Kidney Stones

Kidney Stones Overview
The kidney acts as a filter for blood, removing waste products from the body and making urine. It also helps regulate electrolyte levels that are important for body function. Urine drains from the kidney through a narrow tube called the ureter into the bladder. When the bladder fills and there is an urge to urinate, the bladder empties to the outside through the urethra, a much wider tube than the ureter.
In some people, chemicals crystallize in the urine and form the beginning, or nidus, of a kidney stone. These stones are very tiny when they form, smaller than a grain of sand, but gradually can grow over time to 1/10 of an inch or larger. Urolithiasis is the term that refers to the presence of stones in the urinary tract, while nephrolithiasis refers to kidney stones and ureterolithiasis refers to stones lodged in the ureter. The size of the stone doesn't matter as much as where it is located and whether it obstructs or prevents urine from draining.
When the stone sits in the kidney, it rarely causes problems, but when it falls into the ureter, it acts like a dam. As the kidney continues to function and make urine, pressure builds up behind the stone and causes the kidney to swell. This pressure is what causes the pain of a kidney stone, but it also helps push the stone along the course of the ureter. When the stone enters the bladder, the obstruction in the ureter is relieved and the symptoms of a kidney stone are resolved.

Kidney Stones Causes

There is no consensus as to why kidney stones form.

* Heredity: Some people are more susceptible to forming kidney stones, and heredity may play a role. The majority of kidney stones are made of calcium, and hypercalciuria (high levels of calcium in the urine) is a risk factor. The predisposition to high levels of calcium in the urine may be passed on from generation to generation. Some rare hereditary diseases also predispose some people to form kidney stones. Examples include people with renal tubular acidosis and people with problems metabolizing a variety of chemicals including cystine (an amino acid), oxalate, (a type of salt), and uric acid (as in gout).


* Geographical location: There may be a geographic predisposition, and where a person lives may predispose them to form kidney stones. There are regional "stone belts," with people living in the southern United States having an increased risk of stone formation. The hot climate in this region combined with poor fluid intake may cause people to be relatively dehydrated, with their urine becoming more concentrated and allowing chemicals to come in closer contact to form the nidus, or beginning, of a stone.


* Diet: Diet may or may not be an issue. If a person is susceptible to forming stones, then foods high in calcium may increase the risk; however, if a person isn't susceptible to forming stones, diet probably will not change that risk.


* Medications: People taking diuretics (or "water pills") and those who consume excess calcium-containing antacids can increase the amount of calcium in their urine and potentially increase their risk of forming stones. Taking excess amounts of vitamins A and D are also associated with higher levels of calcium in the urine. Patients with HIV who take the medication indinavir (Crixivan) may form indinavir stones. Other commonly prescribed medications associated with stone formation include dilantin and antibiotics like ceftriaxone (Rocephin) and ciprofloxacin (Cipro).


* Underlying illnesses: Some chronic illnesses are associated with kidney stone formation, including cystic fibrosis, renal tubular acidosis, and inflammatory bowel disease.

Kidney Stones Symptoms and Signs

When a tubular structure is blocked in the body, waves of pain occur as the body tries to unblock the obstruction. These waves of pain are called colic. This is opposed to non-colicky type pain, like that associated with appendicitis or pancreatitis, in which movement causes increased pain and the patient tries to hold very still.

* Renal colic (renal is the medical term for things related to the kidney) has a classic presentation when a kidney stone is being passed.


o The pain is intense and comes on suddenly. It may wax and wane, but there is usually a significant underlying ache between the acute spasms of pain.


o It is usually located in the flank or the side of the mid back and may radiate to the groin. Males may complain of pain in the testicle or scrotum.


o The patient cannot find a comfortable position and often writhes or paces with pain.


* Sweating, nausea, and vomiting are common.


* Blood may or may not be visible in the urine because the stone has irritated the kidney or ureter. Blood in the urine (hematuria), however, does not always mean a person has a kidney stone. There may be other reasons for the blood, including kidney and bladder infections, trauma, or tumors. Urinalysis with a microscope may detect blood even if it is not appreciated by the naked eye. Sometimes, if the stone causes complete obstruction, no blood may be found in the urine because it cannot get past the stone.

