Final answer:
Urinary tract infections affect different parts of the urinary system, with cystitis being the common lower UTI and pyelonephritis representing serious upper urinary tract infections. Cystitis primarily affects the bladder and is usually bacterial, while pyelonephritis is a kidney infection that may follow an untreated bladder infection.
Step-by-step explanation:
A urinary tract infection (UTI) is a bacterial infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a simple cystitis infection; and when it affects the upper urinary tract it is known as pyelonephritis, which is a serious kidney infection.
Cystitis is a very common type of urinary tract infection where the bladder becomes infected. Typical symptoms include pain with urination and frequent urination. It is usually caused by bacteria, most notably Escherichia coli, but can on rare occasions be caused by fungi. A bladder infection is more common in women, partly due to the female urethra being shorter and closer to the anus, thus establishing an easier path for the bacteria from the GI tract.
Pyelonephritis is a kidney infection that can have serious systemic effects. It often stems from bacteria traveling from an infection elsewhere in the urinary tract, particularly an untreated bladder infection. Symptoms can include high fever, abdominal pain, and sometimes bloody urine. Treatment for urinary tract infections typically includes antibiotics.