Spontaneous pubic osteomyelitis - a rare cause of groin pain.

Publication Date

4-27-2007

Abstract

LEARNING OBJECTIVES: 1) Recognize the clinical presentation of osteomyelitis of pubic bone. 2) Differentiate osteomyelitis of pubis from osteitis pubis - a common clinical confounder. CASE: A thirty-one year old male presented to the emergency room with left groin pain, fever and pain with hip motion, especially abduction of the left leg. He had an antalgic gait and difficulty in weight bearing. He was discharged three weeks earlier from our hospital with similar complaints, when methicillin-sensitive Staphylococcus aureus was isolated from blood culture. The source of infection was not identified despite workup during prior admission including negative Computed Tomography of the abdomen and pelvis, Magnetic Resonance of the hip and trans-esophageal echocardiogram. He was treated with intravenous vancomycin for one week. Evaluation of risk factors revealed involvement in strenuous activity during construction work, occasional use of marijuana and high-risk sexual behavior. He denied intravenous drug use and did not have any history of pelvic trauma or surgery. He required incision and drainage of an olecranon bursitis two years ago which was treated with oral antibiotics. On examination, his temperature was 38.3- C, pulse 109/minute, and significant tenderness was found at the left adductor region, especially with resisted adduction. Laboratory evaluation revealed a peripheral white blood count of 11.3 mg/dL with 14 percent bands, a sedimentation rate of 80 mm/hr and unremarkable urinalysis. Blood culture grew Staphylococcus aureus sensitive to methacillin. Gadolinium-enhanced MRI was positive for abnormal intensity within left pubic bone adjacent to the symphysis and Tc-99 three phase bone scan was positive for increased isotope activity in left pubic bone. Fluoroscopic guided needle aspiration and culture of left suprapubic abscess confirmed methicillin-sensitive Staphylococcus aureus. He was treated with six weeks of intravenous nafcillin with resolution of symptoms and pyrexia. DISCUSSION: Osteomyelitis of the pubic bone is extremely rare in patients without risk factors. Predisposing factors include genitourinary surgery (female incontinence surgery most common), intravenous drug abuse, pelvic malignancy and strenuous physical activity in athletes. Typical features of pubic symphysis infection are fever, pubic pain, painful or waddling gait, pain with hip motion and groin pain. A long delay between onset of symptoms and diagnosis is typical (mean: 29 days). In young athletes, culture usually grows Staphylococcus aureus resulting from minor skin abrasion leading to bacteremia. Diagnosis is based on 234 ABSTRACTS JGIM MRI or bone scan and confirmed by culture of affected area. Treatment requires intravenous antibiotics based on culture and sensitivity for a period of six weeks. Almost half the cases require surgical debridement and curettage. The diagnosis must be differentiated from osteitis pubis, a self-limiting inflammation of the symphysis pubis secondary to trauma, pelvic surgery, childbirth, or overuse (usually in athletes). To distinguish between osteomyelitis and osteitis, a biopsy and culture of the affected area is essential, especially since both disorders may exist in the same patient. Providers caring for patients at risk should be familiar with both disorders and their management.

Publication Title

Journal of General Internal Medicine

Volume

22

Issue

S1

First Page

234

Last Page

235

Comments

Oral presentation at the 2007 SGIM National Meeting, Toronto, ONT, Canada, Friday April 27, 2007

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