Paeds hematology Flashcards
pathophysiology ITP
Antibodies are directed against the glycoprotein IIb/IIIa or Ib-V-IX complex. It is an example of a type II hypersensitivity reaction.
when is management indicated for ITP? what are options?
If the platelet count is very low (e.g. < 10 * 109/L) or there is significant bleeding.
- oral/IV corticosteroid eg prednisolone
- IV immunoglobulins
- platelet transfusions can be used in an emergency (e.g. active bleeding) but are only a temporary measure as they are soon destroyed by the circulating antibodies
Philadelphia chromosome t(9;22)
chronic myeloid leukemia
65+
Most common leukemia in children? triad?
Acute lymphoblastic leukemia
anaemia, thrombocytopenia, neutropenia
Genetics and inheritance sickle cell
autosomal recessive
abnormal variant called haemoglobin S (HbS)
abnormal gene for beta-globin on chromosome 11
Definitive diagnosis sickle cell disease
haemoglobin electrophoresis
Management sickle cell
General:
- avoid dehydration and triggers
- vaccines inc pneumococcal polysaccharide vaccine every 5 years
- abx prophylaxis eg penicillin V
- hydroxycarbamide (stimulate fetal HbF)
- blood transfusion
- bone marrow transplant can be curative
vaso-occlusive pripism:
- aspiration of blood
splenic sequestration:
- blood transfusion and fluid resus
aplastic:
- blood transfusion
acute chest:
- abx and antivirals
- blood trans
- ventilation
reticulocyte count sickle cell anaemia?
high (needing to constantly make new rbc)
may be low in aplastic crisis
normal is 0.45–1.8 percent
cause of aplastic crisis sickle cell
parovirus B19
reticulocytes may be low
gold standard investigations sickle cell
Haemaglobin electrophoresis
blood film sickle cell
A blood film shows target cells and Howell-Jolly bodies.
Blood reuslts rickets
Low calcium, low phosphate, high ALP and high PTH
Inheritance of thalassemia?
autosomal recessive
What does FBC show thalassemia?
microcytic anaemia
Investigations thalassmeia
Full blood count shows a microcytic anaemia.
Haemoglobin electrophoresis is used to diagnose globin abnormalities.
DNA testing can be used to look for the genetic abnormality
Pregnant women in the UK are offered a screening test for thalassemia at booking.
On what chromosome is defect that causes alpha thalassemia?
chromosome 16
On what chromosome is defect that causes beta thalassemia?
chromosome 11
beta thalassemia minor pathophysiology, presentaiton and management
Patients with beta thalassaemia minor are carriers of an abnormally functioning beta globin gene. They have one abnormal and one normal gene.
Thalassaemia minor causes a mild microcytic anaemia and usually patients only require monitoring and no active treatment.
Thalasssemia intermedia - pathophysiology, presentation, management
Patients with beta thalassaemia intermedia have two abnormal copies of the beta-globin gene. This can be either two defective genes or one defective gene and one deletion gene.
Thalassaemia intermedica causes a more significant microcytic anaemia and patients require monitoring and occasional blood transfusions. If they need more transfusions they may require iron chelation to prevent iron overload.
Thalassemia major - pathophysiology, presentation, manageement
Patients with beta thalassaemia major are homozygous for the deletion genes. They have no functioning beta-globin genes at all. This is the most severe form and usually presents with severe anaemia and failure to thrive in early childhood.
Thalassaemia major causes:
Severe microcytic anaemia
Splenomegaly
Bone deformities
Management involves regular transfusions, iron chelation and splenectomy. Bone marrow transplant can potentially be curative.
What is haemophilia A caused by
deficiency in factor VIII
What is haemophilia B caused by
Deficiency in factor IX
Diagnosis of haemophilia
bleeding scores
coagulation factor assays
genetic testing.
Management of haemophilia
Infusions of the affected factor (VIII or IX) - either prophylacticly or in response to bleeding
Desmopressin to stimulate the release of von Willebrand Factor
Antifibrinolytics such as tranexamic acid
Most common causes of anaemia in older children?
