5 Critical Signs of Kidney Stones You Can't Afford to Ignore
Medically reviewed by Mr Ivo Dukic, Consultant Urological Surgeon | 5 April 2026
Kidney stones are notorious for causing some of the most intense pain a person can experience. This typically occurs when a stone moves into the ureter — the tube that drains urine from the kidney to the bladder. However, your body usually provides warning signals before that excruciating pain strikes. Recognising these early signs can make a real difference in preventing complications and avoiding more invasive treatments.
As a urologist who specialises in kidney stone disease, here are the 5 most important warning signs of kidney stones — ordered broadly by how frequently they occur.
What Are Kidney Stones? A Urologist Explains
Kidney stones are solid deposits composed of minerals and salts that develop within your kidneys. (1) While they can vary dramatically in size — from tiny grains to stones that fill the entire collecting system of the kidney (staghorn stones) — the real problems begin when these stones migrate or move from the kidney into the urinary tract, potentially causing blockages and significant discomfort. (2)
The 5 Most Common Kidney Stone Symptoms
1. Kidney Stone Back Pain: Where It Starts and How It Spreads
This is the most common symptom and is often the earliest sign. Kidney stone pain characteristically begins in the flank area — the side of your back just beneath the ribs. (2) Initially, you might experience a dull ache, a persistent pressure, or a vague discomfort rather than sharp pain.
What makes this particularly indicative of kidney stones is when the pain radiates downward. As a stone moves from the kidney toward the bladder, the discomfort often shifts to your lower abdomen, groin, inner thigh, or side. (3) This radiating pattern follows the path of the ureter — the tube connecting your kidney to your bladder. When stones enter the ureter, the pain is typically severe, though some stones that remain lodged in the tube can cause a milder, ongoing discomfort. (2)
2. Blood in Urine (Haematuria): A Classic Kidney Stone Symptom
Blood in the urine — known medically as visible blood or haematuria — is present in the vast majority of kidney stone cases. Studies show that between 83% and 95% of patients have blood detectable in their urine, even if it is only visible on a urine dipstick test (non-visible blood in the urine). (4) Whether the urine appears pink, red, brownish, or simply cloudy, this finding indicates that a stone is irritating the lining of your urinary tract. (4)
In most cases, the blood will be microscopic and invisible to the naked eye — but any visible blood is a clear signal to seek medical attention promptly.(4) It is important to note that the absence of visible blood does not rule out a kidney stone, as microscopic haematuria is typically present when stones are active, and some stones cause minimal bleeding altogether.(4)
3. Nausea and Vomiting with Kidney Stones: Why It Happens
Nausea and vomiting are experienced by a significant proportion of patients presenting with acute kidney stone pain from a ureteral stone. (3) These symptoms arise because the urinary tract and gastrointestinal tract share common nerve pathways from early development. When a stone obstructs or irritates the ureter, the brain can interpret signals from the kidney as if they were coming from the gut, triggering nausea and vomiting.(3)
This symptom is often underestimated as a warning sign of kidney stones, yet it is a well-recognised feature of renal colic. (2) If you experience sudden flank pain accompanied by nausea or vomiting — particularly without an obvious gastrointestinal cause — kidney stones should be considered. Severe or persistent vomiting can also make it difficult to stay hydrated and to take oral pain relief, which may mean hospital-level care becomes necessary sooner rather than later.
