Acute Pyelonephritis
What is Acute Pyelonephritis?
Acute pyelonephritis is a sudden bacterial infection of one or both kidneys. It occurs when bacteria travel up from the bladder into the kidneys. This creates inflammation and can damage kidney tissue if not treated quickly.
Your kidneys filter waste from your blood and make urine. When bacteria invade kidney tissue, your immune system fights back with inflammation. This causes fever, back pain, and can make you feel very sick. Most cases start as bladder infections that spread upward through the urinary tract.
Acute pyelonephritis is more serious than a simple bladder infection. It requires prompt medical attention and usually antibiotic treatment. Without treatment, the infection can spread to your bloodstream or cause lasting kidney damage. The good news is that most people recover fully with proper care.
Symptoms
- High fever, often above 101°F
- Pain in your back, side, or groin area
- Nausea and vomiting
- Painful or burning sensation when urinating
- Frequent need to urinate
- Cloudy or foul-smelling urine
- Blood in your urine
- Chills and shaking
- Fatigue and general feeling of being unwell
Some people may have mild symptoms at first that worsen quickly. Children and older adults may show confusion or changes in mental status instead of typical symptoms. If you have fever with back pain, seek medical care right away.
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Causes and risk factors
Acute pyelonephritis usually starts when bacteria from your bowel, most often E. coli, enter your urinary tract. The bacteria travel from your urethra to your bladder, then up to your kidneys. Women have shorter urethras than men, which makes it easier for bacteria to reach the bladder. Anything that blocks urine flow or weakens your immune system raises your risk.
Risk factors include being female, pregnancy, kidney stones, urinary catheter use, and structural problems in the urinary tract. Diabetes weakens immune function and makes infections more likely. A history of bladder infections increases your chances of kidney infection. Not drinking enough water can allow bacteria to multiply in your urinary tract. Sexual activity can also introduce bacteria near the urethra opening.
How it's diagnosed
Doctors diagnose acute pyelonephritis through symptoms, physical exam, and laboratory tests. Your doctor will check for tenderness in your back or side. A urine test is essential to confirm infection. The presence of white blood cells and bacteria in your urine indicates infection.
Urine leukocyte esterase testing detects white blood cells that fight infection in your urinary tract. A positive result with fever and flank pain strongly suggests kidney infection. Rite Aid offers urine testing at over 2,000 Quest Diagnostics locations nationwide. Your doctor may also order a urine culture to identify the specific bacteria and blood tests to check if infection has spread.
Treatment options
- Antibiotics are the main treatment, usually for 7 to 14 days
- Drink plenty of water to help flush bacteria from your urinary tract
- Take pain relievers like acetaminophen or ibuprofen for fever and discomfort
- Rest to help your body fight the infection
- Avoid caffeine and alcohol, which can irritate your bladder
- Severe cases may require hospital admission for IV antibiotics and fluids
- Prevent future infections by urinating after sexual activity
- Wipe front to back after using the bathroom to keep bacteria away from the urethra
- Cranberry products may help prevent recurrent urinary infections
- Follow up with your doctor to ensure the infection has cleared
Concerned about Acute Pyelonephritis? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
A bladder infection affects only your bladder and causes urinary symptoms like burning and frequency. Acute pyelonephritis is a kidney infection that causes fever, back pain, and makes you feel sick all over. Kidney infections are more serious and always require antibiotic treatment to prevent complications.
Symptoms usually develop within a few hours to two days after bacteria reach your kidneys. You may notice bladder infection symptoms first, then develop fever and back pain. Some people get very sick very quickly, while others have a more gradual onset of symptoms.
No, acute pyelonephritis requires antibiotic treatment. Without antibiotics, the infection can spread to your bloodstream and cause sepsis. It can also lead to permanent kidney damage or kidney abscesses. Always see a doctor if you suspect a kidney infection.
Most people start feeling better within 2 to 3 days of starting antibiotics. Complete recovery usually takes 1 to 2 weeks. You should finish all your antibiotics even if you feel better. Severe cases that require hospitalization may take longer to heal.
Yes, several steps can lower your risk of recurrence. Drink 6 to 8 glasses of water daily to flush bacteria from your urinary tract. Urinate when you feel the urge rather than holding it. Empty your bladder after sexual activity and practice good hygiene. If you get frequent infections, your doctor may recommend preventive antibiotics.
Yes, acute pyelonephritis during pregnancy is serious and requires immediate medical care. It can lead to premature labor, low birth weight, and complications for both mother and baby. Pregnant women with kidney infections usually need hospital treatment with IV antibiotics. Regular prenatal urine screening helps catch infections early.
A urine test is the primary diagnostic tool for kidney infection. Urine leukocyte esterase testing detects white blood cells that indicate infection and inflammation. A urine culture identifies the specific bacteria causing infection. Your doctor may also order blood tests to check kidney function and see if infection has spread to your bloodstream.
Yes, if left untreated, acute pyelonephritis can cause scarring and permanent kidney damage. Repeated kidney infections over time increase the risk of chronic kidney disease. This is why prompt antibiotic treatment is so important. Most people who receive timely treatment recover completely with no lasting damage.
Women have shorter urethras than men, which makes it easier for bacteria to travel from outside the body to the bladder. The female urethra opening is also closer to the anus, where E. coli bacteria live. Pregnancy, menopause, and sexual activity also increase risk. Men can still get kidney infections, especially if they have prostate problems or kidney stones.
Go to the emergency room if you have high fever with shaking chills, severe back or side pain, persistent vomiting, or confusion. Inability to keep down fluids or antibiotics also requires emergency care. These symptoms may indicate severe infection or sepsis. Prompt IV antibiotic treatment can prevent life-threatening complications.