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Urinary tract infections are an all-too-common experience and usually resolve after a few days of antibiotics. Sometimes, however, the bacteria infecting the bladder can work their way up to the kidneys and provoke a much more urgent and hazardous infection. Fortunately, kidney infections can be rapidly resolved with the right antibiotics, but early diagnosis and treatment are crucial.
What is a kidney infection?
Kidney infection, or pyelonephritis, is a bacterial infection of the kidneys that constitutes a medically urgent condition requiring immediate antibiotic treatment. Untreated kidney infection runs the risk of an abscess, kidney damage, loss of kidney function, blood poisoning (sepsis), and, in a worst-case scenario, kidney failure.
Kidney infections are a commonly experienced type of kidney disease, accounting for over 250,000 cases per year. They are typically caused by an active urinary tract infection (UTI) that begins in the bladder, called cystitis. Because women are at a higher risk for cystitis, they are also at a higher risk for kidney infection. Approximately 15-17 out of every 10,000 women are diagnosed with kidney infection annually compared to 3-4 out of every 10,000 men. Other risk factors include urinary system blockage, a compromised immune system, urinary catheters, or vesicoureteral reflux, a condition in which urine flows up from the bladder back into the kidneys.
Most kidney infections are the result of urinary tract infections caused by a bacteria called Escherichia coli, or E. coli, which normally lives in the colon. Bacteria that finds its way into the bladder and goes untreated can travel up the ureters, the tubes that connect the kidneys to the bladder, and spread to the kidneys and their collecting systems.
In some cases, however, the infection can be caused by a stone blocking urine flow, or in very care cases a pathogen may infect the kidneys directly from the bloodstream.
Healthcare professionals distinguish between uncomplicated and complicated kidney infections. Uncomplicated kidney infection occurs in women with a healthy immune system and functioning kidneys, and generally occur in the childbearing age-range of 15-45 years of age. Complicated kidney infection occurs in people with compromised immune systems, kidney damage, chronic kidney disease, transplanted kidneys, kidneystones, kidneys with structural abnormalities, or diabetes. A kidney infection which occurs in men automatically defaults to the complicated category. Infancy, advanced age, pregnancy, and kidney infection that does not improve with antibiotics also count as complications. Complicated kidney infection is a more hazardous condition and can sometimes require hospitalization.
Both uncomplicated and complicated kidney infections are urgent medical conditions. Early diagnosis and treatment are critical to preserving the full, healthy functioning of the kidneys.
How is a kidney infection diagnosed?
Kidney infection diagnosis is based on physical symptoms and urine testing. Most typically, a kidney infection diagnosis will be made by a general practitioner, urgent care physician, or emergency room physician.
Kidney infection is a type of urinary tract infection, so symptoms will typically include symptoms of a bladder infection (cystitis) such as pain over the pubic area, frequent urination, and cloudy urine. The healthcare professional will look for specific symptoms of a kidney infection in addition to the UTI symptoms:
- Pain in the side (flank pain) or lower back pain
- Costovertebral angle tenderness, which is pain caused by tapping the back above the kidney
- Fever
- Chills
- Nausea
Fever, flank pain, and nausea are the strongest indicators of kidney infection.
The diagnosis is confirmed with urinalysis and a urine culture. The urine test will confirm the diagnosis by identifying white blood cells and other substances indicating infection. The urine culture is used to both identify the type of bacteria responsible for the infection and determine its resistance to antibiotics. Both are critical in determining the most effective antibiotic therapy.
Blood tests are not usually ordered for patients with an uncomplicated kidney infection, but blood will be tested for hospitalized patients.
Imaging tests are not required for uncomplicated kidney infection. If there are complications, however, a physician may order a CT scan of the abdomen and pelvis to assess the structural health of the kidneys. A contrast dye might be taken orally or injected directly into the bloodstream to make kidney structures show up better in the scan.
Kidney infection treatment options
Kidney infections are treated with antibiotics, pain relievers, and fever reducers. Uncomplicated kidney infection and few complicated kidney infections will be treated on an outpatient basis by a general practitioner, but people with a complicated kidney infection likely require hospitalization and intravenous antibiotics.. Pregnant women may require additional consultation with an obstetrician or gynecologist.
Outpatient treatment
Patients with an uncomplicated kidney infection can be treated on an outpatient basis with a one- to two-week course of oral antibiotics. The doctor will prescribe an antibiotic specific to the type of bacteria found in the urine culture. In some cases, the doctor will start treatment with a single, antibiotic injection. A follow-up visit will be scheduled one or two days after starting antibiotic treatment. By that time, most symptoms will markedly fade. If symptoms do not improve in that time, the physician will order more tests and possibly admit the patient to a hospital.
