Kidney Function And Urine Routine Are Normal, But Kidney B-ultrasound Has Found Abnormalities, How To Treat?

Today, a 28-year-old boy was seen in the outpatient clinic. He said that during the unit physical examination, his kidney function and urine routine were normal, but the ultrasound doctor said that his kidneys were different from others. He suggested that he go to a regular hospital like ours for a good check-up one time.

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With doubts, let's first understand the disease, and then combine it with reality to make suggestions for the treatment of patients.

etiology and pathogenesis

Medullary sponge kidney is not a common kidney disease, its incidence rate in the population is 1/20000-1/5000[1], and it is a congenital abnormal kidney development disease. The age of onset is 30 to 50 years old, more women than men, with familial aggregation characteristics, manifested as an autosomal dominant inheritance.

The typical pathological manifestations are single or multiple papillae in one or both kidneys. Intrarenal medullary collecting ducts and papillary ducts in the pyramidal part are fusiform or small cystic expansions, which contain high-density substances, and there are many different sizes. Calcium-containing small stones are uniform, and a few are renal parenchymal calcifications.

Medullary sponge kidney disease can be asymptomatic when localized and uncomplicated, so early diagnosis is very important. As the disease progresses, kidney stones and nephrocalcinosis are most often complicated. Other clinical manifestations include hematuria, urinary tract infection, hyperparathyroidism, and even chronic renal insufficiency, while hypertension and proteinuria are rare. The medullary sponge kidney is often accompanied by other congenital diseases, such as Sjogren's syndrome, hemihypertrophy, horseshoe kidney, Marfan syndrome, and congenital intrahepatic bile duct dilatation, etc.[1,2].

The etiology of the medullary sponge kidney is still unclear. In recent years, breakthroughs have been made in the study of its pathogenesis based on genetics. It is believed that polymorphic neurotrophic factors and receptor tyrosine kinases derived from glial cell lines in embryonic development One or more mutations or polymorphisms of the gene lead to disruption of the "ureteric bud-metanephric mesenchyme" interface, triggering abnormal development of the renal ureter and collecting ducts leading to pathogenesis [2].

imaging diagnosis

The most commonly used clinically for the diagnosis of medullary sponge kidney is renal B-ultrasound and CT.

B ultrasound

Like the patients in this article, most of them were diagnosed with renal B-ultrasound in the early stage. Typical ultrasound shows that the echoes of the renal pyramids are enhanced with cotton-like changes in radial distribution, and the strong echo spots are mostly calcifications and small stones, accompanied by acoustic shadows in the rear, and multiple anechoic spots of different sizes can also be shown The area is mostly formed by cystic dilation of the collecting duct, and generally, there is no hydronephrosis of the renal pelvis and calyces.

However, due to the small size of medullary cavernous renal cysts, B-ultrasound is difficult to clearly show, and there are limitations in diagnosis.

CT

The typical CT image of the medullary sponge kidney shows that the dilated collecting duct presents low-density, striated small cystic shadows. If accompanied by kidney stones, it appears as scattered, clustered, or fan-shaped high-density shadows. Enhanced CT showed that the dilated collecting duct was striated or small sac-like contrast agent accumulation, and when accompanied by kidney stones, it showed that the collecting duct was filled with contrast agent around the stone. CT is currently the preferred method for the diagnosis of the medullary sponge kidney.

As for intravenous pyelography (IVP) and MRI, these two examinations are not only expensive but also inferior to the above two examinations in terms of comprehensive advantages in the diagnosis of the medullary sponge kidney. Studies have found that although the sensitivity of IVP in diagnosing medullary sponge kidney is higher than that of CT, CT is significantly better than IVP in displaying the number, location, and shape of small renal stones, and it is easy to detect renal papilla calcification, so it has been replaced by CT.

MRI lacks sensitivity in the diagnosis of medullary sponge kidneys and has low sensitivity to calcifications and stones. MRI can only be displayed when the cystic expansion of the collecting duct in the medullary medulla of the medullary sponge kidney is obvious, so it is not recommended.

treat

If the patient has no clinical symptoms or complications, no special treatment is required. Advise the patient to drink plenty of water and eat a low-calcium, low-oxalate diet to reduce the incidence of stones and prevent complications.

Patients with high calcium metabolism can be appropriately treated with thiazide diuretics and potassium citrate and other calcium-lowering drugs to prevent stone formation.

The medullary sponge kidney is often accompanied by microscopic hematuria. Gross hematuria is less common. It is often caused by secondary kidney stones, infection, and increased fragility of dilated renal tubules. Generally, hematuria does not require special treatment.

