PAEDS - ONCOLOGY/HAEM AND GENETICS/ENDOCRINE Flashcards
(104 cards)
FANCONI SYNDROME
What is fanconi syndrome?
- Generalised reabsorptive disorder of renal tubular transport in the PCT resulting in…
– Type 2 (proximal) renal tubular acidosis
– Polydipsia, polyuria, aminoaciduria + glycosuria
– Osteomalacia/rickets
FANCONI SYNDROME
What are some causes of fanconi syndrome?
- Usually secondary to inborn errors of metabolism
– Cystinosis (AR > intracellular accumulation of cysteine, most common)
– Wilson’s disease, galactosaemia, glycogen storage disorders
ANAEMIA OVERVIEW
What are some causes of decreased red cell production?
What are some clues?
- Ineffective erythropoiesis (Fe, folate deficiency, CKD)
- Red cell aplasia
- Normal reticulocytes, abnormal MCV in nutrient deficiencies
ANAEMIA OVERVIEW
What are some causes of haemolysis?
What are some clues?
- G6PD deficiency, haemoglobinopathies, hereditary spherocytosis
- Raised reticulocytes, abnormal appearance on blood films, +ve direct antiglobulin test if immune cause
ANAEMIA OVERVIEW
How does haemolysis cause anaemia?
What is the difference in haemolytic anaemias in neonates + children?
- Red cell survival reduced significantly but bone marrow production increases too, anaemia = bone marrow cannot compensate
- Neonates = immune haemolytic anaemias, children = instrinsic abnormalities (G6PD)
ANAEMIA OVERVIEW
List 4 features of haemolytic anaemias
- Anaemia
- Hepatosplenomegaly
- Unconjugated bilirubinaemia
- Excess urinary urobilinogen
ANAEMIA OVERVIEW
What are some causes of anaemia in the neonate?
- Reduced RBC production = congenital red cell aplasia + congenital parvovirus infection > red cell aplasia
- Haemolytic anaemia = immune (haemolytic disease of newborn) or hereditary (G6PD etc)
ANAEMIA OVERVIEW
What are the main causes of anaemia of prematurity?
- Inadequate erythropoietin production
- Reduced red cell lifespan
- Frequent blood sampling whilst in hospital
- Iron + folic acid deficiency after 2-3m.
IRON DEF ANAEMIA
What are some sources of iron?
What can affect iron absorption?
- Breast milk, formula, cow’s milk or weaning (cereals)
- Markedly increased when eaten with food rich in vitamin C + inhibited by tannin in tea
IRON DEF ANAEMIA
What is…
i) transferrin saturation?
ii) total iron binding capacity?
i) Proportion of transferrin bound to iron
ii) Total space on transferrin for Fe to bind
IRON DEF ANAEMIA
What are some side effects of treatment with oral iron supplementation?
- Constipation
- Black coloured stools
- Nausea
SICKLE CELL DISEASE
What is the pathophysiology of sickle cell disease?
How does it arise?
- Abnormal variant (haemoglobin S) which polymerises to be an abnormal sickle (crescent) shape + so more fragile + easily destroyed > haemolytic anaemia
- Amino acid substitution (glutamine > valine)
SICKLE CELL DISEASE
What is the genetics behind sickle cell disease?
- Autosomal recessive
- Abnormal gene for beta-globin on C11
- Heterozygous = sickle-cell trait
- Homozygous = sickle cell disease (HbSS)
SICKLE CELL DISEASE
What is acute chest syndrome?
What can cause it?
Management?
- Fever or resp Sx (CP, tachypnoea) with new infiltrates on CXR
- Can be due to infection (pneumonia, bronchiolitis) or non-infective (pulmonary vaso-occlusion or fat emboli)
- Emergency > Abx or antivirals, blood transfusions for anaemia, may need NIV or intubation
SICKLE CELL DISEASE
Name 2 other vaso-occlusive crises
- ‘Hand-foot syndrome’ common leading to dactylitis
- Priapism in men > urological emergency, aspiration
SICKLE CELL DISEASE
Sickle cell disease may present with acute anaemia (sudden drop in Hb).
What can cause this?
- Haemolytic crises (sometimes with associated infection)
- Aplastic crises (parvovirus causes cessation of RBC production)
- Sequestration crises
SICKLE CELL DISEASE
What is a sequestration crisis?
What is the management?
- Sudden hepatic or splenic enlargement, abdo pain + circulatory collapse from accumulation of sickled cells blocking blood flow
- Supportive = blood transfusions, fluid resus, splenectomy can prevent this + used in recurrent crises as can lead to splenic infarction > increased infection susceptibility
SICKLE CELL DISEASE
What are some investigations for sickle cell disease?
- Prenatal Dx via CVS
- Detection via Guthrie test
- FBC = low Hb, high reticulocytes
- Blood film = sickled RBCs
- Dx with Hb electrophoresis showing high amounts of HbSS + absent HbA
SICKLE CELL DISEASE
What are some complications of sickle cell disease?
- Short stature + delayed puberty
- Stroke + cognitive issues
- Pulmonary HTN
- Chronic renal failure
- Psychosocial issues
SICKLE CELL DISEASE
What is the general management for sickle cell disease?
- Fully immunised (PCV, HiB, meningococcus)
- Avoid vaso-occlusive crisis triggers
- PO phenoxymethylpenicillin prophylaxis
- PO folic acid as increased demands due to haemolysis
- Hydroxycarbamide + hydroxyurea can stimulate HbF production to prevent painful crises
- Bone marrow transplant curative + offered if failed response
SICKLE CELL DISEASE
What is the management of an acute crisis?
- PO or IV analgesia according to need (?opiates)
- IV fluids, oxygen
- Infection treated with Abx, blood transfusion for severe anaemia
- Exchange transfusion if severe (e.g. neuro complications)
THALASSAEMIA
What is thalassaemia?
Consequence?
What are the 2 types?
- AR disorder arising from ≥1 gene defects, resulting in a reduced rate of production of ≥1 globin chains
- RBCs more fragile + breakdown easily
- Alpha = defect in alpha globin chains
- Beta = defect in beta globin chains
THALASSAEMIA
What is a complication of beta-thalassaemia major which isn’t common in developed countries?
- Extramedullary haematopoiesis can occur if no regular blood transfusions
- Leads to hepatosplenomegaly + bone marrow expansion leading to maxillary overgrowth + skull bossing
THALASSAEMIA
What are some investigations for beta thalassaemia?
- FBC + blood film = hypochromic microcytic anaemia
- HbA2 raised in beta-thalassaemia trait, HbA2 + HbF raised in major
- Serum ferritin to differ between Fe anaemia + check iron overload
- Hb electrophoresis for Dx
- DNA testing via CVS before birth