Cysts are sacs enclosed by epithelial cells which contain liquid inside them. Almost all kidney cysts are benign and are formed by the dilation of a segment or a collecting duct.
Kidney cysts usually have a significant genetic component and their prevalence increases with age, with it being calculated that up to a third of the population aged 50 has some type of kidney cyst.
Conditions and types of kidney cysts:
Simple and complex kidney cysts.- We call complex cysts those which visually have a thicker wall on an ultrasound scan or some characteristic that makes a complementary study (such as a tomography) advisable to rule out other conditions.
Polycystic kidney disease.- This is an inherited condition in which groups of cysts are formed that can grow and become very large.
Autosomal dominant and recessive polycystic kidney diseases have their origin in the genes ERPAD and ERPAR, respectively.
In these cases, unlike isolated cysts, a regular follow-up is necessary since they can damage the kidneys and cause high blood pressure, headaches and back pain, haematuria, etc. and even kidney failure.
Medullary cystic kidney disease.-
Medullary sponge kidney (Cacchi-Ricci disease).- This presents from childhood due to anomalies in the precalyceal terminal collecting ducts forming diffuse cysts.
In the majority of people, these cysts go unnoticed and without complications, but they can be a factor for the development of stones.
They are usually revealed after a urography or CT urogram between the ages of 30 and 50.
Multicystic dysplastic kidney.- This is a condition produced during the development of the fetus and which is characterised by the appearance of irregular cysts of different sizes in one of the kidneys.
It is often accompanied by other cardiac and intestinal anomalies and abnormalities in the urinary tract. It has a prevalence in the left kidney of male babies.
Nephroptosis.- Of genetic origin, this set of conditions is the most common cause of kidney failure in childhood and adolescence.
In addition to cysts forming in the renal medulla, they are also formed in the corticomedullary junction, accompanied by glomerular sclerosis and tubular atrophy.
The symptoms include anaemia, stunted growth in children, high urine production, etc.
As we have seen, kidney cysts can go unnoticed on many occasions and without major complications, but in other cases they can cause alterations in the production of urine, excessive intake of water, anaemia, kidney failure, etc.
They will sometimes be the cause of other conditions such as kidney stones, with symptoms which could be:
- Pain in the upper abdomen, pelvis and ribs.
- Haematuria (blood in the urine).
- Fever (usually indicates infection).
As kidney cysts are asymptomatic most of the time, their discovery is usually made by doing X-rays or ultrasound scans which are done for other reasons.
Only in cases in which complex kidney cysts are discovered are additional imaging tests of the abdomen and pelvic floor requested. These can be ultrasound, CT or magnetic resonance tests.
Treatment is not usually performed, unless they cause damage to kidney function, and the treatment could be:
- Laparoscopic surgery: Through a small incision, the cyst is accessed with a laparoscope. The cyst may be resectioned, burnt or drained by the surgeon.
- Sclerotherapy: The surgeon inserts a long needle into the skin, guided by ultrasound. First, the cyst will be drained and then subsequently a solution of alcohol will be infiltrated, which will make the cyst shrink and harden.