Pyelonephritis - Symptoms, Types, Causes & Diagnosis

Pyelonephritis - Symptoms, Types, Causes & Diagnosis

One form of urinary tract infection is pyelonephritis, which affects the kidneys (UTI). It is brought on by bacteria moving up to one or both of your kidneys from another area of your body, such as your bladder.

Pyelonephritis: Health Tips

What is a Kidney Infection (pyelonephritis)?

One form of urinary tract infection is pyelonephritis, which affects the kidneys (UTI). It is brought on by bacteria moving up to one or both of your kidneys from another area of your body, such as your bladder.

Compared to lower UTIs, kidney infections can be more dangerous. If you experience kidney infection symptoms, consult a doctor.

Classification of Pyelonephritis

Pyelonephritis is an infection of the kidneys that can be classified into two main types:

  • IAcute Pyelonephritis: This is a sudden onset of the infection that usually lasts for a short period. It is the most common type of pyelonephritis and is often caused by bacteria entering the urinary tract and then spreading to the kidneys.

An unexpected and serious kidney infection is known as acute pyelonephritis. The swelling it produces in the kidneys could result in long-term harm. Pyelonephritis poses a serious risk to life.

  • Chronic Pyelonephritis: This is a long-term, recurrent type of infection that can cause scarring and damage to the kidneys over time. It is usually caused by an underlying condition that makes the kidneys more susceptible to infection, such as kidney stones, a blockage in the urinary tract, or an abnormality in the structure of the kidneys.

When episodes occur frequently or chronically, the condition is known as chronic pyelonephritis. Although the chronic variety is rare, it usually affects children or those who have frequent urinary obstructions.

In addition, pyelonephritis can also be classified according to the route of infection:

  • Ascending Pyelonephritis: This occurs when bacteria from the bladder travel up the ureters to infect the kidneys.
  • Hematogenous Pyelonephritis: This occurs when bacteria from an infection elsewhere in the body spread to the kidneys via the bloodstream.

Overall, pyelonephritis is a serious condition that requires prompt medical attention and treatment to prevent complications and further kidney damage.

What are the Symptoms?

Symptoms usually appear within two days of infection. Common symptoms include:

  • A fever greater than 102°F (38.9°C)
  • Pain in the abdomen, side, abdomen and groin
  • Painful or burning urination
  • Cloudy urine
  • Pus or blood in the urine
  • Urgent or frequent urination
  • Fishy-smelling urine

Other Symptoms can Include:

  • Shaking or chills
  • Nausea
  • Vomiting
  • General aching or ill feeling
  • Fatigue
  • Moist skin
  • Mental confusion

Children and older individuals may experience distinct symptoms than other people do. For instance, mental confusion is a frequent symptom in older persons and is frequently the only one.

Individuals who have chronic pyelonephritis may only have minor symptoms or possibly no discernible symptoms at all.


The gastrointestinal tract is home to the organisms that are most frequently implicated:-

  • Escherichia coli (most common)
  • Klebsiella spp.
  • Proteus spp.
  • Enterobacter spp.
  • Pseudomonas spp.
  • Haemophilus influenzae

By traveling retrogradely from the bladder up the ureter, the infection enters the upper urinary tract. This is made possible by virulence factors that enable bacteria to adhere to the urothelium and inhibit ureteric peristalsis. After entering the collecting tubules, the infection causes interstitial nephritis, which alters renal filtration and blood flow in the afflicted area. Imaging is altered as a result of localized ischemia brought on by inflammatory alterations, which may eventually result in necrosis and scarring.

What are the Causes?

  1. Bacterial Infection: Often, the infection begins as a urinary tract infection in the lower urinary tract (UTI). In the urethra, bacteria enter the body where they grow and move up to the bladder. The bacteria then proceed to the kidneys via the ureters. The infection is frequently caused by bacteria like E. coli. Any severe bloodstream infection, however, has the potential to travel to the kidneys and result in acute pyelonephritis.
  2. Mechanical Causes: Pregnancy, neurogenic bladder (caused by spinal cord damage, spina bifida, or multiple sclerosis), benign prostatic hyperplasia in men, any structural abnormalities in the urinary tract, vesicoureteral reflux (urine from the bladder flowing back into the ureter), kidney stones, urinary tract catheterization, ureteral stents, or drainage procedures (such as nephrostomy) are all examples of mechanical causes of the pyelonephritis.
  3. Constitutional: diabetes mellitus, immunocompromised states
  4. Behaviour: usage of spermicide and change in sexual partner within the past year
  5. Family History: Successful family history (close family members with frequent urinary tract infections)

Do risk variables exist?

