Renal Calculus

November 30, 2019

Renal stones are a common problem in India. Up-to 16 % of men and 8 % of women will have at least one symptomatic stone by the age of 70 and this prevalence appears to be increasing.

The prevalence of kidney stones appears to be increasing in India

There are wide variations in the incidence of the disease in different ethnic groups along with regional factors such as temperature, sunlight, and consumption of fluids.

The goal of a diagnostic evaluation is to identify, as efficiently and economically as possible, the particular physiologic differences present in a given patient so that effective therapy can be established.

Thus, the type and extent of evaluation depends upon:

  1. The severity and type of stone disease
  2. Whether it is the first or a recurrent stone
  3. Presence of systemic disease and/or risk factors for recurrent stone formation
  4. Family history of Renal stones

The classical presentation is of pain (renal colic) and/or blood in urine. Some may have no pain or may have a discomfort as vague abdominal pain.

More severe complains may be of acute abdominal or flank pain, nausea, vomiting, and urgency to pass urine, difficulty urinating, penile pain, or testicular pain.

Proper care for the patient with adequate relief from the pain and other complains is of utmost importance. A thorough clinical examination with adequate diagnostic tests is warranted to assess the case and to plan for further course of action.

CAUSE

Majority of stones (~80 %) in the kidneys are calcium stones, made primarily of calcium oxalate/calcium phosphate. The other main types include uric acid, struvite (magnesium ammonium phosphate), and cysteine stones.

Stone formation occurs when normally soluble material (e.g. calcium oxalate) supersaturates the urine and begins the process of crystal formation. These crystals may form in the interstitium and eventually erode through the renal papillary epithelium, forming the classic Randall’s plaque.

Risk factors

The risk is influenced by urine composition, which can be affected by certain diseases and patient habits.

For calcium oxalate stones —> higher urine calcium, higher urine oxalate, and lower urine citrate and dietary risk factors such as a calcium intake, higher oxalate intake, higher animal protein intake, lower potassium intake, higher sodium intake, or lower fluid intake. A prior history of kidney stone is a definite risk factor as recurrence rates are as high as unto 30-45 percent.

Patients with a family history of stones have an increased risk of developing the same, it may also suggest the presence of rare inherited forms such as Dents disease ( hypercalciuria), adenine phosphoribosyltransferase deficiency, and cystinuria.

Renal Stone disease is more common in individuals with diabetes, obesity, gout, and hypertension. Low fluid intake is associated with increased stone risk. A persistently acidic urine (pH ≤5.5) promotes precipitation and leads to the formation of stones.

Struvite stones only form in patients with an upper urinary tract infection due to a urease-

producing organism such as Proteus or Klebsiella.

CLINICAL MANIFESTATIONS

Presentation in very wide clinically. Few patients are incidentally detected during routine imaging test of the abdomen. Patients occasionally present after having passed gravel or a stone (esp. Uric acid stones)

Symptoms develop when stones pass from the kidneys to the ureter. Pain is the most common presentation which may, occasionally, require intravenous analgesia due to its severity. The pain typically waxes and wanes in severity and develops in waves or paroxysms which last 20 to 60 minutes. Pain is due to urinary obstruction with distention of the renal capsule hence pain due to a kidney stone resolves quickly after passage of the stone.

Location of the pain changes as the stone migrates varying from upper abdomen, flank to mid abdomen and/or radiating to the groin.

In some patients present with chronic back pain and on proper imaging test are found to have renal stones.

Blood in urine (Hematuria) — Gross or microscopic hematuria occurs in the majority of patients presenting with symptomatic renal stones. Other symptoms are nausea, vomiting, dysuria, and urgency of urine.

Complications — Stones lead to persistent renal obstruction, which could cause permanent renal damage if left untreated. Chronic infection due to the stones leads to scarring of kidneys and damage.

DIFFERENTIAL DIAGNOSIS

Other possibilities may be present with patients presenting with complains similar to a renal stone

  1. Bleeding in the kidney causing clots that lodge in the ureter.
  2. Infections of the kidneys (Pyelonephritis) – have flank pain, fever, and pyuria.
  3. Pain due to an ectopic pregnancy
  4. Tumors causing obstruction
  5. Appendicitis
  6. Ovarian cysts

When a diagnosis is clinically suspected, imaging of the kidneys, ureters, and bladder should be performed to confirm the presence of a stone and assess for signs of urinary obstruction (eg, hydronephrosis).

ACUTE THERAPY

Many patients with acute renal colic can be managed conservatively with pain medication and

hydration until the stone passes. Most patients with acute renal colic can be managed

conservatively with pain medication.

Forced intravenous hydration does not seem to be more effective in reducing the amount of pain medication required or increasing stone passage compared with minimal intravenous hydration.

Urgent intervention is required if complications or damage to kidneys occur.

Pain control — Patients can be managed at home if they are able to take oral medications and fluids. Hospitalization is required for those who cannot tolerate oral intake or who have uncontrollable pain or fever.

Stone passage — Stone size is the major determinant of the likelihood of spontaneous stone

passage

EVALUATION AND SUBSEQUENT TREATMENT

Once the acute stone episode is over and the stone, if retrieved, is sent for analysis, the patient should be evaluated for possible underlying causes of stone disease, including hypercalcemia (most often due to primary hyperparathyroidism), and 24-hour urine composition. How and when this evaluation should be performed

Surgical Intervention

Surgical intervention is warranted in cases where the stone size is large, unrelenting pain with nausea and vomiting,

The choice of intervention depends upon the location of the stone, its size, shape and the anatomy of the individual

As with advancement of technology newer modalities of treatment are being explored every day.

Presently minimally invasive techniques are present which facilitates the operating surgeon to get the best results with minimal morbidity.

Few of the options presently available are:-

  • ESWL ( Shock wave lithotripsy)
  • PCNL ( per cutaneous approach to kidneys for stone removal)
  • MiniPerc ( Laser procedure )
  • RIRS (Retrograde intrarenal flexible fibre optic approach into kidneys with laser assistance)
  • URSL (Uretero qrenoscopic lithotripsy )
  • Laparoscopic Ureterolithotomy ( For large chronic stones in ureter)
  • Laparoscopic Pyelolithotomy ( when stone removal and repair of renal pelvis is required)
  • Anatrophic Nephrolithotomy ( Conventional method of directly kidney- for very large stones )

Every interventional procedure has a definite indication and no one approach is superior to the other.

The factors which determine with choice of interventions depends on factors such as stone position, stone composition, patient habits, anatomy, ease of access and approach, patient comfort, expertise.

OUTCOME

Patients have a high rates of satisfaction and comfort on follow up with less morbidity and improved renal functions, stone free rates are high. Stone analysis helps in tailoring patient diet and to recommend life style modifications to prevent stone recurrence in the future.

Dr. Bivek Kumar
Consultant – Urology and Andrology
Apollo Spectra Hospitals, Koramangala