A kidney infection, known formally as pyelonephritis is an infection, associated with inflammation, of bacterial origin, of the urinary tract in its upper part (the kidneys), the responsible germ of which is most often Escherichia coli. 

This bacterium is naturally present in mammals in the anogenital area or the skin but can succeed in ascending, in some cases, in the bladder. 75 to 90% of cases of pyelonephritis are due to this infectious agent.

Other germs such as chlamydia and gonococci are usually the cause in the remaining cases.

In its acute form, usually, only one of the two kidneys is affected; this is called acute pyelonephritis. During the transition to chronicity (that is, when the infection persists, for example, during recurrent urinary tract infections), both kidneys can be affected. It is called chronic pyelonephritis.

Below of the main symptoms of a kidney infection.

Symptoms of Kidney Infection – Video Summary

1. Pain when urinating

When germs build up in the urinary system, an infection can occur. The urethra, which transports urine out of the body, connects the kidneys to the bladder and urethra. Chlamydia, gonorrhea, and herpes are all sexually transmitted diseases that can infect the urinary system and cause pain when peeing. Pain during urination can therefore be a symptom of kidney infection.

2. Frequent urination

Frequent urination also referred to as polyuria can also be a sign of a kidney infection. We talk of polyuria when you go to the toilet more than 7 times a day and/or more than once a night to urinate in small quantities. This phenomenon is sometimes accompanied by leaks or urinary burns.

3. Back pain

Back pain can also be a pyelonephritis symptom. The pain is usually located in the lumbar region (lumbar fossa) and/or abdominal area, usually on one side only. It can be spontaneous or appear during palpation. It can radiate under the ribs or descend to the pubis.

4. Urinating in small amounts

In addition to having to pee more frequently, a kidney infection may paradoxically cause less urine to come out. If you notice that you are peeing more frequently but less abundantly, especially, if this symptom is accompanied by other symptoms mentioned here for the kidney infection, you should go see your doctor.

5. Urine with a strong smell

A strong ammonia odor, comparable to sulfur from your urine, is one of the earliest indications of a kidney infection. This peculiar odor is caused by the bacteria that cause the infection. It might also make your urine hazy or crimson in appearance. If your urine suddenly starts smelling bad despite drinking lots of water, contact a doctor right away rather than waiting for it to become worse. This will ensure that you receive the proper medication therapy.

6. High fever

A kidney infection can also cause fever. Indeed, any bacterial infection triggers an inflammatory reaction, and therefore a fever. Researchers still do not completely understand the exact mechanism of this biological process. But when an infection occurs, viruses or bacteria stimulate the immune system to produce substances that cause fever, called pyrogens.

7. Nausea and vomiting

In renal patients, nausea and vomiting are quite prevalent. This can be caused by a variety of things, including uremic toxins, medicines, gastroparesis, ulcers, gastroesophageal reflux disease, gall bladder illness, a kidney infection, and so on. You should talk to your physician if your start to vomit and become nauseous inexplicably.

8. Blood in the urine

When filtering wastes from the blood to generate urine, the kidneys generally prevent blood cells from reaching the urine. However, when a kidney infection occurs, the filters in the kidneys stop working correctly, allowing blood cells to seep into the urine. Therefore, a kidney infection might be the cause of the blood in your urine. This is frequently accompanied by a strong desire to pee, urination discomfort and burning, and unusually strong-smelling urine.

9. Cloudy urine

A kidney infection frequently begins as a urinary tract infection (UTI) that spreads to the kidneys due to a lack of appropriate treatment. Kidney infections include symptoms that are similar to UTIs, such as murky urine.

10. Tiredness

When the kidneys cease working correctly, toxins and wastes can build up in the blood. This can make people weary, weak, and make it difficult for them to focus on daily tasks.