Paeds haematology Flashcards
Why is iron required in the body?
The bone marrow requires iron to produce haemoglobin
There are several scenarios where iron stores can be used up and the patient becomes iron deficient:
Dietary insufficiency. This is the most common cause in children.
Loss of iron, for example in heavy menstruation
Inadequate iron absorption, for example in Crohn’s disease
Iron is mainly absorbed in the
duodenum and jejunum
Conditions that result in inadequate iron absorption
*
Conditions that result in inflammation of the duodenum or jejunum such as coeliac disease or Crohn’s disease can also cause inadequate iron absorption.
Which medications can interfere with iron absorption
Iron 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.
Management of iron deficiency anaemia in children
Total iron binding capacity (TIBC) basically means
total space on the transferrin molecules for the iron to bind. Therefore, total iron binding capacity is directly related to the amount of transferrin in the blood.
transferrin saturation is
If you measure iron in the blood and then measure the total iron binding capacity of that blood, you can calculate the proportion of the transferrin molecules that are bound to iron. This is called the transferrin saturation. It is expressed as a percentage. The formula is:
Transferrin Saturation = Serum Iron / Total Iron Binding Capacity
Iron travels around the blood in which form
ferric ions (Fe3+) bound to a carrier protein called transferrin
Ferritin is the form that iron takes when
Ferritin is the form that iron takes when it is deposited and stored in cells.
Extra ferritin is released from cells when
when there is inflammation, such as with infection or cancer.
If ferritin in the blood is low, this is highly suggestive of
iron deficiency
High ferritin is indicative of:
High ferritin is difficult to interpret and is likely to be related to inflammation rather than iron overload. A patient with a normal ferritin can still have iron deficiency anaemia, particularly if they have reasons to have a raised ferritin, such as infection.
Serum iron indicates and varies with:
Serum iron varies significantly throughout the day, with higher levels in the morning and after eating iron containing meals. On its own serum iron is not a very useful measure.
Transferrin saturation gives a good indication of
Transferrin saturation gives a good indication of the total iron in the body. In normal adults it is around 30%, however if there is less iron in the body, transferrin will be less saturated. When iron levels go up, transferrin will be more saturated. It can increase shortly after eating a meal rich in iron or taking iron supplements, so a fasting sample is better.
total iron in the body can be measured best how?
tranferring saturation
Two things can increase the values of all iron results including serum ferritin and serum iron (except for …, which will be low), giving the impression of iron overload:
Supplementation with iron
Acute liver damage (lots of iron is stored in the liver)
Thalassaemia cause
Thalassaemia is related to a genetic defect in the protein chains that make up haemoglobin
Is Thalassaemia a recessive or dominant condition?
autosomal recessive
Thalassaemia potential signs and symptoms
- Microcytic anaemia (low mean corpuscular volume)
- Fatigue
- Pallor
- Jaundice
- Gallstones
- Splenomegaly
- Poor growth and development
- Pronounced forehead and malar eminences
Thalassaemia diagnosis
Thalassaemia patients have serum ferritin levels monitored to check for…
Iron overload occurs in thalassaemia as a result of the faulty creation of red blood cells, recurrent transfusions and increased absorption of iron in the gut in response to anaemia.
Management of iron overload involves
limiting transfusions and performing iron chelation.
Iron overload in thalassaemia causes which effects
Alpha-thalassaemia is caused by
Alpha-thalassaemia is caused by defects in alpha globin chains. The gene coding for this protein is on chromosome 16.
Alpha-Thalassaemia management
Beta-Thalassaemia is caused by?
Beta-thalassaemia is caused by defects in beta globin chains. The gene coding for this protein is on chromosome 11.
Based on the type of defect, beta-thalassamia can be split into three types:
Thalassaemia minor
Thalassaemia intermedia
Thalassaemia major
Thalassaemia minor presentation and treatment
Thalassaemia intermedia presentation and treatment
Thalassaemia major presentation, causes, and management
ITP definition. What type of hypersensitivity reaction is it?
ITP presentation and features
ITP in children is typically more acute than in adults and may follow an infection or vaccination.
Features
* bruising
* petechial or purpuric rash
* bleeding is less common and typically presents as epistaxis or gingival bleeding
ITP investigations
ITP management
HSP definition and cause
Which organ systems of the body does HSP affect? What are the 4 classic features of HSP?
Cause of rash in HSP
HSP features
-
Purpura:100% of patients with HSP. Red purple in colour, palpable under the skin.
Typically, they start on the legs and spread to the buttock. Can also affect the trunk and arms. In severe cases, skin ulceration and necrosis can develop. - 75% of patients with HSP develop arthralgia or arthritis, mostly affecting the knees and ankles. The joints can become swollen and painful, with a reduced range of movement.
- Abdominal pain is indicative of gastrointestinal involvement. This affects around 50% of patients with HSP. In severe cases, it can lead to gastrointestinal haemorrhage, intussusception and bowel infarction.
