this rate is increasing owing to greater numbers of elderly , immunocompromised patients.1 ) in uncomplicated pyelonephritis cases , appropriate antibiotics improve fever within 72 hours and reduce leukocytosis and elevated c - reactive protein ( crp ) levels .
uncomplicated pyelonephritis generally requires 714 days of antibiotic therapy.23 ) however , when staphylococcus aureus is the pathogen , dissemination can occur , and a prolonged duration of antibiotic treatment is required.4 ) s. aureus rarely causes pyelonephritis in the general population . in 1997 , s. aureus accounted for only 0.5% and 1.3% of isolates obtained from urine in general populations from great britain and france , respectively .
5 ) in south korea , s. aureus is classified as a rare cause of community - acquired pyelonephritis.3 ) we describe a patient who was diagnosed with complicated epidural and paraspinal abscesses after insufficient evaluation and treatment of acute pyelonephritis due to s. aureus .
a 62-year - old man was admitted with a 5-day history of fever , increased urinary frequency , and left flank pain . he had no specific medical or surgical history , except for a 5-year history of type 2 diabetes treated with insulin and oral hypoglycemic agents .
physical examination revealed a blood pressure of 120/70 mm hg , temperature of 38.4 , heart rate of 76 beats / min , and respiration rate of 20 breaths / min .
the initial laboratory data revealed a white blood cell ( wbc ) count of 14,680/mm , hemoglobin level of 12.2 g / dl , platelet count of 373,000/mm , crp level of > 12 mg / dl , and hemoglobin a1c level of 12.5% , indicating that his diabetes was poorly controlled .
blood urea nitrogen , serum creatinine , alanine transaminase , and aspartate transaminase levels were within the normal range .
urinalysis showed white and red blood cell counts of 35/high - power field ( hpf ) and 1015/hpf , respectively .
contrast - enhanced abdominal computed tomography ( ct ) scans showed a multifocal decreased perfusion defect of the left kidney .
blood and urine culture samples were obtained , and intravenous ceftriaxone ( 2 g / d ) was administered immediately .
five days after admission , the initial urine and blood cultures revealed growth of methicillin - sensitive s. aureus ( mssa ) .
however , the patient declined further evaluation , as his discomfort had subsided , and his poor socioeconomic status impeded the payment of additional medical costs .
eight days after admission , laboratory data demonstrated further improvement ( wbc count , 8,760/mm ; crp level , 1.95 mg / dl ) .
follow - up urine and blood cultures obtained on day 5 revealed no bacterial growth .
the patient was therefore discharged with oral ciprofloxacin ( 500 mg every 12 hours ) for 7 days .
he was asked to attend the outpatient clinic for 1 month to receive maintenance ciprofloxacin , but he failed to attend .
approximately 1 month later , the patient presented with a 7-day history of symptoms consistent with those at his initial visit .
his vital signs were as follows : a blood pressure of 110/70 mm hg , temperature of 38.4 , heart rate of 115 beats / min , and respiration rate of 20 breaths / min . bilateral costovertebral angle tenderness was noted .
laboratory data revealed a wbc count of 15,870/mm , hemoglobin level of 9.6 g / dl , platelet count of 375,000/mm , and crp level of > 12 mg / dl .
blood urea nitrogen , serum creatinine , alanine transaminase , and aspartate transaminase levels were within the normal range .
urinalysis showed a wbc count of 3050/hpf with many bacteria and a red blood cell count of 510/hpf .
a ct scan showed a multifocal decreased perfusion defect of both kidneys ( figure 1 ) with bladder distension .
an oral alpha blocking agent and intravenous ciprofloxacin ( 400 mg every 12 hours ) were administered .
two days after readmission , his left lower flank pain persisted , despite a fentanyl patch ( 12 g / h ) .
although there were no neurologic deficits , a neurosurgeon was consulted regarding his severe pain and the possibility of concomitant spinal disease .
magnetic resonance imaging ( mri ) with gadolinium enhancement was performed , revealing epidural abscesses at l45 and paraspinal abscesses of the muscles at l3s2 ( figure 2 ) .
ultrasound - guided aspiration of the paraspinal muscle layer was performed using an 18-gauge needle , and approximately 10 ml of yellow - white mucoid fluid was aspirated .
cultures of blood and drained fluid revealed mssa growth ( table 1 ) with antimicrobial sensitivity identical to that of the initial culture .
urine cultures revealed growth of < 1,000 colony forming units / ml , although the bacterial strain could not be identified .
however , neutropenia occurred , and nafcillin was replaced with vancomycin for an additional 30 days . on day 57 after readmission , mri showed the abscesses had decreased in size ( figure 3 ) .
laboratory data were nearly within the normal range ( wbc count , 6,490/mm ; crp level , 0.35 mg / dl ) . on day 59 , he was discharged without neurologic sequelae and was prescribed ciprofloxacin ( 500 mg every 12 hours ) until a repeat mri showed no remnant abscesses .
