What is pyelonephritis and its causes?

What is pyelonephritis and its causes?


Acute pyelonephritis is an upper urinary tract infection caused by germs that travel up through the ureters that connect the kidneys to the bladder. Its early treatment avoids complications.

Acute Pyelonephritis defined as an infection of the upper urinary tract which affects the pelvis and renal parenchyma. It is a clinical syndrome characterized by low back pain, fever, and chills; however, only 60% of patients with this triad are later found to have pyelonephritis.

Its importance is due to the severe complications that it can cause, although an early diagnosis and early treatment allow the patient to evolve favorably. Acute pyelonephritis is divided into complicated or uncomplicated, depending on whether an anatomical or functional disorder of the urinary tract may influence the response to treatment and the patient’s clinical evolution. The presence of recurrent cystitis, kidney stones, or alterations in the kidneys or urinary tract’s standard shape increases the risk of developing this disease.

Pyelonephritis diseases most frequently affect the kidney, although it is not as common as lower urinary tract infections. About 4-8 cases occur per 10,000 inhabitants. It is common in women than in men due to the anatomy of the female genital tract (the urethra is shorter and more exposed to the outside, so access to it is more comfortable), which makes it easier for bacteria to colonize the bladder and reach the kidneys through the ureters, thus producing pyelonephritis. With age, pyelonephritis incidence increases in men due to the development and enlargement of the prostate.

Causes of pyelonephritis

The most common mechanism by which acute pyelonephritis occurs is the rise of microorganisms from the fecal flora through the ureters, which are the tubes that connect the kidneys with the bladder. Less frequently, it occurs by hematogenous spread, that is, through the blood. The germs that tend to invade the urinary tract by this method are Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp, and Mycobacterium tuberculosis.

The microorganisms that most frequently cause pyelonephritis are Enterobacteriaceae such as Escherichia coli, Klebsiella spp, and Proteus spp, with E. Coli being the most frequent cause of pyelonephritis in patients without known urological diseases (it produces almost 80% of cases).

On the other hand, in patients with risk factors (recent manipulation of the urinary tract, carriers of urinary catheters, who have recently received antibiotic treatment, or have acquired the infection in hospital), germs resistant to antibiotics are more frequent. Conventional.

Symptoms of pyelonephritis

The common symptoms that appear in patients with pyelonephritis are the following:

  • Fever (body temperature greater than 38.5ºC) and chills.
  • Pain in the lumbar region, although sometimes it can radiate to other areas of the abdomen. If the pain is colicky (spasmodic, intense, that begins and ends suddenly) and radiates to the groin, it suggests renal lithiasis (presence of stones or stones in the kidney).
  • Nausea and vomiting Decreased appetite.
  • Headache.