Kidney Stones Treatment

Kidney Stone Home Remedy

* Prevention is always the preferable way to treat kidney stones. Remaining well hydrated keeps the urine dilute and helps prevent kidney stones from forming.


* Those who have never passed a kidney stone may not appreciate the severity of the symptoms. There is little a person can do at home to control the debilitating pain and vomiting that can occur with a kidney stone other than to seek emergency care. If this is the first episode and no previous diagnosis has been established, it is important to be seen by a health-care provider to confirm the diagnosis.


* For those who have a history of stones, home therapy may be appropriate. Most kidney stones, given time, will pass on their own, and treatment is directed toward symptom control. The patient should be instructed to drink plenty of oral fluids. Ibuprofen may be used as an anti-inflammatory medication if there is no contraindication to its use. If further pain medication is needed, the primary-care provider may be willing to prescribe stronger narcotic pain medications.


* Please note, if a fever is associated with the symptoms of a kidney stone, this becomes an emergency, and medical care should be accessed immediately. Urinary tract infections associated with a kidney stone often require urgent assessment and may need intervention by a urologist to remove or bypass the stone.

Medical Treatment

* In the emergency department, intravenous fluids may be provided to help with hydration and to allow the administration of medications to control pain and nausea. Ketorolac (Toradol), an injectable anti-inflammatory drug, and narcotics may be used for pain control, with the goal being to relieve suffering and not necessarily to make the patient pain free. Nausea and/or vomiting may be treated with anti-emetic medications like ondansetron (Zofran), promethazine (Phenergan), or droperidol (Inapsine).


* The decision to send a patient home will depend upon the response to medication. If the pain is intractable (hard to control) or if vomiting persists, then admission to the hospital is necessary. Also, if an infection is associated with the stone, then admission to the hospital will be considered.


* Pain control at home follows the lead of the hospital treatment. Over-the-counter (OTC) ibuprofen is used as an anti-inflammatory medication, and narcotic pain pills may be provided. Anti-nausea medication may be prescribed either by mouth or by suppository. Tamsulosin (Flomax, a drug used to help urination in men with an enlarged prostate gland) may be used to help the stone pass from the ureter into the bladder.


* Because of their size or location, some stones may not be able to be passed without help. If the stone is high up in the ureter, near the kidney, and is large, then a urologist may need to consider using lithotripsy, or shock wave therapy (EWSL), to break the stone up into smaller fragments to allow those small pieces to pass more easily into the bladder. Shock waves work by vibrating the urine surrounding the stone and causing the stone to break up. Stones that are lodged nearer the bladder do not have surrounding urine to allow this procedure to work successfully.


* If the stone is not located in a place where lithotripsy can work or if there is a need to relieve the obstruction emergently (an example would include the presence of an infection), the urologist may perform ureteroscopy, in which instruments are threaded into the ureter and can allow the physician to place a stent (a thin hollow tube) through the urethra, past the bladder, and into the ureter to bypass the obstructing stone. This stent may be left in place for a longer period of time. Occasionally, the urologist may be able to use instruments to grab the stone and remove it.

Complications

* Since most patients have two kidneys, a temporary obstruction of one is not of great significance. For those patients with only one kidney, an obstructing stone can be a true emergency, and the need to relieve the obstruction becomes greater. A kidney that remains completely obstructed for a prolonged period of time may stop working.


* Infection associated with an obstructing stone is another emergent situation. When urine is infected and cannot drain, the situation is like an abscess that can spread the infection throughout the body (sepsis). Fever is a major sign of this complication, but urinalysis may show an infection and cause the urologist to consider placing a stent or removing the stone to relieve the obstruction.

Kidney Stone Prevention

* While kidney stones and renal colic probably cannot be prevented, the risk of forming a stone can be minimized by avoiding dehydration. Keeping the urine dilute will not allow the chemical crystals to come out of solution and form the beginning nidus of a stone. Making certain that the urine remains clear and not concentrated (dark yellow) will help minimize stone formation.


* Medication may be prescribed for certain types of stones, and compliance with taking the medication is a must to reduce the risk of future episodes.