according to the infectious diseases society of america guidelines , uncomplicated s. aureus bacteremia ( sab ) is defined by five factors : the exclusion of endocarditis , no implanted prostheses , s. aureus - negative blood cultures 24 days after initial presentation , defervescence within 72 hours of therapy , and no evidence of metastatic infection sites .
these guidelines suggest administering antibiotic treatment for a minimum of 2 weeks for uncomplicated sab , and a minimum of 4 weeks for complicated sab , personalized to the patient 's condition.4 ) s. aureus can disseminate , and it is therefore difficult to differentiate primary pyelonephritis caused by s. aureus from secondary s. aureus bacteriuria ( sabu).56 ) there is controversy regarding the appropriate diagnostic tests required to exclude occult foci caused by sab .
consequently , it is difficult to determine the minimum duration of antibiotic treatment required for sab.4 ) in 2009 , choi et al.6 ) showed that patients with sab and sabu had higher rates of urinary tract infection , bladder obstruction , and spinal infection compared with patients with sab only .
the association of sabu with spinal infection may result from the venous system acting as a route for propagation of infection between the pelvic organs and spinal region without systemic dissemination.7 ) in agreement , our patient had concomitant pyelonephritis , neurogenic bladder , and epidural and paraspinal abscesses without infective endocarditis . on initial admission ,
the patient 's fever and pain subsided within 72 hours of treatment , and laboratory data showed significant improvements .
the patient declined additional examinations to assess bladder obstruction and metastatic infection , as his poor socioeconomic status impeded the payment of additional medical costs .
however , his condition worsened after readmission , and he agreed to undergo the required examinations .
epidural abscess is rare , with a frequency of 0.22 cases/10,000 hospital admissions and a mortality rate of 10% to 30% owing to potentially permanent neurological deficits .
however , the incidence is increasing , owing to increased numbers of immunocompromised patients and advancements in diagnostic imaging techniques .
epidural abscesses characteristically have an insidious onset of symptoms , with the classic symptom triad being localized pain , fever , and neurological deficits .
overall , 74% , 64% , and 10%15% of patients reportedly present with pain , fever , and all three symptoms , respectively .
hence , the diagnosis of an epidural abscess is often missed on initial examination , and delays in treatment dramatically worsen prognosis owing to the risk of neurologic sequelae .
therefore , a high level of clinical suspicion is important for timely diagnosis and treatment.8 ) as the patient in this case had both epidural and paraspinal abscesses , his pain was likely more severe than it would have been due to an epidural abscess alone , and therefore , the suspicion of spinal infection was relatively high .
the current gold standard for the diagnosis of an epidural abscess is mri with gadolinium contrast , and the most common causative pathogen is s. aureus .
infection with s. aureus can be managed successfully with conservative treatment comprising antibiotics and spinal bracing .
surgical intervention is indicated when neurologic deficits are present.9 ) it is uncertain whether the abscesses were present initially , in which case they may have been partially treated and then worsened after the cessation of antibiotics .
however , this case emphasizes the importance of investigating concomitant bladder obstruction and metastatic infection in patients diagnosed with community - acquired pyelonephritis due to s. aureus .
the adequate treatment of bladder obstruction with antibiotics , despite improvements in patient symptoms and laboratory tests , should be carefully considered by the primary care physician .
 diagnoses of pyelonephritis caused by staphylococcus aureus should be accompanied by investigations of concomitant bladder obstruction and metastatic infections , especially to the spine or heart . 
 complicated pyelonephritis due to s. aureus requires more than 2 weeks of antibiotics , which is the typically recommended treatment duration for pyelonephritis . 
 we describe a patient who was diagnosed with complicated epidural and paraspinal abscesses after insufficient evaluation and treatment of acute pyelonephritis due to s. aureus . 
 a 62-year - old man with type 2 diabetes was admitted with fever , increased urinary frequency , and left flank pain . 
 he was diagnosed with acute pyelonephritis caused by s. aureus . 
 his fever and flank pain subsided after 3 days of intravenous antibiotics . 
 evaluation of bladder obstruction and metastatic infection were not performed , as he declined further evaluation . 
 the patient was discharged with oral antibiotics and was requested to attend weekly appointments but was lost to follow - up . 
 one month later , the patient presented at the outpatient clinic with similar symptoms . 
 computed tomography showed recurrent pyelonephritis and a distended bladder . 
 his flank pain persisted despite administration of an opioid agent . 
 therefore , magnetic resonance imaging was performed , revealing epidural and paraspinal abscesses . 
 ultrasound - guided aspiration of the paraspinal muscle layer was performed , and blood and percutaneous aspirated fluid cultures revealed s. aureus growth . 
 the pattern of antimicrobial sensitivity was identical to that at his first admission . 
 following more than 4 weeks of antibiotics , magnetic resonance imaging showed the abscesses had decreased in size . 
 the patient was discharged without neurologic sequelae and was provided with oral antibiotics . 