renal artery thrombosis is a rare but serious clinical problem because it frequently causes renal infarction . if perfusion of kidney is not restored in time , the involved segment or whole kidney may lose function . however , early diagnosis is not easy because clinical presentation , such as hematuria or flank pain , is not specific . renal artery thrombosis is mainly associated with thromboembolism from heart , atherosclerosis , fibromuscular dysplasia , or cocaine abuse , . there are some reports of renal vein thrombosis associated with acute pyelonephritis , , , , , , but renal artery thrombosis related to acute pyelonephritis has not been reported yet . herein , we describe a case of renal artery thrombosis that developed during the recovery phase of acute pyelonephritis complicated with sepsis in a patient with diabetes . a 65-year - old woman presented to the emergency room complaining of right flank pain and fever . she has suffered from diabetes for 20 years and was using oral hypoglycemic agents . physical examination revealed the following : blood pressure , 80/50  mmhg ; temperature , 39  c ; pulse , 130 beats / minute ; and respiration rate , 20 breaths / minute . knocking tenderness her blood test results were as follows : white blood cell ( wbc ) count , 23,400/l ; hemoglobin , 9.7  g / dl ; platelet count , 97,000/l ; c - reactive protein , 21.97  mg / dl ; blood urea nitrogen , 35.3  mg / dl ; creatinine ( cr ) , 2.21  mg / dl ; sodium , 142 meq / l ; potassium , 3.7 meq / l ; total protein , 4.8  g / dl ; albumin , 2.4  g / dl ; lactate dehydrogenase ( ldh ) , 472 u / l ; and hba1c , 9.8% . prothrombin time ( pt ) was found to be 17.5  seconds ( international normalized ratio or inr : 1.63 , 46.8% ) and activated partial thromboplastin time ( aptt ) increased to 52.8  seconds . antithrombin iii level decreased to 70.5% and fibrin degradation products ( fdps ) and fibrinogen levels were elevated to 49.2  g / ml and 429.3  mg / dl , respectively . results of urinalysis revealed the following : specific gravity , 1.028 ; ph : 5.0 ; traces of protein ; 1019 wbcs and 01 red blood cells ( rbcs ) per high power field . a kub finding was nonspecific . to verify the cause of acute abdominal pain , a contrast - enhanced abdominal computed tomography ( ct ) scan 1 ) . there was a focal wedge - shaped perfusion defect in the upper pole of right kidney , but no evidence of intravascular filling defect in renal vessels was found . escherichia coli was isolated from both blood and urine cultures . under the diagnosis of right acute pyelonephritis complicated with sepsis , intravenous ceftriaxone 2  g per day was administered . five days later , her mental status became drowsy , blood pressure fell to 80/60  mmhg , and fever developed . laboratory tests revealed the following : wbc count , 27,800/l ; platelet count , 26,000/l ; and cr 0.8  mg / dl . to rule out pneumonia , a chest ct scan was performed , which revealed passive atelectasis in both lungs , but no evidence of pneumonia . an echocardiography showed mildly decreased cardiac wall motion and left ventricular dysfunction ( ejection fraction : 47% ) , but no evidence of thrombus in all cardiac chambers . with the impression of septic shock combined with acute heart failure , diuretics and inotropes were administered , and antibiotics were changed to piperacillin sodium 4  g and tazobactam 0.5  g every 8  hours . her clinical course gradually improved after changing antibiotics . on the 13th day of hospitalization , she complained of sudden onset of severe right flank pain and tenderness . an abdominal ct revealed newly developed large perfusion defect in the upper to mid portion of the right kidney and intravascular filling defect in the right renal artery ( fig . 2 ) . to evaluate coagulation defects , additional laboratory tests were carried out which revealed the following : pt , 12.3  s ( inr : 1.14 , 78.3% ) , aptt , 23.8  s ; antithrombin iii , 84.7% ; fdp , 19.5  g / ml ; fibrinogen > 500  mg / dl ; and factor assay v , 81% . on the 16th day of hospitalization , the patient s flank pain resolved and hematuria disappeared . a follow - up abdominal ct scan demonstrated that the perfusion defect in the right kidney and the size of right renal artery thrombus were partially regressed . in this report , renal artery thrombosis was observed in the recovery phase of acute pyelonephritis and septic shock . the patient has suffered from diabetes for 20 years , but did not have other risk factors for arterial thrombosis . although the cause of renal artery thrombosis is not fully understood in this case , several mechanisms are suggested . arterial thrombosis can occur in the condition of endothelial damage , hypercoagulable state , kidney transplantation , or thromboembolism from heart . mostly , it is generated in the heart with arrhythmia , valvular heart disease , or ischemic heart disease . there was no abnormality in protein c / s activity or factor v leiden mutation . therefore , it is not likely that the hypercoagulability and emboli from heart contribute to the thrombus formation . because she has suffered from diabetes for 20 years , atherosclerosis could have contributed to arterial thrombosis formation , but no thrombus or stenosis was noted on initial abdominal