The occurrence of stones in the kidney and ureter is a very common condition affecting both men and women of all age groups. Kidney stones are more common in males as compared to females.
What are the symptoms and signs of kidney and ureteric stones.?
Kidney stones most commonly present with
sudden onset pain in flanks which may be associated with nausea, vomiting.
blood in the urine ( hematuria).
In case of ureteric stones, pain may radiate to lower abdomen, the tip of the penis in males and urethral opening( meatus) in females.
Difficulty in passing urine.
What are the Complications of untreated stones
Repeated episodes of pain and the need for repeated hospitalization.
Repeated urinary infections (UTI).
A progressive decrease in kidney function and kidney failure.
TYPES OF KIDNEY STONES
CALCIUM CONTAINING STONES
NON CALCIUM CONTAINING STONES
URIC ACID STONES
STRUVITE STONES( magnesium ammonium phosphate)
Drug induced stones rare (triamterene, silica, 2,8-dihydroxyadenine
WHAT ARE THE CAUSES AND RISK FACTORS FOR OCCURRENCE OF RENAL STONES
Kidney stones are formed when urine becomes supersaturated with certain minerals like calcium, uric acid, phosphates, etc. Normally these substances are present in the dissolved state but certain conditions cause the urinary concentration of these substances to rise to result in crystal formation.
Decreased fluid intake (Dehydration) producing concentrated urine
Consumption of diet containing excess amounts of oxalate, proteins and excessive calcium supplementation.
Low levels of citrate in urine( Hypocitraturia). Citrate is an inhibitor of calcium stone formation.
High levels of uric acid in the urine (hyperuricosuria) seen in Gout, excess protein intake.
Deficiency of vitamin A and vitamin C.
Recurrent urinary tract infections leading to struvite stones.
Obstruction to urine flow anywhere in the urinary tract leading to urinary stasis.
Urine analysis shows the presence of red blood cells,
Ultrasonography (USG) is often the first investigation done in a patient presenting with flank pain. It is reasonably accurate in determining the presence of kidney and ureteric stones, it also helps in identifying the amount of swelling in the kidney (hydronephrosis) and ureter (hydroureteronephrosis). However, ultrasonography can miss stones in distal ureter and small kidney stones. There is no radiation exposure so it can be safely done in pregnancy and small children.
NON CONTRAST CT ABDOMEN (NCCT KUB)
It is the most accurate investigations for diagnosing kidney and ureteric stones and should be the investigation of choice for someone who presents with sudden onset flank pain. All types of stones both radiopaque and radiolucent can be easily detected with NCCT KUB. It should not be done in pregnancy.
Kidney function test
A baseline kidney function test is done in all patients with kidney and ureteric stones.
IVP (INTRAVENOUS PYELOGRAPHY)
Before the advent of CT Abdomen, IVP was the investigation of choice for diagnosis and evaluation of kidney and ureteric stones. It is less sensitive as compared to noncontrast CT KUB hence used less frequently as compared to NCCT KUB. However, IVP and Contrast CT are usually done to assess the functional status of the kidney before surgical intervention.
Renal calculi/ kidney stones
Small renal stones smaller than 5mm which are asymptomatic and incidentally detected are treated conservatively/watchful waiting. If the stones size increases during follow up or the patient start developing above mentioned symptoms then it needs active intervention.
Treatment options for kidney stones are
Extra corporeal shock wave lithotripsy ( ESWL )
RIRS ( RETROGRADE INTRA RENAL SURGERY)
PCNL/MINI PCNL ( PERCUTANEOUS NEPHROLITHOTOMY )
Rarely OPEN SURGERY (pyelolithotomy/ nephrolithotomy)
Selection of the treatment option depends upon several factors
Stone factors—– size, number, composition.
Kidney anatomical factors like location of the stone, degree of swelling(hydronephrosis), obstruction, horseshoe kidney, etc
Patient factors patient choice, obesity, age, infection, bleeding disorders, renal functional status of the kidney.
In ESWL shock waves are generated outside the body and then transmitted through the body and focused onto the stone. These shockwaves generate enough force to fragment the stone.
Advantages of ESWL
Non invasive method, no incision to the body, can be done without anesthesia or under short acting anesthetic agents.
Disadvantages of ESWL
The low stone clearance rate
Not effective for hard stones like cysteine stones ( Stone HU VALUE > 800)
Need for multiple treatment sessions
Contraindications of ESWL
Poor kidney function.
RIRS (RETROGRADE INTRA RENAL SURGERY)
In RIRS a flexible ureteroscope is passed from the urethra into the bladder then the scope is passed into the ureter extending up to the kidney. The stone is visualized and fragmented under direct vision with the help of holmium laser. The stone fragments are then removed with the help of a basket.
Minimally invasive procedure and no incision to the body
No risk of bleeding
Shorter hospitalization / day care procedure
Need for staged procedure(repeat procedure) in many cases.
PCNL (PERCUTANEOUS NEPHROLITHOTOMY)
In PCNL a small incision(hole) is made in the back , the kidney is punctured by a fine needle and the track from the back to the kidney is dilated . Through this tract an endoscope called nephroscope is passed into the kidney , the stone is visualized and fragmented under direct vision with the the help of laser or lithoclast and the fragments are taken out. Superior stone clearance rate compared to ESWL or RIRS.
Very effective for large stones
Risk of bleeding
Risk of injury to adjacent organs like lungs/pleura, colon etc
HOW TO PREVENT KIDNEY STONES
Drink plenty of water 2.5 to 3 liters
Avoid soft drinks
Low salt intake
Eat less animal protein
Avoid excess intake of oxalate rich diet like chocolates, dry fruits
What are the medications used to prevent recurrence of kidney stones
The type of medication will depend on the type of stone
Citrate salts (alkalinizing agents). Citrate binds calcium dissolved in urine preventing calcium crystals from developing. These agents make urine alkaline thus preventing calcium oxalate, uric acid, cystine stones.
Thiazide diuretics. These drugs reduce calcium excretion in urine thus preventing calcium stone formation
Allopurinol, this drug decreases blood and urine levels of uric acid thus preventing uric acid stones.