In the UK, knowing when to seek urgent medical attention for a suspected kidney stone is vital for preventing complications like kidney damage or sepsis. While the pain of a kidney stone (renal colic) is often severe, not every stone requires an emergency ambulance. However, certain “red flag” symptoms such as a high fever, the inability to pass urine, or uncontrollable vomiting indicate a medical emergency that requires immediate intervention. Clinicians categorise stone symptoms based on the risk of infection and the degree of obstruction to ensure patients receive the correct level of care.
What We will cover in this Article
- Identifying the “Red Flag” symptoms that require a 999 call
- When to contact NHS 111 for urgent advice and pain management
- The difference between severe pain and a medical emergency
- Recognising the signs of urosepsis (kidney stone infection)
- What to expect during an emergency urological assessment
- A clear comparison table for 111 vs. 999 decision making
When to Call 999: Life-Threatening Emergencies
You should call 999 or go to your nearest Accident and Emergency (A&E) department immediately if you have symptoms that suggest a blocked and infected kidney or systemic illness. In the UK, a “blocked and infected” kidney is treated as a surgical emergency because it can lead to sepsis within hours.
The most critical sign is a fever or chills accompanied by stone pain. This suggests that bacteria are trapped behind the stone. Additionally, if you are completely unable to pass urine, it indicates a total obstruction that can cause rapid kidney swelling and permanent damage.
- Fever and Chills: A temperature over 38°C or uncontrollable shivering (rigors).
- Inability to Urinate: A total blockage of the urinary tract.
- Signs of Sepsis: Confusion, slurred speech, extreme shivering, or mottled/blue skin.
- Uncontrollable Pain: Pain so severe that it does not respond to strong over-the-counter medication.
When to Call 111: Urgent but Stable Symptoms
NHS 111 is the correct choice if you believe you have a kidney stone but your symptoms are currently stable. If you are in significant pain but do not have a fever and are still able to pass urine and keep fluids down, 111 can help direct you to an Out-of-Hours GP or a Minor Injuries Unit for a clinical assessment.
They may also be able to provide advice on which local hospital has the shortest waiting times for a scan. Calling 111 ensures that the healthcare system is not overwhelmed by cases that can be managed through urgent care centres rather than emergency departments.
- New, severe pain in your side or back (flank pain) that comes in waves.
- Blood in your urine (pink, red, or brown tint) without a high fever.
- Nausea or vomiting that is manageable and allows you to sip fluids.
- Burning or urgency when urinating, suggesting the stone is moving.
Recognising Urosepsis: The Greatest Risk
The most dangerous complication of a kidney stone is urosepsis. This occurs when an infection from a blocked kidney enters the bloodstream. In the UK, the “Sepsis Six” protocol is used by emergency services to treat this condition rapidly.
If you have a suspected stone, you must watch for signs that your body is struggling to cope with an infection. This often includes feeling dizzy, a racing heart, and feeling generally very unwell, as if you have a severe case of the flu. This is never “just a stone” and must be treated as a 999 emergency.
Table: 111 vs. 999 Decision Guide
| Symptom | Call 111 (Urgent) | Call 999 (Emergency) |
| Pain Level | Severe but manageable | Agonising/Unbearable |
| Temperature | Normal | High Fever (≥38°C) |
| Shivering | None | Uncontrollable Rigors |
| Urine Flow | Passing some urine | No urine passed at all |
| Vomiting | Occasional/Can sip water | Persistent/Cannot keep water down |
| Mental State | Alert and oriented | Confused or drowsy |
To Summarise
While the pain of a kidney stone is famously intense, the decision to call 999 should be based on the presence of “red flags” like fever, chills, or a total inability to urinate. For severe pain without these life-threatening signs, NHS 111 is the appropriate first step to access urgent care. Being able to distinguish between a standard stone attack and an infected blockage is the most important factor in ensuring a safe and successful recovery.
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.
What if the pain stops before I call?
Even if the pain stops, you should still call 111 or see a GP. The stone may have shifted into a “silent” area, but it could still cause a blockage later.
Can I drive myself to A&E with stone pain?
It is not recommended. The pain of renal colic comes in unpredictable waves and can be so intense that it makes driving dangerous. Ask someone to drive you or call a taxi.
Will A&E give me a scan immediately?
Usually, yes. If you present with suspected renal colic, UK hospitals typically use a low-dose CT scan (CT KUB) to confirm the size and location of the stone.
Is blood in the urine a 999 emergency?
On its own, no. It is a common symptom of a stone. However, if it is accompanied by a fever or the inability to pee, it becomes an emergency.
What is a ‘rigor’?
A rigor is an episode of uncontrollable shivering and a feeling of coldness, which often signals that a high fever is about to start due to an infection.
How long should I wait for the pain to pass at home?
If you cannot manage the pain with paracetamol or ibuprofen, or if you begin to feel unwell with a temperature, you should not wait seek medical advice immediately.
Can a kidney stone cause a heart attack?
No, but the extreme pain can cause a racing heart and high blood pressure, and a severe infection (sepsis) can put a significant strain on the heart.
Authority snapshot
This article was reviewed by Dr. Stefan Petrov, a UK-trained physician with an MBBS and postgraduate certifications including ACLS and BLS. Dr. Petrov has extensive experience in NHS emergency departments, where he has triaged and treated hundreds of acute urological cases. This guide follows the clinical safety standards set by NICE and the NHS to ensure patients can accurately identify when life-saving intervention is required.
