patients with diabetes mellitus ( dm ) are generally more susceptible to infections 14 , but the exact underlying mechanism for the increased infection risk remains uncertain 5,6 . the defects in the immune system seem to be most strongly associated with poorly controlled diabetes 2,7,8 , suggesting that glycemic control may influence immune function . in most cases , patients with dm have the same infections that affect the general population 3 ; however , occasionally , diabetic patients will present with infections caused by rare organisms at unusual sites 9 . iliopsoas abscess is a rare potentially life - threatening form of extraperitoneal infection , that involves the iliopsoas compartment , which contains the psoas and iliacus muscle 10 . primary abscess results from hematogenous spread of an infectious process from an occult source in the body 10 ; local trauma with resultant intramuscular hematoma formation seems to predispose to primary iliopsoas abscess formation 11,12 . the secondary abscess develops by spreading from contiguous anatomical structures , such as gastrointestinal and genitourinary tract , musculoskeletal system , or vascular tissue 11 . before the discovery of modern antituberculosis treatment , iliopsoas abscess was a well - recognized complication of spine tuberculosis 10 currently , medical conditions , such as defects in the immune system , dm , intravenous drug use , and alcoholism are predisposing risk factors 13 . both primary and secondary iliopsoas abscesses have been reported in diabetic adults 14,15 . to the best of our knowledge , only one case has been previously reported in an adolescent with t1 dm 16 . in that case , a 12-year - old boy presented with diabetic ketoacidosis ( dka ) and low back pain , and was subsequently diagnosed with both a left psoas abscess and an extensive thoracolumbar spinal epidural abscess . here , we describe the clinical features , diagnostic findings , management and outcomes of three t1 dm adolescents with primary and one case of secondary iliopsoas abscess . a 14-year - old girl presented to the pediatric unit at the general hospital of trento with a 4-day history of right - sided back pain , fever , weight loss , and difficulty breathing . her medical history was characterized by a 6-year history of poorly controlled t1 dm and her most recent glycated hemoglobin ( hba1c ) value was 11.1% ( 98  mmol / mol ) . on examination , she was febrile ( 39c ) and dehydrated ; she had kussmaul breathing and complained tenderness in the right flank . initial investigations showed a blood glucose of 380  mg / dl , white cell count 26.6    10/l with a neutrophilia of 24.2    10/l , c - reactive protein ( crp ) of 199  mg / l , a ph of 7.35 , and bicarbonate of 12 urinalysis revealed 3 + glucose and 3 + ketones , and was negative for white cells . an abdominal ultrasound ( us ) scan showed an extensive loculated right - side perinephric abscess , measuring 73  mm in length with a 45  mm anteroposterior diameter . abdominal computed tomography ( ct ) showed that the abscess extended from the perinephric space to the psoas muscle , pushing the right kidney anterolaterally ( fig.1 ) . the loculated right - sided psoas abscess extending from psoas muscle and pushing the right kidney anterolaterally . the patient was hydrated with intravenous fluids with added potassium and an insulin infusion according to the local protocol . she was put on intravenous antibiotics ceftriaxone , gentamicin , and metronidazole to treat the infection . three days later , because of the absence of improvement , the patient underwent an open abscess evacuation under general anesthesia . staphylococcus aureus was grown from the pus , and antibiotics were changed to intravenous teicoplanin and oral ciprofloxacin . her condition and metabolic derangements improved over the next 48  h and subcutaneous insulin was reintroduced . the duration of hospitalization was 15  days and the patient was discharged from the hospital with oral ciprofloxacin and no further complications . two years later , the patient re - presented with a primary right iliopsoas abscess , which was readily recognized and treated with intravenous teicoplanin and oral ciprofloxacin . a 17-year - old girl was admitted to the pediatric unit at the general hospital of trento with a 3-day history of left - side back pain , high fever , malaise , and concomitant hyperglycemia . she had been treated at home with oral ciprofloxacin for almost 48  h. she had a history of well - controlled t1 dm diagnosed at the age of 13  years with no history of dka . on examination , she had a fever ( 38c ) and marked tenderness on palpation of the left flank . initial laboratory findings revealed blood glucose of 347  mg / dl , crp of 14.9  mg / l , and mild leukocytosis 10    10/l . twenty - four hours later , the left - sided back pain had progressed and abdominopelvic ct was performed . treatment was changed to intravenous teicoplanin and oral ciprofloxacin , and