Kidney Infection: When to Go to the Hospital?

A kidney infection is more than just a urinary tract infection (UTI). While many UTIs affect only the bladder, a kidney infection happens when bacteria move up into one or both kidneys. This can cause serious illness if left untreated.

If you have symptoms of a kidney infection, you may wonder whether you can manage it at home or if you need hospital care. The truth is that kidney infections should always be taken seriously, and in some cases, immediate hospital treatment is the safest option.

This guide explains the signs of a kidney infection, when to go to the hospital, what treatment involves, and how to prevent infections in the future.

What is a kidney infection?

A kidney infection, also called pyelonephritis, occurs when bacteria travel from the bladder into the kidneys. Since the kidneys filter blood and remove waste, an infection here can quickly spread to the bloodstream and cause sepsis. That is why doctors often treat kidney infections more urgently than bladder infections.

Learn how to track your liver health with the at-home liver tests guide.

What are the symptoms of a kidney infection?

Kidney infection symptoms are usually stronger than those of a simple bladder infection. Watch for:

• Fever and chills

• Pain in the back, side, or groin

• Nausea or vomiting

• Frequent or urgent urination

• Burning or pain while urinating

• Cloudy, dark, or foul-smelling urine

• Blood in the urine

• Fatigue and weakness

If these symptoms appear suddenly or worsen quickly, it may be a sign that hospital treatment is needed.

Because kidney infections directly impact kidney function, see the kidney function test at home guide.

How is a kidney infection different from a UTI?

A urinary tract infection that affects only the bladder may cause burning during urination, frequent urges, and cloudy urine. A kidney infection includes these symptoms plus systemic signs such as fever, nausea, back pain, or chills.

The difference matters because bladder infections can often be treated with oral antibiotics at home, while kidney infections may require stronger or intravenous antibiotics in a hospital.

Since most kidney infections start as bladder infections, our UTI tests guide explains prevention and early detection.

When should you go to the hospital for a kidney infection?

Not every kidney infection requires hospitalization, but certain symptoms and risk factors mean you should seek emergency care. Go to the hospital if you have:

• High fever that does not improve with over-the-counter medication

• Severe pain in your side or back

• Persistent vomiting, making it impossible to keep down fluids or medicine

• Signs of dehydration (dizziness, low urine output, very dry mouth)

• Confusion or extreme fatigue

• Blood in your urine

• Rapid heartbeat or difficulty breathing

• Symptoms that worsen within 24 hours of starting antibiotics

As high blood sugar can raise the risk of kidney and urinary infections, explore understanding high glucose in urine.

Who is at higher risk of needing hospital care?

Some people are more likely to develop complications from kidney infections and should be cautious. Hospital care may be required if you are:

• Pregnant

• Over age 65

• Living with diabetes

• Living with a weakened immune system (such as from HIV, chemotherapy, or steroids)

• Someone with kidney disease or structural abnormalities in the urinary tract

• Prone to recurrent UTIs

• Recently had a urinary tract surgery or catheter

For simple home monitoring, the Ribbon Checkup urine test helps detect early warning signs of infection and kidney strain.

What happens at the hospital for a kidney infection?

If you are admitted to the hospital, your care team will focus on stopping the infection and preventing complications. Common steps include:

• IV antibiotics: Fast-acting treatment for infection

• IV fluids: Prevent dehydration and support kidneys

• Lab tests: Detect bacteria and signs of sepsis

• Symptom relief: Manage pain and nausea

• Imaging: Check for stones, blockages, or abscesses

Most people improve within a few days of hospital treatment.

How are kidney infections diagnosed?

Even before hospitalization, your doctor may order tests to confirm a kidney infection:

• Urine culture: Identifies bacteria causing the infection

• Blood tests: Check kidney function and signs of infection in the blood

• Urinalysis: Looks for white blood cells, red blood cells, and bacteria

• Imaging tests: Used if you are not responding to antibiotics or if complications are suspected
  
  

What are the possible complications of untreated kidney infections?

Without treatment, kidney infections can lead to serious problems such as:

• Sepsis: A life-threatening infection in the bloodstream

• Kidney abscesses: Pockets of pus that may require drainage

• Chronic kidney disease: Repeated or severe infections can damage kidney tissue

• Pregnancy complications: Infections increase the risk of premature labor and low birth weight

These risks are why doctors emphasize timely treatment.

Can a kidney infection be treated at home?

Mild cases may be treated with oral antibiotics, rest, and plenty of fluids. However, if your symptoms are severe or if you fall into a high-risk group, home treatment is not enough. Always follow up with your doctor, and do not wait to seek hospital care if symptoms worsen.

How can you prevent kidney infections?

