What Is Renal Calculi

Published Date: 02 Nov 2017

The term calculi refer to the stones that are developed within human body. Calculi (plural) or calculus (singular) do not only occur in the urinary system but they can also occur anywhere in the body. The term use to describe those calculi are different based on which part they are formed. According to Francis (n.d) calculi can present in kidney, gallbladder, bladder, gastrointestinal system and salivary glands. The present of those stones can cause either inflammation or obstruction inside the human body.

Renal calculi refer to solid mass that are developed in the kidneys resulting from aggregation of crystals in the urine. According to National Kidney and Urologic Diseases Information Clearinghouse (n.d) renal calculi are one of the most painful and common urinary tract disorders that can happen in human body. Renal calculi are commonly known as kidney stone or in medical term it is called nephrolithiasis. Generally, renal calculi are formed when the urine becomes concentrated, hence chemical substances that should be dissolved in the urine will crystallize and form a hard mineral deposit that is too large to pass through the urine (Health Central,n.d.). Kidney Stone Diagram

Figure 1.1: Renal calculus that is formed within the kidney

Renal calculi are classified based on their composition of substances. There are many types of renal calculi that have been found. The presence of certain substances that are exceeding their normal level in the urine will contribute to the types of stone. There are about four types of stones that commonly occur within human body.

The most common type of stones that is formed within human body is calcium stones. These types of stones are developed as a result of combination of calcium with oxalate, phosphate, or carbonate and it is accounted about 75 to 85 percent of all stones (Health Central, n.d.). According to Francis (n.d.) the formation of this stones may be as the result of bowel disease or dietary imbalances. These types of stones mostly affect men rather than women whose aged between 20 to 30 years old and usually easy to see on x-ray.

Other types of stones are uric acid stones which are accounted for 5 to 10 percent of all stones (Health Central, n.d.). It is formed as the uric acid in the urine is too much than other chemical substances and is more likely to occur in men than in women. According to Dugdale (2011) the patients who are having gout or chemotherapy are susceptible to experience uric acid stones. These types of stones can only be seen under special test such as CT, ultrasound, or intavenous pyelography (IVP).

The most common stone that usually affects women is struvite stone which is accounted for 10 to 15 percent of all stones. It is formed by the combination of calcium, magnesium and ammonium phosphate (Health Central, n.d.). As women have short urethra, they are more likely to get urinary tract infection which will cause them susceptible to get struvite stones. This type of stones can be easily seen on x-ray studies (Francis, n.d.) and it can grow very large which can block the kidney, ureter or bladder.

Cystine stones are the types of stones that are less common to occur which is accounted for only 1 percent of all stones. It is a combination of cystine with lysine, arginine and ornithine and usually affects men and women equally. Besides, cystine stones also can be found in the patients who are having cystinuria, a type of hereditary disorder which occurs as kidney tubules do not reabsorbing certain amino acids adequately (Dugdale, 2011).

HISTOPATHOLOGY

2.1 Etiology

Renal calculi can happen if there is an increasing in the certain chemicals that become super saturation in the urine (SingHealth, n.d.). The waste products that are carried by the urine such as calcium oxalate, uric acid and cystine can become extremely concentrated if there is not enough urine. When the salt concentration levels reach the point at which they are no longer dissolved in the urine, these salts will form crystals known as calculi.

It can also form if there is low concentration of urinary inhibitors such as citrate, magnesium, enzymes and pyrophosphate. These substances is needed in human body in order to prevent stone formation by allowing salts in the urine to be at higher than normal concentrations without forming crystals. They also act to coat the crystals and prevent them from sticking to the surface of kidney tubes (Simon, 2009).

2.2 Risk Factors

There are many risk factors that lead to the formation of renal calculi. The common factor is because inadequate intake of fluid by a person. It will cause the chemical substances become too much to be dissolved in the urine.

