Difference Between Bladder and Kidney Infection

Bladder infections (cystitis) and kidney infections (pyelonephritis) are both urinary tract infections. There are only a few differences between the two.

Urinary tract infections are the commonest bacterial infection in women. They mostly occur in women aged 16 to 35 years (child bearing age group). 60% of women get a urinary tract infection sometime in their lives while 10% get it yearly. It is also the commonest type of infection acquired in the hospitals. Females are at a higher risk of getting urinary tract infection than males. Females have a shorter tube leading to outside from bladder. The position of the opening of the urinary tract in the vulva close to the anus makes it easier for the gut bacteria to enter the urinary tract. Sexually active women, elderly people, pregnant ladies, and people with reduced defenses against infections get urinary tract infections.

Most urinary tract infections are due to bacteria that are normally found in the gut (gut commensals); Escherichia coli are the most common organism (80-85%). Staphylococcus saprophyticus causes around 5-10% of urinary tract infections. Klebsiella, Pseudomonas, and Proteus are occasionally isolated organisms; these are unusual and are related to abnormalities in the urinary tract and instruments such as urinary catheters. Staphylococcus auerus can be transmitted through blood into the urinary tract. Viruses and fungi can cause urinary tract infections in individuals with severely weakened defenses such as AIDS patients, individuals on long term steroid therapy.

Clinical features include pain or burning feeling during urination, lower abdominal pain, frequent urination, cloudy urine, passage of blood with urine, and difficulty to hold it in. Urine full report or urinalysis gives a lot of information. The specific gravity (density) of urine is increased in a urinary tract infection. The appearance may be clear or cloudy. Urine color may be affected by the infection as well as by food, drugs etc. Epithelial cells may be present (In females >10 per high power field is taken as significant and in males it is >5 per high power field). Red cells may be present, and any number is significant because red cells should not be in urine in a healthy individual. Organisms may also be seen in urine and these should be identified as disease causing organisms and not commensals. Crystals in urine can give a hint towards the biochemical components of the urine as well as possible organisms.

Urine culture and antibiotic sensitivity testing – Urine culture sample collection is very important because erroneous reports can lead to mistakes. You need to wash the genitalia with soap and water first and dry it thoroughly. Males should pull back the foreskin and females should separate the vaginal lips. Let the first part of the urine flow out and don’t collect it in to the container. Collect the middle part of the urine flow in to the container. Close it tightly and hand it over to the lab. Don’t wash the container before collecting urine as it is sterile. If the culture shows a growth, it will be analyzed under the microscope. Presence of >105 colony forming units (in adults) is considered significant. The offending organism will also be identified, and various samples or antibiotics will be tested against it. The best antibiotic will be suggested in the report. Doctor may decide to do a complete blood count, C-reactive proteins, ultrasound scan of kidneys, serum creatinine, blood urea nitrogen, serum electrolytes depending on the clinical judgment.

What is the difference between Bladder and Kidney Infection? Cystitis vs Pyelonephritis

• Kidney infections (pyelonephritis) causes flank pain while bladder infection (cystitis) doesn’t.

• Fever is more common in kidney infections than in bladder infections.

• All the investigations yield similar results in both.

• Pyelonephritis may need intravenous antibiotics while bladder infections usually do not.