ABSTRACT

Acute focal bacterial nephritis (AFBN) is characterised by a complicated upper urinary tract infection ranging from acute pyelonephritis to renal abscess. Timely diagnosis of AFBN is important because antibiotic therapy of longer duration is required. A 10-year-old boy presented with fever for 5 days and bilateral flank pain. He was oriented and cooperative but appeared ill. Physical examination did not reveal any oedema or costovertebral angle tenderness. Acute phase reactants such as erythrocyte sedimentation rate and C-reactive protein were raised, serum creatinine was 1.25 mg/dL (0.31–0.88) and leucocyte esterase was positive in the urine. Ultrasonographic examination demonstrated bilaterally enlarged kidneys with increased echogenicity. Because of the high creatinine level, abdominal magnetic resonance imaging (MRI) was performed instead of computed tomography (CT) for further evaluation. The MRI showed an increase in the size of both kidneys, renal cortical heterogeneity and multiple cortical nodular lesions with diffusion restriction (constrained Brownian movement of water molecules) on diffusion-weighted MRI. A negative urine culture result in children presenting with fever and abdominal pain may mislead the clinicians, causing them to miss a nephro-urological diagnosis. It is therefore recommended that patients in whom the cause of fever cannot be determined be scanned by ultrasound and examined by CT or MRI so that undiagnosed and/or suspected cases of AFBN might be detected.

摘要

急性局灶性细菌性肾炎（AFBN）的特点是复杂的上尿路感染，范围从急性肾盂肾炎到肾脓肿。及时诊断 AFBN 非常重要，因为需要较长时间的抗生素治疗。一名10岁男孩发烧5天，双侧胁腹疼痛。他定向力强且合作，但看上去生病了。体检未发现任何水肿或肋椎角压痛。红细胞沉降率、C反应蛋白等急性期反应物升高，血清肌酐为1.25mg/dL（0.31～0.88），尿白细胞酯酶阳性。超声检查显示双侧肾脏增大，回声增强。由于肌酐水平较高，采用腹部磁共振成像（MRI）代替计算机断层扫描（CT）进行进一步评估。MRI 显示双肾体积增大，肾皮质异质性增加，扩散加权 MRI 上出现扩散受限（水分子布朗运动受限）的多发性皮质结节性病变。出现发烧和腹痛的儿童尿培养结果呈阴性可能会误导临床医生，导致他们错过肾泌尿科诊断。因此，建议对无法确定发热原因的患者进行超声扫描并进行 CT 或 MRI 检查，以便发现未确诊和/或疑似 AFBN 病例。