RENAL STONES

Samah Bataineh & Ghofran Mestarihi

Definition and Incidence

Stones; a Solid concretion or calculi(crystal aggregations) formed in the kidney from dissolved urinary materials.

The 3rd most common disease in urology exceeded by UTI and BPH.

Pathogenesis of stones :

Supersaturation of the urine by stone-forming constituents

Chemical composition of urine that favors stone crystallization.

Impairment of inhibitors that prevent crystallization in normal urine…

These inhibitors include: Organic: Glycosaminoglycans, Nephrocalcin. Inorganic: Mg, Pyrophosphate, Citrate

Etiology :

Metabolic Problems

Non Metabolic Problems

Metabolic Problems :

1- Hepercalciuria 2- Hypercalcemia 3- Hyperuracemia 4- Hyperoxaluria

5- Hypocitrateuria (The urinary excretion of citrate is under hormonal control and decreases during menstruation )

6- Hypomagnesemia 7- Cystinuria (is an

inherited autosomal recessive disease )

Non Metabolic Problems:

* Anatomical causes and Primary renal diseases - strictures , stenosis , congenital anomalies - Polycystic kidney disease. - Renal tubular acidosis

* Infections Urease-producing bacteria(Proteus , Klebsiella )

* Drugs: - Ca stones: Loop diuretics, antacids, glucocorticoids, theophylline, Vitamins D & C, actazolamide. - Uric acid stones: Thiazides and salicylates.

*Previous history of Urolithiasis.* Family history of Urolithiasis.

Risk factors

Male sex Obesity White people Warm climates Family History H/o stone disease (1/2 will have recurrence) Dietary factors

Lower fluid intake, higher animal protein, higher Vitamin C

Medical factors

Types of stones :

Oxalate calculus (calcium oxalate) Most common

. Irregular in shape and covered with sharp projections, which tend to cause bleeding . The surface of the calculus is discolored by altered blood. A calcium oxalate monohydrate stone is hard and radio dense ( radio-opaque )

Struvite stones

A phosphate calculus [calcium phosphate often with ammonium magnesium phosphate (struvite)] is smooth and dirty white. It tends to grow in alkaline urine, especially when urea-splitting (Proteus) organisms are present. The calculus may enlarge gradually to fill most of the collecting system, forming a staghorn calculus. Even a very large staghorn calculus may be clinically silent for years until it signals its presence by haematuria, urinary infection or renal failure. Because they are large, phosphate calculi are usually easy to see on radiographic films

Uric acid and urate calculi These are hard, smooth and often

multiple. They vary from yellow to reddish brown and sometimes have multifaceted appearance.

Pure uric acid stones are radiolucent

Cystine calculus

- These uncommon stones appear in the urinary tract of patients with a congenital error of metabolism that leads to cystinuria. Hexagonal, translucent, white crystals of cystine appear only in acid urine.

They are often multiple and may grow to form a cast of the collecting system. Pink or yellow when first removed, they change to a greenish color when exposed to air. Cystine stones are radio-opaque because they contain sulphur, and they are very hard. ( faint radio opaque )

Case- study

A 32-year-old female presented to the emergency room with a chief complaint of right flank pain for 7 hours in duration. The pain was sudden in onset, she described it as 'knifelike', intermittent , radiating to the right groin, it wasn’t aggravated by movement , no relieving factors .

the pain was associated with nausea but no vomiting , fever (37.6) , no history of trauma . No dysuria ,no hematuria , no chills , no previous similar attack , she had a history of stone passage last month .

Past surgical hx : free Past medical hx : free Family hx : no family hx of stone .

What are the DDx ?

1- Renal : urolithiasis, UTI,Pyelonephtitis .

2- G.I :Acute cholecystitis ,Acute Pancreatitis, diverticulitis, colitis

3- R.S: Rt Lower lobe pneumonia

4- gynecological : ovarian torsion,ovarian cyst, ectopic pregnancy .

What’s your next step ?

Lab Investigations CBC, KFT, serum electrolytes, urine

analysis and culture

Radiography CT without contrast, US , KUB ,IVP

Why to do urine analysis and culture ?

Should be performed in all patient with suspected calculi.

Microhematuria, pH, crystals,bacteria Uric acid stones – acidic urine Infection – alkaline urine Limited pyuria is fairly common response

to irritation caused by a stone.

Radiological investigations 1- CT scan without contast:

The best imaging tool to diagnose any acute flank pain

Sensitivity 95-100% , Specificity 94-96%. Show all stone types in all location. It can give idea about Extra- urinary

causes of the pain.

2- U.S…….WHY ? Sensitivty19%, specificity 97% Accessible Good for diagnosis of hydronephrosis and

renal stones Poor visualization of ureteral stone. Procedure of choice for patients who

should avoid radiation, including those with known allergy to IV contrast, pregnant women and woman in childbearing age.

3- KUB:

May be sufficient to document the size and location of radio opaque urinary calculi (Ca oxalate, Ca phosphate)

Disadvantages: Will miss radiolucent uric acid stones (15%), small

stones, stones with overlying bony structures (unfortunately stones are frequently obscured by stool or bowel gas, ureteral stones overlying the bony pelvis or transverse processes of vertebrae).

Opacities on a plain abdominal radiograph that may be confused with renal stones: calcified mesenteric lymph nodes, gallstones in the appendix , stool and phleboliths ( calcification in walls of vein) .

4-Intravenous pyelogram :

Relatively safe despite the need for contrast

Provides information about obstruction the stone (size, location, radiodensity) and degree of obstruction.

Contra-indication : 1- Allergy such as Asthma, Urticaria ( may cause

anaphylactic shock ).

2- Renal impairment

3- Pregnancy

Complications :

Calculous hydronephrosis : Aseptic dilatation due to back pressure .

Calculous pyonephrosis : Septic dilatation – kidney turns into bag of pus

Renal failure :Bilateral staghorn stones may be asymptomatic till presentation with features of renal failure.

Now … You diagnose her as a case of renal stone .. Do you admit her ?

When to admit the patient ?

Infection on top of obstruction Fever Intractable pain or vomiting Solitary kidney or transplanted kidney

with obstruction bilateral kidney stones VIP persons

How to treat ?

Line of treatment : Conservative ESWL PCNL Open surgery : Pyelolithotomy or Nephrolithotomy

conservative

NSAID : analgesic of choice is rectal diclofenac, some cases opiates will be required

rehydration

Calculi smaller than 0.5 cm pass spontaneously in up to 80% of people

Urgent temporary procedures Indications:1. Significant Obstruction that dangers

kidney function 2. Infection Aim :1. Drain urine from the kidney2. to relief the obstruction

Double J stent

A thin, hollow tube placed inside the ureter during surgery to ensure drainage of urine from the kidney into the bladder. J shaped curls are present at both ends to hold the tube in place and prevent migration *

Nephrostomy Tube

1-Extracorporeal shock wave lithotripsy (ESWL) :

A urinary calculus has a crystalline structure. When hit with shock waves of sufficient energy it disintegrates into fragments.

INDICATION:first-line treatment for ureteral and renal stones smaller than 2 cm.

Contraindications:• Pregnancy , bleeding disorders, uncontrolled UTI

severe skeletal malformations and severe obesity, which prevent targeting of the stone;

• arterial aneurysm in the area of the stone

Complication • Hematuria• Incomplete stone fragmentation & obstruction• Uretric colic ( NSAID ) • “Steinstrasse” ( stone street ) usually due to a large “ Leading fragment”

2-Ureteroscopy

passes through urethra and bladder into the ureter. then move the scope through ureter until it reaches the location of the kidney stone. No cuts are made in the body. we can take out the kidney stone using a small "basket" that comes out of the end of the ureteroscope. Small stones can be removed all in one piece. Larger stones may need to be broken up before you can remove them

3-Percutaneous nephrolithotomy (PCNL)

The aim is to remove all fragments if possible, and this may take some time if the calculus is large

is sometimes combined with ESWL in the treatment of complex (stag-horn) calculi. The surgeon removes the central part of the stone percutaneously and the more peripheral fragments are treated by ESWL.

PCNL and open surgery are equally effective for the management of renal stones.

Indication • Large (>2 cm in diameter) or complex calculi• Cystine stones (relatively resistant to shock wave lithotripsy).

Contraindication All contraindications for general anaesthesia apply. Patients

receiving anticoagulant therapy must be monitored carefully pre and postoperatively. Anticoagulant therapy must be discontinued before PCNL

Complications haemorrhage from the punctured renal parenchyma perforation of the collecting system perforation of the colon or pleural cavity during placement of

the percutaneous track.

4-Open surgery

Indication Treatment failure of ESWL and/or PCNL. Intrarenal anatomical abnormalities: (infundibular

stenosis, stone in the calyceal diverticulum, obstruction of ureteropelvic junction, strictures)

Morbid obesity Skeletal deformities Non-functioning kidney (Nephrectomy) Patient’s choice; patient may prefer a single

procedure and avoid the risk of undergoing multiple PCNLs

Treatment

Treatment depends on size, location and type of stone.

Location and size: >>> Kidney;

1- < 0.5 cm may resolve spontaneously we advice patient to increase fluid intake plus pain killers.

2- < 2 cm ESWL 3- > 2 cm by PCNL +/- ESWL

..

>>> Ureter; 1- <= 4 mm leave it, drinking water, pain killer +/-

CCB or alpha blockers “esp. in lower ureter”. 2- > 4 mm ESWL.

Type of stone: Uric acid stone: by alkalizing the urine

environment by alkalizing agents (e.g potassium citrate or sodium bicarbonate) and dilution of urine by increase fluid intake. Allopurinol to reduce the frequency of stone with recurrent uric acid stone or gout.

..

Cystine stone; High fluid intake(4-5 L/day), alkalization

of urine and chelating agents (D-pincillamine) to prevent formation of cystine stone in patients with cystinuria. PCNL for stone if it’s formed.

Strutive;PCNL treatment.

Antibiotics is the mainstay of therapy. ?