DOS 2017

DOS Kongressen 2017 ·

107

Obturator pyomyositis related to staphylococcus au-

reus bacteremia: can mimic or be complicated by ipsi-

lateral septic coxitis

Rasmus Cleemann, Mathias Bünger, Martin Gottliebsen, Klaus Kjær Petersen

Elective Surgery Center, Silkeborg Regional Hospital, Silkeborg, DK; Department

of Orthopedic Surgery, Aarhus University Hospital, Aarhus, DK; Department of

Orthopedic Surgery, Aarhus University Hospital, Aarhus, DK; Department of Or-

thopedic Surgery, Aarhus University Hospital, Aarhus, DK

Background:

Staphylococcus aureus (SA) bacteremia can develop into a broad

array of infections foci, which can be difficult to recognize initially. Obturator

pyomyositis (OP) is a rare differential diagnosis in patients presenting with fever

and complaints from the hip area.

Purpose / Aim of Study:

We would like to bring attention to a rare but impor-

tant cause to fever and hip pain.

Materials and Methods:

Four patients with OP were identified from 2013 to

2017. Patient files, radiological examinations and microbiological etiology were

reviewed.

Findings / Results:

Patients included 3 children (age 6-12) and 1 adult (age

31). Patients presented with fever (38.5-40.5°C), pain from the hip/groin area,

a limp and elevated CRP (21.7-236.2 mg/L). 4/4 hip ultrasound examinations

at admission were without joint effusion. OP was diagnosed by MRI 3 days after

admission in 3/4 patients and after 7 days in 1 patient. Diagnosis in the last pa-

tient was delayed 6 days by use of CT and PET CT as initial imaging. 4 patients

had affection of the internal obturator muscle, 3 included the external obturator

muscle and 2 patients developed ipsilateral hip joint effusions. 4/4 initial blood

cultures were positive for SA and patients were started on empiric antibiotics

prior to surgery. Drainage was performed 1 day after MRI. 2 patients received

a hip arthrotomy, 2 patients obturator muscles were incised and 1 patient re-

ceived an additional ultrasound guided drainage procedure. Initial abscess/joint

fluid samples were positive for SA except for the patient with delayed MRI.

Conclusions:

Although not common OP as a course of hip pain should be sus-

pected in patients with fever, hip pain and SA bacteremia. OP caused by SA can

be accompanied by ipsilateral septic coxitis. We advocate MRI as the best mo-

dality to diagnose OP and to distinguish it from septic coxitis.

No conflicts of interest reported

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