  • Blockage: Any issue that prevents the regular flow of urine increases the chance of developing acute pyelonephritis. This includes uterine prolapse, enlarged prostate, and kidney stones. Moreover, pressure on your bladder when pregnant can raise your risk.
  • Being affected by a condition that causes the pee to flow incorrectly: Little amounts of urine flow back into the tubes that join the bladder and kidneys when there is vesicoureteral reflux. Kidney infections are more likely to occur in both children and adults who have this illness.
  • Immune system deficiencies: Situations that make you more susceptible to illnesses. They include having diabetes, HIV, or taking immunosuppressive drugs.
  • Anatomy - Your anatomy makes it easier for bacteria to enter women's bodies because their urethras are substantially shorter than those of men. Because of this, women are more likely to contract kidney infections and develop acute pyelonephritis.
  • Nerve damage - The bladder surrounding nerves is damaged. Due to this, it may be challenging to detect kidney infections.
  • Urinary catheter - A urinary catheter is used. Urinary catheters are those used to remove urine from the bladder. Catheters may be used after a surgical procedure or a diagnostic examination. They are also employed in bedridden patients.

Individuals at higher risk include:

  • Anyone who suffers from persistent kidney stones or other kidney or bladder issues
  • Older people
  • Those with immune systems that are weakened, such as those who have cancer, diabetes, or HIV/AIDS
  • Those who experience vesicoureteral reflux (a condition where small amounts of urine back up from the bladder into the ureters and kidneys)
  • Individuals with enlarged prostate
  • Catheter use
  • Cystoscopic examination
  • Urinary tract surgery
  • Certain medications
  • Nerve or spinal cord damage

Diagnosing Pyelonephritis

The diagnosis of pyelonephritis usually involves a combination of medical history, physical examination, and laboratory tests.

Here are some of the common methods used to diagnose pyelonephritis:

  • Medical history: The doctor will ask about your symptoms, such as fever, chills, pain in the lower back or sides, and frequent urination. They will also ask about any recent urinary tract infections or other medical conditions that may increase your risk of developing pyelonephritis.
  • Physical examination: The doctor will examine your abdomen and back for tenderness or swelling, and may also check your temperature and blood pressure.
  • Urine test: A urine sample will be collected and analyzed for the presence of bacteria, white blood cells, and other signs of infection.
  • Blood test: A blood test may be done to check for signs of infection, such as an elevated white blood cell count.
  • Imaging tests: Imaging tests such as an ultrasound, CT scan or MRI may be used to visualize the kidneys and urinary tract and check for any abnormalities, such as kidney stones, abscesses or blockages.

If a patient doesn't improve after 72 hours of treatment, a CT scan (with or without injectable dye) may be prescribed.

  • Urine culture: A urine culture may be done to identify the specific type of bacteria causing the infection and determine the most effective antibiotic treatment.

Overall, a prompt diagnosis of pyelonephritis is important to prevent complications and ensure appropriate treatment.

  • Radioactive imaging: If your doctor suspects scarring as a result of pyelonephritis, a DMSA test may be prescribed. This imaging approach monitors a radioactive material injection.

The substance is injected by a medical expert into an arm vein. The kidneys are the next stop for the substance. Pictures captured while the radioactive substance is passing through the kidneys reveal diseased or damaged regions.

Multiple Diagnoses

It is wise to keep the differential broad when diagnosing acute pyelonephritis. When patients complain of fever, flank pain, and tenderness at the costovertebral angle, doctors should also take other illnesses into account.