the patient rapidly improved . she was discharged from the hospital after 15  days of intravenous therapy with instructions to continue oral ciprofloxacin therapy for 8  days . fifteen days later , an abdominal magnetic resonance imaging ( mri ) revealed a complete resolution of the abscess . a 14-year - old boy initially presented to the emergency department ( ed ) of the la spezia general hospital with a chief compliant of a right low back pain after a trauma during a football match . the x - ray of the pelvis revealed no fractures and the physical exam was unremarkable , so he was discharged with a prescription of nonsteroidal anti - inflammatory drugs ( nsaids ) . the patient had a medical history that was significant for poorly controlled t1 dm diagnosed at age 2  years , characterized by poor compliance to self - management and inconsistent follow - up . fifteen days later , he returned to the ed with fever , worsening back pain , and signs of major gastric hemorrhage . the exam revealed a gastric ulcer as the cause of bleeding , that was attributed to the prolonged use of nsaids . a noncontrast ct scan of the abdomen was also performed and documented an area of attenuation in the right psoas muscle , that seemed consistent with a voluminous psoas hematoma . a ct scan revealed a voluminous right psoas abscess extending to the ipsilateral gluteus muscle . the patient was treated with intravenous antibiotic ( teicoplanin , ceftriaxone , piperacillin / tazobactam ) and clinical conditions gradually improved . the patient was discharged on oral antibiotic therapy ( amoxicillin / clavulanate and rifampicin ) with the diagnosis of psoas abscess due to hematogenous infection from s.  aureus on a psoas hematoma . a 14-year - old girl presented to the pediatric unit at the general hospital of trento with a 4-day history of right - sided back pain , fever , weight loss , and difficulty breathing . her medical history was characterized by a 6-year history of poorly controlled t1 dm and her most recent glycated hemoglobin ( hba1c ) value was 11.1% ( 98  mmol / mol ) . on examination , she was febrile ( 39c ) and dehydrated ; she had kussmaul breathing and complained tenderness in the right flank . initial investigations showed a blood glucose of 380  mg / dl , white cell count 26.6    10/l with a neutrophilia of 24.2    10/l , c - reactive protein ( crp ) of 199  mg / l , a ph of 7.35 , and bicarbonate of 12 urinalysis revealed 3 + glucose and 3 + ketones , and was negative for white cells . an abdominal ultrasound ( us ) scan showed an extensive loculated right - side perinephric abscess , measuring 73  mm in length with a 45  mm anteroposterior diameter . abdominal computed tomography ( ct ) showed that the abscess extended from the perinephric space to the psoas muscle , pushing the right kidney anterolaterally ( fig.1 ) . the loculated right - sided psoas abscess extending from psoas muscle and pushing the right kidney anterolaterally . the patient was hydrated with intravenous fluids with added potassium and an insulin infusion according to the local protocol . she was put on intravenous antibiotics ceftriaxone , gentamicin , and metronidazole to treat the infection . three days later , because of the absence of improvement , the patient underwent an open abscess evacuation under general anesthesia . staphylococcus aureus was grown from the pus , and antibiotics were changed to intravenous teicoplanin and oral ciprofloxacin . her condition and metabolic derangements improved over the next 48  h and subcutaneous insulin was reintroduced . the duration of hospitalization was 15  days and the patient was discharged from the hospital with oral ciprofloxacin and no further complications . two years later , the patient re - presented with a primary right iliopsoas abscess , which was readily recognized and treated with intravenous teicoplanin and oral ciprofloxacin . a 17-year - old girl was admitted to the pediatric unit at the general hospital of trento with a 3-day history of left - side back pain , high fever , malaise , and concomitant hyperglycemia . she had been treated at home with oral ciprofloxacin for almost 48  h. she had a history of well - controlled t1 dm diagnosed at the age of 13  years with no history of dka . , she had a fever ( 38c ) and marked tenderness on palpation of the left flank . revealed blood glucose of 347  mg / dl , crp of 14.9  mg / l , and mild leukocytosis 10    10/l . twenty - four hours later , the left - sided back pain had progressed and abdominopelvic ct was performed . treatment was changed to intravenous teicoplanin and oral ciprofloxacin , and the patient rapidly improved . she was discharged from the hospital after 15  days of intravenous therapy with instructions to continue oral ciprofloxacin therapy for 8  days . fifteen days later , an abdominal magnetic resonance imaging ( mri ) revealed a complete resolution of the abscess . a 14-year - old boy initially presented to the emergency department ( ed ) of the la spezia general hospital with a chief compliant of a right low back pain after a trauma during a football match . the x - ray of the pelvis revealed no fractures and the physical exam was unremarkable , so he was discharged with a prescription of nonsteroidal anti - inflammatory drugs ( nsaids ) . the patient had a medical history that was significant for poorly controlled t1 dm diagnosed at age 2  years , characterized by poor compliance to self - management and inconsistent follow - up . fifteen days later , he returned to the ed with fever , worsening back pain , and signs of major gastric hemorrhage . the exam revealed a gastric ulcer as the cause of bleeding , that was attributed to the prolonged use of nsaids . a noncontrast ct scan of the abdomen was also performed and documented an area of attenuation in the right psoas muscle , that seemed consistent with a voluminous psoas hematoma . a ct scan revealed a voluminous right psoas abscess extending to the ipsilateral gluteus muscle . the patient was treated with intravenous antibiotic ( teicoplanin , ceftriaxone , piperacillin / tazobactam ) and clinical conditions gradually improved . the patient was discharged on oral antibiotic therapy ( amoxicillin / clavulanate and rifampicin ) with the diagnosis of psoas abscess due to hematogenous infection from s.  aureus on a psoas hematoma . we describe three cases of primary iliopsoas abscesses and one case of secondary iliopsoas abscess occurred in three adolescents affected by t1 dm . in our case series , a previous study revealed that primary iliopsoas abscesses in children accounts up to 92% of cases 12 . the classic presentation triad of iliopsoas abscess is fever , flank pain , and limitation of the hip movement 10 , but in our cases fever and flank or back pain were the only presenting symptoms . that is consistent with the observation that the classic triad is present only in a small percentage of patients 17,18 , favoring the frequent delay in diagnosis usually seen in patients with psoas abscess . the iliopsoas abscess was demonstrated with abdominal us in patient 1 , and with abdominopelvic ct in patients 2 and 3 . in the literature , us is recommended first as a screening procedure to detect psoas abscess in patients with prolonged fever or sepsis of unknown origin 11,17 , but us is highly operator dependent and retroperitoneal space can be difficult to visualize because can be obscured by bowel gas reducing drastically its sensitivity to only about 60% 10 . nevertheless , some authors believe that mri is superior to ct , because of better discrimination of soft tissue and the ability to visualize the abscess wall and the surrounding structures 10 . moreover , recently , the value of gallium-67 scanning in the diagnosis of psoas abscess in adult patients initially diagnosed as having fever of unknown origin has been reported 20 . patient 1 and patient 3 had a history of chronically poorly controlled diabetes , confirming what has already been observed in diabetic adults , where poor glycemic control has been associated with a predisposition to unusual and more serious infections 9,14,21 . staphylococcus aureus was the causal organism in all cases , confirming the observation that individuals with diabetes , in particular those who are insulin - dependent , have an increased risk of infection with this organism 22 . staphylococcus aureus is also the most frequent causative organism of iliopsoas abscess in diabetic adults 12 . adjustments of the therapy were based on report of abscess fluid culture , but a better knowledge of the common causative organisms could guide the initial choice of antibiotics . in the literature , it is reported that the mortality rate in primary psoas abscess is 2.4% and in secondary abscesses is 18.9% 10,11 . the major cause of death is delayed diagnosis or inadequate therapy 11 ; therefore it is extremely important to recognize and treat these unusual infections promptly . the signs and symptoms of psoas abscess easily mimic other disorders , thus the differential diagnosis is extensive . septic hip joint , arthritis of the hip , osteomyelitis of the pelvis , trauma , tumor or osteomyelitis of the spine , renal or perirenal abscess , abdominal abscess solid , or hollow viscera injury because of its relative infrequency and often subtle or nonspecific presentation , psoas abscess often is not considered in diabetic adolescents presenting with fever , flank , or back pain , but our cases suggest that an increased awareness of psoas abscess is required for early recognition and prompt treatment of this condition .
key clinical messageiliopsoas abscesses have been reported in adult diabetic patients , but only one case has been so far reported in the pediatric diabetic literature . 
 we report three cases of iliopsoas abscesses in three adolescents with type 1 diabetes mellitus , suggesting that an increased awareness of this condition is required for its early recognition and prompt treatment .