The patient was admitted to the hospital with low back pain and fever for 3 days. 3 days ago, he had low back pain without any cause, mainly on the right side, accompanied by frequent urination, dark urine, fever, self-test temperature of 37.5 degrees Celsius, no cough, chest pain, hemoptysis, hot flashes, low back pain not related to breathing, no abdominal pain, arthralgia, rash. He went to the local hospital and examined: body temperature 37.8 degrees Celsius, general condition slightly poor, acute painful appearance, mild pharyngeal congestion, bilateral lung breath sounds symmetrically heard, no dry and wet sounds, no percussion in both lungs, heart borders are not large, heart rate 80 beats/min, rhythmical, no pathological murmur heard in each valve area, service soft, no pressure pain, liver and spleen not felt under the rib cage, right kidney area percussion pain, pressure pain is obvious. Examination: urine routine: hematuria, leukocytes +, ultrasound: right kidney urine salt crystals, blood routine: WBC15*109/l, N91%; emergency diagnosis: renal colic with infection, and given treatment, the condition did not improve, 2 days ago the back pain increased, especially when breathing, fever 39.5 degrees Celsius, accompanied by chills, urgent to our hospital, physical examination is similar to the previous description, given chest CT examination The examination was similar to that described above. The above case was misdiagnosed because (1) the patient’s first symptom was lumbago, which lacked the typical manifestations of pleurisy; (2) the patient’s hematuria and high white blood cells in urine misled the physician’s thinking. What about in clinical practice? The author believes that: it is important to dynamically observe the evolution of the patient’s condition, which appears to worsen the day after the onset of the disease, and the lumbar pain is related to breathing. Usually the pain caused by urological diseases due to the anatomical relationship of the kidney is not directly related to respiration, and the rise and fall of the diaphragm exerts little pressure on the kidney. The presence of low back pain associated with respiration in this patient would suggest that the lesion may be in the diaphragm or/and above the diaphragm. Although the subpleural border is known to be at the level of the 11th thoracic vertebra, the right and left diaphragmatic feet can reach the 2nd to 3rd lumbar vertebrae, which would cover the kidneys and can manifest as low back pain when the patient develops a rib-diaphragmatic angle or diaphragmatic pleurisy. For an already diagnosed disease, if the treatment is poor and the condition worsens, the patient can be consulted and then arrange for examination of adjacent areas. Just as a patient with pneumonia in the lower part of the lung or inferior wall myocardial infarction can present with abdominal pain.