pyelonephritis (inflammation of the renal pelvis)

pyelonephritis (inflammation of the renal pelvis)
International Classification (ICD) N12



Renal pelvic inflammatory disease describes an acute or chronic infection of the renal pelvis and possibly kidney tissue. Women are far more likely to be affected by the acute condition than men because of their shorter urinary tract.

A previous bladder infection is usually responsible for renal pelvic inflammation. In the case of an ascending urinary tract infection, germs can pass from the bladder via the ureters into the renal pelvis. The course of the disease is characterized by high fever, often severe pain, nausea and general malaise. If left untreated, abscesses can form in the kidney, leading to chronic inflammation and reduced kidney function.

Acute renal pelvic inflammation can become chronic and asymptomatic over a long period of time due to impaired urinary drainage (e.g. vesicoureteral reflux, ureteral stricture). Kidney tissue becomes scarred and can be damaged to the point of total failure. Dialysis (artificial blood washing) is then unavoidable.


In healthy people, there are no germs in the urinary tract or in the urine that can cause inflammation of the renal pelvis. Often the bacteria originate from the intestine (e.g. E.Coli).

Favouring are disturbances of urinary drainage (kidney stones, tumours, prostate enlargement), paraplegia or malformations of the urinary tract.

Other influencing factors:

  • Sexual activity
  • Pregnancy
  • Urinary tract infections (last 12 months)
  • Metabolic disorders (gout, diabetes mellitus)
  • Immunodeficiency
  • Painkiller abuse
  • Urinary tract surgery


Acute inflammation of the renal pelvis

  • Sudden, high fever
  • Severe flank pain (may radiate to the pelvis)
  • Nausea, vomiting
  • Defensive tension between ribs and spine
  • Frequent and painful urination (rare)

Chronic inflammation of the renal pelvis

Due to the slow and continuous course of the disease, the symptoms are rather uncharacteristic.

  • Unexplained fever
  • Chronic backache and headache
  • General malaise
  • Difficulty urinating
  • Stomach pain, vomiting
  • High blood pressure

If you suspect that you have chronic pyelitis, you should consult a doctor, as this limits the performance of the kidneys.


In addition to the anamnesis (medical history) and a precise description of the existing complaints, a physical examination is necessary. Samples of blood and urine provide information about kidney function. In the case of high fever, a bacterial culture can be grown from the blood sample.

An ultrasound examination will reveal possible causes of urinary retention (e.g. kidney stones). If fever persists for more than 72 hours despite antibiotic therapy, further examinations are necessary:

  • X-ray examination
  • Spiral CT (special computer tomography)
  • Scintigraphy of the kidneys


Drug therapy is started even before the results of the examination are received. An antibiotic with a broad spectrum of activity is used to cover as many potential pathogens as possible. The medication is taken for 7 to 21 days. The therapy can be adjusted as soon as the germ has been identified.

The success of the treatment is supported by sufficient fluid intake (at least 2 litres per day), bed rest and avoidance of all medications that can stress the kidneys. Antispasmodic drugs and painkillers can help against severe pain, e.g.: Buscopan or Novalgin.

A disturbed urine flow must also be treated. In case of recurrent inflammation, medication or duration of therapy is varied.

Abnormalities in the urinary tract may require surgical intervention.


Normally, acute pyelitis heals without consequences. Urinary findings normalise after only a few days.

Recurrent infections may lead to impaired kidney performance, and more rarely to sepsis (blood poisoning) or abscesses (accumulation of pus). However, if the cause is found and treated, the recurrent inflammation will also heal.


  • Drink at least 2l of fluid a day (water or unsweetened tea). The kidneys are supported in their function and germs can possibly be flushed out.
  • Avoid hypothermia and soaking.
  • For intimate hygiene, do not use sprays, perfumed sides or disinfectants. These damage the delicate skin and make it more susceptible to germs.
  • Urinary drainage problems and kidney stones should be treated.

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Danilo Glisic

Danilo Glisic

As a biology and mathematics student, he is passionate about writing magazine articles on current medical topics. Due to his affinity for facts, figures and data, his focus is on describing relevant clinical trial results.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.



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