Kidney stones form over time when crystals of certain minerals clump together in the kidneys or elsewhere in the urinary tract such as the ureters or the urinary bladder.
Some stones are silent while most present with typical prominent symptoms, pain being the most typical.
Kidney stones are of various types and diagnosis is just not about diagnosing their presence. It is also necessary to find out what type of stone is present, its location, and its size. This helps the urologist to formulate the right treatment option and also helps prevent its recurrence.
A confirmatory diagnosis is arrived at with the help of blood tests, urine analysis, X-rays, ultrasound, CT scan, and analysis of a stone that has been collected after passing out through urine.
Treatment of kidney stones involves the use of conservative measures such as tablets for pain and other symptoms and for facilitating faster passing out of the stone. Treating kidney stones without surgery involves the use of procedures such as shock wave lithotripsy (SWL) and Ureteroscopy.
Surgery for kidney stone is called Percutaneous nephrolithotomy in which the surgeon makes a cut in the abdomen or flank to approach the kidney and physically break and remove the stone(s).
Kidney stones may be detected accidentally in “silent” cases where no symptoms are present. This usually happens during a health checkup where the stones are seen on a plain x-ray or on the ultrasound of the abdomen and pelvis.
However, most stones are detected when the patient presents with typical urinary symptoms and the pain of kidney stones.
Once your doctor suspects a kidney stone, he will want to confirm its presence and get additional knowledge about its location and the size of the stone to plan its treatment and to prevent a recurrence.
The process of diagnosing kidney stones consists of blood tests, urine analysis, radiology procedures, and laboratory analysis of the stones that have passed out through the urethra.
Blood tests for kidney stones
- A complete blood count may be done if there are any signs of infection.
- Renal function blood tests (mainly blood urea nitrogen and serum creatinine) are performed to evaluate kidney function.
- Blood tests measure the elevated or decreased amounts of substances in urine that are commonly associated with kidney stone formation. These include tests to find levels of calcium, uric acid, and electrolytes (sodium, potassium, chloride, bicarbonate).
A routine urine analysis is done to check the pH and the presence of crystals, blood, and pus cells. The presence of crystals and blood in urine raises the possibility of the presence of stones in the urinary tract and pus cells confirm the presence of infection.
You will be asked to collect a 24-hour urine sample on two consecutive days. The lab will test these samples to find out if you are excreting too many stone-forming minerals or too few stone-inhibiting substances.
A urine test will look for the following substances: Some are minerals, which make up the different types of stones, some are stone-forming substances and others are stone inhibiting substances.
- Urine calcium
- Urine oxalate
- Urine uric acid
- Urine citrate (stone inhibitor)
- Urine cystine
- Urine phosphorus
- Urine magnesium (stone inhibitor)
- Urine sodium (indirectly cause stone formation)
Kidney stone diagnostic imaging
- A plain x-ray (KUB) is not used nowadays because it can miss small stones.
- Computerized tomography (CT scan) is the most reliable method to diagnose stones in the urinary tract. A dual-energy computerized tomography (DECT) may reveal even tiny stones and can help assess the composition of the stone.
- At times, your urologist may ask for a contrast CT scan in which a contrast dye is injected through your vein and the scan is taken. It makes it easier to see the structures inside the abdomen and the pelvis.
- Ultrasound of the abdomen and pelvis is a noninvasive test that is easy to perform and is the most preferred initial imaging test done to diagnose kidney stones. It will also show the location and size of the stones in the kidneys, ureters, urinary bladder and will also reveal any swelling of the kidneys (hydronephrosis).
Analysis of passed stones
You may be asked to urinate through a sieve to catch any stone that you may pass through urine. Your healthcare provider will send the collected stone to the lab for analysis to know what type of stone it is. This helps him to plan the right treatment and prescribe measures to prevent its recurrence.
Treatments of small and large stones
Treatment of kidney stones focuses on managing the symptoms, removing the stones, and preventing their recurrence. There are several options to treat and your urologist will choose the option that will suit you and your stones the best.
Your healthcare provider will invariably first ask you to increase fluid intake to an adequate level. He will give you medication to relieve your symptoms (especially the pain) and to help you pass the stone out of your urinary tract as soon as possible.
Medications for kidney stone pain and prevention
Your urologist will prescribe medications to relieve pain, control infection, and prevent a recurrence.
- Ibuprofen (Advil), acetaminophen (Tylenol), naproxen sodium (Aleve) is given for pain
- Allopurinol (Zyloprim) is advised for uric acid stones
- Thiazide diuretics are prescribed to prevent the formation of calcium stones
- Sodium bicarbonate or sodium citrate is advised to make the urine less acidic
- Phosphorus solutions are advised to prevent the formation of calcium stones
Treatment to pass out small kidneys stones fast
This is the most used option for small stones. The size of the stone is a major factor that will decide if the stone will pass out by itself and after how much time.
Most stones smaller than 4 mm pass out on their own in about one month. Stones that are 4–6 mm may require some sort of treatment, but most pass out naturally in about 45 days. Stones larger than 6 mm usually require medical intervention to remove them.
To help the small stones to pass out quickly on their own, your doctor will advise you the following:
- Drink an adequate amount of water during the day – about 3 to 4 liters. This way your urine will stay well diluted and will prevent stones from forming. You will urinate more often and with added force, which will help to pass out the small stones.
