Kidney Infection - Symptoms, Risk factors and Treatment

Kidney infection, also known as pyelonephritis, is an infection of one or both kidneys. 

What causes a kidney infection?

Kidney infection most commonly occurs due to bacteria. The most common cause is E.coli, a bacteria which is present in the feces. Other than E.coli, bacteria such as Proteus, Enterobacter, and Klebsiella can cause pyelonephritis.

Viruses can also cause pyelonephritis. In patients who have had a kidney transplant, a virus called polyomavirus can also cause pyelonephritis.

What are the risk factors for getting a kidney infection?

Pyelonephritis is a complication of a urinary tract infection (UTI), in which infection of the urinary bladder (cystitis) and urethra (urethritis) occurs. 

Due to some conditions in the body, which cause the urine to flow in the wrong direction, the risk of getting pyelonephritis is increased. Other than that, many general factors can increase the risk of getting both a UTI and pyelonephritis.

General risk factors:

Female gender: 

Females are more likely to get UTI than men due to the short length of the urethra, which makes it easier for bacteria to ascend. Along with that, the anus and the urethra are closely located in females, which allows bacteria to easily move from the feces to the urethra. 

Urinary tract obstruction: 

If the urinary tract gets obstructed, it causes stasis of urine which allows unhindered multiplication of bacteria. The urinary tract can be obstructed due to different conditions such as a stone in the urinary tract, benign prostatic hyperplasia- an enlargement of the prostate gland in men, tumors, etc.

Bladder dysfunction: 

A dysfunctional bladder refers to a condition in which the signals between the brain and the urinary bladder are not properly transmitted. It can be due to numerous neurological causes and health conditions such as long-standing uncontrolled diabetes and spinal cord damage.

Lowered immunity:

Any condition that causes the immune system to be suppressed causes different bacteria to infect an individual as the immune system is responsible for fighting off different infections. Conditions like AIDS, cancer chemotherapy, diabetes, etc. can make a person more vulnerable to catching infections like pyelonephritis.

Urinary catheterization: 

Catheterization can increase the risk of getting a kidney infection. The catheter can serve as a medium on which bacteria can grow and multiply, and then ascend into the urinary tract.

Problems with the urine flow:

Vesicoureteral reflux:

The vesicoureteral reflux refers to the reflux of the urine from the bladder to the ureters. Normally, in the part where your ureters meet the urinary bladder, there is a valve present, called the vesicoureteral valve. In some people, the valve is incompetent which causes the urine to reflux (flow back) in the opposite direction from the urinary bladder to the ureters, allowing bacteria to ascend. The vesicoureteral valve may be incompetent congenitally or due to spinal cord injury.

Intrarenal reflux:

Intrarenal reflux is an extension of vesicoureteral reflux and plays an important role in kidney infections. In this condition, the morphology of the renal papillae is altered, promoting backflow of urine in the kidney. The renal papillae are the part in your kidney where the urine flows into the ureters. Some of these papillae are flat and concave in intrarenal reflux, rather than the normal, raised, and convex-shaped papillae. It promotes the backflow of urine and infections to get access to the kidney.

Symptoms of a kidney infection:

The symptoms of a kidney infection include:

• Fever
• Chills
• Sudden onset of pain
• Malaise
• Burning sensation in the urethra
• Painful urination
• Frequent urination
• Feeling an urgency to urinate

Complications of a kidney infection:

The complications of pyelonephritis include:

Abscess formation: 

It is a condition in which a pocket of pus forms in the kidney.

Sepsis: 

Sepsis is a response to an infection that spreads throughout the body. If the infection spreads to the whole body from the kidney, it can cause sepsis. 

In sepsis, the patient’s blood pressure can fall too low (septic shock) causing damage to organs (multiple organ damage) such as the heart, liver, kidneys, and can ultimately cause death. 

Acute renal failure (ARF):

Kidney failure or renal failure is when kidney function deteriorates significantly. 

Kidney damage: 

The infection causes inflammation which can permanently damage the kidney (renal scarring).

Diagnosis of kidney infection:

A kidney infection is mostly diagnosed by a urine culture, a test in which a sample of urine is collected and examined under the microscope. To check for more problems in your urinary tract and kidneys, your doctor may suggest imaging tests such as ultrasound, CT scan, voiding cystourethrography, etc.

Treatment of kidney infection:

The treatment of pyelonephritis usually involves giving antibiotics to clear up the infection. Along with that, if there is any obstruction, it is corrected. Pain killers may be given to relieve pain.

Conclusion:

Kidney infection or pyelonephritis is the infection of one or both kidneys. If detected on time, the infection can be easily treated, and life-threatening complications can be prevented. If you notice any symptoms of pyelonephritis, it is advisable to seek medical care as soon as possible.