Pain is the most common symptom of kidney stones and unfortunately, it is not subtle or tolerable pain. The pain that comes with stones migrating from the kidney through the ureters is excruciating. kidney stone pain is often described as flank pain that begins beneath the rib cage and travels down toward the testicles in men or the labia in women. Intensity and location of pain varies from person to person. Kidney stones can range from the size of a grain of sand to as big as a pea or even as large as a golf ball. The person may not experience any pain if the stone does not cause a block to the path of the urine. On the other hand, pain can be so severe that women who have experienced passing a kidney stone described the pain as being similar to that of child birth.
How acute is the pain?
The kidney is said to be an exquisitely sensitive organ and passing a stone can cause acute pain mainly due to the following reasons:
- First, the ureter is a small and inflexible tube that cannot stretch to accommodate a stone.
- Second, when a stone from the kidney reaches the ureter, in an attempt to squeeze it out, clamps down with spasm on the stone leading to significant pain.
- Third, urine not being passed out but backed up into the kidney due to the block causes pressure within the kidney.
kidney filtration system does not have nerves with classical pain fibres but the tissue surrounding the kidney, called the capsule does contain nerve fibres that transmit pain. A neuronal network exists submucosally in the renal pelvis, calyces, capsule and ureter. Certain nerve fibres within the network are nociceptive in function, meaning they sense injury and communicate it to the higher nervous system. Kidney stone obstruction leading to backed-up urine in the kidney, swells and expands the capsule, activating the nociceptive nerves.
Corresponding higher levels for neuronal activation are T11 – L1 at the spinal cord. Persistent increase in renal pelvis pressure from prolonged obstruction causes the release of prostaglandin E2. This chemical mediator of injury response, induces extreme pain as a protective mechanism to safeguard kidney functions. The intensity of contractions of the ureter to push urine down to the bladder is coordinated in a wave form giving the renal colic a typical high – low pattern. The intensity of the pain pattern is described as being similar to the force of waves during a storm. Consistent increased ureteral contractions known as hyperperistalsis, lead to ureteral spasm tightening the ureter around the stone. This peak pain limits experienced at severe, intense, extreme and intolerable grade.
In a Scandinavian study with 70 first-time mothers, the worst pain during labour was rated as being on average between 7/8 on a scale of 1 to10, with 10 being the worst pain imaginable. Mothers with multiple childbirths, who often have a slightly easier experience, rated their worst pain as 6/7. A recent survey on 287 kidney stone patients reported that they rated their worst pain as being very similar to that of childbirth, with an average pain score of 7.9 out of 10. It turns out that the reported amount of pain in both situations is almost identical.
Where exactly is the pain?
The location of pain changes as the stone moves from the kidney to the bladder. It typically starts in the flank region between the ribs and the hip, at the side of the lower back. As the stone progresses down the ureter, the pain tends to migrate caudally and medially. Sometimes, as the stone moves, the pain migrates to the front of the body. The pain transcends down till the testicles or even the tip of the penis in men and till the labia which is the inner and outer folds of the vulva in women. In certain cases, pain may be felt only in the back near the kidneys, which are located on either side of the spine below the rib cage.
The location of pain changes as the stone moves from the kidney to the bladder. It typically starts in the flank region between the ribs and the hip, at the side of the lower back. As the stone progresses down the ureter, the pain tends to migrate caudally and medially. Sometimes, as the stone moves, the pain migrates to the front of the body. The pain transcends down till the testicles or even the tip of the penis in men and till the labia which is the inner and outer folds of the vulva in women. In certain cases, pain may be felt only in the back near the kidneys, which are located on either side of the spine below the rib cage.
Patients frequently dismiss the pain until it evolves into waves of severe pain. In instances when the stone is stuck where the kidney opens in to the ureter, the pain can be severe. The pain grade on a scale of 1 to 10, can be a 10. There is no position in which the person may feel comfortable. Pain has a tendency to rise and dip in 10 to 30-minute cycles radiating down to the groin area and the front of the thigh. Pain tends to move towards the ipsilateral groin or the abdomen while the stone moves down to the part of the ureter closer to the bladder.
As the stone moves down the ureter, it can also mimic the pain of other conditions. For instance, if the stone is in the right kidney travelling down the ureter, it may feel like appendicitis. Similarly, a stone with pain on the left side may be mistaken for diverticulitis or an infection within the small or large intestine. And as the kidney stone migrates into the bladder, pain may not be dominant, rather, symptoms can be similar to a urinary tract infection. Pain while voiding, frequent urination and urgency to urinate may be major concerned symptoms. Fortunately, the stone can usually pass much easier from the bladder out through the urethra, which is because, the urethra is typically twice the diameter of the ureter.
Relationship of stone location to symptomatic pain can be as follows:
- Kidney – vague pain in the flank area, hematuria
- Upper end of the Ureter – Renal colic, pain in the flank/upper abdomen
- Middle of the Ureter – Renal colic, pain in the flank/anterior abdomen
- Lower end of Ureter – Renal colic, pain in the flank/anterior abdomen, urinary frequency, dysphoria
Depending on the size and location, a stone can take days to weeks to pass and the pain normally lasts till the stone is passed. Migration of stones can be known through imaging scans but it is difficult to predict a time frame to passage of the stone and the end of pain along. Mild medication such as Non-Steroidal Anti-Inflammatory drugs are usually prescribed by doctors as medication to alleviate the pain for a certain period of time, allowing the stone to pass. Fortunately, less invasive emergency screening and treatment techniques are available to remove the stone and relieve the pain if necessary.
It is advisable to get kidney test done once every 6 months as advised by best urologist in Chennai. As they say, “prevention is better than cure”, you can have a heads up on your kidney’s health before bigger and expensive damage happens.
