Kidney stones are solid, hard masses that form within the kidneys from minerals and salts found in urine. These formations can vary in size, from as small as a grain of sand to, in rare instances, larger than a golf ball. While some small stones may pass unnoticed, kidney stones are known to cause intense pain as they move through the urinary tract.
Typical Pain Locations
The pain from kidney stones often begins when a stone moves from the kidney into the ureter, the narrow tube connecting the kidney to the bladder. This pain typically manifests in the flank, which is the area on either side of the lower back, just beneath the rib cage. Patients report severe, sharp pain in their side and back.
Pain location can shift depending on which kidney is affected and the stone’s position within the urinary tract. The discomfort may also extend to the lower stomach area or abdomen. In some cases, the pain can even radiate down into the groin region.
How Pain Changes
Kidney stone pain is dynamic as the stone navigates the urinary tract. This pain is frequently described as colicky, meaning it comes in waves of intense, sharp, and spasmodic discomfort. Each wave of pain can last for several minutes, disappear, and then return.
As the stone progresses through the ureter, the pain may migrate from the back and side towards the lower abdomen and groin. For males, the pain can be felt down to the testicles, and in females, it may extend to the labia. The severity of the pain does not correlate with the stone’s size, as even small stones can cause intense discomfort if they obstruct urine flow.
Why Kidney Stones Cause Pain
The severe pain associated with kidney stones stems primarily from two mechanisms. First, if a stone becomes lodged in the ureter, it can block the flow of urine from the kidney to the bladder. This blockage causes urine to back up, leading to pressure buildup and swelling within the kidney, a condition known as hydronephrosis.
Second, the ureter, a narrow and inflexible tube, reacts to the presence of a stone by contracting in an attempt to push it along. These strong, involuntary spasms of the ureter contribute to the intense pain experienced. The combination of pressure from urine backup and ureteral spasms accounts for the severity of kidney stone pain.
Other Symptoms
While pain is the primary symptom, kidney stones are often accompanied by other symptoms. Nausea and vomiting are common, occurring due to shared nerve connections between the kidneys and the gastrointestinal tract. Blood in the urine, known as hematuria, is another frequent symptom, which can make urine appear pink, red, or brown.
Individuals may also experience a frequent or urgent need to urinate, or a burning sensation during urination. Urine might also appear cloudy or have a foul odor.
When to Seek Urgent Care
Immediate medical attention is warranted for kidney stone pain if it becomes so severe that it cannot be managed or prevents finding a comfortable position, seek urgent care. Persistent nausea and vomiting that lead to dehydration also require prompt medical attention.
The presence of fever or chills alongside kidney stone pain can signal an infection, which requires urgent treatment to prevent complications. Additionally, an inability to pass urine or significantly reduced urine output suggests a complete blockage, requiring immediate medical attention.