A 26-year-old man with sickle cell trait (HbAS) asks about health implications. Which complication is correctly attributed to sickle cell trait itself?
- A Recurrent pain crises under general anaesthesia
- B Inability to concentrate urine due to papillary damage, causing polyuria ✓
- C Chronic transfusion requirement from baseline haemolysis
- D Autosplenectomy by adolescence
Correct answer: B. Inability to concentrate urine due to papillary damage, causing polyuria
Explanation
In sickle cell trait, sickling occurs only in the hyperosmolar, acidic, hypoxic renal medulla, damaging vasa recta and papillae. This causes impaired urinary concentrating ability, isosthenuria, and painless haematuria; it also confers increased risk of renal medullary carcinoma. Trait carriers have normal life expectancy, normal haemoglobin, no haemolysis, and no autosplenectomy or pain crises, all of which characterise homozygous HbSS disease.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.