Kidney Stones

What are Kidney Stones?

Kidney stones - scientifically known as Renal Calculi and medically termed as Nephrolithiasis or Urolithiasis (depending on its location)

It is a condition characterized by the presence of hard mineral and salt crystals in one or both kidneys. The causes range from genetics and diet to medications and metabolic diseases.

Kidney stones vary in size as well as shape. The smaller ones may pass on their own while passing urine with little or no pain, but those that are larger may get obstructed, leading to severe pain and bleeding.

On experiencing any symptoms, one must seek care from a doctor or urologist to avoid any further complications.

What are the types of Kidney Stones?

Kidney stones can be made up of different types of crystals depending upon their composition. Identifying it helps determine the course of treatment and prevents its reoccurrence. The various types are:

Calcium Stones: They are the most common (in form of calcium oxalate stones). Eating an excess of oxalate-rich foods may increase the likeliness to develop them. These include certain fruits and vegetables (beets, okra, spinach, etc), nuts, tea, chocolate, black pepper and soy products, potato chips, etc. Calcium phosphate stones may occur in a condition called Renal Tubular Acidosis and on having certain medications (used to treat migraines).

Uric Acid Stones: These are more common in men and in those with gout or those undergoing chemotherapy. It also develops when urine is too acidic due to a diet rich in animal proteins (fish and meat).

Struvite Stones: These are found mostly in women with Urinary Tract Infections (UTIs) and cause urinary obstruction due to their larger size. Treating the underlying infection helps prevent its occurrence.

Cystine stones: These are rare and occur in those who have the genetic disorder- Cystinuria wherein, an amino acid- cystine is secreted in excess and leaks from the kidneys into the urine and is found on analysis.

What are the causes and risk factors associated with Kidney Stones?

The causes of kidney stones are multifactorial. It forms due to an excess amount of the minerals and salts in the urine that crystallize and stick together, becoming more in composition than the fluid in the urine can dilute. 

Factors that increase the risk of developing kidney stones include:

Dehydration: This is the most important cause of kidney stones. This is the case especially for those who drink less than 1 liter of water per day, live in tropical climates, and sweat a lot.

Other factors that increase the risk of Kidney stones: 

• Family history of kidney stones: If in the past you have had one or more kidney stones.
• Men are more likely to develop kidney stones.
• Obesity 
• Digestive diseases and surgery: Gastric bypass surgery, inflammatory bowel disease, chronic diarrhea, etc. that affect digestive functions.

Medical conditions that could lead to kidney stones:

• Renal tubular acidosis
• Cystinuria
• Hyperparathyroidism
• If you are facing constant urinary tract infections, you might be at an increased risk of developing Kidney stones.
• Long-term and excessive use of vitamin C, dietary supplements, laxatives, calcium-based antacids, triamterene diuretics (often called water pills), anti-seizure medication, and certain medications used to treat migraines and depression.

What are the signs and symptoms?

A patient with kidney stones may be asymptomatic unless the stones move through the urinary tract, with the most common symptom being- severe abdominal pain (known as renal colic) associated with nausea and vomiting.

Gastrointestinal symptoms include

• Pain type: Severe, sharp pain that comes in waves and fluctuates in intensity, and may shift to a different location as the stone moves through the urinary tract.
• Pain areas: In the side and back, below the ribs that may radiate to the lower abdomen and groin.

Urinary signs and symptoms of kidney stones:

What happens if kidney stones are left untreated?

Complications that arise from leaving kidney stones untreated are:

• Urinary Tract Infections (UTIs)-including kidney infections.
• Urinary obstructions can lead to kidney infection, kidney damage, and ultimately loss of kidney function.

How are kidney stones diagnosed?

Kidney stones can be diagnosed using the following:

• A complete health history assessment.
• A physical exam.
• Tests that include: Blood tests for calcium, phosphorus, uric acid, and electrolytes.
• Blood Urea Nitrogen (BUN) and Creatinine to assess kidney functioning.
• Urine analysis to check for crystals, bacteria, blood, and white cells.
• Examination of passed stones to determine their type

Imaging that can help to rule out obstruction are:

• Abdominal X-rays.
• Ultrasound of the kidney (the preferred test).
• Abdominal CT scan.
• Intravenous Pyelogram (IVP).
• Retrograde Pyelogram.
• MRI scan of the abdomen and kidneys.

*Point to note: The contrast dyes used in imaging tests can cause kidney damage in those with impaired kidney function and hence patients must inform about medications that he/she is taking prior to tests being performed.

What are the treatment options available for kidney stones?

It depends on the type of stone and intensity of symptoms. The kidney stones which are smaller with minimal symptoms can be treated as follows:

Medical therapy:

Medications known as an alpha-blocker, relaxes the muscles in the ureter, helping the patient pass the kidney stone more quickly and with less pain. 

The kidney stones that are larger in size causing severe pain, blood in the urine, and those associated with urinary tract infections may require extensive treatment options such as:

Extracorporeal Shock Wave Lithotripsy (ESWL) 

ESWL is a procedure that uses sound waves to break up kidney stones — depending on size and location. It may require sedation or light anesthesia.

Ureteroscopy

This procedure uses a ureteroscope to remove a smaller stone in the ureter or kidney. 

The scope has a small wire with a camera attached when inserted into the urethra and is passed into the bladder. The doctor then uses an instrument to remove the stone.

Retrograde Intrarenal Surgery (RIRS)

This procedure may require general or spinal anesthesia. 

An endoscope with fiber optics is inserted in the retrograde fashion i.e. through the urinary tract opening, via the ureter that connects to the kidneys.

Once the stones can be accessed, they are subjected to Holmium laser and fragments may be grabbed by forceps or ancillary devices-stone baskets.

Percutaneous nephrolithotomy

This surgery uses a small incision on the back that removes the larger stones in the kidney under general anesthesia. The doctor may recommend this surgery if ESWL is unsuccessful.

Parathyroid Gland Surgery

Kidney stones may arise as a complication of hyperparathyroidism.

It becomes important to treat this underlying condition to avoid the occurrence of stones in the future.

Parathyroid glands are located on the four corners of the thyroid below Adam's apple are affected by this condition due to any growth or starts to function by excessively producing a parathyroid hormone that causes the calcium levels to become very high and calcium phosphate kidney stones may form as a result. 

The formation of kidney stones can be controlled by removing the growth from the gland. 

The doctor may recommend treatment of the condition that's causing the parathyroid gland to overproduce the hormone.