Hereditary Spherocytosis Flashcards
Wha kind of anaemia is HS
INHERITED HAEMOLYTIC ANAEMIA
Where is HS common
Northern Europe
Inheritance pattern of HS
Autosomal dominant
Can occur in 25% affected SPONTANEOUSLY as well
Pathophysiology of HS
- Defects in RC membrane causes RBC to lose part of their membrane as they pass through the spleen
- Abnormal cell membrane causes increased permeability to Na
- Increased rate of AT of Na out of the cells is dependant on ATP produced in glycolysis
- Spherocytes form as SA to V ratio decreases
Spherocytes vs RBC
More rigid and less deformable
Consequence of spherocytes being deformable
Can’t pass through splenic microcirculation and become trapped in the spleen = shortened lifespan + destroyed via extravascular haemolysis
Clinical presentation of HS at birth
- Jaunice at birth or later in life
- Anaemia
- Splenomegaly
- Leg ulcers
- Gall stones
What can interrupt the course of HS
Aplastic anaemia Megaloblastic anaemia (caused by folate depletion)
What is aplastic anaemia
Sudden stop in RBC (due to erythrovirus)
What would a blood film show for HS
Spherocytes + reticulocytes
Blood count in HS
- Anaemia
2. Increased reticulocytes
Haemolysis in HS
Serum bilirubin + urinary urobilinogen is RAISED
What would a Coombs’ test show in HS
- NEGATIVE
Rules out autoimmune haemolytic anaemia (spherocytes are found here too)
How is HS treated
Splenectomy (relieves symptoms due to anaemia - prevent gallstones)
When should splenectomy be done
After childhood - reduces infection risk post-op
