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　　First, etiology:

　　This disease is caused by insufficient blood supply to the kidney during the embryonic period or other reasons, leading to some postrenal primordia losing normal development, and only a part develops into normal functional renal units. The collecting system is reduced, the ureter and renal blood vessels are small but without obstruction.

　　Second, pathogenesis:

　　The kidney shape is幼稚型, has embryonic lobation, more than half smaller than the normal kidney, weight30～100g. The renal calyces are short and thick, the number is reduced, the pelvis is narrow, the renal excretion function is poor, and the contralateral kidney is mostly normal or has compensatory hypertrophy.

　　In addition to its clinical manifestations, renal hypoplasia can also cause other diseases. Renal hypoplasia is often prone to complications such as hypertension. In some cases, malformed kidneys can be associated with ectopic ureteral orifice, ureteral diverticulum, urethral obstruction, and pelvic syndrome.

　　Individuals with unilateral renal hypoplasia may have no clinical symptoms. When complications such as hypertension, infection, and stones occur, corresponding clinical manifestations can be observed. About half of the children with this condition have pain in the flank on the affected side or hypertension, and they are suspected of having renal origin and are discovered only when checked. Due to the variation of the renal artery, the hypertension syndrome that occurs in patients often has an unsatisfactory response to antihypertensive drugs and develops rapidly.1～2Vision impairment or even blindness may occur within the year, and this condition can also be bilateral. However, there may be differences in the size of the two kidneys. Such children often have symptoms of renal insufficiency and can be accompanied by dwarfism and rickets. Abnormal blood pressure can be found during physical examination, and the contralateral compensatory hypertrophied kidney can sometimes be palpated.

　　The diagnosis of renal hypoplasia mainly depends on imaging findings. For suspected cases of renal hypoplasia, the first step should be to perform an ultrasound examination, and if necessary, perform intravenous pyelography or retrograde pyelography. The kidneys are smaller, closer to the spine, and have an irregular shape; the excretion of contrast agent is slow, and the contrast is not satisfactory, or it does not appear. The pelvis is underdeveloped or narrow, showing a triangular or pyramidal shape; the number of renal calyces is less, with varying degrees of deformation. Arteriography not only can understand the condition of the kidneys but also can observe the changes in renal blood vessels in detail.

　　The key health care for renal hypoplasia is to prevent the healthy kidney from developing lesions, and regular check-ups can be arranged at the hospital. In women, although one kidney has good compensatory function, during pregnancy and the perinatal period, due to the increased kidney burden, it poses a threat to the health of both the fetus and the mother, so it is advisable to proceed under the supervision of a doctor. In addition, when treating diseases, attention should be paid to using drugs with high nephrotoxicity as little as possible to avoid damaging the normal compensatory kidney and eventually leading to uremia.

　　1Due to renal artery variation leading to concurrent hypertension:Renin can be measured, and the level of angiotensin exceeds the normal range. In individuals with bilateral renal hypoplasia, creatinine and abnormal blood urea nitrogen can be detected.

　　2、B超检查：可发现一侧或双侧肾脏明显较正常者小，放射性肾图检查可见一侧或双侧肾功能受损，排泄延缓。

　　3、KUBIVU检查：可见一侧或双侧肾影明显缩小，患肾显影欠佳，CT检查可发现患肾体积明显缩小。

　　4、肾动脉、造影检查：可见肾动脉细小，肾血管网范围狭小，稀疏。

　　肾功能不全食疗方：

　　1、限止蛋白摄入量

　　这是相当矛盾的事情。蛋白质对小儿生长发育是最重要的营养素，如果过早地加以限止或者限止偏严都对成长不利。因此要根据临床症状表现，以及血中尿素氮水平来把握时机。限止蛋白质摄入主要是限止植物蛋白质(生物价低)。优质的动物蛋白质应适量供给。中度肾功能减退按逐日每公斤体重1～2克蛋白质(正常小儿须要2～3克为宜)。严重肾功能减退者则按逐日每公斤体重0。6～1克供给。

　　2、热能和碳水化物要充足

　　一、治疗

　　双肾发育不全或单侧肾发育不全并对侧肾严重病患，患儿可出现肾功能衰竭 、脱水、发育障碍等，单侧肾发育不全对侧正常者可无症状。无症状者可不处理，如肾功能不全可行饮食指导，透析或肾移植处理。

　　节段性肾发育不全多表现为高血压症状，如为单侧，可行肾切除术或肾部分切除术;如为双侧病变并肾功能不全考虑药物控制。有时可采用透析和肾移植治疗。控制反流可防止进一步肾损害 ，但可能对血压控制无效。

　　肾发育不全合并异位输尿管开口，尿道梗阻或梨状腹综合征，可根据具体情况行小肾切除或相应的重建术。

　　二、预后

　　在对侧肾功能良好情况下，切除患肾，血压多数在术后即恢复正常，一般都在短期内恢复正常，视力亦在术后短期内恢复。根据临床观察，年龄越小，术后恢复越快，预后越好。