The kidneys in paroxysmal nocturnal hemoglobinuria

Area of Science:

• Nephrology
• Hematology
• Pathology

Background:

• Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired blood disorder.
• The renal manifestations of PNH are not well-characterized, often underestimated.
• Previous understanding suggested limited renal involvement in PNH.

Purpose of the Study:

• To investigate the incidence and nature of renal abnormalities in a cohort of PNH patients.
• To characterize the functional and anatomic renal changes associated with PNH.
• To explore the underlying mechanisms of renal pathology in PNH.

Main Methods:

• Long-term clinical observation of 21 PNH patients.
• Assessment of renal function including urinalysis, tubular function tests, and creatinine clearance.
• Radiological imaging (e.g., ultrasound, CT) and autopsy studies for anatomic evaluation.
• Clinical monitoring for complications like hypertension and urinary tract infections.

Main Results:

• High incidence of functional renal abnormalities: hyposthenuria, tubular dysfunction, declining creatinine clearance.
• Frequent anatomic renal abnormalities: enlarged kidneys, cortical infarcts, cortical thinning, papillary necrosis.
• Hypertension developed in 8 patients; urinary tract infections were uncommon.
• Renal findings closely resemble those observed in sickle cell anemia.

Conclusions:

• PNH is associated with unexpectedly high rates of significant renal pathology, challenging previous assumptions.
• Repeated microvascular thrombosis is the likely cause of widespread renal damage in PNH.
• The renal pathology in PNH shares similarities with sickle cell nephropathy, suggesting common pathomechanisms.