Kidney Infection Symptoms

A kidney infection happens when bacterial or viral infections move from the bladder or the tube that expels urine from the body i.e., the urethra, and infect one or both kidneys. This kind of Urinary Tract Infections (UTI) can start in the bladder as cystitis, and spread quickly and aggressively, causing inflammation of the kidneys.

Symptoms of Kidney Infection

If you face any of these symptoms, along with fever and chills/shivers, it is indicative of a possible kidney infection.


You may experience sharp pain in the lower abdomen, sides of the abdomen, groin/urethra, and/or lower back.

Abnormal Urination

Your urine may appear cloudy, have blood and/or pus in it, and smell foul. Sudden urges to urinate, or a persistent urge that doesn’t reduce even after urinating are common signs of infection. You may feel the need to relieve yourself very often - more frequently than normal. Urination may be accompanied by a burning sensation or pain.

Digestive Issues

Nausea, vomiting, diarrhea, upset stomach, and a loss of appetite alongside other symptoms also present themselves during a kidney infection.

When to See a Doctor

If the pain persists beyond a few days, or increases in intensity, consult a doctor immediately. Seek urgent medical attention if the pain is accompanied by fever, rashes, elevated heart rate, fatigue, and/or mental confusion. Address any UTIs on a priority basis to prevent an escalation to a full-blown infection.

Causes and Risk Factors for Kidney Infection

Bladder cystitis and UTIs have already been cited as the most common cause of kidney infection. This risk increases with women because their urethra is shorter compared to men’s and is nearer the anus, making bacterial transmission easier.

Other than these, common causes include −

Blockage of the Urinary Tract

The urinary tract could be blocked by kidney stones, an enlarged prostate in men, a pinched/narrow urethra in women, or a structural problem in the shape of the urinary tract. These issues prevent full emptying of the bladder, which in turn raises the risk of developing a kidney infection. Rare causes include prostatitis or a tumor blocking the tract.

Compromised Immune System

Those suffering from immune system disorders such as HIV/AIDS, Type 2 diabetes, autoimmune diseases, or who have undergone organ transplants and taking immunosuppressives are more susceptible to contracting a kidney infection because their bodies are already fragile.

Nerve and Spinal Cord Damage

People with spinal cord damage, or who have suffered spinal cord/ nerve injuries anywhere in the body, but particularly around the bladder may have undiagnosed kidney infections for a long time. People with multiple sclerosis (MS) or spina bifida don't feel pain due to nerve damage, and this may delay their ability to identify symptoms and seek treatment

Catheter Use

A urinary catheter is often used for urine drainage or to administer fluids for diagnosis and treatment. This hollow, flexible and thin tube made of latex/silicone/polyurethane is inserted through the urethra into the bladder to drain urine for bed-ridden or post-surgical patients. External tubes can cause infection.


A pregnant woman has multiple other risk factors that make contracting bacterial infections easier. The pressure of the baby on the urethra causes slower urine discharge, there may be positional shifts of the urinary tract and hormone changes.

VUR - Vesicoureteral Reflux

This condition, most common in infants and children happens when urine backwashes back into the urinary tract instead of going out because the flap valve between the bladder and urethra malfunctions.


The use of a cystoscope, a thin tube with a tiny camera to do an endoscopy of the bladder may introduce infections to the area.

Diagnosis of Kidney Infection


Urine samples are analyzed for the presence of pus, blood, bacteria, and white blood cell count to determine signs of infection.

Urine Culture

Bacteria are grown in urine samples in the laboratory to specify what kind of bacteria/disease-causing micro-organisms you have exactly are causing a distinct type of UTI or other infection.

Additional tests may be done, if basic urine tests don’t yield results or if you don’t recover within a couple of days.

These include −

Ultrasound/CT Scan/MRI

These imaging exams can reveal the presence of any urinary tract blocks along with detailed images of the kidneys.

Rectal Exam

Men may receive a digital rectal exam in which the doctor manually inserts a lubricant-covered gloved finger, to check if the prostate is enlarged/swollen, and causing a bladder blockage.

VCUG (Voiding Cystourethrogram) or CT Urethrogram

In both these methods, the bladder is filled with contrasting material like fluorescent or iodine, injected through the veins. The dye outlines the urinary tract and highlights the movement of liquid as the patient empties their bladder. An X-Ray video and a series of X-Ray images are taken to observe bladder function and possible backflow in children with VUR. Alternatively, ultrasounds can also be used.

Dimercaptosuccinic Acid (DMSA) Scintigraphy

This test is used in rare instances such as for patients with repeated infections, kidney scarring, and significant kidney malfunction. A radioactive material/ isotope and trace medicine are injected intravenously to assess the kidneys’ size, structure, and position.

Treatment of Kidney Infection

Treatment of moderate kidney infection is usually done with a 1–2-week course of antibiotics and over-the-counter analgesics like Paracetamol for pain relief. Avoid aspirin, naproxen, and ibuprofen as they aggravate the risk – use only acetaminophen.

For severe infections, intravenous (IV) fluids will be administered in the hospital. If the infection doesn’t resolve past this point, there may be a problem with the urinary tract structure/shape, which could require corrective surgery to prevent future infections.


Left untreated, the bacteria can spread to the bloodstream from the kidneys causing septicemia (blood poisoning) which can be fatal. It can also cause pus-filled kidney abscesses, high blood pressure, chronic renal disease, and in rare cases, scarring of renal tissue and toxic gas formation due to emphysematous pyelonephritis (EPN). Kidney infection during pregnancy can also cause low birth weight babies.

So never take kidney infections lightly - maintain sexual and genital hygiene and drink tons of water.

Updated on: 02-Feb-2023


Kickstart Your Career

Get certified by completing the course

Get Started