Differential diagnosis of pyelonephritis includes:

  • Appendicitis
  • Abdominal abscess
  • Nephrolithiasis
  • Cholecystitis
  • Urinary tract obstruction
  • Pelvic inflammatory disease
  • Pancreatitis
  • Ectopic pregnancy

Treating Pyelonephritis


The primary line of treatment for acute pyelonephritis is antibiotics. The kind of antibiotic your doctor prescribes, though, will depend on whether or not the bacteria can be located. A broad-spectrum antibiotic is applied if not.

The medication must be used for the entire prescribed duration even if it can treat the illness in two to three days (usually 10 to 14 days). Even if you feel better, this is still true.

The antibiotic options are:

  • Levofloxacin
  • Ciprofloxacin
  • Co-trimoxazole
  • Ampicillin

Hospital Admission

In some cases, drug therapy is ineffective. Your doctor might send you to the hospital if you have a serious kidney infection. The severity of your ailment and how well you respond to treatment will determine how long you stay.

Intravenous fluids and antibiotics for 24 to 48 hours are possible treatments. Doctors will keep an eye on your blood and urine while you're in the hospital to find the infection. Following your hospital discharge, you'll most likely be given oral antibiotics to take for 10 to 14 days.


An underlying medical condition may be the cause of recurrent kidney infections. In some cases, surgery may be required to remove obstructions or correct structural problems with the kidneys. If antibiotics are ineffective in treating an abscess, surgery may be necessary to drain it.

Complications of pyelonephritis

Prenatal pyelonephritis in women

The physiological makeup of the urinary tract is altered during pregnancy, among other transient alterations to the body. Pyelonephritis risk can increase with increased progesterone and pressure on the ureters.

Pregnant women with pyelonephritis often need to be admitted to the hospital. Both the mother's and the child's life may be in danger. Premature birth is another risk that it may raise. Beta-lactam antibiotics are administered to expectant mothers for at least 24 hours or until their symptoms subside.

Between the 12th and 16th weeks of pregnancy, a urine culture should be performed to avoid pyelonephritis in pregnant women. Pyelonephritis might arise from a UTI that doesn't show any symptoms. Early UTI detection helps avoid kidney infections.

Children's pyelonephritis

More than a million visits to paediatricians are made in the US each year for children's UTIs, according to the American Urological Association. If a girl is older than one year old, her risk increases. Under one-year-old boys are more vulnerable, especially if they are uncircumcised.

Fever, discomfort, and urinary tract symptoms are common in children with UTIs. Before these symptoms progressing to pyelonephritis, a doctor should treat them right away.

The majority of kids can be cured without hospitalisation by taking oral antibiotics. Find out more about UTIs in kids.

Possible Difficulties

Chronic kidney disease can develop as a side effect of acute pyelonephritis. The kidneys may suffer irreparable damage if the infection persists. It is also possible for the infection to enter the bloodstream, though this is uncommon. This may lead to sepsis, a potentially fatal illness.

Other Issues Include:

  • Recurrent kidney infections that extend to the kidneys
  • Surrounding tissues
  • Chronic kidney failure
  • Kidney infection

How to Avoid Pyelonephritis

A dangerous condition is pyelonephritis. As soon as you think you could have pyelonephritis or a UTI, call your doctor. The sooner you begin therapy for this ailment, the better because it demands immediate medical attention.


By taking precautions against urinary tract infections, you can lower your chance of kidney infection.

As soon as necessary, urinate - When the urge to urinate strikes, act immediately.

After sexual activity, empty the bladder - After intercourse, urinate as quickly as you can to help rid the urethra of bacteria. Thus there is less chance of becoming sick.

Carefully wipe - After peeing and after a bowel movement, wipe from front to back. This aids in limiting the transmission of bacteria to the urethra.

Do not use irritating products - Keep products out of the genital area. Deodorant douches or vaginal sprays can irritate some.

Early diagnosis and treatment of pyelonephritis are important to prevent serious complications, such as sepsis or kidney damage. Treatment usually involves a course of antibiotics and adequate hydration. In some cases, hospitalization may be necessary, especially for people with severe symptoms or underlying medical conditions.

Overall, pyelonephritis is a treatable condition with a good prognosis if detected and treated promptly.