The clinical appearance of small abdominal cramps accompanied by lumbar acidity is most commonly due to low water intake or various other causes of oxalate crystals forming in the kidney stones blocking the ureter, causing the symptoms of hydronephrosis. Clinical examination may show percussion pain in the kidney area, and further ultrasound examination is needed to clarify the diagnosis. The treatment of kidney stones mainly adopts medication for stone removal, and surgery can be considered if necessary. Other causes of small abdominal cramps with lumbago may be seen in female patients with pelvic inflammatory disease or urinary tract infection, which usually requires further ultrasound examination or urine routine or even bacterial culture examination to clarify the diagnosis. Conservative treatment is preferred for pelvic inflammatory disease, while surgery is required if septicemia develops, and urinary tract infections can usually be cured with antibiotic medication.