Case Discussion 【Presentation of Case】 A 62-year-old woman, with a previous history of staghorn stone of the right kidney, visited our clinic because of a 1-month-history of fever, chills and fatigue. The spiking fever had occurred at least one time every day, which lasted about 1-2 hours with spontaneous recovery. Besides, she experienced nausea, acid regurgitation and right flank soreness at the same time. She also had a weight loss of about 6 kilograms in one month. There was no headache, cough, sneezing, sore throat, abdominal pain, diarrhea, frequency, urgency, dysuria, arthralgia, or skin rash. No other family members were reported to have similar symptoms. The staghorn stone of the right kidney had been detected by ultrasound during a routine health checkup 8 years earlier. However, she was lost to follow-up thereafter. She did not have a recent history of travel or drug or food allergies. On physical examination, her consciousness was clear. The temperature was 37.4°C, pulse rate 84 beats per minute, respirations 18 breaths per minutes and the blood pressure was 108/68 mmHg. The conjunctivae were pale, sclerae were anicteric and the pupils were isocoric with prompt light reflex. The neck was supple without stiffness and no lymphadenopathy was noted. Chest and heart were normal. The abdomen was soft without tenderness. Significant percussion tenderness was noted at the right lower back. Neurological examinations were unremarkable. Image survey showed clear lung fields in chest X-ray. A staghorn renal stone in the right kidney was noted by X-ray of the abdomen. The right kidney silhouette was enlarged and the margin of ipsilateral psoas muscle was blurred. Laboratory surveys revealed leukocytosis with left shifting, normocytic anemia and high C-reactive protein level. Analysis of a urine specimen showed pyuria with WBC > 100 cells per high power field. The remaining renal function and other general laboratory survey were normal. Under the impression of urinary tract infection, she was admitted. After admission, empirical antibiotic with cefazolin was prescribed. However, low grade fevers persisted. Follow-up renal ultrasound showed an enlarged right kidney with nodularity of the contour and a staghorn renal stone (figure 1). The computer tomography (CT) of the kidneys revealed multiple lobulated fluid accumulation at the right kidney with extension to posterior pararenal space, right psoas muscle, and right paraspinal muscles (figure 2). The image finding suggested the diagnosis of xanthogranulomatous pyelonephritis. Cefazolin was changed to ceftriaxone and percutaneous drainage of abscess was performed. Fever gradually resolved later. Urine culture grew Gram-negative bacilli with insignificant colony forming units per milliliter. The pus culture from percutaneous drainage was negative for bacterial, mycobacterial and fungal cultures. Twenty days later, she underwent transarterial embolization of the right renal artery and, subsequently, right nephrectomy. The pathology of the resected right kidney was compatible with xanthogranulomatous pyelonephritis. The post-operative course was uneventful and she was discharged. 