Causes of Pyelonephritis

Kidney infections are common in women, especially because the bacteria causing urinary tract and bladder infections may easily travel to the kidneys and cause the infection. Most such infections are the result of recurrent or severe and untreated lower urinary tract infections. Infections in the bladder may turn into kidney infections, if left unchecked. The bacteria travel from the vaginal or anal region to the kidneys. As the urethra is shorter in women, the bacteria find it easier to travel up and reach the upper parts of the urinary tract, including the kidneys.
The kidneys have a mechanism in which they prevent urine from flowing back into them from the bladder. However, when the bladder or the urinary tract is infected, this mechanism no longer works properly. Therefore, urine flows back into the kidneys and causes infection. As the infected urine flows back, it can spread the infection to the kidneys.

Other causes of pyelonephritis include common birth defects in the urinary system. Such defects in the tract may cause an increased risk of developing recurrent infections, and that may ultimately lead to chronic pyelonephritis. Blockages from kidney stones, tumors or blood clots may also increase the risk of developing kidney infections. Women are more at risk of developing pyelonephritis than men. Additionally, pregnant women who have lowered immunity may also have increased risk of developing kidney diseases such as pyelonephritis.

Some of the most common risk factors associated with kidney infections include:

  • Age: infants and elderly are especially prone to developing kidney infections because of low immunity.
  • Genetic Factors: Studies indicate that women with a family history of urinary tract infections in female relatives may be more prone to urinary tract infection recurrence and pyelonephritis.
  • Functional or anatomic abnormalities in the urinary or renal tract. These include conditions such as polycystic kidney disease, horseshoe kidney, a double ureter, ureterocele and vesicoureteric reflux.
  • Presence of foreign bodies in the urinary tract or the renal system.
  • Urinary or ureteric catheters that may be inserted surgically for treating specific health conditions.
  • Calculus or kidney stones.
  • Diseases that suppress the immune system or being in an immunosuppressed state.
  • Diseases like diabetes mellitus and sickle cell anemia.
  • Organ transplant or a recent surgery
  • Malignant tumors or cancer
  • Chemotherapy or radiation therapy
  • Prolonged use of corticosteroids
  • HIV infections and AIDS
  • Prostatic obstruction in males
  • Bladder neck obstruction or obstruction of posterior urethral valve.
  • Benign prostatic hypertrophy or neurogenic bladder.

Frequently asked questions
  1. George Ward, Robert C Jorden, Harry W Severance, Treatment of pyelonephritis in an observation unit, Annals of Emergency Medicine, Volume 20, Issue 3, March 1991, Pages 258-261, ISSN 0196-0644, 10.1016/S0196-0644(05)80935-7.
  2. Delia Scholes, Thomas R. Hawn, Pacita L. Roberts, Sue S. Li, Ann E. Stapleton, Lue-Ping Zhao, Walter E. Stamm, Thomas M. Hooton, Family History and Risk of Recurrent Cystitis and Pyelonephritis in Women, The Journal of Urology, Volume 184, Issue 2, August 2010, Pages 564-569, ISSN 0022-5347, 10.1016/j.juro.2010.03.139.