"Well-treated pyelonephritis generally cures without sequelae, but on certain occasions (especially when there is vesico-renal reflux or obstruction), the disease runs its course and produces inflammatory and scarring lesions that atrophy the kidney".


Pyelonephritis is a urinary infection defined as the presence of germs in the urine. Usually these are bacteria (bacterial) and exceptionally, fungi (fungal) or viruses (viral).

After evidence of significant bacteriuria, it is necessary to identify the anatomical location of the infection, using clinical symptoms and, if necessary, complementary explorations.

We call cystitis a urinary tract infection affecting the bladder defined by a characteristic clinical picture of pain or burning sensation during urination, very increased and scarce frequency of urination (frequency), permanent sensation of desire to urinate (urgency) and sometimes bloody urine (hematuria). The picture is always without fever.

If fever is present, it indicates that another organ is also affected. In a male, and to elucidate if the prostate is the affected organ, a finger is introduced in the rectum (rectal touch) with which the prostate is touched and the diagnosis is made. The picture is called acute prostatitis.

If the affected organ is the kidney, the picture is denominated acute pyelonephritis and it is characterized by fever, chills, lumbar pain, malaise..., accompanied by significant bacteriuria. The acute pyelonephritis, well treated, cures in general without sequelae, but in certain occasions (especially when there is vesico-renal reflux or obstruction) the disease follows its course and produces inflammatory and cicatricial lesions that atrophy the kidney and are identified radiologically. The picture is called chronic pyelonephritis.

What are the symptoms of pyelonephritis?

There are situations where predisposition is more important:

  • Diabetes: The number of infections is higher in women with diabetes, but not in men. However, when a diabetic has an infection it is usually more aggressive.
  • Pregnancy: includes a higher risk of asymptomatic bacteriuria that, if left untreated, can cause pyelonephritis in the last trimester. It is necessary to make urine controls through culture and treat the bacteriuria if it occurs.
  • Infection in children and vesico-renal reflux: children under 2 years of age with urinary infection associate vesico-renal reflux in half of the cases. The risk of renal lesions is associated with reflux as the most important factor and is higher in children under 5 years old.
  • Infectious lithiasis: Struvite stones are a consequence of infection. The infection will not disappear until the stones are removed.
  • Obstruction: the most important risk factor. It allows greater growth and intrarenal penetration of germs and is decisive in renal destruction.

Most common symptoms:

  • Itching and urinary itching.
  • Increased need to urinate.
  • Fever.

Do you have any of these symptoms?

You may have pyelonephritis

Who can get pyelonephritis?

It is a fundamentally feminine pathology. Only in infants is the ratio of boys to girls higher (1.51). In the rest of the ages the predominance is female.

In pre-school age, 4.5% of girls and 0.5% of boys suffer from infection (proportion: 1/10). In school age, the ratio boy/girl is 1/30.

In adults, almost 50% of the female population suffers from at least one infection. 3-5% suffer from repeat infections, compared to 0.1% of adult males (ratio: 1/50). Although in the elderly the disproportion decreases (110 in the 60-70 years old group), it is equal in hospitalized elderly patients.

What is the prognosis of pyelonephritis?

Urinary tract infection is the most common disease of the urinary system and of the whole body after respiratory ones.

Worldwide, the number of urinary tract infections is estimated at 150 million per year. In Spain, it includes 10% of general practitioner visits and 40% of urologist visits. In the hospital environment is the most common infection.

It should be qualified to all infection from a prognostic perspective as:

  • Uncomplicated: afebrile infection in a patient without structural or functional alterations of the urinary system.
  • Complicated: pyelonephritis or prostatitis or with structural or functional renal alterations (stones, cystic renal disease, obstruction, anatomical abnormalities, neurogenic bladder, foreign bodies, diabetes, pregnancy, renal transplant).

How is pyelonephritis diagnosed?

Imagen de recogida de orina para análisis. Clínica Universidad de Navarra

Pyelonephritis is diagnosed by culture of urine on appropriate growth media. Significant bacteriuria is required in the culture, a concept that includes all of the following conditions:

  • The growth of more than 100,000 cfu (cubic colony forming units) in a symptomatic or non-symptomatic patient.
  • The growth of 100 cfu of E. Coli in a woman with symptoms.

  • The growth of more than 1000 cfu in a symptomatic male.
  • Any growth of germs in urine obtained by suprapubic puncture.
  • The growth of 100 cfukcs in a patient with a bladder catheter.
  • There is a special condition of significant bacteriuria, is called asymptomatic bacteriuria, which is defined as the growth of more than 100,000 cfukcs in two consecutive cultures in any asymptomatic patient.

How is pyelonephritis treated?

It is antibiotic and should be done, if possible, selectively, choosing the best of those to which the germ is sensitive (should therefore be done urine culture and antibiogram).

The application of treatment is different depending on age, location, type of infection, recurrence, etc.

Different guidelines can be made, in single-dose, 3-day treatment or longer treatments of 7-10 days.

The prophylactic treatment consists of administering an antibiotic or antiseptic at low doses, in one daily intake, for a prolonged period of time. It has the advantage that during the treatment period the patient remains free of disease.

Where do we treat it?


The Department of Urology
of the Clínica Universidad de Navarra

The Department of Urology of the University of Navarra Clinic offers the patient a medical team, composed of first-rate professionals, and state-of-the-art diagnostic and therapeutic means such as the Da Vinci® robotic surgery.

The Department of Urology possesses the certificate of accreditation of the European Board of Urology, a reinforcement of the excellence of the service at the level of care, teaching and research, which in Spain only three hospital centers possess.

Diseases we treat:

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clinica?

  • A team of top-level professionals trained in international centers.
  • State-of-the-art technology for diagnosis and treatment.
  • In 24-48 hours you can start the most appropriate treatment.