- If you are dehydrated or suffering from nausea and vomiting, you may need to be given I.V. fluids to restore proper hydration.
- To relieve the pain of the kidney stone and the pain caused by its passage through the urethra, your doctor will prescribe pain relievers.
- To speed up the passage of stones through urine, your doctor may prescribe alpha-blockers, which relax the muscles of the urinary tract and enable faster expulsion of the stones with less pain. Today, alpha-blockers form the first line of treatment for medical expulsive therapy (MET) and are advised for 4 to 6 weeks. According to The American Academy of Family Physicians, the alpha-blocker, tamsulosin (Flomax), fast tracks passage of stones larger than 5 mm, shortens the time for removal, and reduces hospitalization. Its combination of dutasteride and tamsulosin (Jalyn) is also used.
Treatment to remove large kidney stones
Kidney stones that are large and cannot be expelled through urine may require some medical intervention.
Such intervention becomes necessary when
- The stone fails to pass out.
- It causes severe pain and discomfort to the patient.
- It affects kidney function.
- The stone causes repeated urinary tract infections.
Procedures and surgery to remove large kidney stones include:
- Shock wave lithotripsy
- Using a scope to remove stones
Shock wave lithotripsy (SWL)
In this procedure, shock waves break up the large kidney stone into small pieces, which then pass out through the urine. This procedure makes the use of high-energy sound waves that create strong vibrations, which pass through your body breaking the stone into small pieces. The shock waves are focused on the stone under ultrasound guidance.
This procedure is an OPD procedure done under sedation or light anesthesia and takes about an hour. There is no overnight admission required.
Shock wave lithotripsy is indicated in a person who has a kidney stone that is causing severe pain or blocking the urine flow. This procedure is mostly used for stones that are situated in the kidney or in the ureters close to the kidney and are between 4 mm and 2 cm in diameter.
SWL is not effective on hard stones, such as cystine, calcium oxalate, calcium phosphate stones, and very large stones.
Post-procedural side effects include blood in the urine, bruising around the abdomen and back, bleeding around the kidney, and pain as the broken stone fragments pass through the urinary tract.
It is contraindicated in pregnant women, in the presence of urinary tract infection and if there is any abnormality in the kidney structure or function.
Cystoscopy and Ureteroscopy
Cystoscopy involves the use of a cystoscope to look at and break stones that are situated in the urethra and the bladder.
Ureteroscopy involves the use of a ureteroscope, which is thinner and longer than the cystoscope to inspect the ureters and the kidneys.
In these procedures, the urologist inserts a small wire with a camera attached, through the urethra into the bladder or the ureter and kidney as indicated. It is done under general anesthesia.
Once the urologist views the stone, a small device grabs the smaller stones and removes them. A large stone is broken into smaller pieces with a laser or other tools.
Telescopes used to break stones in the lower part of the ureter are rigid while flexible telescopes are used to treat stones in the upper ureter and kidney.
After ureteroscopy, once the stone has been dealt with, the urologist places a stent (a tiny, rigid plastic tube) in the ureter to relieve any post-procedural swelling. This helps to keep the ureter patent and facilitates the urine formed in the kidneys to drain into the urinary bladder.
You go home the same day and can begin your routine activities within two days. The urologist will remove the stent within four to ten days.
Kidney stone surgery
Surgical removal of stones is an option used when other less invasive treatments have failed.
Percutaneous nephrolithotomy is surgery that removes the stone from the kidney
Parathyroid gland surgery is done for hyperparathyroidism to prevent the formation of calcium stones.
Percutaneous nephrolithotomy (PCNL)
In this surgical procedure, the urologist uses a nephroscope (a thin viewing tool) to locate and remove the stone in the kidney.
The urologist places the nephroscope through a small cut in the patient’s back or flank into the renal pelvis. The stone(s) are then directly viewed and fragmented. He then sucks the fragments through the scope. This facility to break and suck the broken pieces makes PCNL the best treatment of choice for large stones.
For larger kidney stones, the urologist may use a laser to break the kidney stones into smaller pieces.
This surgery is performed in the hospital operation theater under general anesthesia. After the PCNL, the urologist usually places a drainage tube in the kidney to drain urine into a bag placed outside the body. This allows for drainage of urine and to stop any bleeding. The tube is left in overnight or for a few days. You may have to stay in the hospital for several days after the procedure.
Your urologist may choose to do an ultrasound of the abdomen and pelvis while you are still in the hospital to see if any stone pieces remain. If there are any, your urologist may want to remove them with a telescope again. You can begin normal activities after about one-to-two weeks.
Parathyroid gland surgery
Parathyroid glands are located on the four corners of your thyroid gland, just below your Adam’s apple
Some calcium phosphate stones are caused by overactive parathyroid glands (hyperparathyroidism), which cause the production of too much parathyroid hormone. This can cause your calcium levels to become too high and give rise to kidney stones.
Hyperparathyroidism is sometimes caused by a small, benign tumor in one of your parathyroid glands or due to some other condition that causes the glands to become overactive and produce more parathyroid hormone.
Surgically removing the growth from the gland prevents the formation of these stones. At times, your doctor may recommend conservative treatment for a condition that is causing your parathyroid gland to become overactive and produce more hormones.