- HSP affects the kidneys in around 50% of patients, causing an IgA nephritis. This is sometimes referred to as HSP nephritis. This can lead to microscopic or macroscopic haematuria and proteinuria. If there is more than 2+ of protein on the urine dipstick the child has developed nephrotic syndrome and will have a degree of oedema.
Differentials to exclude in HSP
meningococcal septicaemia and leukaemia.
Idiopathic thrombocytopenic purpura and haemolytic uraemic syndrome are also differentials for a non-blanching rash.
Investigations done in HSP, especially to exclude other pathology:
sets of criteria for diagnosing HSP
management of HSP
- Supportive: rest, fluid, analgesia
- Urine dipstick repeated: check for haematuria, proteinuria (kidney involvement)
- BP checks: for HTN
HSP prognosis
- Abdominal pain settles within a few days.
- Patients without kidney involvement can expect to fully recover within 4 to 6 weeks.
- A third of patients have a recurrence of the disease within 6 months.
- A very small proportion of patients will develop end stage renal failure.
Haemophilia is what type of disorder?
Haemophilia is an X-linked recessive disorder of coagulation
so mostly males are affected as females need to have 2 copies of X to be affected (usually carriers)
Haemophilia A is caused by
deficiency of factor VIII
Haemophilia B (also known as Christmas disease) is caused by
deficiency in factor IX
Haemophilia features and presentation
- haemoarthroses: Spontaneous bleeding into joints such as the ankle, knee or elbow can lead to joint damage and deformity. Bleeding into the muscles can cause compartment syndrome.
- haematomas
- prolonged bleeding after surgery or trauma
- increased risk of sponstaneous bleeding in other areas such as :
Oral mucosa
Nosebleeds (epistaxis)
Gastrointestinal tract
Urinary tract, causing haematuria
Intracranial haemorrhage
Surgical wounds
Most cases present in neonates or early childhood. It can present with intracranial haemorrhage, haematomas and cord bleeding in neonates.
Investigations in hameophilia
Diagnosis is based on bleeding scores, coagulation factor assays and genetic testing.
Blood tests
* prolonged APTT
* bleeding time, thrombin time, prothrombin time normal
Management of haemophilia and side effect of treatment
- The affected clotting factors (VIII or IX) can be given by intravenous infusion, either regularly or in response to bleeding.
- A complication of this treatment is the formation of antibodies (called inhibitors) against the treatment, resulting in it becoming ineffective.
Sickle cell definition and what it leads to
autosomal recessive affecting the gene for beta-globin on chromosome 11
Pathophysiology of sickle cell disease
Sickle cell screening test
- Sickle cell disease is tested for on the newborn blood spot screening test at around five days of age.
- Pregnant women at high risk of being carriers of the sickle cell gene are offered testing.
- definitive diagnosis of sickle cell disease is by haemoglobin electrophoresis
Sickle cell complications
Sickle cell crisis definition, triggers and management
Vaso-occlusive crisis definition, causes and presentation
Splenic sequestration crisis cause, presentation, consequence and management
Aplastic crisis definition, trigger, consequence and management
Acute chest syndrome definition, triggers , presentation, and management
General management of sickle cell disease
Hydroxycarbamide works by
Hydroxycarbamide works by stimulating the production of fetal haemoglobin (HbF). Fetal haemoglobin does not lead to the sickling of red blood cells (unlike HbS). It reduces the frequency of vaso-occlusive crises, improves anaemia and may extend lifespan.
Crizanlizumab MOA
Crizanlizumab is a monoclonal antibody that targets P-selectin. P-selectin is an adhesion molecule found on endothelial cells on the inside walls of blood vessels and platelets. It prevents red blood cells from sticking to the blood vessel wall and reduces the frequency of vaso-occlusive crises
Lymphoma definition
Lymphoma is a type of cancer affecting the lymphocytes inside the lymphatic system. Cancerous cells proliferate inside the lymph nodes, causing the lymph nodes to become abnormally large (lymphadenopathy).
The many types of lymphoma fall into two categories:
Hodgkin’s lymphoma (a specific disease)
Non-Hodgkin’s lymphoma (which includes all other types)
Hodgkin’s lymphoma age distribution and risk factors
Non-Hodgkin’s lymphoma includes many types. A few notable ones are:
Risk factors for non-Hodgkin’s lymphoma include:
- HIV
- Epstein-Barr virus
- Helicobacter pylori (H. pylori) infection is associated with MALT lymphoma
- Hepatitis B or C infection
- Exposure to pesticides
- Exposure to trichloroethylene (a chemical with a variety of industrial uses)
- Family history
Lymphoma key symptoms, systemic symptoms and non-specific symptoms
Lymphoma investigation and findings
Name and components of the classification used for lymphoma
Hodgkin’s and non-Hodgkin’s lymphoma management and side effects of treatments
