Kidney infection (also called pyelonephritis) is a bacterial infection of the kidney itself. It represents one specific type of urinary tract infection. Urinary tract infections that only involve the bladder (cystitis) can cause frequent urination, painful urination, urine accidents, bloody urine, foul-smelling urine and abdominal pain. Usually, when a urinary tract infection (or UTI) involves the kidneys, there are additional, significant associated symptoms, including fever (usually over 101.5 degrees F or 38.6 degrees C) and possibly nausea, vomiting or flank pain. When a kidney infection is very severe, a child may appear lethargic (overly sleepy and difficult to wake up), pale, with a racing heartbeat and very low blood pressure. This particular set of symptoms is called uro-sepsis and can be life threatening.
The causes of kidney infections are many but usually related to poor drainage or stagnation of the flow of urine at any point in the urinary tract, backward flow of urine into the kidneys (vesicoureteral reflux), or abnormal neurologic or muscular function of the bladder (neurogenic bladder). Testing may include a urine culture, blood tests and imaging studies (ultrasound of the kidneys/bladder, CT scan or MRI).
Treatment of kidney infection usually involves antibiotic therapy. Thankfully, most kidney infections can be treated with oral antibiotics or a combination of injection of antibiotics and some oral antibiotics. Other treatments needed can include helping any obstructed part of the urinary tract drain better either using drainage tubes or surgery.
In addition, treatment and prevention of kidney infections may involve further testing and treatment for any underlying condition, which your pediatric urologist will discuss and plan with you.