Symptoms of Kidney Stones: Early Signs and When to Seek Care 

Kidney stones are small, hard deposits of minerals and salts that form in the kidneys and sometimes move into the ureter (the tube to the bladder). Many are tiny and pass unnoticed; others irritate or block the urinary tract, triggering sharp pain, blood in the urine, and a sudden urge to pass water. Because the symptoms can overlap with other conditions—and infection can develop if a stone blocks urine flow—knowing what to look for matters.

This article explains the early warning signs of kidney stones, what the pain typically feels like and where it’s felt, the urinary changes to watch for, and the red flags that mean you should seek urgent care in the UK. You’ll also find practical advice on what to do at home, how stones are diagnosed, what treatment may involve, and how to reduce the risk of future stones. Let’s start with why stones cause symptoms.

What are kidney stones and why they cause symptoms

Kidney stones are hard crystals made from minerals and salts in urine, most commonly calcium compounds. Many stay small and pass silently. Symptoms start when a stone moves, usually into the ureter, where it can scrape the lining and block the flow of urine. This raises pressure in the kidney and triggers ureteric spasm, producing severe, wave-like (colicky) pain. Irritation can cause visible or microscopic blood in the urine, and the blockage can provoke urgency or poor flow. If urine can’t drain, bacteria may multiply, leading to infection.

Early warning signs you might notice

Some symptoms of kidney stones start subtly. While very small stones can pass without fuss, the early warning signs often appear as a stone begins to move and irritate the urinary tract. These symptoms may start and stop or build in waves as the stone shifts.

• Dull side/back ache: A nagging pain below the ribs that comes and goes.
• Urinary urgency or frequency: A strong need to pass urine, often in small amounts.
• Burning when you pee: Discomfort or stinging during urination.
• Blood in urine: Pink, red or brown urine, or blood only found on testing.
• Cloudy or bad-smelling urine: A sign of irritation within the urinary tract.
• Nausea or queasiness: Sometimes progressing to vomiting during painful episodes.

What kidney stone pain feels like and where

Classically called renal colic, kidney stone pain is sudden, severe and hard to ignore. It often starts in the side of the back, just below the ribs, and builds in waves as the ureter spasms around the stone. The pain may shift location as the stone moves, and many people find they cannot sit still or get comfortable. Nausea and vomiting commonly accompany the worst episodes.

• Where it starts: Sharp pain in the flank (side/back) below the ribs.
• How it spreads: Can radiate to the lower abdomen and groin as the stone descends.
• In men: Pain may be felt in the testicle on the affected side.
• Pattern: Colicky—intense waves that rise and fall, with pain varying as the stone moves.

Urinary changes and other common symptoms

When a stone irritates the ureter or bladder, you may notice clear changes in how you pass urine. These urinary symptoms may be subtle at first and can come and go as the stone moves, so it’s worth paying attention even if the pain settles between episodes. Urinary changes are among the most telling symptoms of kidney stones.

• Blood in the urine (haematuria): Pink, red or brown; sometimes only found on testing.
• Burning or pain when you pee: Irritation of the urinary tract lining.
• Frequency or urgency: Needing to go often but passing only small amounts.
• Cloudy or foul‑smelling urine: Suggests inflammation in the tract.
• Nausea or vomiting: Often accompanies the painful waves.

Red flags: symptoms of infection or blocked kidney

A stone that blocks the ureter can trap bacteria and trigger a kidney infection, which can escalate quickly. Know the red‑flag symptoms of kidney stones that mean you need prompt medical assessment. These clues often appear alongside typical stone pain and urinary changes, but signal a higher risk situation.

• High temperature, chills or shivering: Classic signs of infection.
• Feeling very unwell, weak or tired: Especially with sweats.
• Cloudy or foul‑smelling urine: Suggests infection behind the stone.
• Trouble passing urine or only small amounts: Or an inability to urinate.
• Severe pain with nausea/vomiting that won’t ease: Unable to get comfortable.
• Visible blood in urine: Pink, red or brown urine warrants urgent review.

When to seek urgent care in the UK

If you develop symptoms of kidney stones with signs of infection or obstruction, you need same‑day assessment. In the UK, go to A&E or call 999 for life‑threatening symptoms. If you’re unsure, call NHS 111 for advice. If pain is manageable and you’re well otherwise, arrange an urgent GP or same‑day clinic review.

• Severe, unrelenting flank/abdominal/groin pain: You can’t get comfortable.
• Fever, chills or shivering: Especially with sweats.
• Vomiting with pain: Unable to keep fluids down.
• Blood in your urine: Pink, red or brown.
• Trouble passing urine: Only small amounts, or you cannot pass urine.
• Cloudy, foul‑smelling urine with feeling very unwell: Suggests infection behind a blockage.

How symptoms vary by stone size and location

The symptoms of kidney stones often reflect how big the stone is and where it sits. Tiny stones may glide through with little more than a twinge. Larger stones, or those with sharp edges, are more likely to scrape, block and trigger classic colicky pain, blood in the urine and nausea as the ureter spasms around them.