4. Urinary Symptoms of Kidney Stones: Urgency, Frequency and Burning
Pay close attention to any alterations in your normal bathroom habits. Several urinary changes can signal a kidney stone that has moved into the ureter:
Increased urgency: A sudden, compelling need to urinate, even when your bladder is not full
Increased frequency: Needing to urinate more often than usual, both during the day and at night
Burning or pain during urination: While commonly associated with urinary tract infections, this symptom can also occur with kidney stones, particularly when they are irritating the lower ureter close to the bladder
These changes occur because stones can interfere with normal urinary function and irritate the entire urinary tract as they travel downward. Lower urinary tract symptoms such as dysuria, urgency, and frequency are recognised features of ureteral stone disease in clinical guidelines. (2)
5. Cloudy Urine and Kidney Stone Infections: When to Act Fast
While the stone itself does not directly cause infection, cloudy urine and other signs suggestive of a urinary tract infection (UTI) — such as foul-smelling urine, fever, or chills — are important warning signs associated with kidney stones. (1) A stone can obstruct urine flow, creating an environment in which bacteria thrive more easily, and the relationship between kidney stone disease and UTIs is well established.(5)
A systematic review confirmed a strong association between kidney stone disease and recurrent UTIs, and demonstrated that surgical clearance of stones often leads to resolution of recurrent infections. (5) Kidney stones are therefore an important consideration in patients presenting with recurrent UTIs, and clinical guidelines recommend ruling them out as a key step in management. (6)
If you notice changes in your urine's appearance or have a history of recurrent UTIs — especially alongside other symptoms on this list — it is essential to investigate further. An infection occurring alongside an obstructing kidney stone can become rapidly serious and will usually require hospital treatment.
When to See a Doctor for Kidney Stone Symptoms
Recognising these warning signs early can be life-changing. Prompt diagnosis and treatment can:
Prevent severe pain: Addressing kidney stones before they grow larger or cause complete obstruction helps you avoid the excruciating pain of renal colic(2)
Allow for less invasive treatment: Smaller stones are often manageable with increased fluid intake, medication to help the stone pass, or minimally invasive procedures when necessary(1)
Reduce the risk of complications: Untreated kidney stones can lead to UTIs, kidney damage, and in serious cases, loss of kidney function(1)
Mr Ivo Dukic is a Consultant Urological Surgeon based in Birmingham with over 20 years of clinical experience across NHS and private practice. He holds sub-speciality expertise in endourology and kidney stone disease, and has treated thousands of patients with urinary tract stones using the full range of modern techniques, including ureteroscopy and laser lithotripsy, PCNL, and ESWL. Mr Dukic is a Fellow of the Royal College of Surgeons of Edinburgh (Urology), an active member of the British Association of Urological Surgeons (BAUS) and the European Association of Urology (EAU), and serves as Deputy Chief Clinical Information Officer at his NHS Trust.
Mr Dukic offers personalised consultations in Birmingham and Worcestershire, United Kingdom. Schedule an appointment with him for bespoke advice by booking an appointment through Harborne Hospital, HCA Healthcare, the Priory Hospital, Edgbaston, Circle Health Group or Droitwich Spa, Circle Health.
References
National Institute for Health and Care Excellence. Renal and ureteric stones: assessment and management. NICE guideline NG118. London: NICE; 2019. Available from: https://www.nice.org.uk/guidance/ng118
European Association of Urology. EAU guidelines on urolithiasis [Internet]. Arnhem: EAU; 2024. Available from: https://uroweb.org/guidelines/urolithiasis
Fontenelle LF, Sarti TD. Kidney stones: treatment and prevention. Am Fam Physician. 2019;99(8):490–496.
Türk C, Petřík A, Sarica K, Seitz C, Skolarikos A, Straub M, et al. EAU guidelines on diagnosis and conservative management of urolithiasis. Eur Urol. 2016;69(3):468–474.
De Coninck V, Keller EX, Rodríguez-Monsalve M, Doizi S, Traxer O, Bhatt A, et al. Association of kidney stones and recurrent urinary tract infections: the chicken and egg situation — a systematic review of the literature. Urolithiasis. 2022;50(5):497–506.
Cheshire and Merseyside Antimicrobial Prescribing Group. Recurrent urinary tract infection in adults [Internet]. NHS Pan Mersey Area Prescribing Committee; 2025. Available from: https://www.cheshireandmerseysideformulary.nhs.uk