A kidney infection, medically known as pyelonephritis, is a serious urinary tract infection (UTI) that has traveled up to one or both kidneys. This condition causes significant systemic inflammation and pain. While pyelonephritis primarily affects the urinary system, the body’s inflammatory response and the close proximity of the kidneys to the digestive organs can sometimes result in gastrointestinal discomfort.
The Connection Between Kidney Infection and Digestive Distress
Bloating and constipation are not primary or typical symptoms of a kidney infection, but they can be indirectly related due to the body’s reaction to the infection. The kidneys are situated in the retroperitoneal space, meaning they lie behind the abdominal lining, in close proximity to the intestines and the colon. Inflammation of the kidney (pyelonephritis) can irritate nearby gastrointestinal structures.
This irritation can stimulate nerves shared by both the urinary and digestive systems, leading to referred pain or generalized abdominal discomfort. Systemic inflammation from a severe infection can also slow down the normal wave-like contractions of the intestines, a condition known as ileus. This slowdown results in a temporary build-up of gas and stool, which the patient experiences as bloating and constipation.
Digestive issues are a secondary effect, and the severe symptoms of the kidney infection typically overshadow them. Nausea and vomiting are much more common gastrointestinal symptoms associated with pyelonephritis than isolated bloating or constipation. The pain and discomfort of the infection may also cause a person to unintentionally reduce fluid and food intake, which further contributes to constipation and abdominal fullness.
Recognizing the Defining Symptoms of a Kidney Infection
A kidney infection presents with a distinct and severe set of symptoms that differentiate it from a standard lower UTI. Defining characteristics include a sudden onset of high fever, often exceeding 100.4°F (38°C), and shaking chills. These systemic signs indicate the infection has moved beyond the bladder and into the renal tissue.
Intense, localized pain is a primary indicator, presenting as severe flank or back pain, usually on one side of the body. This pain is often felt just below the ribs and above the hips. It is sometimes described as costovertebral angle tenderness, a specific finding a healthcare provider will check for. This pain can radiate into the abdomen or groin area.
In addition to the high fever and flank pain, patients frequently experience symptoms related to the lower urinary tract. Nausea and vomiting are also highly common, often accompanying the fever and pain.
Lower Urinary Tract Symptoms
- Painful urination (dysuria)
- Increased urge to urinate (urgency)
- Passing urine more often than usual (frequency)
- Cloudy, dark, or foul-smelling urine
- Visible blood in urine (hematuria)
Diagnosis and Treatment for Kidney Infections
Immediate medical attention is necessary if a kidney infection is suspected, as it can rapidly lead to serious complications like sepsis. Diagnosis is confirmed through a physical exam and laboratory tests. A urinalysis checks the urine sample for white blood cells and bacteria, indicating an active infection.
A urine culture identifies the type of bacteria causing the infection, most commonly Escherichia coli, and determines effective antibiotics. Blood tests, including a complete blood count and kidney function markers like creatinine, assess the severity of the infection. Imaging, such as a CT scan or renal ultrasound, may be used if symptoms do not improve after treatment or if the patient has recurrent infections.
Treatment for pyelonephritis relies on antibiotics to eliminate the bacterial infection. For mild, uncomplicated cases, oral antibiotics, such as a fluoroquinolone, are prescribed for a course lasting five to fourteen days. More severe infections, or those in high-risk patients, generally require initial hospitalization.
In the hospital, intravenous antibiotics are administered until the patient is stable and fever-free for at least 24 hours. Patients then switch to oral medication to complete the full course. It is important to finish the entire prescribed course of antibiotics to ensure the complete eradication of the bacteria. Follow-up testing may be necessary to confirm the infection has fully resolved.