Symptoms of Kidney Problems

Where kidney pain is felt

The kidneys sit high in the back, under the lower ribs on either side of the spine, not in the lower back. Kidney pain is felt in the flank: the side of the back between the bottom of the ribs and the top of the hip.

Most chronic kidney disease does not cause pain at all.

Symptoms of acute kidney problems

Kidney stones

Kidney stones cause sudden, severe, cramping flank pain that comes in waves and moves toward the groin as the stone travels, with nausea, vomiting, blood in the urine and an urge to urinate.

Kidney infection

Kidney infection (pyelonephritis) causes fever, chills, flank pain, nausea and vomiting, often with bladder infection symptoms: burning, frequency and cloudy or smelly urine. It needs prompt antibiotics.

Acute kidney injury

A sudden fall in kidney function from dehydration, severe infection, blockage, or medicines such as NSAIDs. It causes reduced urine, swelling, confusion, nausea and breathlessness, but can also be silent and found only on blood tests.

Symptoms of chronic kidney disease

Chronic kidney disease (CKD) develops slowly over years. Early stages usually have no symptoms. As function declines, symptoms appear:

• Changes in urination: urinating more at night, foamy or bubbly urine (protein), blood in the urine, or passing less urine
• Swelling of the ankles, feet, hands or around the eyes, from fluid and salt retention
• Tiredness and weakness, from anemia and buildup of waste products
• Itchy skin, often severe and widespread
• Poor appetite, nausea and vomiting, and a metallic taste
• Muscle cramps, especially in the legs at night
• Shortness of breath from fluid on the lungs or anemia
• Trouble concentrating and sleeping
• High blood pressure that is hard to control

When kidney function falls below about 15 percent, this is kidney failure, and dialysis or a transplant is needed.

Other kidney conditions and their signs

• Nephrotic syndrome: heavy protein loss in urine, causing very foamy urine and marked swelling of the face and legs.
• Glomerulonephritis (nephritic syndrome): blood in the urine (cola-colored), swelling and high blood pressure, sometimes after a throat or skin infection.
• Polycystic kidney disease: an inherited condition causing flank pain, blood in the urine, high blood pressure and enlarged kidneys.
• Kidney cancer: often silent, sometimes blood in the urine, flank pain or a lump.
• Blockage from an enlarged prostate or tumor: reduced urine flow, swelling of the kidney seen on ultrasound.

Who is at risk

The main risk factors for chronic kidney disease are:

• diabetes (the leading cause)
• high blood pressure (the second leading cause)
• heart disease
• obesity
• age over 60
• a family history of kidney disease
• Black, Hispanic, Native American or South Asian heritage
• long-term use of NSAIDs or certain other medicines
• previous kidney injury

How kidney problems are diagnosed

Two simple tests detect most chronic kidney disease:

1. Blood creatinine with eGFR (estimated glomerular filtration rate). An eGFR below 60 for 3 months or more indicates CKD.
2. Urine albumin-to-creatinine ratio (ACR). Albumin in the urine is often the earliest sign of kidney damage, especially in diabetes.

Other tests include a urinalysis for blood and infection, blood tests for potassium, phosphate, calcium and hemoglobin, a kidney ultrasound, a CT scan for stones, and sometimes a kidney biopsy.

Stages of CKD

Protecting your kidneys

• Keep blood pressure and blood sugar on target.
• Ask about medicines that protect the kidneys, such as ACE inhibitors, ARBs and SGLT2 inhibitors, if you have CKD or diabetes.
• Avoid regular NSAID use (ibuprofen, naproxen) if you have kidney disease, and check with a pharmacist about other medicines and supplements.
• Stop smoking, stay active, and maintain a healthy weight.
• Drink enough water, especially if you have had kidney stones.
• Get tested every year if you are at risk.

Frequently asked questions

What are the first signs of kidney problems?

Early chronic kidney disease usually has no symptoms. When signs appear, they include foamy urine, swelling of the ankles or around the eyes, urinating more at night, tiredness and high blood pressure. Blood and urine tests can find problems before symptoms appear.

Where is kidney pain felt?

Kidney pain is felt in the flank, the side of the back just below the ribs, usually on one side. It may spread to the groin or belly. Pain in the lower middle back that changes with movement is more likely from muscles or the spine.

What does urine look like with kidney problems?

Urine may be foamy or bubbly from protein, pink, red or cola-colored from blood, or cloudy and smelly with infection. Very dark urine usually means dehydration. Producing much less urine than usual can be a sign of kidney injury.

Can kidney problems cause itching?

Yes. Advanced chronic kidney disease often causes widespread, persistent itching, partly from waste products and mineral imbalances building up in the blood. It is common in people on dialysis and can be treated.

How can I check if my kidneys are working properly?

Ask your doctor for two tests: a blood test for creatinine and eGFR, and a urine test for albumin (ACR). Together they show how well your kidneys filter blood and whether there is early damage.