Red blood cell abnormalities Flashcards
(32 cards)
What type of haemoglobinopathy is sickle cell disease?
A disorder of quality (abnormal molecule or varient haemoglobins)
What is the pathophysiology of sickle cell disease?
- Valine is substituted for glutamic acid in the β-globin chain
- Sickle cell haemoglobin (HbS) is insoluble and polymerises when deoxygenated
- Cell flexibility is decreased and the sickle appearance occurs
- Irreversibly sickled cells are dehydrated and dense and won’t return to normal when oxygenated
How can sickle cell disease present clinically?
• Asymptomatic (except in hypoxia) for heterozygotes • Vaso-occusive crises • Acute chest syndrome Pulmonary hypertentsion • Anaemia
What are some long-term growth and development problems of sickle cell disease?
- Young children are short but regain height by adulthood
- Below normal weight
- Delayed sexual maturation
What are some long-term bone problems of sickle cell disease?
- Avascular necrosis of hips and shoulders
- Compression of the vertebrae
- Shortening of hand and foot bones
- Osteomyelitis
What are some long-term cardiac problems of sickle cell disease?
- Cardiomegaly
- Arrhythmias
- Iron overload cardiomyopathy
- MI
What are some long-term neurological problems of sickle cell disease?
- TIAs
- Fits
- Cerebral infarcts
- Coma
Approximately what percentage of sickle cell patients have neurological problems?
25%
What are some long-term liver problems of sickle cell disease?
- Chronic hepatomegaly
* Liver dysfunction
What are some long-term renal problems of sickle cell disease?
Chronic tubulointestinal nephritis
What are some long-term eye problems of sickle cell disease?
- Retinopathy
- Vitreous haemorrhage
- Retinal detachments
What is a pregnancy-related problem in sickle cell disease?
Impaired placental blood flow can lead to spontaneous abortion
How would you diagnoses sickle cell disease?
• Blood count - Hb level in the range of 60-80g/L - Raised reticulocyte count • Sickled erythrocytes on blood film • Sickle solubility test will be positive • Hb electrophoresis confirms diagnosis
How would you treat sickle cell disease?
- Treat precipitating factors (e.g. infection, dehydration, etc.) quickly
- Folic acid to all haemolysis patients
- IV fluids
- Analgesia
- Oxygen and antibiotics if required
- Blood transfusion
- Oral hydroxycarbamide
- Stem cell transplant
What type of haemoglobinopathy are thalassaemias?
Disorders of quantity (reduced production)
What are thalassaemias?
Genetic diseases of unbalanced Hb synthesis
What are the 3 classifications of thalassamia severity?
- Thalassaemia major
- Thalassaemia intermedia
- Thalassaemia minor
Are thalassaemias macrocytic or microcytic?
Microcytic
What are α-thalassaemia defects normally caused by?
Gene deletions
What are β-thalassaemia defects normally caused by?
Point mutations
At what age does thalassaemia major usually present?
Between 6-12 months
Why does thalassaemia major usually present at the age it does?
Between 6-12 months when there is a switch from foetal to adult Hb
What is the usual clinical presentation of thalassaemia major?
- Listlessness
- Crying
- Pale
- Failure to feed
How would you treat thalassaemia major?
- Regular transfusion
- Iron chelation
- Endocrine supplementation
- Fertility treatment
- Bone health
- Psychological support
