What is Bilateral Renal Hypoplasia?

1. Renal hypoplasia refers to a kidney with a volume less than 50% of the normal size, yet with normal nephron units and differentiation. Due to blood supply disruptions or other causes during embryogenesis, the renal tissue fails to fully develop, resulting in a small organ with a lobulated surface, retaining a primitive and immature renal state. The ureter is often also underdeveloped, leading to abnormal urinary function, and the blood vessels, particularly the arteries, are often sclerosed and small. Most patients suffer from hypertension. This kidney may be located in its normal position and is often accompanied by ectopic kidneys, which have a higher chance of dysplasia. The contralateral kidney is mostly normal in position, form, and function, potentially exhibiting compensatory hypertrophy. The incidence of bilateral renal hypoplasia is approximately one in 600 people.

2. Undeveloped kidneys usually have incomplete branching of the ureteric bud. The kidney is small but has a normal nephron unit. Segmental renal hypoplasia can lead to hypertension. When the contralateral kidney function is good, nephrectomy is performed. Most blood pressures return to normal after surgery, and vision recovers within a short period post-operation. Younger patients tend to recover faster post-surgery and have better prognoses.