A urinary tract infection can rise from the bladder higher up — to the kidneys. That is pyelonephritis: inflammation of kidney tissue that, without treatment, can end in sepsis. There is no shame here — kidneys are discussed as calmly as a runny nose.
When to see a doctor
You go to your family doctor if there is pain, burning, or stinging when urinating, if urges become more frequent and urgent, or if urine is dark or cloudy. Also if symptoms of a kidney infection have not resolved after antibiotic treatment.
See a doctor the same day if, alongside suspected kidney infection, there is very high fever, heat, chills and shivering, a temperature below 36, pain in the lower abdomen or in the back under the ribs, blood in the urine, nausea or vomiting, no urine for a whole day, or pregnancy.
Confusion, drowsiness, or slurred speech — call 103 or 112 immediately.
How infection rises to the kidneys
Urine is normally sterile — this has been known since Pasteur's time. Among the causative agents of pyelonephritis are E. coli, enterococcus, proteus, staphylococci, streptococci, Pseudomonas aeruginosa, and enterobacteria.
A kidney infection often arises as a result of cystitis, but it can occur without it. Pyelonephritis can be primary, when nothing obstructs the outflow of urine, or secondary, when there is an obstruction: stones, congenital anomalies, a duplicated kidney, nephroptosis. Urine stasis and weakened immunity make the bacteria's job easier.
Inflammation can be unilateral or bilateral. With bilateral inflammation, there are often signs of kidney failure.
The term "pyelonephritis" was introduced by Pierre Rayer in 1837 in the "Atlas of Kidney Diseases." Before that, it was believed that the kidneys were resistant to inflammation. In 1956, Edward Kass of the Mallory Institute of Pathology established the quantitative basis for counting bacteria to diagnose urinary tract infection.
Symptoms
Onset is usually acute, and the picture is vivid.
- fever and chills;
- pain in the lower back or side;
- nausea and vomiting;
- muscle aches and flu-like symptoms;
- cystitis-like symptoms: burning when urinating, frequent urges.
Diarrhea can also occur. In children under two, sometimes there is only a high fever; older children may wet the bed or become drowsy. In adults, high fever is among the symptoms. In acute pyelonephritis, blood tests may show leukocytosis and elevated ESR, and urine tests may show leukocytes and protein. Tapping the lower back area is painful, and the Pasternatsky sign is sometimes positive. Cystitis is inflammation of the bladder; symptoms can be similar, but fever, lower back or side pain, and nausea indicate that the infection has risen to the kidneys.
Risk groups and complications
Women are affected more often, but anyone can get a kidney infection. Pregnancy is a separate group: pregnant women with a kidney infection may need treatment in a hospital. People with chronic illnesses and weakened immune systems are also more vulnerable to the consequences of infection.
Acute pyelonephritis ends in recovery, transition to a chronic form, or death. The chronic form leads to sclerosis and deformation of the kidney, high blood pressure, and chronic kidney failure. It can be latent, relapsing, hypertensive, anemic, or azotemic. Sometimes the only noticeable sign is persistently high blood pressure.
The purulent form of acute pyelonephritis can progress to apostematous nephritis and a kidney carbuncle. Chronic pyelonephritis is one of the components of chronic kidney disease.
Diagnosis
The family doctor checks the urine — this is the basic test. Next, the sediment and a bacteriological culture are examined, and kidney function is checked: urine density and azotemia. If needed, ultrasound of the kidneys, excretory urography, scintigraphy, CT, or MRI are ordered. Examinations also reveal an obstruction to urine outflow, if one is present.
This is reference material; it does not replace a doctor's consultation.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer