Renal hypoplasia

　　1. Etiology:

　　This disease is caused by insufficient blood supply to the kidney during embryonic development or other reasons, causing part of the metanephric blastema to lose normal development, only part of which develops into a normal functional renal unit. The collecting system is smaller, the ureter and renal blood vessels are small but without obstruction.

　　2. Pathogenesis:

　　The shape of the kidney is幼稚型, with embryonic lobation, more than half smaller than the normal kidney, weighing 30-100g. The calyces are short and thick, the number is reduced, the pelvis is narrow, and the excretion function is poor. 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 often easily complicates hypertension and other conditions. In some cases, malformed kidneys can be associated with ectopic ureteral orifice, ureteral diverticulum, urethral obstruction, and Meckel diverticulum syndrome.

　　Individuals with unilateral renal hypoplasia may have no clinical symptoms. When complications occur, such as hypertension, infection, stones, etc., they often manifest corresponding clinical manifestations. About half of the children with this condition have pain in the lumbar region of the affected side or hypertension, and they are suspected of having a renal source and are discovered only when examined. Due to the variation of renal arteries, the hypertension syndrome that occurs in patients often has an unsatisfactory response to antihypertensive drugs and develops rapidly, and vision impairment, even blindness, may occur within 1 to 2 years. This condition can also be bilateral, but the size of the two kidneys may vary. Such children often have symptoms of renal insufficiency and may be accompanied by dwarfism and rickets. Abnormal blood pressure can be found during physical examination, and the compensatory hypertrophied kidney on the contralateral side can sometimes be palpated.

　　The diagnosis of renal hypoplasia mainly relies on imaging findings. For those suspected of having renal hypoplasia, the first step should be an ultrasound examination, and if necessary, intravenous pyelography or retrograde pyelography should be performed. The kidneys are smaller, closer to the spine, and not very regular in shape. The excretion of contrast medium is slow, and the shadowing is not satisfactory, or there is no shadowing. The pelvis is underdeveloped or narrow, presenting a triangular or pyriform shape. The number of minor calyces is reduced, and there are varying degrees of deformation. Arterial angiography 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 it is recommended to undergo regular checks at the hospital. In women, although the compensatory function of one kidney is good, due to the increased kidney burden during pregnancy and peripartum period, it poses a threat to the health of both the fetus and the mother. Therefore, it is advisable to undergo under the supervision of a doctor. In addition, in everyday treatment, attention should be paid to minimizing the use of nephrotoxic drugs as much as possible to avoid damaging the normal compensatory kidney and eventually leading to uremia.

　　1. Secondary hypertension due to renal artery variation:Renin and angiotensin levels can be measured, and creatinine and blood urea nitrogen levels may be abnormal in individuals with bilateral renal hypoplasia.

　　2. Ultrasound examination:It can be found that one side or both sides of the kidneys are significantly smaller than normal, and radioactive renal imaging examination can show that one side or both sides of the renal function are impaired, and excretion is delayed.

　　3. KUBIVU examination:It can be seen that the renal shadow on one side or both sides is significantly reduced, the affected kidney is poorly visualized, and CT examination can detect significant reduction in the volume of the affected kidney.

　　4. Renal artery, angiography examination:It can be seen that the renal artery is small, the renal vascular network is narrow and sparse.

　　Dietary recipes for renal dysplasia patients:

　　1. Limit protein intake

　　This is a rather contradictory matter. Protein is the most important nutrient for the growth and development of children, and early restriction or excessive restriction is detrimental to growth. Therefore, it should be based on clinical symptoms and blood urea nitrogen levels to determine the timing. The restriction of protein intake mainly involves restricting plant protein (with low biological value). High-quality animal protein should be provided in moderate amounts. For moderate renal insufficiency, 1 to 2 grams of protein per kilogram of body weight per day (2 to 3 grams per normal child is appropriate). For severe renal insufficiency, 0.6 to 1 gram per kilogram of body weight per day should be provided.

　　2. Ensure adequate energy and carbohydrate intake

　　I. Treatment

　　In cases of bilateral renal dysplasia or unilateral renal dysplasia with severe contralateral renal disease, children may experience renal failure, dehydration, developmental disorders, etc. Those with unilateral renal dysplasia and normal contralateral kidneys may be asymptomatic. Those without symptoms may not require treatment, but dietary guidance, dialysis, or kidney transplantation may be considered for renal insufficiency.

　　Segmental renal dysplasia often manifests as hypertension symptoms. If it is unilateral, nephrectomy or partial nephrectomy can be performed; if it is bilateral and renal insufficiency is considered, drug control may be required. Dialysis and kidney transplantation may be used sometimes. Controlling reflux can prevent further renal damage, but may be ineffective for blood pressure control.

　　For renal dysplasia with ectopic ureteral orifice, urethral obstruction, or pelvic syndrome, small renal resection or corresponding reconstruction can be performed according to specific conditions.

　　II. Prognosis

　　In the case of good renal function on the contralateral side, the affected kidney is removed, and blood pressure is usually restored to normal immediately after surgery, and generally returns to normal in the short term. Vision also recovers in the short term after surgery. According to clinical observations, the younger the age, the faster the postoperative recovery, and the better the prognosis.