Yes. A kidney infection can cause pain in the back or side, sometimes felt as lower back pain. It often occurs with other symptoms, such as fever, chills, nausea, painful or frequent urination, or cloudy or bloody urine. However, many cases of lower back pain come from muscles or the spine. Pain alone cannot tell you the cause, so symptoms that suggest infection need prompt medical assessment.
How Can a Kidney Infection Cause Back Pain?
The kidneys are two bean-shaped organs located toward the back of the upper abdomen, just below the rib cage. A kidney infection, medically called pyelonephritis, occurs when an infection affects one or both kidneys. It often begins as a urinary tract infection (UTI) in the bladder and spreads upward to the kidneys.
When a kidney becomes infected, pain may develop in the back, side, or area between the lower ribs and hips. Some people describe it as a deep, aching discomfort, while others experience more pronounced pain. It may affect one side or both sides, depending on the area involved. According to the Mayo Clinic, back, side, or groin pain is one of the possible symptoms of a kidney infection, alongside fever and urinary changes.
Although kidney infections can cause pain that feels like lower back pain, the location is important to understand. Kidney-related discomfort is often felt higher in the back, beneath the ribs, rather than directly over the lower spine or near the hips. However, symptoms do not always follow a clear pattern, so location alone cannot establish the cause.
Which Symptoms May Occur Alongside Lower Back Pain?
Lower back or side pain is more concerning for a possible kidney infection when it occurs with symptoms affecting urination or the whole body. These symptoms can develop together or appear at different times.
- Fever and chills: A raised temperature, shivering, or feeling unusually cold can occur with an infection.
- Changes in urination: Urinating more often than usual, needing to urinate urgently, or experiencing pain or burning while urinating may occur.
- Changes in urine: Urine may look cloudy, appear darker than usual, smell unusually strong, or contain blood.
- Nausea or vomiting: Some people feel sick to their stomach or have difficulty keeping food and fluids down.
- General illness: Tiredness, body aches, or abdominal discomfort may accompany the back pain.
These are examples of symptoms that may occur, not a checklist for confirming an infection. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), kidney infections can cause back, side, or groin pain along with fever, chills, urinary changes, and nausea or vomiting. The combination and timing of symptoms can help a healthcare professional determine what needs to be investigated.
How Is Kidney-Related Pain Different From Ordinary Lower Back Pain?
Lower back pain has many possible causes, including muscle strain, spinal problems, and other conditions affecting the surrounding tissues. A kidney infection is one possible cause, but it is not the most appropriate explanation for every episode of back discomfort.
The differences below describe common patterns that can help explain why the source of pain may need closer assessment. They are not reliable enough to distinguish the causes without considering the wider clinical picture.
- Where the pain occurs: Pain related to the back or spine often affects the middle of the back or the area around the lower spine. Kidney-related pain is more commonly felt deeper in the side or back, beneath the ribs.
- Other symptoms: Back pain associated with a muscle or spinal problem may occur without fever or urinary changes. A kidney infection may cause these additional symptoms, including chills, painful urination, or nausea.
- How the pain feels: Musculoskeletal pain can feel sore, tight, or tender. Kidney-related pain may feel like a deeper ache or discomfort in the flank, although the sensations can overlap.
- How the symptoms develop: A recent physical strain may help explain some types of back pain. Fever, urinary changes, and feeling generally unwell alongside back or side pain raise concern for an infection.
The Cleveland Clinic explains that kidney pain is typically felt deeper in the side, while many forms of ordinary back pain affect the area around the spine. However, symptoms can overlap, and neither the location nor the feeling of the pain can confirm whether the kidneys are involved.
Can a Kidney Infection Occur Without Burning During Urination?
Yes. Burning or pain during urination is one possible symptom, but it is not the only way a kidney infection can present. Back or side pain, fever, chills, nausea, or changes in urine may also occur. The absence of one particular symptom does not rule out an infection.
Symptoms can also differ by age. Children younger than two years may have a kidney infection that causes mainly a high fever, without the urinary symptoms an adult might expect. In young children, unusual drowsiness, feeding difficulties, or other changes in their usual behavior can also be important. Adults who are pregnant should seek prompt medical assessment if a kidney infection is suspected because pregnancy increases the risk of complications.
For these reasons, it is important to consider the full pattern of symptoms rather than waiting for every familiar sign to appear.
When Should You Seek Medical Care for Back Pain and Possible Kidney Infection?
Seek urgent medical assessment if back or side pain occurs with fever, chills, painful urination, blood in the urine, or nausea and vomiting. These symptoms can indicate a kidney infection that needs prompt treatment. Do not delay seeking care simply because the pain is manageable or the urinary symptoms are mild.
Prompt assessment is especially important during pregnancy, in young children, and for people with conditions that increase the risk of infection-related complications. The UK National Health Service (NHS) recommends urgent medical assessment when kidney infection symptoms occur, including back pain beneath the ribs, fever, blood in the urine, or vomiting.
Seek emergency medical help if symptoms include confusion, unusual difficulty staying awake, difficulty speaking, rapid or difficult breathing, or a sudden, serious deterioration in overall health. These can be signs of a severe infection or sepsis, which requires immediate treatment.
If you have lower back pain without these accompanying symptoms, arrange a medical assessment if the pain persists, worsens, repeatedly returns, or interferes with daily activities. New or unexplained pain should also be evaluated when its cause is unclear. The appropriate timing depends on the symptoms and any other health conditions present.
How Do Doctors Check Whether Back Pain Is Related to a Kidney Infection?
A healthcare professional will usually ask where the pain occurs, when it began, whether it is changing, and whether other symptoms are present. Questions about fever, urination, recent illnesses, previous urinary infections, medications, pregnancy, and existing medical conditions can help guide the assessment. A physical examination may also help identify areas of tenderness and other relevant findings.
Urine testing is often an important part of evaluating a suspected kidney infection. A urine sample can be checked for signs of infection, and additional laboratory testing may be used when appropriate. Blood tests or imaging, such as an ultrasound or CT scan, may be considered depending on the symptoms and clinical findings.
According to the NIDDK's guidance on kidney infection, healthcare professionals use medical history, a physical examination, and laboratory tests to make a diagnosis, sometimes with imaging tests. The choice of tests depends on the individual situation.
How Is Lower Back Pain From a Kidney Infection Treated?
If a healthcare professional determines that a bacterial kidney infection is the cause, treatment generally involves antibiotics. The choice of medicine and the treatment plan depend on the clinical assessment and the person's circumstances. Some people need hospital treatment, particularly if the infection is severe or they cannot keep fluids or medication down.
It is important to take prescribed antibiotics as directed and follow the instructions provided by the treating professional. If symptoms worsen or fail to improve as expected, seek further medical advice. A kidney infection can cause serious complications if left untreated, so pain relief alone should not replace appropriate assessment and treatment.
Until you receive medical advice, rest and drink fluids as tolerated, unless a healthcare professional has instructed you to restrict fluids. Ask a clinician or pharmacist which pain-relief medicines are suitable for you, particularly if you have kidney problems, take other medicines, or are pregnant. Do not rely on home remedies to treat a suspected kidney infection.
What Should You Remember About Lower Back Pain and Kidney Infections?
A kidney infection can cause pain in the back or side, sometimes experienced as lower back pain. The possibility becomes more concerning when the pain occurs alongside fever, chills, urinary changes, nausea, or vomiting. However, pain near the lower spine is also commonly related to muscles or other back structures.
The safest way to understand unexplained back pain is to consider its location, accompanying symptoms, timing, and medical history. When an infection is possible, prompt professional assessment can help identify the cause and ensure that appropriate treatment is started.