Cystic kidney disease is a large group of diseases characterized by the presence of “cystic lesions” in the kidneys. According to the etiology, most cystic kidney diseases are congenital, while a few are acquired and uncharacterized. The classification of renal cystic disease is shown in Table 1.
Table 1: Classification of renal cysticercosis
Disease name
Incidence
Congenital
congenital
Congenital
Autosomal dominant polycystic kidney disease (ADPKD)
1/400~1000
Multicystic dysplastic kidney (MCDK)
1/1000~4000
Medullary sponge kidney (MSK)
1/5000
Juvenile nephronophthisis (JNPHP)
1/5000
Autosomal recessive polycystic kidney disease (ARPKD)
1/6000~55,000
Medullary cystic kidney disease (MCKD)
1/100,000
Glomerulocystic kidney disease (GCKD)
Rare
after
Acquired
acquired
Acquired cystic renal disease (ACRD)
>1/10 (uremic population)
muhilocular cyst of kidney (MCK)
Missing statistics
Not available
determined
unspecified
Simple renal cysts (SRC)
>5/100
Parapelvic cysts (PPC)
1 to 3/100
Pyelogenic cyst (PGC)
Missing statistics
I. Simple renal cysts
Simple renal cysts (SRC) are the most common cystic disease of the kidney. It increases with age, up to 25% or more in people over 50 years old. It can be unilateral, single or multiple, or bilateral and multiple. It is usually asymptomatic, with occasional pressure symptoms.
Diagnosis
(A) Clinical manifestations
Usually asymptomatic, mostly found incidentally during health checkups or imaging examinations for other diseases. Rarely, the cysts are large enough to be palpable. The most common conscious symptom is pain in the affected kidney area. The pain is exacerbated by intracapsular bleeding or secondary infection. Some patients may present with hematuria or proteinuria. 6.4% may have carnal hematuria; 40% may have microscopic hematuria; and 12% may have proteinuria. The degree of hematuria or proteinuria is not related to the size of the cyst.
Cysts increase in size with the duration of the disease. The rate is variable, usually slow; if the increase is rapid, be aware of the possibility of hemorrhage or cancer.
(ii) Ancillary tests
Ultrasound examination is preferred for simple cysts. If the ultrasound result is suspicious or ambiguous, CT scan is necessary.CT scan, the criteria of benign cyst include: ① sharp cyst boundary, smooth and thin wall; ② uniform fluid inside the cyst, usually density < 20HU, high density is seen in cyst fluid high protein or cyst bleeding; ③ cyst without enhancement.
【Treatment
Simple renal cysts progress slowly and have a good prognosis. Those with no conscious symptoms or imaging changes such as pressure obstruction rarely require surgical intervention and regular imaging review is sufficient. The indications that are generally considered to require surgical management are: ① those with painful symptoms or psychological stress; ② those larger than 4 cm or with compression-obstruction imaging changes; ③ those with secondary bleeding or suspected cancer.
Treatment methods include cyst puncture sclerosis, open renal cyst decompression, or laparoscopic cyst decompression.
Anhydrous alcohol puncture sclerosis, with an efficiency close to 80% for cysts smaller than 8 cm, should be recommended as the first choice. With the popularity of laparoscopic techniques, laparoscopic renal cyst depanalization and decompression, is expected to become the gold standard for the treatment of cysts larger than 8 cm. Open surgery, which is not aimed at relieving the symptoms of pressure obstruction caused by cysts or removing suspected cancerous lesions, but only at eliminating cysts, should not be recommended.