A kidney stone attack, medically known as renal colic, is often described as one of the most intense physical sensations a person can experience. While the stones themselves may have been growing silently for months, the symptoms typically begin with sudden, sharp, and overwhelming pain. This occurs when a stone moves out of the kidney and enters the ureter (the narrow tube leading to the bladder), causing a blockage and subsequent pressure build-up. In the UK, renal colic is a frequent reason for emergency admissions, and understanding its distinct patterns is key to seeking prompt and appropriate medical care.
What We will cover in this Article
- The characteristic ‘loin to groin’ pain pattern
- Why the pain comes in waves (renal colic)
- Common physical responses: Nausea, vomiting, and restlessness
- Early warning signs before a full-blown attack
- Differentiating stone pain from other medical conditions
- When a kidney stone becomes a medical emergency
The Nature and Location of the Pain
The primary characteristic of a kidney stone attack is sudden, severe pain that often starts in the flank the area of your back just below the ribs on one side. This pain is not typically relieved by changing position, lying down, or resting.
As the stone travels through the ureter, the pain follows a distinct path. Clinicians often refer to this as ‘loin to groin’ radiation. The sensation can shift from the side of the back down into the lower abdomen, the groin, and even the genitals. The intensity is frequently compared to childbirth or being stabbed, and patients are often seen ‘writhing’ or pacing because they cannot find a comfortable position to ease the pressure.
- Colicky Waves: The pain is rarely constant; it typically comes in ‘waves’ as the ureter spasms to push the stone forward.
- Deep Sensation: Unlike muscle pain, which feels close to the surface, stone pain feels deep and internal.
Associated Physical Symptoms
A kidney stone attack involves more than just localized pain. Because the nerves serving the kidneys and the digestive tract are linked, the body often reacts with systemic symptoms that can be confusing for the patient.
Nausea and vomiting are extremely common during a stone attack. This is a reflexive response to the intensity of the pain and the pressure within the urinary system. Additionally, as the stone moves closer to the bladder, it can irritate the urinary tract, leading to a constant and urgent need to urinate, even if very little urine is produced.
- Haematuria (Blood in Urine): The stone’s jagged edges can scratch the lining of the ureter, making urine appear pink, red, or brown.
- Dysuria: A sharp or burning sensation when passing urine, often felt as the stone nears the exit.
- Restlessness: A tell-tale sign of renal colic is the inability to sit still, which differs from conditions like appendicitis where movement typically makes the pain worse.
Causes and Triggers of the Attack
While the stone may have been present for some time, specific triggers can cause it to shift and block the flow of urine, initiating the attack.
The most common cause is the stone’s physical journey from the kidney’s renal pelvis into the much narrower ureter. This movement causes the ureter to stretch and spasm, which is the primary source of the ‘colicky’ pain. Chronic dehydration remains the leading underlying cause, as it allows minerals to crystallize and form the stones in the first place. Sudden spikes in physical activity or jarring movements can also dislodge a ‘silent’ stone, causing it to enter the tubing system.
- Obstruction: The stone physically blocks urine flow, causing the kidney to swell (hydronephrosis).
- Inflammation: The presence of the stone causes the ureter walls to become inflamed and sensitive.
- Ureteral Spasms: Involuntary muscular contractions attempting to move the blockage.
Differentiation: Kidney Stones vs. Other Conditions
Because abdominal and back pain can stem from various sources, it is important to distinguish a kidney stone attack from other medical issues that may require different treatments.
| Condition | Primary Pain Location | Pain Nature | Key Distinguishing Feature |
| Kidney Stone | Flank/Back to Groin | Intense waves (Colic) | Restlessness and blood in urine |
| Appendicitis | Belly button to lower right | Constant and worsening | Worse with movement/touching tummy |
| Muscle Strain | Localised back muscle | Dull ache or sharp pull | Improves with rest and specific positions |
| Kidney Infection | Flank and back | Constant ache | Accompanied by high fever and chills |
To Summarise
A kidney stone attack typically feels like sudden, excruciating waves of pain that start in the flank and radiate toward the groin. Unlike muscle pain, it does not improve with rest and is often accompanied by nausea, vomiting, and restlessness. While the pain is severe, most small stones will eventually pass on their own with hydration and pain management. However, understanding the pattern of renal colic is essential for distinguishing it from other conditions and ensuring you receive the correct clinical support.
If you experience severe, sudden, or worsening symptoms, such as intense pain in your side, blood in your urine, or a high fever with chills, call 999 immediately.
Why does the pain come in waves?
The waves occur because the ureter (the tube connecting the kidney to the bladder) uses rhythmic muscular contractions to try and push the stone through. These spasms cause the ‘colicky’ pain that waxes and wanes.
Does a small stone hurt less than a large one?
Not necessarily. Even a stone as small as a grain of sand can cause intense pain if it becomes stuck in a narrow part of the ureter and blocks the flow of urine.
Is blood in the urine always visible during an attack?
No. While many people see pink or red urine, sometimes the blood is ‘microscopic’ and can only be detected by a dipstick test at a GP surgery or hospital.
Can I have a stone attack without pain?
If a stone stays inside the kidney and does not cause a blockage, it is often ‘silent’. The attack only begins once the stone moves or causes an obstruction.
How long does a typical attack last?
A wave of intense pain usually lasts between 20 and 60 minutes. The entire process of passing a stone can take anywhere from a few days to a few weeks.
Why do I feel like I need to pee constantly?
As the stone moves closer to the bladder, it irritates the nerves in the lower urinary tract, triggering a false signal that your bladder is full.
Is it normal to feel sick during a stone attack?
Yes, nausea and vomiting are very common reflexive responses to the extreme pain and the pressure being placed on the kidneys.
Authority snapshot
This article was reviewed by Dr. Stefan Petrov, a UK-trained physician with an MBBS and postgraduate certifications including ACLS and BLS. Having worked in emergency care and surgical wards within the NHS, Dr. Petrov has extensive experience in the acute diagnosis and management of renal colic. This guide follows the clinical standards set by NICE and the British Association of Urological Surgeons to ensure accurate and safe patient information.
