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Educational Materials

Kidney stone

“I can't go to toilet as much as I like as I am stuck in the car, so I can't drink too much water” Limited by the working environment, drivers tend to drink less water to minimize the frequency of urination. However, this may cause substances in urine accumulate and even crystalized to become kidney stone. Kidney stone belongs to upper urinary tract stone. If the urethra is obstructed by the stone, it may cause renal failure. Kidney stone is common in Hong Kong. In average, about 9000 patients require in-patient treatment. Currently there are three minimally invasive surgeries for kidney stone treatment, depending on the needs of the patients.

Cause of kidney stone

There are many types of kidney stone; most of them are calcium-containing stone, while the rest are mainly uric acid stones. Little water intake may increase the chance of kidney stone formation, as well as salty diet, over ingestion of vitamin C, steroids or antacids, hyperkalemia or hypophosphatemia may also lead to kidney stone formation. Abnormal metabolism, inheritance, inflammation in the urinary system or imbalanced endocrine are also causes of kidney stone.

Symptoms of kidney stone

“Do you have any intermittent colic pain or lower abdominal pain?” If so, please be alarmed. This may be a sign of kidney stone. In general, early stages of kidney stones have no obvious symptoms. As the size grows larger or falls into the urethra, colic pain or lower abdominal pain may be present. Sometimes the pain may be referred to the pain in the groin or the external reproductive organs. Meanwhile, patients may experience other symptoms such as nausea, pain and difficulty in urination, UTI, hematuria or vomiting.

Examination of kidney stone

  • Blood test and urine test: test for uric acid, phosphate and calcium content
  • X-ray with contrast: examine renal function and the condition of kidney stone
  • Ultrasound scan or CT scan: detect micro-kidney stone or hydronephrosis

Minimally invasive lithotripsy

If the stones are small enough, water drinking and medication alone can help dissolve some of the stones and eliminate it with urine. For larger stones, minimally invasive lithotripsy may be necessary. Doctors would provide suitable treatment based on patient’s conditions.

Extracorporeal shock wave lithotripsy (ESWL) is a common non-invasive treatment for kidney stones. With the use of X-ray to locate the stone, the acoustic pulse is used to break the stone apart and removed along with urine. Patients are encouraged to drink more water after the surgery to facilitate the elimination of the stone. This is a simple surgery with only IV anesthesia and it is non-invasive. Patients can be discharged on the same day and recovered within a few days. Success rate is about 40-80%. However, this surgery is not advised for bladder stone, large stone, pregnant women or obese patients.

Another minimally invasive surgery is ureteroscopic lithotripsy. Patients are under general anesthesia and urologist would place an endoscope into the ureter with x-ray confirmation of the stone. Once the location is confirmed, the stone will be broken down by laser. Since the endoscope is inserted through the urethra, no incision is required and the pain is minimal. Patients may have to be hospitalized for 1-3 days and recovered in a few days. The success rate is about 90%.

Percutaneous nephrolithotomy (PCNL) is also a minimally invasive surgery. Under general anesthesia, a catheter will be placed into the bladder with X-ray guidance. Then the skin at the lower back will be punctured in order to place the endoscope. The stone will be broken down by lithotripsy instrument and be extracted with forceps. The success rate is over 90% with one week hospitalization and 2 weeks for recovery, depending on patient’s condition.

Risk of lithotripsy

  • Blood in urine, pain or discomfort during urination
  • Ureter puncture
  • Urinary tract infection
  • Injuries to renal vessels, causing bleeding

Prevention of Kidney stone

  • Adequate water intake, at least 1.5L of water each day. For patients with heart or liver diseases, please consult your doctors first.
  • Avoid food and drinks that are rich in salt and oxalic acid, such as beer, nuts, and dark tea. Have more food or drinks that are rich in citrus acids.
  • Weight control and regular body check.

The information on this website is for general educational purpose only.
Readers should consult their physician before considering treatment, and should not interpret their condition solely based on the information above.