You can lower your risk of kidney infections by taking steps to prevent UTIs:

• Drink plenty of water every day

• Empty your bladder regularly and fully

• Wipe front to back after using the toilet

• Urinate after sex

• Avoid holding urine for long periods

• Avoid excessive use of irritants such as douches or perfumed products in the genital area

For people with recurrent infections, a doctor may recommend preventive antibiotics or further testing to rule out structural problems in the urinary tract.

What should you ask your doctor if you have a kidney infection?

• Do I need to go to the hospital, or can this be treated at home?

• What type of antibiotic is best for me?

• How long should I expect to take medication?

• Are there lifestyle changes that can prevent future infections?

• What warning signs should make me return to the hospital?
  
  

Key takeaway

Kidney infections are serious and can become life-threatening if untreated. Go to the hospital if you have high fever, severe pain, vomiting, dehydration, or other concerning symptoms. With prompt treatment, most people recover fully and avoid long-term damage.

Prevention matters. Stay ahead of urinary and kidney issues with the Ribbon Checkup UTI Test.

Related Resources

Want to dive deeper into kidney health? Check out these helpful reads:

• The Complete Guide to At-Home Kidney Function Tests – Stay on top of kidney health with simple home testing.
  

• How Long Do Kidney Stones Last? Must Know – Get clarity on how long kidney stones typically last.
  

• What Can Mimic Kidney Stone Pain? – Learn about other conditions that cause similar pain.

 

References

References

1. American Academy of Family Physicians. (2020). Acute pyelonephritis in adults: Rapid evidence review. American Family Physician. https://www.aafp.org/pubs/afp/issues/2020/0801/p173.html 

2. Belyayeva, M. (2024). Acute pyelonephritis. In StatPearls. U.S. National Library of Medicine. https://www.ncbi.nlm.nih.gov/books/NBK519537/ 

3. Cleveland Clinic. (n.d.). Kidney infection (pyelonephritis): Symptoms & treatment. https://my.clevelandclinic.org/health/diseases/15456-kidney-infection-pyelonephritis 

4. IDSA. (2025, July 17). Complicated urinary tract infections (cUTI): Clinical guidelines. Infectious Diseases Society of America. https://www.idsociety.org/practice-guideline/complicated-urinary-tract-infections/ 

5. Medscape. (2025, August 20). Acute pyelonephritis treatment & management. https://emedicine.medscape.com/article/245559-treatment 

6. Nelson, Z., Aslan, A. T., Beahm, N. P., et al. (2024). Guidelines for the prevention, diagnosis, and management of urinary tract infections in pediatrics and adults: A WikiGuidelines group consensus statement. JAMA Network Open, 7(11), e2444495. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2825634 

7. Ramakrishnan, K. (2005). Diagnosis and management of acute pyelonephritis in adults. American Family Physician, 71(5), 933-942. https://www.aafp.org/pubs/afp/issues/2005/0301/p933.html 

8. Uroweb. (n.d.). EAU guidelines on urological infections. https://uroweb.org/guidelines/urological-infections/chapter/the-guideline 

9. U.S. Centers for Disease Control and Prevention. (2024, January 22). Urinary tract infection basics. https://www.cdc.gov/uti/about/index.html

 

Frequently Asked Questions

Q: What is a kidney infection?

A: A kidney infection, or pyelonephritis, happens when bacteria travel from the bladder to the kidneys, causing a more serious illness than a bladder infection.

Q: How do kidney infection symptoms differ from a UTI?

A: UTIs often cause burning urination and urgency. Kidney infections add fever, back pain, nausea, and chills, which indicate a more severe infection.

Q: When should you go to the hospital for a kidney infection?

A: Seek hospital care if you have high fever, severe pain, vomiting, dehydration, confusion, rapid heartbeat, or worsening symptoms after starting antibiotics.

Q: Who is at higher risk of needing hospital care?

A: Pregnant women, older adults, people with diabetes, weakened immune systems, kidney disease, or recurrent UTIs are at higher risk.

Q: How are kidney infections treated in the hospital?

A: Treatment includes IV antibiotics, IV fluids, lab testing, and imaging if needed. Most patients improve within a few days.

Q: What complications can happen if kidney infections are untreated?

A: Untreated infections may cause sepsis, kidney abscesses, chronic kidney disease, or pregnancy complications.

Q: Can kidney infections be treated at home?

A: Mild cases may be treated with oral antibiotics and rest, but severe symptoms or high-risk patients usually require hospital care.

Q: How can you prevent kidney infections?

A: Drink plenty of water, empty your bladder fully, urinate after sex, wipe front to back, and avoid irritants like perfumed products. Preventing UTIs lowers the risk of kidney infections.