Acute pyelonephritis refers to an acute inflammatory disease caused by bacteria invading the renal pelvis. It is commonly seen in women of childbearing age, the elderly, individuals with weakened immune systems, and patients with urinary tract obstructions. The main clinical manifestations of acute pyelonephritis typically include frequent urination, increased urination frequency, painful urination, back pain, fever, cold stomach, and it can even present symptoms such as headache, whole body muscle soreness, nausea, and vomiting. The most common pathogen causing acute pyelonephritis is Escherichia coli, while other bacteria such as Klebsiella pneumoniae, Proteus, and Pseudomonas aeruginosa can also cause infections of acute pyelonephritis. Therefore, it is crucial to actively choose sensitive antibiotics for the treatment of acute pyelonephritis.