8- Paediatric Haematology and Oncology Flashcards
Anaemia
Background
- Low haemoglobin in the blood
- Result of underlying disease
pathophysiology of anaemia
- Hb is a protein found in RBC
- transports oxygen from the lungs to cells of the body
- iron is an essential ingredient in creating Hb
types of anaemia
microcytic anaemia
normocytic anaemia
macrocytic anaemia
causes of microcytic anaemia
Thalassaemia
Anaemia of chronic disease
Iron deficiency
Lead poisoning
Sideroblastic anaemia
causes of macrocytic anaemia
Anaemias where the average red cell size is greater than normal (increased MCV)
Megaloblastic
* B12 def
* Folate def
Normoblastic
* Blood cancers
* Alcohol
* Reticulocytes
* Hypothyroidism
* Liver disease
* Azathioprine
causes of normocytic anaemia
(2As and 2Hs)
- Acute blood loss
- Anaemia of chronic disease
- Aplastic anaemia
- Haemolytic anaemia
- Hypothyroidism
general causes of anaemia in children
- physiologic anaemia of infancy
- anaemia of prematurity
- blood loss
- haemolysis
- twin twin transfusion (blood unequally distributed between twins that share a placenta)
symptoms of anaemia
Generic symptoms of anaemia:
- Tiredness
- Shortness of breath
- Headaches
- Dizziness
- Palpitations
- Worsening of other conditions
There are symptoms specific to iron deficiency anaemia:
- Pica describes dietary cravings for abnormal things such as dirt and can signify iron deficiency
- Hair loss can indicate iron deficiency anaemia
signs of anaemia
Generic signs of anaemia:
- Pale skin
- Conjunctival pallor
- Tachycardia
- Raised respiratory rate
Signs of specific causes of anaemia: - Koilonychia refers to spoon shaped nails, which can indicate iron deficiency
- Angular chelitis can indicate iron deficiency
- Atrophic glossitis is a smooth tongue due to atrophy of the papillae and can indicate iron deficiency
- Brittle hair and nails can indicate iron deficiency
- Jaundice occurs in haemolytic anaemia
- Bone deformities occur in thalassaemia
normal range of Hb
- Depends on age
- Varies significant for the first 6 months as a the child transitions from fetal to adult Hb and adapts to taking oxygen via their lungs rather than placenta
- At puberty values between males and females varies due to menstruation
investigating anaemia
1) FBC
- Hb
- MCV
2) Blood film
3) Reticulocyte cunt
4) Ferritin
5) B12/folate
6) Bilirubin
7) Direct coombs test (autoimmune haemolytic anaemia)
8) Haemoglobinopathies
how can reticulocyte count be helpful
The presence or absence of reticulocytosis ( has the marrow responded normally?)
–> Would expect increase in reticulocyte if marrow was working normally
Reticulocytes
- Immature red blood cells (those which just been released from marrow into blood)
- Slightly LARGER than mature RBC so increase reticulocyte number will increase MCV
- No nucleus, some RNA
- 1% of all RBC
- Take 1 day to mature
Physiologic Anaemia of Infancy
- There is a normal dip in haemoglobin around six to nine weeks of age in healthy term babies.
- High oxygen delivery to the tissues caused by the high haemoglobin levels at birth cause negative feedback.
- Production of erythropoietin by the kidneys is suppressed and subsequently there is reduced production of haemoglobin by the bone marrow.
BASICALLY: The high oxygen results in lower haemoglobin production.
Anaemia of Prematurity
Premature neonates are much more likely to become significantly anaemic during the first few weeks of life compared with term infants.
The more premature the infant, the more likely they are to require one or more transfusions for anaemia. This becomes more likely if they are unwell at birth, particularly with neonatal sepsis.
Premature neonates become anaemic for a number of reasons:
* Less time in utero receiving iron from the mother
* Red blood cell creation cannot keep up with the rapid growth in the first few weeks
* Reduced erythropoietin levels
* Blood tests remove a significant portion of their circulating volume
Haemolytic disease of the newborn
Pathophysiology
- is a cause haemolysis (red blood cells breaking down) and jaundice in the neonate.
- It is caused by incompatibility between the rhesus D antigens on the surface of the red blood cells of the mother and fetus.
- When a woman that is rhesus D negative (does not have the rhesus D antigen) becomes pregnant, we have to consider the possibility that the fetus will be rhesus D positive (has the rhesus D antigen).
- It is likely at some point in the pregnancy the blood from the fetus will find a way into her bloodstream.
- When this happens, the fetal red blood cells display the rhesus D antigen.
- The mother’s immune system will recognise the rhesus D antigen as foreign and produce antibodies to the rhesus D antigen.
- o The mother has then become sensitised to rhesus D antigens.
- Usually, this sensitisation process does not cause problems during the first pregnancy (unless the sensitisation happens early on, such as during antepartum haemorrhage).
- During subsequent pregnancies, the mothers anti-D antibodies can cross the placenta into the fetus.
- If that fetus is rhesus positive, these antibodies attach themselves to the red blood cells of the fetus and causes the immune system of the fetus to attack its own red blood cells.
- This leads to haemolysis, causing anaemia and high bilirubin levels.
investigations for haemolytic disease of the newborn
Investigations
- Direct coombs test (DCT) can be used to check for immune haemolytic anaemia
Causes of anaemia in older children
The key causes of anaemia in older children are:
- Iron deficiency anaemia secondary to dietary insufficiency. This is the most common cause overall.
- Blood loss, most frequently from menstruation in older girls
Rarer causes of anaemia in children include:
- Sickle cell anaemia
- Thalassaemia
- Leukaemia
- Hereditary spherocytosis
- Hereditary eliptocytosis
- Sideroblastic anaemia
Management of anaemia
- Depends on cause
- Iron deficiency - iron supplementation
- If severe- blood transfusion
Management of anaemia
- Depends on cause
- Iron deficiency - iron supplementation
- If severe- blood transfusion
Disseminated intravascular coagulation
Background
- Pathological activation of coagulation that occur in response to a variety of severe disease
–>Type of microangiopathic haemolytic anaemia - Thrombo-haemorrhagic condition
Pathophysiology DIC
- Pathological activation of coagulation due to trigger causes numerous microthrombi are formed in the circulation
- Leads to consumption of clotting factors and platelets and a haemolytic anaemia