Pyomyositis in a Patient with AIDS

A 58-year-old man with hepatitis C and AIDS developed left flank pain 5 days prior to presentation. The pain was exacerbated by movement of the left leg and it was accompanied by fever, night sweats and malaise. The patient denied urinary or gastrointestinal symptoms. The patient admitted that he was an active intravenous drug user. On physical examination, tenderness and erythema were observed in the left lower quadrant. No left CVA tenderness was elicited. A 1×1 cm open wound was observed on the left antecubital fossa. An abdominal/pelvic CT scan was performed (Picture 1, 2) and aspiration of the affected muscle yielded E. coli.

Picture 1.

Picture 2.

Pyomyositis is defined as an intramuscular bacterial infection. This etiology was once considered a tropical disease; however, the increasing incidence of pyomyositis in other areas has been reported, particularly in immunocompromised patients, including individuals with HIV.

It is important to maintain a high suspicion of pyomyositis because its clinical presentation may mimic other infections etiologies, including pyelonephritis.

Pyomyositis is commonly caused by Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus species; however, Gram-negative bacteria may be involved in immunocompromised hosts. Pyomyositis due to E. coli has been reported in patients with hematological malignancies and patients with HIV infection (1,2). Although the source of E. coli could not be clearly elucidated in our case, a diminished hepatic capacity due to hepatitis C may have decreased the clearance of bacteremia and increased the risk of the metastatic spread of infection.

The author states that he has no Conflict of Interest (COI).