Sickle Cell Management
On this page
Direct answer
A single substitution — glutamate to valine at position 6 of the beta globin chain — makes deoxygenated haemoglobin polymerise, and every manifestation of sickle cell disease follows from vaso-occlusion and chronic haemolysis. India's central belt (Chhattisgarh, Madhya Pradesh, Odisha, Maharashtra) carries the Arab-India haplotype, which retains higher fetal haemoglobin and runs a milder, though not trivial, course. Management stands on four pillars: prompt analgesia with opioids for painful crises, infection prevention with penicillin prophylaxis and vaccination, hydroxyurea 15 mg/kg titrated to 25–35 mg/kg to raise HbF, and transfusion programmes for stroke and acute chest syndrome, with exchange transfusion when HbS must fall fast. The National Sickle Cell Anaemia Elimination Mission, launched in 2023, has made screening and counselling questions fair game.
What you must remember
- Painful crisis care: early parenteral opioids on a fixed schedule (not PRN), isotonic fluids at roughly 1.5 times maintenance, and incentive spirometry — undertreated pain, not overhydration, is the usual failure.
- Hydroxyurea: start 15 mg/kg daily, escalate 5 mg/kg every 8 weeks to maximum 35 mg/kg while counts allow; target fetal haemoglobin above 20% and stop escalation if neutrophils fall below 2 × 10⁹/L.
- Acute chest syndrome: new infiltrate with fever or chest pain — treated with oxygen, antibiotics, incentive spirometry and simple or exchange transfusion; it is the leading cause of death in young adults.
- Stroke prevention: annual transcranial Doppler in children; velocity above 200 cm/sec in the internal carotid or middle cerebral artery mandates a chronic transfusion programme keeping HbS below 30%.
- Exchange transfusion targets: HbS below 30% for stroke, acute chest syndrome with rapid progression, and multi-organ crisis; keep haemoglobin near 10 g/dL and never above 11 after exchange (hyperviscosity).
- Splenic sequestration: sudden haemoglobin drop over 2 g/dL with reticulocytosis and an enlarging spleen in a child — transfuse urgently; recurrent episodes lead to splenectomy after the age of 5 years.
- Aplastic crisis: parvovirus B19 shuts erythropoiesis for days — reticulocytopenia with a stable-size spleen; transfuse and observe.
- Infection package: penicillin V prophylaxis twice daily from birth to at least 5 years, pneumococcal, meningococcal, Haemophilus influenzae b and hepatitis B vaccination, and annual influenza — functional asplenia begins in infancy.
Managing an acute painful crisis, step by step
A 19-year-old known sickle patient arrives with 8/10 back and thigh pain, afebrile, saturations 96%. Step one: assess severity and search for a trigger — infection, dehydration, altitude, or nothing findable. Step two: analgesia within 30 minutes; a patient on steady opioids needs his home dose plus breakthrough, and morphine or a fentanyl patient-controlled infusion is appropriate for severe pain. Step three: isotonic saline, keeping overhydration in check because pulmonary oedema worsens sickling. Step four: baseline haemoglobin, reticulocytes and, on any hypoxia or fever, a chest radiograph — the Exam expects the sixth-hour chest film that turns a "pain crisis" into acute chest syndrome.
If saturations drop to 88% with a new basal infiltrate, escalate in order: oxygen, incentive spirometry every two hours while awake, a macrolide plus third-generation cephalosporin, and simple transfusion if haemoglobin is below 9 g/dL; deterioration mandates exchange transfusion to drive HbS under 30%. Meanwhile, ask the discharge question: is he on hydroxyurea, and what is his fetal haemoglobin? If not on therapy, start at 15 mg/kg with counts every two weeks during titration. Between crises, confirm his vaccination record and annual transcranial Doppler history — in India, the 2023 Elimination Mission now funds exactly this package of screening, hydroxyurea and comprehensive care through district sickle cell clinics.
High-yield viva angles
Viva examiners probe why sickle retinopathy, priapism and avascular necrosis spare no organ despite the milder Indian haplotype, and why sickle trait is generally benign yet contraindicated at extreme altitude and complicated by haematuria from renal papillary necrosis. A favourite question pairs a pregnant sickle woman with a pain crisis — treatment unchanged, plus hydroxyurea withheld during pregnancy. The screening sequence also recurs: sickle solubility test for mass screening, but HPLC or capillary electrophoresis to quantify HbS, HbF and HbA2 and to distinguish SS disease from S-beta thalassaemia, where an elevated HbA2 and microcytosis change genetic counselling.
Frequently asked questions
How is hydroxyurea dosed and monitored?
Start 15 mg/kg daily, escalate every eight weeks to a maximum of 35 mg/kg, monitoring counts every two to four weeks; hold for neutrophils below 2 × 10⁹/L and target HbF above 20%.
What transcranial Doppler velocity mandates transfusion?
Above 200 cm/sec in the internal carotid or middle cerebral artery — begin a chronic transfusion programme to keep HbS below 30% and prevent first stroke.
When is exchange transfusion indicated?
Overt or evolving stroke, severe acute chest syndrome, multi-organ failure and before major surgery in high-risk patients, aiming at HbS below 30%.
How does splenic sequestration present?
Sudden splenic enlargement with a haemoglobin fall of 2 g/dL or more and brisk reticulocytosis in a child — urgent transfusion, and splenectomy after recurrent episodes.
Which infections dominate and how are they prevented?
Encapsulated bacteria — pneumococcus, Haemophilus influenzae b, meningococcus — through functional asplenia; prevented by penicillin prophylaxis until at least 5 years plus full vaccination.
What is the National Sickle Cell Anaemia Elimination Mission?
A 2023 Government of India programme of universal screening in endemic states, counselling, distribution of hydroxyurea and linking patients to comprehensive care, targeting elimination by 2047.