Sickle Cell Disease Flashcards
What is the sickle cell disease aetiology (5)
- Autosomal recessive condition
- Sub-Saharan Africa and the Middle East
- 10% Afro-Caribbeans in the UK
- Normal quaternary structure of Hb replaced
- ‘Protective’ against malaria
How does the sickle cell shape come about (2)
- When a haemoglobin molecule isn’t carrying oxygen one end of the beta chain forms a pocket – Hb S forms a hook
- If cells get trapped they hook & form long strands that take on the form of a sickle-shaped cell – polymerisation
What causes a sickle cell crisis (6)
- Sickle cells are less flexible
- So they stick together
- And get trapped in vessels
- Therefore they obstruct normal blood flow causing pain and damage
- Can occur anywhere in the body
- Infants first crisis usually over 6/12 of age
What are the symptoms of sickle cell (9)
- Psychological
- Neurological
- Ophthalmological
- Respiratory
- GI
- Renal/ GU
- Pain
- Anaemia
- Infection
How can sickle cell be diagnosed (3)
- Screening parents
- HPLC and Hb electrophoresis
- Newborn screening
What screening is there for sickle cell (4)
- Preconception
- Pre-marriage
- Antenatal
- Newborn screening
What are the vaso-occlusive (acute pain) symptoms of a sickle cell crisis (3)
- Severe bone/muscle pain
- Long bones, spine
- Occlusion of small blood vessels
What are the triggers of vaso-occlusive symptoms of a sickle cell crisis (4)
- stress
- dehydration
- alcohol
- infection
what are the acute chest symptoms a sickle cell crisis (3)
- Fever
- Chest wall pain (similar to heart attack)
- Dyspnoea
what are the spleen/liver sequestration (pooling of blood in liver/spleen) symptoms a sickle cell crisis (2)
- Post viral
- Acute hypotension/ anaemia
What acute medication/treatment is there for sickle cell disease (6)
- Pain relief with a regular pain score (paracetamol, ibuprofen, diclofenac, dihydrocodiene, morphine, diamorphine)
- Oxygen Therapy
- IV Fluids/Increased oral intake
- IV antibiotics (if evidence of infection)
- Physiotherapy – Incentive Spirometry for those with chest or abdominal pain or on PCA
- Blood Transfusion (If clinically indicated – can be used to correct anaemia or dilute of HbS cells)
What is the pain management in acute sickle cell stage 1: Mild pain (pain score 1-2) (2)
- regular paracetamol
- non-drug methods reassessed after 30 mins - if not improved move to next stage
What is the pain management in acute sickle cell stage 2: Moderate pain (pain score 3-4) (3)
- regular paracetamol
- regular ibuprofen/diclofenac
- non-drug methods reassessed after 30 mins - if not improved move to next stage
What is the pain management in acute sickle cell stage 3: Moderate to severe pain (pain score 5-6) (4)
- regular paracetabol
- regular ibuprofen/diclofenac/IV parecoxib (unable to take oral)
- dihydrocodeine/oral morphine
d. non-drug methods reassessed after 45 mins - if not improved move to next stage
- dihydrocodeine/oral morphine
What is the pain management in acute sickle cell stage 4: Severe pain (pain score 7+) (3)
- IV paracetamol, oral morphine and NSAID
- reassess pain after 30 mins (oral morphine takes longer to be effective)
- if pain score is 7+ start an opion PCA or NCA. Stop oral morphine/dihydrocodeine
What medication is used in chronic sickle cell (3)
- Penicillin
- Folic Acid
- Hydroxycarbamide (hydroxyurea)
How is penicillin used in sickle cell (5)
- 600 times more likely to get encapsulated bacterial infections than their peers
- Prophylaxis penicillin (erythromycin if allergic) to reduce infection risk
- under 1yr - 62.5mg BD
- 1yr-5yrs – 125mg BD
- 5+ yrs – 250mg
How is folic acid used in sickle cell (4)
- Improve production of healthy red bloods cells
- Stopped when established on hydroxycarbamide and no evidence of haemolysis
- Twice yearly folate levels checked
- Restarted in periods of increased haemolysis or anaemia, low folate levels
How is hydroxycarbamide used in sickle cell (10)
- Induces HbF production
- Reduced white cells & platelets
- Helps to slow haemolysis
- HbF binds to oxygen increasing oxygen exchange in tissues
- Higher the HbF less sickle cell complications
- Reduces mortality by over 40%
- Reduction in acute painful episodes – length of episode and frequency
- Decrease in use of blood products
- Prevent chronic organ damage
- Second line for stroke prevention
What are the guidelines hydrox for sickle cell disease (5)
- Recommendations (BSH,2018)
- Offer hydrox at 9 months of age for HbSS/HbSβ thal
- Treat patients who have had 3 or more painful crisis in 12 month period
- Treat patients where pain affects activities of daily life
- Treat those with a history of ACS
What is the dosing and monitoring for hydrox with sickle cell disease (5)
- Aim: to increase HbF without causing bone marrow suppression
- Starting dose 15-20mg/kg
- Escalate 5mg/kg every 8 weeks until MTD
- Bloods done 2-6 weekly
- Patient specific dosing
What are the side effects of hydroxycarbamide (6)
- Well tolerated
- Hair thinning
- GI
- Skin Ulcers
- Hyperpigmentation
- Marrow suppression –Transient, Reversible
What are the concerns surrounding hydroxycarbamide (4)
- Growth and development
- Leukogenesis
- Fertility
- Teratogenicity
What suggests toxicity from hydroxycarbamide (3)
- Hb: >2g/dl drop from baseline
- Neutrophils: 0.5-0.75
- Platelets: 50-75
