant is the only cure but can only be carried out if the child has a HLA-identical sibling. Cure rate is 90%.

Question 52

What is thalassaemia?

Answer 52

A haemoglobinopathy that causes haemolytic anaemia due to reduced or absent HbA. It occurs due to a mutation in either the alpha or beta subunits and causes impaired oxygen carriage.

Question 53

What is alpha-thalassaemia?

Answer 53

Major has 4 alpha gene mutations resulting in sever anaemia and death in either utero or within the first hours of life.
Minor has 3 alpha gene mutations and results in mild to moderate anaemia.
Alpha thal trait has 1 or 2 gene mutations which is usually asymptomatic or can result in hypochromic MICROcytic anaemia (may be confused with IDA)

Question 54

What is beta-thalassaemia?

Answer 54

Major-more severe, HbA cannot be produced

Minor- milder form with some HbA/HbF

Question 55

Who are thalassaemias most common in?

Answer 55

Mediterranean and indian populations.

Question 56

What are the clinical features of thalassaemia?

Answer 56

Severe anaemia which is transfusion dependant from 3-6 months, jaundice and FTT and growth failure.

Question 57

How do you manage thalassaemia?

Answer 57

Beta-thalassaemia is fatal without transfusion- patients given lifelong transfusions.

Question 58

What can chronic transfusions cause?

Answer 58

Iron overload- cardiac failure and liver cirrhosis, diabetes osteoporosis etc.

Question 59

RECAP on thal….

Answer 59

There are two main types, alpha thalassemia and beta thalassemia. The severity of alpha and beta thalassemia depends on how many of the FOUR genes for alpha globin or two genes for beta globin are missing.
The thalassemias are classified according to which chain of the hemoglobin molecule is affected. In α-thalassemias, production of the α globin chain is affected, while in β-thalassemia, production of the β globin chain is affected.

The β globin chains are encoded by a single gene on chromosome 11; α globin chains are encoded by two closely linked genes on chromosome 16. Thus, in a normal person with two copies of each chromosome, two loci encode the β chain, and four loci encode the α chain. Deletion of one of the α loci has a high prevalence in people of African or Asian descent, making them more likely to develop α-thalassemia. β-Thalassemias are not only common in Africans, but also in Greeks and Italians.

Question 60

What does von willebrand factor do and therefore how does it present?

Answer 60

It binds to factor 8 and prevents its clearance from the plasma, it causes epistaxis, bleeding from the mucosa, menorrhagia, spontaneous joint bleeding etc.