• Stone still in the kidney: May cause no symptoms or a mild, nagging flank ache.
• Upper ureter (near the kidney): Sudden, severe flank pain that can make you pace or curl up.
• Mid‑ureter: Pain wraps from the side to the front of the abdomen.
• Lower ureter (near the bladder): Pain radiates to the groin; men may feel it in the testicle; urinary urgency and burning are common.
• Bigger or impacted stones: More persistent pain, visible haematuria, vomiting; higher risk of blockage and infection.

What could be mistaken for a kidney stone

Because the symptoms of kidney stones overlap with other problems, it’s easy to misread the signs—especially when pain comes in waves and you feel sick. Infections in the urinary tract can look very similar, and some abdominal, pelvic or back conditions can also mimic flank or groin pain. If you’re unsure, get assessed rather than self‑diagnosing.

• Urinary tract or kidney infection: Fever, chills, burning when you pee, and cloudy or foul‑smelling urine can mirror stone symptoms.
• Musculoskeletal back pain: Side or back ache without urinary changes.
• Appendicitis or diverticulitis: Lower abdominal pain, nausea; may overlap when pain radiates.
• Gynaecological causes (women): Ovarian cysts or torsion can cause sharp lower abdominal/groin pain.
• Testicular conditions (men): Epididymitis or torsion can present with severe groin/testicular pain.

What to do at home if you suspect a kidney stone

If your symptoms are mild and you feel otherwise well, simple measures can help a small stone pass and keep you comfortable. The priorities are hydration, pain control and watching closely for any red‑flag changes.

• Hydrate steadily: Drink water throughout the day to keep urine pale; take small, regular sips if you feel nauseated.
• Use pain relief: Take over‑the‑counter pain medicine as directed to manage waves of pain.
• Try to keep the stone: Urinate through a clean sieve or filter; if you pass a stone, keep it for analysis.
• Monitor symptoms: Track pain, urine colour and how much you pass.
• Act on red flags: If you develop fever, chills, vomiting, visible blood, severe unrelenting pain or trouble passing urine, seek urgent care (A&E/NHS 111).

How kidney stones are diagnosed once you present with symptoms

Your clinician will take a focused history, examine your abdomen and back, and check vital signs to rule out red flags. Tests aim to confirm a stone, judge its size and position, and detect infection or kidney strain so treatment can be tailored promptly.

• Urine tests: Dipstick and microscopy for blood, white cells and nitrites; a urine culture if infection is suspected.
• Blood tests: Kidney function (creatinine/eGFR), inflammation/infection markers, and electrolytes.
• Imaging: A non‑contrast CT scan is the most accurate way to confirm a stone, its size, location and any blockage. Ultrasound is often used to avoid radiation; a plain X‑ray may help track certain stones.
• Stone analysis: If you pass or have a stone removed, it’s sent to the lab to identify its type for prevention planning.

What to expect from treatment based on your symptoms

Treatment is guided by how severe your kidney stone symptoms are, the stone’s size and location, and whether there’s infection or blockage. Many stones pass with pain relief and steady hydration; others need hospital care or a procedure. Here’s what typically happens.

• Mild symptoms, no fever: Manage at home with fluids and over‑the‑counter pain relief, strain your urine to catch the stone, and watch for red flags.
• Severe pain or vomiting: Expect urgent assessment for strong painkillers, anti‑sickness medicines, IV fluids and imaging to confirm size and position.
• Fever, chills or trouble passing urine: You’ll be treated as an emergency for suspected infection behind a blockage; hospital care is needed to control infection and restore urine flow.
• Large or persistent stones: Your team will discuss intervention. Surgery or other treatments may be advised; for certain larger stones this can include percutaneous nephrolithotomy.
• Specific stone types: If a uric acid stone is confirmed, medicines may sometimes help dissolve it; prevention plans follow once the acute episode has settled.

After the pain: follow-up and preventing future stones

Once the acute pain eases, good follow‑up helps confirm the stone has passed, checks for infection or kidney strain, and reduces your risk of another episode. Your clinician may review urine and blood tests, assess the stone type if caught, and discuss drivers such as dehydration, salt intake, animal protein and oxalate‑rich foods. Even when symptoms of kidney stones settle, prevention starts immediately.

• Hydrate: Aim for pale urine; roughly 2 litres/day output.
• Cut sodium; moderate animal protein: Keep dietary salt low; don’t overdo meat.
• Keep calcium in food; be cautious with supplements.
• Limit oxalate foods if advised: e.g., spinach, nuts, chocolate, beets.
• Medicines by stone type: Thiazide or potassium citrate (calcium), allopurinol/potassium citrate (uric acid); targeted plans for struvite/cystine.
• Ask for a dietitian‑guided plan if stones recur or risks are complex.

Key takeaways

Kidney stones can be silent, then strike with sharp, wave‑like flank pain, urinary changes and sometimes blood. Recognise red flags—fever, chills, vomiting or difficulty passing urine—and act promptly, as infection behind a blockage is an emergency. Diagnosis and treatment depend on the stone’s size, location and type.

• Colicky flank‑to‑groin pain that prevents you settling suggests a moving stone.
• Blood, burning, urgency or cloudy/foul urine commonly accompany stone episodes.
• Fever, chills, vomiting or little/no urine = same‑day care (A&E/NHS 111).
• Small stones often pass with fluids and analgesia; larger may need a procedure.

For rapid expert assessment and a tailored plan, contact Ashwin Sridhar Urology.