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Pelvis » Female Pelvis (Gynecology)
Pubic osteomyelitis with an abscess
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Author(s) :
Chaitali Shah, FRCR
Presentation A 35 year old woman presents with pain in the suprapubic region and a history of fever for 3 days. Her pain worsens on voiding and also radiates to the vagina. She has had associated nausea, vomiting and diarrhea for 2 days.
Caption: Midline sagittal image
Description: A heterogeneous soft tissue mass is noted anterior-inferior to the urinary bladder in the region of the symphysis pubis, indenting the bladder contour. The bladder wall appears thickened adjacent to the lesion. The uterus appear normal.
Caption: Parasagittal image to right of midline
Description: The heterogeneous soft tissue mass is noted again in this parasagittal image. Irregular echogenic areas are noted caudal to the mass. These echogenic areas cause complete shadowing beneath them.
Caption: Para-sagittal through right adnexa
Description: This image shows the extent of the mass more clearly. The mass appears to involve the superficial soft tissues. The irregular echogenic areas are also seen more prominently here.
Caption: Transverse view of the pelvis
Description: The mass in this transverse view shows a hypoechoic center. This is suggestive of necrosis.
Caption: Transverse color Doppler image
Description: Color Doppler shows some flow within the mass.
Caption: Transverse color Doppler image
Description: Color Doppler of the mass in a different plane.
Caption: Sagittal color Doppler image
Description: This image demonstrates that the mass is in close proximity to the pubic bone and exhibits blood flow primarily around the periphery of the mass.
Differential Diagnosis Spontaneous pubic bone osteomyelitis with associated abscess, a malignant pubic bone tumor with associated soft tissue component.

Final Diagnosis Spontaneous pubic bone osteomyelitis with an associated abscess. The organism that was cultured was methicillin sensitive staph auerus. The patient was an intravenous drug abuser of heroin for many years.

Pubic osteomyelitis, also referred to as infective synchondritis, is an infectious inflammatory condition affecting the pubic bone and symphysis.

Predisposing factors include –
•Extremes of age [children and elderly] where staphylococcus is the main pathogen
•Post parturition
•Post genitourinary procedures
•Parenteral drug abusers
•Pelvic malignancies
Very occasionally it may occur without any underlying cause.

Organisms involved are: Staphylococcal auerus, Pseudomonas aeruginosa, Streptococcus pneumoniae, E.coli.

Most of the patients present with fever, pubic pain, waddling gait, hip and groin pain.

Ultrasound features-
• A soft-tissue mass with a heterogeneous echotexture and mixed echogenicity in the pre-vesical space, or the space of Retzius – suggestive of abscess.
• If the abscess is liquefied, it may show cystic areas in the center with no flow.
• The mass may show increased vascularity due to inflammation.
• Irregular margins of the bone in close proximity suggesting bony erosion or frank destruction may be noted.

Role of ultrasound:
1. Establish a diagnosis
2. Ultrasound guided biopsy/aspiration [for culture of the organisms] and therapeutic aspiration of the abscess.
3. Non-invasive follow up of the patients as this disease requires prolonged treatment.

Differential diagnosis: The most important and possibly the only differential that needs to be considered is osteitis pubis- this is a sterile, painful, inflammatory condition involving the pubic bone, symphysis and surrounding structures. The imaging appearance may be quite similar, with bone destruction seen in a few cases. It is however, self-limiting and responds to anti-inflammatory agents.

Management: Prolonged anti-microbial treatment with occasional surgical debridement and curettage required for complete cure.

Case References 1. Pauli S, Willemsen P, et al. Osteomyelitis pubis versus osteitis pubis: a case presentation and review of the literature. Br J Sports Med. 2002 Feb; 36(1):71-3.
2. Ross JJ, Hu LT. Septic arthritis of the pubic symphysis: review of 100 cases. Medicine (Baltimore). 2003 Sep;82(5):340-5.
3. Seve P, Boibieux A, et al. Pubic osteomyelitis in athletes. Rev Med Interne. 2001 Jun; 22(6):576-81.
4. Lentz SS. Osteitis pubis: a review. Obstet Gynecol Surv. 1995 Apr; 50(4):310-5.
5. Pang KW, Maffulli N, Chan KM. Acute abdomen: an atypical presentation of pubic osteomyelitis. Bull Hosp Jt Dis. 1995; 54(2):106-8.
6. Groeneweg CE, Thurnheer U. Spontaneous pubic osteomyelitis caused by Pseudomonas aeruginosa. Schweiz Med Wochenschr. 1993 Aug 10; 123(31-32):1520-5.
Follow Up This patient had a CT scan which confirmed the diagnosis. Under ultrasound guidance a drainage tube was placed into the collection and she was treated with antibiotics. Follow up imaging done 2 months later revealed resolution of the collection adjacent to the pubic bone, however CT changes of pubic osteomyelitis still persisted.
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