【Laboratory data】 1. Hemogram WBC Hb HCT MCV PLT Seg Lym. K/μL g/dL ％ fL K/μL % % 18.64 9.2 30.4 88.6 194 84.1 13 2. Biochemistries and electrolytes ALB TP T-Bil AST ALT ALP  γ-GT Glucose g/dL g/dL mg/dL U/L U/L U/L U/L mg/dL 3.4 6.2 0.6 33  36 116 17  103 BUN CRE Na  K Ca CRP mg/dL mg/dL mmol/L mmol/L mg/dL mg/dL 14.2 0.7 139 3.7 8.8 14.6 3. Urinalysis Sp. Gr pH Protein Glucose Ketone OB Bilirubin 1.017 5.5 1+ - 1+ 1+ - Urobilirubin RBC WBC Epi Cast Crystal Nitrite - 1-3 >100 0-2 - - + 4. Figure legend of figure 1: Sonography revealed the enlarged right kidney with staghorn stones and multiple lobulated cystic lesions. 5. Figure legend of figure 2: Computerized tomography of the abdomen revealed the enlarged right kidney with staghorn stones and multiple lobulated fluid collections in the renal calyces and parenchyma. 【病例解析】 黃瘤肉芽腫性腎盂腎炎( Xanthogranulomatous Pyelonephritis (XGP))，為嚴重的慢性感染性腎炎，常導致腎臟腫大而失去功能。多因尿路結石造成阻塞所致。好發在中年、肥胖、有腎結石的婦女。常見致病菌為Proteus mirabilis 及Escherichia coli。病理切片下可見腎臟實質內一顆顆的黃色結節(顯微鏡下為充滿脂肪的巨噬細胞(xanthoma cells)所組成)致病機轉至今未明。但實驗中, 當輸尿管被結紮、注入上述Proteus mirabilis 、Escherichia coli及staphylococci菌時便造成像XGP的樣子。典型的症狀有發燒、腰痛或腹痛、噁心、體重減輕、血尿及一些下泌尿道感染的症狀。實驗數據方面可見到白血球增多 (41%), 貧血 (63%), 膿尿( pyuria) (57%)等。半數病人的尿液培養不出細菌 。但嚴重者會併發腰大肌、腎旁等膿瘍或形成腎與皮下或大腸之間的廔管。確定診斷只能由術後病理切片確診，而影像檢查是在術前輔助診斷：一般而言, 儘管有學者建議一些超音波下的特徵來供臨床參考(如 腎臟腫大、其內有不同強度的多處浸潤至週圍組織、集尿系統擴張及腎旁液體堆積)，其表現仍屬非專一性，甚至有可能被誤認為膿瘍或腫瘤，目前仍待前瞻性的研究去作確認，故仍以電腦斷層為佳。在其下可見到腫大甚少排出顯影劑的腎臟及充填於腎盂的鹿角狀結石為特徵。而腎實質已被很多中間低密度、週圍亮亮的液體所取代。治療的方法為抗生素及早期的手術介入—摘除腎臟可以根除此病。 而值得注意的是此疾病的預後尚佳，多半不會造成嚴重的敗血症而死亡。 【參考文獻】 Xanthogranulomatous pyelonephritis: clinical experience with 41 cases. Korkes F, Favoretto RL, Broglio M, Silva CA, Castro MG, Perez MD. Urology. 2008 Feb;71(2):178-80. Review Pyelonephritis: radiologic-pathologic review. Craig WD, Wagner BJ, Travis MD. Radiographics. 2008 Jan-Feb;28(1):255-77; quiz 327-8. Review 繼續教育考題 1. (D) 下列何者是xanthogranulomatous pyelonephritis可能的好發因子? A 中年婦女 B 尿路結石 C 肥胖 D 以上皆是 2. (D) 下列有關xanthogranulomatous pyelonephritis的敘述何者為是? A 為嚴重的慢性感染性腎炎 B 多因尿路結石造成阻塞所致 C 常見致病菌為Proteus mirabilis 及Escherichia coli D 以上皆是 3. (E) 下列何者可能是xanthogranulomatous pyelonephritis的症狀？ A 發燒 B 頻尿 C 小便痛 D 腹痛 E 以上皆可能 4. (B) 有關xanthogranulomatous pyelonephritis,下列何者為非？ A 治療須施用抗生素 B 預後差，致死率極高 C 及早手術切除腎臟才可根治此病 D 發病與尿路阻塞有關 5. (A) 有關xanthogranulomatous pyelonephritis的診斷,下列何者為非？ A 可藉超音波作確定診斷 B 電腦斷層可作術前輔助診斷 C 病理切片才可作確定診斷 D 以上皆是 6. (B) 有關xanthogranulomatous pyelonephritis的臨床表現及實驗數據何者錯誤？ A 有可能白血球上升 B 有可能肝功能上升 C 有可能伴隨發燒 D 有可能表現出下泌尿道感染的症狀 答案解說 (D)Xanthogranulomatous pyelonephritis好發在中年、肥胖、有腎結石的婦女。 (D)Xanthogranulomatous pyelonephritis ，為嚴重的慢性感染性腎炎，多因尿路結石造成阻塞所致。常見致病菌為Proteus mirabilis 及Escherichia coli。 (E)Xanthogranulomatous pyelonephritis典型的症狀有發燒、腰痛或腹痛、噁心、體重減輕、血尿及一些下泌尿道感染的症狀。 (B)預後尚佳，多半不會造成嚴重的敗血症而死亡。 (A)超音波下表現仍屬非專一性，仍待前瞻性的研究去作確認可靠的特徵。 (B)Xanthogranulomatous Pyelonephritis極少有肝功能異常表現。