The urinary system is a group of organs that filter blood and remove waste products from the body in the form of urine. Urine is excreted from the body by going through a series of tubes and channels that lead to the external environment. This series of tubes make up the urinary tract, which is comprised of the following:
- Right and left kidneys, which filter the blood and make the urine
- Right and left ureters, which carry the urine from the kidneys to the bladder
- Urinary bladder, which stores the urine until it can be expelled from the body
- Urethra, which carries the urine from the bladder to the external environment
A urinary stone or urolithiasis can form anywhere in the urinary tract. The presence of stones in the kidneys is called nephrolithiasis; in the ureters, it’s called ureterolithiasis; and in the bladder, it’s called cystolithiasis. Stone forms in the urinary tract when an imbalance of the minerals and salts in the urine causes it to crystalize. Stones can range from a small millimeter to a size of a fist.
Most urinary stones do not present with symptoms at first. Small stones can be passed unnoticed in the urine. However, as the stone enlarges, it begins to obstruct the urinary tract and starts producing symptoms. These symptoms can worsen as the stone passes down along the urinary tract. These symptoms include:
- Severe pain on the back or on the side that is not relieved or aggravated by movement or change in position
- Pain that is waxing and waning in character
- Pain that slowly migrates from the back to the lower abdomen then to the groin
- Dysuria: Painful urination or a burning sensation during urination
- Cloudy or bloody urine
- Frequency: Frequent but often scanty urine
- Fever and chills
- Nausea or vomiting
A visit to the doctor is necessary when any of these signs or symptoms are present. On top of history and physical examination, a physician might request for the following:
- Urinalysis: A microscopic examination of the urine can detect blood cells and crystals which might clinch the diagnosis of stones
- Ultrasound: An ultrasound of the urinary tract can demonstrate the presence of stones. However, it can miss some small stones
- CT stonogram: This is the gold standard for the diagnosis of stones. This CT scan of the urinary tract can accurately detect the small stones that are often missed by ultrasound or X-ray.
The treatment of kidney stones depend on three major factors: the size of the stone, the type of the stone, and the location of the stone.
The size of the stone is important because it determines whether a stone can be passed out spontaneously. In general, stones that are 5mm or smaller have a 90% chance of being passed out spontaneously. With vigorous hydration, these stones can be successfully flushed out of the urinary system. Stones that are 5-10mm have a 50% chance of being passed out. Giving alpha-blockers, which are medications that relax the ureters and make it wider, making it easier for the stone to pass, can increase this chance.
Stones that are 10mm or larger might need to be crushed or extracted surgically. Extracorporeal shock wave lithotripsy or ESWL is a treatment modality that uses sound waves to crush stones into smaller pieces that can be passed down spontaneously. ESWL might cause some pain during the procedure and some bruising at the back and the abdomen. It might also cause a bloody urine and painful urination as the stones are passed out.
For stones that are located in the ureters, ureteroscopy can be done. This involves passage of a thin scope through the urethra up into the bladder and into the ureters to locate the stones. Once sighted, the stone can be crushed or extracted using a basket or a snare.
For very big stones or stones that are not suitable for ESWL or ureteroscopy, the last resort is surgery or nephrolithotomy. This involves opening the abdomen and opening the urinary tract and manually extracting the stone.
Once the stone is extracted, it should be sent for stone analysis. A stone analysis could identify the type of the stone and the possible mineral or salt imbalance that caused it. This can guide the doctor in identifying the lifestyle or diet modifications that are necessary to prevent recurrence of stones. In general, these lifestyles changes include the following:
- Drink plenty of water: Keeping your urine diluted will prevent it from crystallizing and forming stones.
- Decrease salt or sodium in the diet. This can prevent recurrence of calcium stones.
- Cut down on foods rich in oxalate like chocolates, coffee, tea, beans, and soy products
- If you have uric acid stones, cut down on foods that are rich in uric acid meat, anchovies, sardines, mackerel, or tuna.