ct scan . in this report , the patient had acute pyelonephritis and sepsis - induced disseminated intravascular coagulation ( dic ) . biochemical markers revealed low platelet count and prolonged pt , aptt , and elevated fibrinogen levels , which were consistent with dic criteria . there were instances where an autopsy examination revealed the precipitation of fibrin thrombi in multiple organs of cases with dic disorder . while kidney was involved in 15 of the 22 cases studied ( 68% ) , most of the cases involved veins or small vessels such as arterioles . however , only one case that had gram - negative pneumonia - associated dic had renal artery involvement . however , there was an aneurysmal change in the renal artery , which could contribute to thrombus formation . sepsis is often associated with hemostatic abnormalities ranging from isolated thrombocytopenia , hypercoagulability to dic . in sepsis - associated dic dic is frequently associated with gram - negative bacterial infection but it can occur with a similar incidence in gram - positive infection . results of several studies have shown that patients with severe infection are at increased risk of venous thrombosis and pulmonary embolism , . also , there were several reports on renal vein thrombosis associated with pyelonephritis , , , , , . however , there has been no report on renal artery thrombosis associated with acute pyelonephritis and sepsis - induced dic . in sepsis - induced dic , thrombus formation can be explained in three mechanisms and they are as follows : ( 1 ) upregulation of procoagulant pathway , ( 2 ) downregulation of physiologic anticoagulants , and ( 3 ) suppression of fibrinolysis . in this case , increased platelet production can lead to increased immature platelet count and there is evidence that immature platelet fraction was increased in dic . the percentage and absolute number of reticulated platelet were elevated in patients with thrombosis . as immature platelets have more cox-2 and thromboxane than normal platelets , diabetes could have been an aggravating factor for platelet aggregation . besides coagulopathy due to sepsis - associated dic possible options for reperfusion therapy are intra - arterial thrombolytics , percutaneous angioplasty , systemic thrombolytics , and surgery . the success of intra - arterial thrombolytics and percutaneous angioplasty does not warrant recovery of renal function . anticoagulation is still a controversial subject . in the process of getting informed consent from patient , we explained the treatment options , their possible side effects and complication . considering the bleeding risk and possible unwanted results from thrombolytic therapy , we decided not to do thrombolytic therapy . if the thrombolytic therapy had been done in a timely manner , the improvement of kidney perfusion might have been more dramatic . , we encountered the matter of prophylactic anticoagulation during sepsis - induced dic to prevent thrombosis . according to the italian society for haemostasis and thrombosis , the use of antithrombin , gabexate , plasma exchange , or thrombomodulin was not suggested for patients with dic secondary to severe sepsis . also , the use of unfractionated heparin or low - molecular weight heparin was not suggested except for thromboembolic prophylaxis in patients at high risk who do not have active bleeding . currently , activated protein c is the only approved therapy in the united states for sepsis complicated by dic . in this case , the patient was not at high risk for thrombosis . however , diagnosis is not easy due to its nonspecific clinical presentation . in most cases of dic , thrombosis occurs in venous system or small arteries . therefore the possibility of renal infarct might be missed . this report suggests that in a patient with sepsis and improving thrombocytopenia , acute thrombosis can not only occur in microvessels , but can also occur in large arteries such as the renal artery . therefore , we conclude that if there is a sudden onset of abdominal or flank pain , special concern regarding possible renal infarction is warranted .
there are some reports of renal vein thrombosis associated with acute pyelonephritis , but a case of renal artery thrombosis in acute pyelonephritis has not been reported yet . here 
 we report a case of renal artery thrombosis which developed in a patient with acute pyelonephritis complicated with sepsis - induced disseminated intravascular coagulation ( dic ) . 
 a 65-year - old woman with diabetes was diagnosed with acute pyelonephritis complicated with sepsis . 
 escherichia coli was isolated from both blood and urine cultures . when treated with antibiotics , 
 her condition gradually improved . 
 she suddenly complained of severe right flank pain without fever in the recovery phase . a computed tomography scan revealed right renal artery thrombosis with concomitant renal infarction . 
 prophylactic anticoagulation therapy was not suggested because of sustained thrombocytopenia and increased risk of bleeding . 
 flank pain resolved with conservative treatment and perfusion of infarcted kidney improved at the time of discharge . 
 to our knowledge , this is the first case of renal artery thrombosis related to acute pyelonephritis with sepsis - induced dic .