Kidney Stones & Symptoms

About kidney stones

Kidney stones (calculi) are made of substances normally found in the urine. Stones begin as small crystals in the kidney. They form when the urine is too concentrated in calcium or other chemicals that can group together. Over time, these crystals may grow into stones. Small stones can pass out of the body undetected along with urine. But when larger stones fall into and obstruct the ureter (the narrow duct that drains urine from the kidney to the bladder), they can cause sudden, severe pain.

Stones grow in an unpredictable fashion. They can grow in quick spurts or extremely slowly, depending on conditions in the urine.

About 90% of kidney stones contain calcium. Most commonly, the crystals are made of calcium oxalate and occasionally they are made of calcium phosphate. Less common stone types are uric acid, cystine and struvite.

Kidney stone facts

  • Around 10 percent of people will develop a kidney stone in their lifetime.
  • 50 percent of people who experience a kidney stone will have a recurrence within 7 to 10 years.
  • 50 percent of asymptomatic stones within the kidney will cause symptoms within the next 5 years.

Kidney stone symptoms

Most people are diagnosed with kidney stones after experiencing unforgettable pain. This severe pain occurs when the stone drops into the ureter (the narrow duct that drains urine from the kidney to the bladder) and blocks the drainage of urine from the kidney. This is also known as renal colic. The pain may begin in the lower back and may move to the side or groin. Stones in the kidney that do not obstruct urine flow may cause a chronic dull ache.

In addition to pain, other kidney stone symptoms include:

  • Side pain that is not affected by activity
  • Blood in the urine
  • Frequent or persistent urinary tract infections
  • Urinary urgency or frequency
  • Nausea

For many people, kidney stones cause no symptoms and are detected when microscopic amounts of blood are found in the urine. They may also be detected during x-ray tests for other medical problems.

Controlling pain

Patients often describe the pain associated with kidney stones as, "The worst pain I've ever had."

Kidney stones cause severe pain when they drop into the ureter (the narrow duct that drains urine from the kidney to the bladder) and block urine from draining into the bladder. This is known as renal colic.

We work to get your pain and nausea under control as quickly as possible. Pain can usually be treated at home, although in some cases, medications must be administered by IV (intravenously) in the emergency room. The most severe cases of pain require hospitalization and surgery.

Your doctor will determine the best pain medication for you. The following are common medications to relieve pain and nausea.

  • Morphine-based medications (narcotics) are usually the most effective for pain control. Depending on the situation, they may be taken orally (by mouth) or by IV.
  • Non-steroidal anti-inflammatories (aspirin-like drugs such as ibuprofen) may also be suggested by your doctor. In addition to relieving pain, they may also decrease the spasms of the smooth muscle of the ureter.
  • Anti-emetics - Renal colic is often accompanied by tremendous nausea and vomiting. In addition to IV fluids for rehydration, oral or IV anti-nausea drugs provide relief of symptoms.

Kidney stone emergencies

Fever and a stone

This can be a life-threatening emergency. The kidney is essentially a blood filter. If it becomes obstructed and there are bacteria in the kidney, these bacteria can quickly move into the blood stream. The first signs of this are fever or an elevated white blood count. The next signs, particularly in frail individuals, can be severe whole body sepsis and even death. If an obstructing stone is associated with fever, this is a true emergency and urgent drainage (by either a ureteral stent or a nephrostomy tube) is necessary.

No urine

Occasionally a person may have stones blocking both kidneys at the same time or may only have one kidney that works. In this case, there is a significant risk of build-up of waste products in the blood that normally would be excreted by the kidneys. In this situation, urgent drainage is required.

Need for hospitalization

While the vast majority of patients with kidney stones do not need to be admitted to the hospital, sometimes hospitalization is necessary. Reasons for admission include:

If pain cannot be controlled in the emergency room, admission to the hospital and continuous IV narcotics may be required. If the pain does not settle within a short period of time surgical procedures may be needed. The procedure would depend on the stone’s size and location.

Patients who cannot keep fluids down cannot be allowed to leave the emergency room. In that situation, admission to the hospital and administration of IV fluids and potent anti-nausea medication (anti-emetics) may be necessary.

An admission to the hospital does not necessarily mean that a stone needs to be treated immediately. Many small stones will still pass on their own and larger, more complex stones may be better managed electively after the current crisis resolves.

Contact Kidney Stone Institute

A doctor's referral is not required to make an appointment.

1-888-326-3830 (toll-free)


Monday through Friday, 8 am to 4:30 pm
Outside of these hours, you can call us and speak with a registered nurse who will review your symptoms and make recommendations to help you get appropriate care.