Nephrolithiasis (Kidney Stones)

Definition

Kidney stone (nephrolithiasis) is characterized by flank pain and passage of red to brown urine due to the presence of hard crystallized deposits (stones) in the kidney. A number of factors contributes to the formation of kidney stones like high levels of calcium in the urine, intake of certain drugs and some underlying medical conditions. A family history of kidney stones and diminished water intake are common risk factors for kidney stones. Treatment options depend upon the size of the stone(s) or symptoms produced by it. Surgical removal of stones is reserved for large stones whereas small stones with mild symptoms are managed with painkillers and intake of plenty of water to hasten the passage of the stones via the urine.

Symptoms

Kidney stones, when confined to the kidney, may not produce any symptoms. Once the stones pass through ureter it may cause obstruction to urine flow and produce various symptoms such as :

  • Intense colicky pain with fluctuating intensity usually felt on the sides of the body (flank) and gradually radiating towards the groin. Men often complain of pain in the testicles or scrotum. The pain may shift to other places signifying movement of the stone through the urinary tract.
  • Painful urination.
  • Discolored urine (red, brown or pink) associated with a foul smell.
  • Nausea and vomiting.
  • Fever with chill.
  • Feeling of incomplete voiding after urination.

Kidney stones may block the passage of urine through the urinary tract. Urine may accumulate within the kidney with subsequent swelling of the kidney (hydronephrosis) and impaired kidney function.

Causes

Kidney stones arise due to an interplay of a number of factors such as :

  • Family history
  • Certain drug intake like :
    – Excessive intake of calcium containing antacids
    – Anti HIV drugs like indinavir
    = Anticancer drugs
    – Excess amount of calcium, vitamin A and D
    – Antibiotics like ciprofloxacin
  • Underlying medical disease like cystic fibrosis, renal tubular acidosis where increased acidity of urine may precipitate chemicals to form stone and inflammatory bowel disease.

Risk factors

  • Family history
  • Dehydration
  • Male
  • Obesity
  • High protein diet
  • Digestive tract surgery may alter absorption of calcium and water.
  • People who live in a dry climate are more prone to dehydration and therefore kidney stones.

Types

Kidney stones can be of various types and knowing the type may help preventing recurrence in the future by modifying risk factors. The common types of kidney stones includes :

  • Calcium stones (most common) is usually of two types – calcium oxalate and calcium phosphate. High level of oxalate commonly occurs with over intake of certain fruits, vegetables, chocolates and nuts. Calcium levels may increase if there is :
    – Concentrated urine due to intake of water pills.
    – Certain metabolic and familial disease.
  • Struvite stones which are rapidly growing stones due to infection of the urinary tract.
  • Uric acid stones with the intake of high protein diet, less fluid and gout patients suffer from this type of stone.
  • Cystine stones which occurs in patients who excrete large amounts of cystine in urine due to some familial illness.

Treatment

Treatment option depend upon the size of the stones and severity of symptoms. Small stones with mild symptoms are managed by :

  • Plenty of fluid intake.
  • Painkillers to ease pain.
  • Alpha blocker drugs to hasten the passage of the stones.

Large symptomatic stones are treated by :

  • Surgical procedures to physically remove the stones from the renal pelvis or urinary tract.
  • Break down of stone in small pieces by ultrasonic waves so that the fragments can pass out with the urine.

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