Hospitalization
Patients with a complicated kidney infection or patients who are not improving on oral antibiotics will often be admitted to a hospital. They will be treated daily with intravenous infusions of antibiotics and regularly monitored by healthcare professionals. When the infection is under control, patients will be sent home to complete their regimen on an oral antibiotic, when possible.
Surgery
In some cases, the kidney infection may be complicated by kidney stones, structural problems with the kidneys, or enlarged prostate in men. These conditions may need to be treated with surgery or other procedures, such as shockwave therapy, to remove the complication. Severe kidney infections with abscesses or tissue death may require surgical incision and drainage, scraping away dead tissue, or the total removal of the kidney (nephrectomy).
Kidney infection medications
Medical treatment for kidney infection involves antibiotics, pain relievers (analgesics), and fever-reducing medications (antipyretics). The physician will tailor antibiotics based on the bacteria cultured from the urine sample and its drug resistance. Acetaminophen will be used to provide both fever and pain relief.
Antibiotics
Antibiotics are the treatment of choice for kidney infection. First-line therapy will usually involve a five to sevenday course of an oral fluoroquinolone (ciprofloxacin or levofloxacin) ortwo weeks on trimethoprim-sulfamethoxazole (TMP-SMX).
Depending on the symptoms, treatment may start with an initial injection of an antibiotic. For patients admitted to a hospital, patients will usually be started on intravenous antibiotics such as ciprofloxacin, levofloxacin, ceftriaxone, imipenem-cilastatin, or piperacillin-tazobactam.
Depending on the isolated bacteria and its drug resistance profile, the antibiotic will ideally be streamlined to an oral option for outpatient completion with another week or more of therapy. Sometimes, an oral antibiotic is not possible, but patients may receive intravenous antibiotics outside of the hospital.
Pain killers
NSAIDs, such as aspirin or ibuprofen, may risk kidney damage or kidney failure in patients with kidney problems, so healthcare professionals discourage their use in patients with a kidney infection. Instead, both pain relief and fever reduction can be managed with prescription or over-the-counter acetaminophen.
What is the best medication for a kidney infection?
Kidney infections are treated with antibiotics. The “best” antibiotic will be the one most suitable for the bacteria causing the condition, its resistance to specific antibiotics, and taking into account any patient allergies.
| Best medications for a kidney infection | ||||
|---|---|---|---|---|
| Drug Name | Drug Class | Administration Route | Standard Dosage | Common Side Effects |
| Cipro (ciprofloxacin) | Antibiotic | Oral | One 500 mg tablet taken twice daily | Nausea, diarrhea, vomiting |
| Levaquine (levofloxacin) | Antibiotic | Oral | One 750mg tablet taken once daily | Nausea, headache, diarrhea |
| Bactrim (trimethoprim-sulfamethoxazole) | Antibiotic | Oral | One double-strength tablet twice daily | Nausea, vomiting, loss of appetite |
| Rocephin (ceftriaxone) | Antibiotic | Intravenous or Intramuscular injection | 1g once per day | Rash, nausea, diarrhea |
| Zosyn (piperacillin-tazobactam) | Antibiotic | Intravenous injection | 3.375g every 6 hours | Diarrhea, headache |
| Primaxin (imipenem-cilastatin) | Antibiotic | Intravenous injection | 500 mg every six hours | Nausea, vomiting, diarrhea |
| Tylenol (acetaminophen) | Over-the-counter analgesic | Oral | Two 325 mg tablets every 6 hours | Nausea, stomach pain, loss of appetite |
Many of the standard dosages above are from the U.S. Food and Drug Administration (FDA) and the National Institutes of Health. Dosage is determined by your doctor based on your medical condition, response to treatment, age, and weight. Other possible side effects exist. This is not a complete list.
What are the common side effects of kidney infection medications?
Most antibiotics cause gastrointestinal problems including upset stomach, nausea, vomiting, abdominal pain, and loss of appetite. All antibiotics can cause a serious secondary diarrheal infection due to a bacteria known as Clostridium difficile. The most serious side effects of fluoroquinolones are psychiatric disorders, heart problems, and tendon problems.
Analgesics like acetaminophen are relatively safe when taken as directed. The most common side effects are gastrointestinal: nausea, stomach pain, and loss of appetite. Acetaminophen, however, can be toxic in excess. Acetaminophen overdose damages the liver and could require emergency treatment and hospitalization.
Side effects will vary based on the medication. This is not a complete list, and you should consult with a healthcare professional for possible side effects and drug interactions based on your specific situation.
What are the best home remedies for kidney infections?
Kidney infection is a serious illness that cannot be safely treated at home. However, there are several ways to relieve the pain and help speed recovery from a kidney infection.
Drink water
Water helps to flush bacteria out of the kidneys. Six to eight eight-ounce glasses of water should be enough, but no need tooverdo it. Too much water can cause an electrolyte imbalance.
Eat diuretic foods
Consider eating a diet heavy in diuretic foods such as celery, asparagus, parsley, cranberries, or watermelon to increase the flow of urine through the kidneys. Cranberry juice and parsley juice are often recommended for urinary tract infections because of their diuretic properties.
Use a heating pad
A heating pad placed over the kidneys for 10 to 15 minutes can help alleviate flank pain.
Use over-the-counter acetaminophen
Acetaminophen can relieve pain and reduce the fever associated with a kidney infection. NSAIDs, such as aspirin and ibuprofen, aren’t recommended for kidney problems. They may further harm the kidneys.
Frequently asked questions about kidney infection
How can I treat a kidney infection at home?
Treating kidney infection solely at home or with natural remedies is not a good idea. However, several home remedies can help manage the pain while the infection is treated with antibiotics. These include drinking water, using a heating pad to reduce pain, and taking over-the-counter acetaminophen to manage both pain and fever.
How long does it take to recover from a kidney infection?
Antibiotic treatment usually takes seven days to clear the infection but could take as long as two weeks, sometimes longer. The pain should dramatically subside after one or two days of antibiotics.
How do I detox my kidneys?
There is no scientific evidence that kidney cleansing has any effect on kidney health. The best way to detoxify the kidneys is to not toxify them in the first place. Drink plenty of fluids, eat a nutritious diet, avoid processed foods, reduce salt intake, quit smoking, and avoid alcohol, caffeine, and unnecessary medications.
How do you know when a UTI becomes a kidney infection?
The symptoms of a UTI include pain when urinating, abdominal pain above the pubic area, frequent need to urinate, and bad-smelling, cloudy, or bloody urine. If the infecting bacteria migrates up to the kidney, additional symptoms may include flank pain, lower back pain, fever, and maybe chills and nausea. If you have a lower urinary system infection and begin to notice pain on your sides or you have a fever over 100 degrees, it’s time to see a doctor.
Can a kidney infection go away on its own?
An untreated kidney infection can cause permanent kidney damage, loss of kidney function, and even death. To limit kidney damage, a kidney infection should be diagnosed by a healthcare provider and treated with antibiotics as soon as possible.
Can I go to work with a kidney infection?
Most kidney infections are treated on an outpatient basis with oral antibiotics. Symptom relief typically occurs after a few days of treatment, so it may be possible to go to work at that point. Many patients, however, require a week or two before they feel well enough to work. As always, never go to work with a fever.
What is the fastest way to get rid of a kidney infection?
Antibiotics are the most rapid way to clear a kidney infection. A healthcare provider will schedule a follow-up visit a couple of days after the initiation of antibiotic therapy. If there has been no improvement in symptoms, more testing or hospitalization may be required.
What antibiotics are used to treat a kidney infection?
The first-line medications for the treatment of uncomplicated kidney infection are oral fluoroquinolone antibiotics (ciprofloxacin and levofloxacin) or trimethoprim-sulfamethoxazole. Complicated kidney infections may require hospitalization and treatment with daily intravenous antibiotics.
What should I eat if I have a kidney infection?
Healthcare professionals do not believe that diet or nutrition can help treat kidney infections. The National Institutes of Health, however, do recommend drinking six to eight eight-ounce glasses of water daily while being treated for kidney infection.
When should you go to the hospital for a kidney infection?
Kidney infection is a potentially hazardous illness. Early diagnosis and treatment are crucial to prevent potentially permanent loss of kidney function. If you notice kidney infection symptoms such as pain in your side, fever, or nausea, see a doctor immediately. If you can’t make an appointment with your regular doctor, do not hesitate to visit urgent care or an emergency room.
Is a kidney infection urgent?
A kidney infection requires immediate diagnosis and treatment to prevent possible kidney damage and permanent loss of kidney function.