Stone disease

Stone disease

What is urinary stone disease?

Stone disease is the presence of a stone or stones in the urinary system. Depending on the location, we have lithiasis of the kidneys (nephrolithiasis), lithiasis of the ureters, lithiasis of the bladder and finally lithiasis of the urethra. It is one of its most common ailments, affecting 10% of the general population.

Types of stones

There are different types of stones that are determined based on their chemical composition.

  1. Mixed 35%-40% 
  2. Calcium oxalate 30%-35% 
  3. Magnesium ammonium phosphate (inflammatory) 10%-15%
  4. Uric acid 8%-10%
  5. Calcium phosphate 5%-10%
  6. Cystine 2%-3%.

Symptoms

  • Renal colic, a sharp and sudden lumbar pain, which reflects in the front and towards the genitalia and the pain does not improve or worsens with the change of body position.
  • Nausea and vomiting.
  • Painful haematuria (gross or microscopic).
  • Frequent urination, dysuria, fever (when a urinary tract infection is present).

Risk factors

The creation of stones in the urinary system is still unknown, but it is believed to be determined by factors that are either idiosyncratic to each person (endogenous risk factors) or come from their environment (exogenous risk factors). Usually, it is a combination of factors that contribute to the creation of stones.

Endogenous risk factors include: age (more common between 20 and 50 years), gender (three times more common in men) and family history-heredity. Exogenous factors include: hot climate, diet, increased body weight, reduced fluid intake, sedentary work, lack of exercise and some medications.

In all cases, when the stone has been removed from the urinary system, either expelled automatically, or surgical, we send it for chemical analysis and determine its chemical composition. In some types of stones there are preparations that reduce its size or prevent its re-formation. 

Stone disease

Prevention

A specific lithiasis diet has to be followed to avoid the recurrence of lithiasis. In addition, in order to lose weight, moderate intensity physical exercise help to avoid relapse. These measures prevent the reappearance of a stone in a percentage of up to 75%.

As far as the diet is concerned, the foods that should be avoided are:

Calcium oxalate

Uric acid - cystine

Inflammatory stones

Diagnosis

The diagnosis of urinary stone disease is made by the history, the clinical examination and the laboratory and imaging tests. 

Imaging tests:

  • KUB X-ray: 80-90% of stones can been seen, but there are stones that are not visible.
  • KUB ultrasound: kidney or bladder stones can be seen or kidney obstruction.
  • Intravenous pyelography: Shows the exact location of the stones, as well as the existence of anatomical abnormalities that predispose to the formation of stones. It also allows the assessment of renal function and the degree of hydronephrosis.
  • CT scan without contrast: it is superior to intravenous pyelography.

 

Laboratory tests:

  • Urine analysis: Usually, there are red blood cells in the urine and sometimes evidence of a urinary tract infection.
  • Biochemical blood analysis: Measurement of serum urea and creatinine, uric acid and serum calcium.
  • PTH Hormone: it is measured when we have stone disease in both kidneys and may show hyper function of the parathyroid glands.
  • 24-hour urine collection: possible finding of some metabolic abnormality.
  • Chemical stone analysis: finds the type of the stone, so that the appropriate measures can be taken to reduce the chances of recurrence of lithiasis.
Stone disease

Treatment

Treatment of symptoms: When the patient has severe pain, the aim is to relieve him by analgesics.

Drug treatment: In some types of stones, drugs can be prescribed, which may reduce the size of the stone or prevent its re-formation. 

Stone removal: Stone removal: it depends on the size and location of the stone in the urinary system. If the stone is smaller than 5mm, in a percentage of 70% it will be expelled automatically in a waiting period of 4-6 weeks. An a-adrenergic receptor blocker, which increases the diameter of the ureter and urethra, can be prescribed to facilitate passage of the stone. Patients who will need immediate intervention are those with obstruction of the kidney or when there is a urinary tract infection. In these cases, a ureteral catheter (pig-tail) may need to be placed until the stone is removed. In the remaining cases, however, invasive treatment will be needed. Invasive methods include:

  • Extracorporeal shock wave lithotripsy (ESWL): The stone breaks with shock waves. It is usually very well tolerated by the patient and can be up to 90% effective. However, there are stones that cannot be broken by extracorporeal lithotripsy.
  • Endoscopy and intracorporeal lithotripsy: It is used for stones located in the ureter or kidney stones that can’t be broken with extracorporeal lithotripsy. The scope passes through the urethra and finds where the stone is. Then, special stone breakers break the stone, and its fragments are removed. The most modern stone breakers are laser stone breakers.
  • Percutaneous nephrolithotripsy: It is used for large kidney stones or kidney stones that couldn’t been broken with extracorporeal lithotripsy. Through a hole made from the skin to the kidney, the nephroscope is inserted in order to find the stone and break it with special stone breakers, usually ultrasonic or ballistic.
  • Open surgery: It has been restricted today and is reserved for selected cases only.

Depending to its size and its location, the methods that can be used to remove the stone are shown in the table below:

<5mm

5-10mm

10-20mm

>20mm

Kidneys

Follow - up or ESWL

ESWL or Endoscopy and intracorporeal lithotripsy with laser

Repeated ESWL with pig-tail insertion or Percutaneous nephro-lithotripsy

Ureters

Follow - up or ESWL

ESWL or Endoscopy and intracorporeal lithotripsy with laser

Endoscopy and intracorporeal lithotripsy with laser

Urinary Bladder

Follow - up

Follow-up or cystoscopy and intracorporeal lithotripsy with laser

Cystoscopy and intracorporeal lithotripsy with laser (with a possibility of transurethral prostatectomy)

Urethra

Follow - up

Monitoring or removing a stone with tweezers (basket)

Monitoring or removing a stone with tweezers (basket)