Urinary Calculi

Essentials

• The treatment of an acute attack is started with an intravenous NSAID, with a combination of an analgesic and a spasmolytic or with an opioid at the health care setting that the patient first attends.
• Patients suitable for conservative treatment are primarily treated with alpha₁-blockers.
• The diagnosis is confirmed with ultrasonography, in specialized care increasingly with spiral CT. The vitality of the kidneys is verified by follow-up.
• The stone is removed and analysed.
• Laboratory investigations to find out the aetiology of urinary calculi are always indicated to decrease the risk of recurrence.

Types of stones and their aetiology

Symptoms and signs of ureteral colic

• The typical patient is a middle-aged man.
• Intense, colicky pain radiates from the costal arch obliquely to the lower abdomen, groins, and testes. Pain during urination is common if the stone is in the distal ureter.
• Nausea and vomiting is common.
• Microscopic, or rarely macroscopic, haematuria in 90%
• Earlier episodes are often recognized from the history, and there are cases in the family. Tendency for recurrences is 50% in 10 years.
• Tenderness of the kidneys on percussion is often observed.
• The patient has difficulty in keeping still (in contrast to e.g. peritonitis where the patient prefer to lie still).
• 75-90% of the stones are radio-opaque (urate stones are invisible, and cystine stones may be poorly visible).
• Small stones are poorly visible in plain x-rays.
• Renal calculus may cause chronic back pain and infections.

Differential diagnosis

• Colon-related pain
• Appendicitis
• Attack of biliary cholic, dyspepsia
• Aortic aneurysm
• Gynaecological conditions
• Testis torsion
• Renal infarction (not visible in plain CT examination)

First aid for an attack Dipyrone for Acute Renal Colic Pain, Nsaids Versus Opioids and Non-Opioids for Acute Renal Colic, Fluids and Diuretics for Acute Ureteric Colic

• NSAID Nsaids in Acute Renal Colic intravenously Different Routes of Administration of Non-Steroidal Anti-Inflammatory Drugs (most rapid relief) or i.m. (slower onset of action), e.g.
  • diclofenac 75 mg i.m. or a slow i.v. infusion (> 30 min)
  • ketoprofen 50-100 mg i.m. or 100-200 mg as a slow i.v. infusion (> 30 min)
• Combination of an analgesic and a spasmolytic
  • Metamizole sodium and pitofenone hydrochloride
• Opioid
  • Oxycodone 5 mg or 10 mg intramuscularly

Investigation strategy

• If the stone can be analysed at the beginning, the investigations can be directed according to the suspected aetiology.
• After the first attack the following tests are indicated: plasma calcium, urate, creatinine, and urine bacterial culture.
• If repeated attacks occur at intervals less than 2 years the following tests should also be performed: 24-hour urine creatinine, calcium , and citrate. Routine investigation of oxalate, urate and magnesium is not recommended.

Treatment in primary care

• Ultrasonography shows, e.g., possible hydronephrosis. It is the primary investigation during pregnancy and sometimes after plain x-ray (always remember the possibility of aortic aneurysm).
  • If the patient does not have hydronephrosis, and plasma creatinine is normal, only follow-up is needed.
  • The patient is referred to a hospital if the above-mentioned investigations are not locally available, the pain does not stop, the patient has a urinary tract infection, has only one kidney, is pregnant, or has a recurrence.
• Plain x-ray is highly inaccurate (x-ray-negative stones are not visualized) and the findings are often non-specific (phleboliths etc.).
• Spiral CT is used increasingly in specialist hospitals as an emergency investigation.

Follow-up examinations

• If a stone suitable for conservative treatment in the primary care has been detected, the passage of the stone is ascertained with ultrasonography and, if needed, with plain x-ray after 1 month.
• The patient should filter the urine to catch the stone for analysis.
• If the stone persists, the follow-up is continued (ultrasonography and, if needed, plain x-rays, plasma creatinine) until the stone has been passed and the patient is asymptomatic.
• It should be noted that pain subsides within 1 to 2 weeks even if the stone had not passed out of the body. Follow-up is still necessary in order to detect possible hydronephrosis.

Indications for shock-wave lithoripsy and endoscopic stone removal Extracorporeal Shock Wave Lithotripsy (Eswl) Versus Percutaneous Nephrolithotomy (Pcnl) or Retrograde Intrarenal Surgery (Rirs) for Kidney Stones

• The stone is not passed spontaneously and causes recurrent pain. The passing of an asymptomatic stone can be followed up for 6 months if hydronephrosis does not develop.

References

• Teichman JM. Clinical practice. Acute renal colic from ureteral calculus. N Engl J Med 2004 Feb 12;350(7):684-93. [PubMed]