Doctors differentiate between a UTI and a kidney infection (pyelonephritis) by looking at symptoms (kidney infections add fever, chills, back/side pain, nausea/vomiting) and performing a urine test (urinalysis), which confirms an infection but may require further tests like blood work or imaging (ultrasound/CT) for kidney infections to check for systemic issues or blockages, though both are primarily treated with antibiotics. A kidney infection is often a UTI that has traveled up to the kidneys, so key is the presence of more severe, systemic symptoms.
A lower UTI and a kidney infection can have similar symptoms, but a kidney infection is more likely to suddenly make you feel sick, give you a fever or cause pain in your lower back or side.
Urinary Tract/Kidney Infections
Pregnancy predisposes to UTIs and pyelonephritis, which can lead to preterm labor or other complications. When you should go to the ER: fever, chills, flank pain, vomiting. What iCare can do: UA/urine culture, start safe antibiotics, close monitor; transfer if systemic signs.
To check for a kidney infection, you may be asked to provide a urine sample to test for bacteria, blood or pus in your urine. Your health care provider might also take a blood sample for a culture. A culture is a lab test that checks for bacteria or other organisms in your blood.
A urine test can't tell whether the infection – if you have one – is in your kidneys or another part of your urinary system, such as your bladder. For your GP to be confident you have a kidney infection, you need to have a positive urine test plus certain symptoms, such as a fever or a pain in your side.
Kidney pain strikes below the rib cage on either side of the spine and can feel like it is coming from deep inside the body. It's common to feel pain on one or both sides of the body, depending on whether the trouble is in one or both of these bean-shaped organs.
However, if the infection is left unchecked, it can spread up the ureters to your kidneys, leading to a kidney infection. On average, it can take between a few days to a week for a UTI to turn into a kidney infection if left untreated.
drink plenty of fluids so your pee is pale, water is best - this helps to flush out the bacteria from your kidneys.
Leukocyte Esterase: Leukocyte esterase is an enzyme present in your white blood cells. Therefore, the presence of this substance in the urine indicates the presence of white blood cells (leukocyturia). White blood cells in the urine may indicate inflammation of the kidneys or urinary tract due to bacterial infection.
A kidney infection can be serious if it's not treated as it can cause sepsis. Call 111 or get help from 111 online if you cannot speak to or see a GP, or your symptoms are getting worse.
A UTI during pregnancy typically doesn't affect the fetus. But if the bacteria move to your kidneys, the UTI can turn into a more serious kidney infection (pyelonephritis). Kidney infections sometimes cause early labor and/or low birth weight.
Kidney stones can be tricky, since they may have many of the same symptoms as a UTI or a kidney infection – pain when urinating, needing to urinate often, and cloudy or strong smelling urine, blood in the urine, fever, nausea or vomiting.
Symptoms of a kidney infection might include: Fever. Chills. A burning feeling or pain when urinating.
A UTI becomes an emergency when it causes serious symptoms like high fever, confusion, vomiting, or severe back or side pain. These may be signs the infection has spread to the kidneys or bloodstream. Call 911 or go to the ER if you can't stand, think clearly, or breathe easily.
Foods to avoid with a kidney infection
Cranberries are low in potassium and high in vitamin C, making them another great choice for people with kidney disease. Cranberry juice has also been shown to help prevent urinary tract infections, which are typical for people with kidney disease.
Drinking lots of water will help flush bacteria from your urinary tracts. Avoid caffeinated drinks and alcohol. Use heat. Place a heating pad on your back, abdomen or side to help reduce kidney pain.
In mild cases, you might deal with discomfort for about a week or two, but this depends on your immune system's ability to fight off the infection. In other situations, untreated infections can persist for weeks, spreading to the kidneys and causing more severe health issues like pyelonephritis.
In some cases, sepsis can develop within 24 to 48 hours after the onset of severe symptoms, especially if medical intervention is delayed.
Dull or sharp pain in the low back (often confused for kidney pain) is more likely due to a muscle pull, spinal issue, such as sciatica, or an injury. Kidney pain is usually felt higher up in the back and very rarely that low.
See your doctor immediately or go to your local hospital emergency department if you have kidney pain and: you have a fever or feel very unwell. you are unable to pass urine. the pain is on both sides of your body.
To support kidney health, focus on plant-based foods like berries, cabbage, cauliflower, onions, garlic, and leafy greens, plus fatty fish (salmon, tuna), egg whites, and whole grains like buckwheat, while limiting salt, processed foods, and high-potassium options like orange juice, opting for water as your primary drink. A kidney-friendly diet emphasizes fresh, whole foods to help reduce inflammation and manage kidney function.