Iron deficiency anaemia secondary to dietary insufficiency. This is the most common cause overall.
Blood loss, most frequently from menstruation in older girls
Worldwide, a common cause of blood loss causing chronic anaemia and iron deficiency is?
management?
helminth infection, with roundworms, hookworms or whipworms.
This can be very common in developing countries and those living in poverty. It is more unusual in the UK.
Treatment is with a single dose of albendazole or mebendazole.
what is fanconi anaemia?
autosomal recessive aplastic anaemia (pancytopaenia)
what does high total iron binding capacity indicate?
iron deficicency
A total iron-binding capacity (TIBC) test measures the blood’s ability to attach itself to iron and transport it around the body. A transferrin test is similar. If you have iron deficiency anaemia (a lack of iron in your blood), your iron level will be low but your TIBC will be high.
relationship between iron and stomach acid
Iron is mainly absorbed in the duodenum and jejunum. It requires the acid from the stomach to keep the iron in the soluble ferrous (Fe2+) form. When there is less acid in the stomach, it changes to the insoluble ferric (Fe3+) form. Therefore, medications that reduce the stomach acid, such as proton pump inhibitors (lansoprazole and omeprazole) can interfere with iron absorption.
Microcytic anaemia
Thalamssemia
Anaemia of chronic disease
Iron deficiency
Lead posioning
Sideroblastic anaemia
Normocytic anaemia
Anaemia of chronic disease
Aplastic
Acute blood loss
Haemolysis
Hypothyroid
Macrocytic anaemia
megaloblastic macrocytic
- folate, DNA
normoblastic
- alcohol
- liver disease
What is volwillebrand disease
not good at clotting
easy prolonged bleeding
eg gums, periods etc
most common cause of abnormal bleeding
autosomal dominant
Management von willebrand disease
desmopressin
von willebrand infusion
inheritance von willebrand disease
autosomal dominant
jaundice and anaemia in parovirus B19
spherocytosis
diagnostic test g6pd deficiency
G6PD enzyme assay around 3 months after an acute episode of hemolysis
RBCs with the most severely reduced G6PD activity will have hemolysed → reduced G6PD activity → not be measured in the assay → false negative results
things that can ppt a crisis in g6pd
FACS
anti-malarials: primaquine
ciprofloxacin
sulph- group drugs: sulphonamides, sulphasalazine, sulfonylureas
infections
broad (fava) beans
diagnosis of spherocytosis
family history + blood results :MCHC high, high reticulocytes, spherocytes
if ambiguous: EMA binding test and the cryohaemolysis test
for atypical presentations : electrophoresis analysis of erythrocyte membranes is the method of choice
out of g6pd and spherocytosis, which is x linked? which is autosomal dominant
g6pd - X linked
spherocytosis - autosomal dominant
out of g6pd and spherocytosis, which affects people of northen european descent, which affects people of african and mediterranean descent?
g6pd - african and med
spherocytosis - north europe
neonatal jaundice is often seen
intravascular haemolysis
gallstones are common
splenomegaly may be present
Heinz bodies on blood films. Bite and blister cells may also be seen
gdpd deficiency
failure to thrive
jaundice, gallstones
splenomegaly
aplastic crisis precipitated by parvovirus infection
degree of haemolysis variable
MCHC elevated
spherocytes on blood film
spherocytosis
bite and blister cells on blood film
g6pd deficiency
Management of spherocytosis
Folate supplementation
splenectomy
gall stone removal
presentation alpha thalassemia major
hydrops fetalis
incompatible with life
cabot rings
perinicious anaemia
pathophysiology TTP
ADAMTS-13 deficiency
inherited or autoimmune
PResentation TTP
Typically adult females
fever
fluctuating neuro signs (microemboli)
microangiopathic haemolytic anaemia
thrombocytopenia
renal failure
Presentation TTP
Typically adult females
fever
fluctuating neuro signs (microemboli)
microangiopathic haemolytic anaemia
thrombocytopenia
renal failure
