Stones that form in the kidney can grow slowly and not cause any symptoms. However, when they "drop" out of the kidney and into the ureter (tube draining from kidney to bladder) they can cause severe pain.
Classically, the pain starts without warning in the region of the loin (flank) and may radiate down to the groin (see diagram). Patients who have had stones previously recognise the pain again. Often for first-time stone formers the pain is so severe that they call the emergency services and get brought to hospital by ambulance.
Confirmation of the diagnosis requires radiological imaging. The following imaging modalities may be used:
Many studies have now demonstrated that non-contrast CT is the best imaging method to detect even the smallest of stones. However, CT does carry the highest radiation dose. New low-dose CT techniques are being developed to minimise radiation exposure.
Other factors to assess at the time of presentation include: