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Why does a kidney infection still hurt after antibiotics?

Kidney infection still hurts after antibiotics; key fats:

Your kidney infection may still hurt after antibiotics due to antibiotic resistance, recurrence of UTI, and development of complicated UTI. You may see a doctor for further investigations if you fail and your symptoms don’t go away.

  • Kidney infection may still hurt after antibiotics due to antibiotic resistance, recurrence of UTI, and development of complicated UTI.
  • Antibiotic-resistant UTI is the most common reason for persistent symptoms after antibiotics.
  • UTIs caused by E. coli have high rates of recurrence and are often treated empirically without a culture and sensitivity testing.
  • Antibiotic resistance is common among UTIs, with up to 80% of bacteria resistant to two antibiotics.
  • When antibiotic treatment fails, further investigations, such as urine analysis and culture may be required.
  • Treatment for resistant UTI may involve prescribing a stronger antibiotic based on a new culture and sensitivity testing or treating underlying conditions such as stones, uncontrolled diabetes, etc.
  • The development of complicated UTIs can hurt your kidneys even with the use of antibiotics.
  • Warning signs of a worsening kidney infection include high fever, pain in the side, back, or groin, nausea and vomiting, blood in the urine, difficulty urinating, cloudy or foul-smelling urine, fatigue or weakness, confusion or disorientation, rapid breathing or shortness of breath, rapid heartbeat, and swelling in the legs, ankles, or feet.

Common reasons why a kidney infection still hurts after antibiotics

[1] Antibiotic-resistant UTI (The most common reason why your kidney still hurts after antibiotics).

Antibiotics are the definitive treatment of urinary tract infections. However, antibiotic resistance may cause treatment failure and subsequent persistent symptoms of kidney infection.

Most cases of UTI are caused by a bacteria called E. Coli:

  • Up to 60-70% of UTIs are caused by E. coli (reference).
  • E. coli-induced UTI has high rates of recurrence (44% risk of recurrence of UTI within one year (reference)).

So, Many doctors give antibiotics for UTIs without a culture and sensitivity testing, presuming it is due to E. Coli. A culture and sensitivity is a test that accurately detects the causative bacteria and the best antibiotic for it.

One study in 2019 concluded that about 92% of bacteria causing UTIs are resistant to at least one common antibiotic. Moreover, almost 80% of the bacteria are resistant to two antibiotics (reference).

So, the first thing to consider when your kidney infection still hurts after UTI treatment is antibiotic-resistant bacteria.

What to do if you still have UTI symptoms after days of antibiotics?

Report your symptoms to your doctor. At first, your doctor will make investigate the reason why your kidney still hurts after antibiotics.

Typically, your doctor will require another urine analysis (pus cell count, leucocyte esterase) and urine culture.

Your doctor may also require further investigations such as abdominal ultrasound, blood sugar, etc.

The treatment of antibiotic-resistant UTI:

Failure of antibiotics to treat a UTI depends may be due to many factors, such as:

  • The wrong type of antibiotic was given (such as metronidazole).
  • Presences of resistant bacteria (such as Multi-drug resistant E. Coli).
  • The wrong dose or wrong duration of the antibiotics.
  • Atypical bacteria or non-bacterial causes of UTI (such as fungal UTI).
  • Presences of predisposing factors for persistent UTI, such as uncontrolled diabetes, stones, etc.

When an antibiotic fails to cure UTI symptoms, you should work with your doctor to determine the main factor from the above-mentioned causes of failure.

Depending on the cause, your doctor will prescribe treatment, which can be in the form of:

  • Prescribing a stronger antibiotic based on a new culture and sensitivity testing.
  • Prescribing specific agents for other causes of UTI (such as antifungals for Candida UTI).
  • Treatment of predisposing factors, such as stones, uncontrolled diabetes, etc.

[2] Early recurrence of UTI.

It is not uncommon for UTIs to recur shortly after antibiotic treatment, especially if the infection is severe. In some cases, the bacteria causing the infection may not have been completely eliminated by the antibiotics, which can lead to a recurrence of symptoms.

Recurrent UTI in women is a common problem that can be caused by a variety of factors. Some of the most common causes of recurrent UTI in women include:

  • Incomplete eradication of the bacteria causing the infection: Sometimes, despite antibiotic treatment, the bacteria causing the UTI are not completely eliminated. This can lead to a recurrence of the bladder or kidney infection symptoms and the need for further treatment.
  • Reinfection with a different strain of bacteria: Women who have had UTIs in the past are at an increased risk of developing another UTI, potentially caused by a different strain of bacteria.
  • Predisposing factors such as pregnancy, menopause, and sexual activity: Women who are pregnant or going through menopause are at an increased risk of developing UTIs due to changes in their hormonal balance. Sexual activity can also increase the risk of UTIs, as bacteria can be introduced into the urinary tract during sex.
  • Anatomical abnormalities in the urinary tract: Women who have anatomical abnormalities in their urinary tract, such as a bladder prolapse or a urethral stricture, may be more prone to developing UTIs.

In order to prevent recurrent UTIs, it is important to identify and address the underlying cause of the infection. Your doctor may recommend additional testing or treatment to help prevent further infections.

It is important to report any recurrence of symptoms to your doctor, as they may need to prescribe a different course of antibiotics or investigate further for underlying conditions.

[3] Persistence of the cause or risk factor of UTI or kidney infection.

UTI occurs mainly due to bacteria from your stool (entering the bladder through the urethra). Many causes and risk factors may cause the persistence of symptoms as they persist, causing re-infection or persistence of the original infection.

The factors include (reference):

  • Being a female (females have a shorter urethra, increased moisture around the opening of the, and hormonal changes that contribute to the persistence or early recurrence of the infection).
  • Recurrent intercourse during or shortly after UTI treatment may also contribute to the persistence of symptoms.
  • Uncontrolled diabetes (high blood sugar is a good medium for bacteria to grow).
  • Current or persistent use of a urinary catheter.
  • Use of medications that suppress the immune system, such as corticosteroids (as with people with a kidney transplant).
  • Use of spermicide-coated diaphragms or condoms.
  • Urinary incontinence, and others.

Learn More about the causes and risk factors of recurrent UTI.

[4] Presence of Conditions other than UTI (stones, interstitial cystitis, etc.).

UTI can be associated with (or caused by) some conditions that mimic UTI symptoms. The condition may either cause the persistence of UTI or cause symptoms similar to UTI (such as kidney or bladder pain.

Common conditions include:

  • Kidney or bladder stones: They can cause symptoms similar to UTI, such as pain or burning during urination, frequent urination, and cloudy or strong-smelling urine. These stones can also cause UTIs by blocking the flow of urine, which can lead to the growth of bacteria in the urinary tract. If you have symptoms of stones or UTI, seeing a doctor for proper diagnosis and treatment is important.
  • Interstitial cystitis: It is a chronic condition that causes inflammation of the bladder wall, leading to urinary urgency, frequency, and pain. It can mimic the symptoms of a UTI, but unlike a UTI, it is not caused by an infection. Interstitial cystitis is often diagnosed through a process of elimination, as no single test can confirm the condition. Treatment may involve a combination of medications, lifestyle changes, and bladder training exercises.
  • Bladder cancer. Bladder cancer is common in older males. It Causes symptoms such as blood or blood clots in urine, bladder pain (similar to UTI pain), burning urination, etc.
  • Ureteric stricture (Narrowing).
  • Polycystic kidney.
  • Kidney tumors (benign or malignant).
  • Sexually-transmitted diseases.
  • Anatomical abnormalities such as bladder diverticulum.
  • And others.

Warning signs of worsening kidney infection?

UTI can be simple (involving the urinary bladder) or complicated (an infection that spreads to the kidneys or the bloodstream).

The development of complicated UTIs can hurt your kidneys even with the use of antibiotics.

Signs of a worsening kidney infection include:

  • High fever (above 101°F or 38.3°C)
  • Pain in the side, back, or groin
  • Nausea and vomiting
  • Blood in the urine
  • Difficulty urinating
  • Cloudy or foul-smelling urine
  • Fatigue or weakness
  • Confusion or disorientation
  • Rapid breathing or shortness of breath
  • Rapid heartbeat
  • Swelling in the legs, ankles, or feet

If you experience any of these symptoms, seek medical attention immediately, as a kidney infection can quickly become life-threatening.