- Haemoglobinopathies
- Sickle cell disease (HAEMOGLOBIN) - Ch 11
- β-globin chain substitution of glutamic acid to valine results in HbS
- Heterozygous 40% HbS
- Homozygotes 100% HbS
- Often have chronic haemolytic anaemia, vasoocclusive disease and organ dysfunction
- Desaturation forms aggregates and sickling
- SS sickles at pO₂ of ~ 6.5kPa
- AS sickles at pO₂ of ~ 4kPa
- Exacerbated by stasis, cold, dehydration, infection and acidosis
- Diagnosis
- Electrophoresis is gold standard
- Sickledex
- Doesn't differentiate SCD from trait
- Presentations
- Vaso-occlusive
- Aplastic
- Haemolytic
- Splenic sequestration
- Clinical signs
- CVS
- MI, cardiomegaly, PAH due to pulmonary infarction
- Resp
- Dyspnoea, cough, haemoptysis, pleuritic pain
- Head/neck
- Frontal bossing, prominent maxilla, vitreous haemorrhage, asplenism leads to hypertrophy of tonsils and OSAS
- GU
- GIT
- Splenic infraction, gallstones, liver capsule pain
- Skeletal
- Marrow hyperplasia, AVN, dactylitis
- Neuro
- TIA, CVA, cerebral haemorrhage
- Haem
- Thalassaemia
- Defective synthesis of alpha or beta chains
- Heterozygotes
- Homozygotes
- Intra-op
- GA or Regional
- Pre-O₂
- Controlled ventilation
- Fluid Mx to prevent dehydration
- Monitor u.o.
- Warm fluid/BH
- Exsanguinate limb if tourniquet used
- Snr surgeon
- Analgesia
- HDU care
- Normal Hb (HbA) has 2 α (Ch 16) and 2 β chains (Ch11)
- Pre-op investigations
- CXR, bloods, ABGs, PFT, physio, Tx to Hb of 10 if high risk surgery
- Treatments
- Prevent dehydration
- Avoid alcohol
- Hydroxyurea
- Vaccinations (HiB, pneumococcus, N. meningitidis)
- Folate replacement
- Blood Tx
- CEACCP
Link:ceaccp.oxfordjournals.org/content/10/1/24.full.pdf