Besides, a person is also tending to get renal calculi based on dietary habits that he ingests. Mayo Clinic (2012) said that if the person loves to eat food high in protein, sodium and sugar the tendency for him to get renal calculi is high. In addition, the types of stone that will be formed within the body also are different based on which substances have the highest concentration in the urine such as high levels of calcium (hypercalciuria), oxalate (hyperoxaluria) and uric acid (hyperuricosuria) can all lead to the different types of calculi.

If the person have a family member that already suffered from renal calculi before, the probability for him to get the disease is high. Furthermore, if the person had already has the disease before, there are risk for the disease to recur.

Person who is obese and have large waist size and weight gain also have a high risk to get renal calculi as their body may excrete more calcium and uric acid (Simon, 2009).Besides, renal calculi are more likely to occur among men over age 40 years old and above. However, women also have the risk to suffer from renal calculi.

Patients who are suffering from diseases such as renal tubular acidosis, cystinuria, hyperparathyroidism and some urinary tract infection may also have the risk of renal calculi. Furthermore, patients who are undergoing gastric bypass surgery, inflammatory bowel disease or chronic diarrhea also have high risk of formation of renal calculi. This is because the disease had cause changes in digestive process which may affect absorption of calcium and water in the urine (Mayo Clinic, 2012).

2.3 Incidence and Prevalence

According to Right Diagnosis (n.d.) incidence means the rate of occurrence of new case of kidney stones diagnosed each year while prevalence means the estimated population of people who are managing kidney stones at any time.

2.4 Mobility and Morbidity

2.5 Pathophysiology

Normally, the waste products that accumulated from our diet are excreted via the function of kidneys. Normal person without renal problem will have no excessive waste products as they are enough to be dissolved in the urine. The formation of renal calculi can happen if the amount of calcium oxalate and uric acid become too high in the urine. As the concentrations become saturated, crystal can form within urine and will lead to the development of stones as they are grouping together with an organic material called matrix (Stoller, 2012). The stones may remain the same size or may also become enlarge if it is not treated early.

Stoller (2012) also said that the calculi can form within the kidneys if the inhibitors presence in small amount in the urine. The substances which are citrate, magnesium and several proteins help to prevent stone formation by coating the crystals and prevent them from sticking to the kidney tubes. The patients who suffered from renal calculi are believed to have low amount of inhibitors and large amount of promoters that alter towards stone formation.

2.6 Signs and Symptoms

Symptoms mean patient’s perception about a disease that he or she can recognize or feel. Usually the patients who are suffering from renal calculi may not felt any symptoms unless the calculus is too large to pass through urine and has stuck in the ureter. It takes time for the person to detect that they are having renal calculi as the calculus also takes time to build up into a large one. Most patients are accidentally known that they have renal calculi as they are going for abdominal x-ray for other purpose.

According to Uddin, (2011) some patients may feel sharp pain in the back or side of lower abdomen as the early warning sign of renal calculi. The pain can be severe and can spread out into the lower abdominal or groin regions. If the patients are suffering from this pain, their ability to sit up or move can be interfered. This severe pain also can lead to stomach upset in patients. The patients can feel nausea or may begin to vomit because of the pain.

Besides, the patients who are suffering from renal calculi can also see the changes of their urine which may appear dark or red in color. It is because the stone that passes through their urinary tract had damage the small tubes that carry urine out of the body. The red color of the urine results from blood that discharges as stones damage the tubes. This condition also is known as hematuria. Moreover, they may also observe their urine appears cloudy and release unpleasant smell.

Uddin (2012) added that patients who are expecting to have renal calculi also can feel painful during urination. It happens as the stones irritate and inflame the bladder which also can lead to frequent urination. Some patient may also have flulike symptoms that are caused by infection as if stone becomes stuck along the urinary tract. The patients will have early warning signs of fever and chills because of the infection.

IMAGING MODALITIES

Imaging modalities play an important role in detecting patients with renal calculi.