PAEDIATRICS Flashcards
(279 cards)
Describe the haemoglobin concentration at birth and over the first few weeks of life
At birth - fetal Hb in term infants is high to compensate for low oxygen concentration in the foetus
Levels decline over first 6 months as adult Hb synthesis is activated and HbF deactivated
What is the difference between fetal and adult haemoglobin?
HbF has a gamma subunit instead of beta which decreases binding to 2,3-BPG, a substance that decreases affinity of haemoglobin for oxygen
Therefore HbF has greater affinity for oxygen
Define anaemia
Haemoglobin level below the normal range
Give 3 broad causes of anaemia
Decreased RBC production
Increased RBC haemolysis
Blood loss
What is anaemia of prematurity?
Anaemia affecting preterm infants with decreased RBCs - typically due to repeated blood sampling and reduced erythropoiesis with low EPO levels
What is ineffective erythropoiesis?
Premature death of RBCs due to dysfunctional progenitor cells. Normal reticulocytes but lack of mature RBCs
What are the 3 main causes of iron deficiency anaemia?
Inadequate intake - common in children as more is needed to accumulate increasing blood volume and to build stores
Malabsorption
Bleeding
What is a cause of inadequate intake of iron in children?
Delayed weaning onto solids as milk does not contain enough
Symptoms of iron deficiency anaemia (4)
Fatigue
Slow feeding
Pallor
Pica - eating non food
Signs/diagnosis of iron deficiency anaemia (3)
MICROCYTIC (small rbcs)
HYPOCHROMIC (pale rbcs)
Low serum ferritin
Management of iron deficiency anaemia (3)
Dietary advice
Oral iron supplements
Continue for 3 months after normal Hb level
If refractory, Ixs e.g. for coeliac, Meckel’s
3 types of microcytic anaemia
Iron deficiency
Thalassaemia
Anaemia of chronic disease
3 types of normocytic anaemia
Blood loss
Aplastic anaemia
Sickle cell anaemia
Haemolytic anaemia i.e. G6PD deficiency
3 types of macrocytic anaemia
Pernicious anaemia (autoimmune) B12 deficiency Folate deficiency
What is sickle cell disease?
Collective name for HbS inherited haemoglobinopathies
Cause of sickle cell disease
Genetic, point mutation in codon 6 of beta globin gene cusing amino acid from glutamine to valine, forming HbS instead of HbA
4 types of sickle cell disease
Sickle cell anaemia (HbSS)
HbSC disease
Sickle trait (one allele)
Sickle beta thalassaemia
Effect of HbS on blood cells
Causes irreversibly sickled red blood cells with reduced lifespan
Can get trapped, causing vaso-occlusion and ischaemia
What exacerbates sickle cell anaemia? (3)
Hypoxaemia, dehydration, cold
Symptoms of sickle cell anaemia (10)
Anaemia Jaundice Susceptibility to infection Vaso-occlusive crises Sequestration crises Splenomegaly Risk of stroke Cardiomegaly/heart failure Renal dysfunction
What are vaso-occlusive crises?
Episodes of pain caused by ischaemia of tissue usually preceded by infection - symptoms depend on tissue affected
Can include priapism, dactylitis, abdominal pain, acute chest syndrome
What ethnic groups is sickle cell disease more common in and why?
Africa, Hispanic, Mediterranean origin
Sickle shape of RBCs afford some protection against malaria
What is acute chest syndrome?
Vaso-occlusive crisis caused by infarction of the lung parenchyma, can be fatal
How does acute chest syndrome present? (6)
Fever Cough Pain Sputum SoB Low oxygen