Renal Stone

Kidney stones, also called renal calculi, are solid concretions (crystal aggregations) of dissolved minerals in urine; calculi typically form inside the kidneys or bladder.

Nephrolithiasis refers to renal stone disease, while urolithiasis refers to the presence of stones in the urinary system. The majority of stones consist of calcium, usually as calcium oxalate, but they can also contain uric acid and struvite (magnesium, ammonium, and phosphate).

What Causes Kidney Stones?

The kidneys are vital organs that filter waste products from the body. Sometimes, mineral deposits made of calcium, uric acid, and the amino acid cysteine cause kidney stones to form.

Several factors increase the risk of developing kidney stones, including inadequate fluid intake, dehydration, and reduced urinary volume. Anything that blocks or reduces urine flow also increases the risk.

Infection

Organisms such as Proteus, Pseudomonas, and Klebsiella can cause recurrent urinary tract infections (UTIs). These organisms produce urea, which leads to urine stasis, promoting stone formation. The nucleus of the stone may harbor these bacteria.

Hot Climate

Hot climates can cause an increase in solute concentration, leading to the precipitation of calcium and the formation of calcium oxalate stones.

Dietary Factors

• A diet rich in red meat, fish, and eggs can lead to aciduria.
• Foods rich in calcium, such as tomatoes, milk, and spinach, can contribute to the formation of calcium oxalate stones.
• A diet lacking in vitamin A can cause desquamation (shedding) of renal epithelium, which promotes the formation of kidney stones.

Metabolic Causes

• Hyperthyroidism: Increased serum calcium levels result in hypercalcinosis and the formation of pelvic stones.
• Gout: Elevated uric acid levels can lead to the formation of multiple uric acid kidney stones.

Immobilization

Paraplegic patients may secrete large amounts of calcium in their urine, leading to the formation of calcium oxalate kidney stones.

Inadequate Urinary Drainage

In cases such as horseshoe kidney, unascended kidneys are more prone to stone development due to urine stasis.

Other Causes of Renal Stones

• Reduced urinary citrate levels.
• Injury to the renal epithelium.

Types of Kidney Stones

• Calcium oxalate stones.
• Phosphate stones.
• Uric acid stones.
• Cystine stones.
• Xanthine and indigo stones.

Symptoms of Kidney Stones

Kidney stones often do not produce symptoms while they are silent in the kidneys. However, once a stone moves, it can cause intense pain. The pain usually first appears in the back, just below the ribs. Over hours or days, the pain follows the stone’s course through the ureter toward the groin. The pain typically stops once the stone passes.

The classic symptoms of kidney stones include intense pain in the loin or renal angle, extending toward the urethra. Other symptoms may include:

• Severe pain in the side, back, or below the ribs.
• Nausea and vomiting, often accompanied by sweating.
• Blood in urine (hematuria).
• Reduced urine flow or output.
• Recurring urinary tract infections.
• Guarding and rigidity of the back and abdominal muscles during severe pain episodes.
• Constant urge to urinate.
• Painful urination with a burning sensation.
• Fever and chills when infection occurs.