Kidney Stone Symptoms: Recognizing Renal Colic

Kidney stones (nephrolithiasis) are hard mineral deposits that form in the kidneys and affect approximately 12% of men and 7% of women during their lifetime, with recurrence rates of 50% within 5 years after a first episode. The pain of passing a kidney stone is often described as one of the most severe pains a person can experience.

Renal colic is the characteristic pain of a kidney stone moving through the ureter. It begins suddenly and severely in the flank (back between ribs and hip) and radiates to the lower abdomen, groin, and inner thigh as the stone descends. It comes in waves lasting 20–60 minutes, with the patient unable to find a comfortable position (unlike peritoneal pain, where patients lie still). Associated symptoms include nausea, vomiting, restlessness, blood in urine (hematuria), and frequent urge to urinate.

Different stone types have different causes: calcium oxalate stones (most common, 70–80%) are associated with low fluid intake, high oxalate diet, and low urinary citrate; uric acid stones form in acidic urine and are linked to gout and high-protein diets; struvite stones result from urinary infections with urease-producing bacteria; cystine stones are rare and hereditary.

Small stones (< 5 mm) pass spontaneously in 68–98% of cases. Management includes aggressive hydration (> 2 litres/day), pain control with NSAIDs (first-line) or opioids, and alpha-blockers to facilitate stone passage. Indications for urgent urological intervention: obstructing stone with fever (infected obstruction — surgical emergency), complete obstruction of solitary kidney, intractable pain or vomiting, and stones > 10 mm.

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