Sickle Cell Nephropathy

Sickle cell nephropathy is renal injury from sickling in the vasa recta and glomerular hyperfiltration.

• Present in up to 30 to 40% of adults with HbSS; ESKD in 4 to 18%.
• Features: hyposthenuria (early, from childhood), albuminuria, glomerular hyperfiltration then FSGS, papillary necrosis, haematuria, renal medullary carcinoma (HbAS trait, young black patients), type 4 RTA.
• Risk factors: older age, hypertension, severe haemolysis, APOL1 high risk variants.

• Nocturia, enuresis, polyuria, gross haematuria, flank pain.
• Proteinuria, hypertension, anaemia worsening more than expected, hyperkalaemia.
• Renal medullary carcinoma: haematuria, flank pain, weight loss.

• Urine albumin to creatinine ratio annually from age 10, eGFR (creatinine based may overestimate; cystatin C helps).
• Urinalysis, ultrasound (large kidneys early, small in CKD, papillary necrosis calcification).
• Renal biopsy for rapid decline or nephrotic range proteinuria.
• Imaging (CT/MRI) for haematuria, cystoscopy when hyperperfusion cannot explain.
• Check haemoglobin, potassium, bicarbonate, hepatitis B/C, HIV.

• ACE inhibitor or ARB for albuminuria: losartan 25 to 100 mg or lisinopril 5 to 20 mg daily; monitor potassium and creatinine.
• Hydroxyurea 15 to 35 mg/kg daily reduces hyperfiltration and albuminuria; SGLT2 inhibitors emerging.
• Blood pressure below 130/80 mmHg, hydration, avoid NSAIDs and nephrotoxins.
• Haematuria: bed rest, hydration, alkalinisation; tranexamic acid and aminocaproic acid can precipitate clots (use with caution); embolisation or nephrectomy for refractory.
• Renal medullary carcinoma: chemotherapy (platinum, taxane, gemcitabine) and nephrectomy; prognosis poor.
• ESKD: dialysis, transplantation (graft and patient outcomes lower than general population), erythropoietin carefully (hyperviscosity risk).
• Annual screening and nephrology referral for persistent albuminuria or reduced eGFR.