If it is caused by stones, surgical removal of stones may be considered.

If it is caused by infection, anti-infection treatment should be given. Low back pain is rare in the medullary sponge kidneys, and if it occurs, it needs to be differentiated from low back pain caused by other diseases[2].

Treatment of Complications

▌renal cyst

If there is a large renal cyst that causes hematuria and low back pain, the treatment is mainly ultrasound-guided percutaneous renal cyst puncture and injection of a sclerosing agent or laparoscopic renal cyst decompression combined with absolute alcohol sclerotherapy.

▌Acid metabolism abnormalities

Patients with medullary sponge kidneys often have renal tubular acidosis and hypocitraturia.

▌Urinary tract infection and stones

Long-term retention of urine in the dilated collecting duct and stone formation can lead to repeated urinary tract infections, and active anti-infective treatment should be performed at this time. At present, it is believed that the medullary sponge kidney leads to renal calcium leakage in the distal tubules leading to hypercalciuria and distal renal tubular acidosis are the main causes of calculi.

At present, there is no uniform method for the prevention and treatment of sponge kidney stones. Clinically, comprehensive treatment (such as drinking more water, low calcium, low oxalate diet, alkalization of urine, and control of urinary tract infection), extracorporeal shock wave lithotripsy, and surgical treatment are used.

▌Hyperparathyroidism

Calcium metabolism disorder is mostly caused by the medullary sponge kidneys, and long-term hyperuria causes hypocalcemia, resulting in secondary hyperparathyroidism. Clinical treatment is mostly combined therapy of lowering blood calcium and regulating endocrine, which can be considered when the symptoms are severe Parathyroidectomy was performed.

After understanding the disease, let's look at some subsequent examinations and treatments for this patient

Complete related inspections in outpatient clinics:

Blood routine: red blood cell count 4.5×1012/L, hemoglobin 135g/L.

Urine routine: urine specific gravity 1.015, protein-, white blood cells 126/μl, sediment red blood cells 3/μl.

Biochemical analysis: albumin 42.5g/L, creatinine 86μmol/L, urea nitrogen 4.5mmol/L, uric acid 223μmol/L, calcium 2.07mmol/L.

Quantitative 24-hour urine protein: 135.44mg/24h.

Five items of microalbuminuria and parathyroid hormone return were normal.

Urinary calcium returns were normal.

B-ultrasound return: Spongy renal changes in both kidneys.

Urinary tract CT is as follows:

CT showed that the patient had many small stones in both kidneys. After consulting a urologist for CT evaluation, there was no indication for extracorporeal shock wave lithotripsy and surgical treatment.

The patient’s family history was inquired about in detail, and he was told that his father had undergone multiple operations for kidney stones, and his renal function gradually declined until he developed uremia. He has been treated with hemodialysis for 3 years, so the possibility of family clustering cannot be ruled out.

The patient was very anxious after learning of his condition, fearing that he would end up relying on dialysis for life support like his father.

I advise the patient not to be overly anxious. The current condition is stable. Except for the treatment of urinary tract infections, no other special treatment is needed. The main thing is to follow up regularly to prevent the occurrence of medullary sponge kidney complications. In addition, it is recommended that patients drink more water, eat more vegetables and fruits, control a high-calcium diet, and regularly review urinary CT and follow-up. The patient's condition is currently good.

why eating cistanche can treat kidney disease

Cistanche is believed to have therapeutic effects on kidney diseases due to its beneficial properties. Some of the reasons why it is believed to help in treating kidney disease include:

1. Anti-inflammatory properties: Cistanche has potent anti-inflammatory properties that may help reduce inflammation in the kidneys, which can be beneficial for individuals with kidney disease.

2. Anti-oxidant properties: Cistanche contains antioxidants that help neutralize harmful free radicals in the body, which may contribute to the development of kidney disease.

3. Immunomodulatory properties: Cistanche has been shown to have immunomodulatory effects, which means it may help regulate the immune system and reduce inflammation and damage to the kidneys caused by an overactive immune response.

4. Kidneyprotective effects: Cistanche has been shown to have renal protective effects that can help prevent damage to kidney cells and tissues, which may slow the progression of kidney disease.

References:

[1] Lin Lu, Yu Shengqiang. New understanding of medullary sponge kidney [J]. Chinese General Medicine, 2016, 18 (18): 2213-2216

[2] Huang Fan, Li Zhipeng, Ye Chunwei. Understanding of medullary sponge kidney and its complications [J]. Medical Review, 2019, 25 (2): 302-306