Haem + onc Flashcards
what is the cause of physiological anaemia?
- around 6-9 weeks in healthy term babies, caused by negative feedback prompted by high oxygen delivery seen at birth
- EPO by kidneys suppressed hence Hb reduced by BM
what are some other causes of anaemia in children?
infants: anaemia of prematurity, blood loss, haemolysis, twin to twin transfusion
neonates - hereditary spherocytosis, G6PD deficiency
older - iron deficiency, blood loss, sickle cell, thalassaemia, leukaemia, helminth infection
low RBC production or high RBC loss
what is anaemia of prematurity?
- 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 testsremove a significant portion of their circulating volume
what is haemolytic disease of the new born?
- incompatibility between rhesus antigens on surface of red blood cells of mother and foetus
- woman rhesus D negative becomes pregnant consider the possibility of foetus becoming rhesus D positive as mothers immune system will recognise this as foreign and and produce antibodies for this
- not a problem during first pregnancy usually, but in second mothers anti-D antibodies will cross placenta and if foetus positive antibodies will cause immune system of foetus to attack its own blood cells by binding to RBC of foetus
- causes anaemia and high bilirubin
- DCT done to assess
what are some key examination findings of anaemia?
generic: pale skin, conjunctival pallor, tachycardia, raised RR
koilonychia, angular chelitis, atrophic glossitis, brittle hair, jaundice, bone deformities
what are some initial investigations for anaemia?
- 1st line - FBC, reticulocytes, film, ferritin, CRP/ ESR
- Full blood count forhaemoglobinandMCV
- Blood film
- Reticulocyte count
- Ferritin (low iron deficiency)
- B12 and folate
- Bilirubin (raised in haemolysis)
- Direct Coombs test (autoimmune haemolytic anaemia)
- Haemoglobin electrophoresis (haemoglobinopathies)
- reticulocytes
how is anaemia managed?
- Management depends on establishing the underlying cause and directing treatment accordingly
- Iron deficiency can be treated with iron supplementation
- Severe anaemia may require blood transfusions
what is the pathophysiology of DIC?
- new-borns (particularly pre-terms) have low levels of coagulation factors and hence vulnerable to DIC
- causes - sepsis, NEC, HIE, RDS
- the above causes activates the coagulation cascade, promotes fibrin production and deposition and consumption of clotting factors
- consumption of coagulation factors and platelets, inhibition of natural anticoagulants and fibrinolysis, and fibrin deposition result in the clinical picture of DIC
- a bleeding diathesis accompanied by microvascular thrombosis that often leads to end-organ damage
how does DIC present?
- Bleeding, from many sites in the body
- Blood clots
- Bruising
- Drop in blood pressure
- Shortness of breath
- Confusion, memory loss or change of behavior
- Fever
*petechiae
- bleeding (cutaneous, mucosal, umbilical, GI)
what complications are associated with DIC?
birth asphyxia, acidosis, respiratory distress syndrome, infection, necrotising enterocolitis, meconium aspiration, aspiration of amniotic fluid, brain injury, hypothermia
how is DIC investigated?
- platelets low
- schistocytes (fragmented RBC)
- increased INR
- increased APTT
- fibrinogen low
how is DIC managed?
- get help
- treat cause - NEC, sepsis
- give vitamin K 1mg IV & blood products - platelets, cryoprecipitate etc
- severe cases consider exchange transfusion
what is the function of the spleen?
- spleen is important in reticuloendothelial system for antibody synthesis and clearance of opsonised organisms by phagocytosis
- Antibody-mediated phagocytosis is the primary mechanism to destroy encapsulated microbes, such as pneumococcus, meningococcus, andHaemophilus
- absence of spleen or reduced activity means the polysaccharide rich capsules of these bacteria protect them from destruction and permit them to create systemic infection
when would you suspect hyposplenia?
hyposplenia should be suspected in any patient with overwhelming infection with an encapsulated organism
How is impaired splenic function investigated?
- blood smear - Howell-jolly bodies, Heinz bodies, target cells
- USS with doppler to assess spleen size
- CT/ MRI to detect spleen shape
- radionucleotide (technetium-99m) liver and spleen scan to detect functional reticuloendothelial cells
