Image Quiz

Shoulder Pain, Fever, and Chills in a Fifty-Three-Year-Old Man (continued)

Answer: Abscess between the subscapularis and posterior portion of the chest wall.

Multiplanar magnetic resonance images of the area about the right shoulder girdle, including T1-weighted images, STIR (short-tau-inversion-recovery) images, and T1-weighted images with fat saturation following intravenous injection of gadolinium, demonstrated a multiloculated fluid collection between the subscapularis muscle and the posterior portion of the chest wall (Figs. 1 and 2). The rotator cuff muscles, including the subscapularis muscle, demonstrated no abnormalities. The walls of the lesion were thickened and irregular, with multiple septations that were enhanced with the gadolinium. There was moderate surrounding edema. The abscess extended inferiorly from the area anterior to the scapula, along the midaxillary and posterior axillary lines, to the level of the diaphragm. The pleura, hilum, and mediastinum of the lung appeared to be normal. Aspiration of fluid from the lesion was not performed before the operation.

Fig. 1	Fig. 1 Axial T1-weighted magnetic resonance image (with fat saturation following intravenous injection of gadolinium) through the middle portion of the chest, demonstrating an extensive subscapular fluid collection (arrow). For larger view, click on image
Fig. 2	Fig. 2 Coronal magnetic resonance image demonstrating the abscess (arrow). For larger view, click on image

The patient was taken to the operating room for urgent open drainage of the abscess on the evening of admission. After induction of general anesthesia, the patient was placed in the lateral decubitus position on a beanbag. Routine preparation and draping were performed. A curvilinear incision was made over the medial border of the scapula and was extended inferiorly. The inferior border of the trapezius muscle was retracted superiorly to expose the lower half of the medial scapular border. Electrocautery was used to release the rhomboid musculature from the medial scapular edge and to expose the underlying space. Upon entrance into the scapulothoracic space, a massive amount of purulent fluid was immediately encountered. Approximately 500 mL of purulent material was evacuated. Intraoperative gram-staining of the specimen yielded gram-positive cocci in clusters.

Multiple areas of loculation were released by gently sweeping an index finger through the area. A moderate degree of necrotic tissue was found to be forming the septations and lining the edges of the abscess and was removed with a rongeur. The space was then irrigated with pulsatile lavage with use of 9 L of saline solution with cefazolin antibiotic (2 g of cefazolin per 3-L bag). Two large Hemovac drains were placed to evacuate fluid from the scapulothoracic space. The rhomboid musculature was reapproximated to the medial scapular border with absorbable PDS (polydioxanone) monofilament suture. Prolene monofilament suture (Ethicon, Somerville, New Jersey) was used for skin closure. A shoulder sling (DonJoy UltraSling; dj Orthopedics, Vista, California) was used postoperatively, with the arm positioned at the side to allow unstressed wound-healing.

The patient was initially given intravenous vancomycin antibiotic therapy until the culture sensitivities were available. Staphylococcus aureus that was sensitive to oxacillin grew on final culture. Anaerobic and fungal cultures were ultimately negative. When sensitivities were reported on the third postoperative day, the intravenous antibiotic therapy was changed to nafcillin (2 g every four hours), in accordance with the recommendation of our infectious disease consultant. The two Hemovac drains were removed on the third postoperative day.

The patient was hospitalized for ten days postoperatively for the administration of intravenous antibiotic therapy.

Discussion

The development of an isolated, spontaneous subscapular abscess has not been reported to occur in a healthy individual without a preceding causative event such as penetrating trauma, blunt trauma with hematoma formation, or a previous infectious condition. In a Medline search (with use of the key words subscapular, scapulothoracic, shoulder abscess, and infection) we identified only two reported cases of subscapular abscesses.

The first case involved a fifteen-month-old girl in whom an extensive subscapular abscess developed as a result of infection with β-lactamase-negative Haemophilus influenzae type B. The child was diagnosed with otitis media prior to admission. Incision and drainage was performed. A large abscess was found deep to the fascia of the axilla, with extension into the subscapular area. After drainage of the abscess, the fever promptly subsided and the subsequent course was uneventful.

The second case involved a nineteen-year-old man in whom a subscapular abscess developed as a result of infection with Staphylococcus aureus. Septicemia developed and rapidly progressed, ultimately leading to the patient's death. Six days before admission, the patient had been struck on the shoulder by a baseball bat but had noted no immediate effects except for localized soreness. He was initially admitted with a high fever, abdominal pain, shortness of breath, and left shoulder pain. A chest radiograph demonstrated infiltrates consistent with pneumonia. Cultures of the sputum and the blood as well as fluid from the left glenohumeral space all revealed the growth of Staphylococcus aureus. Overwhelming sepsis followed, and, after cardiac arrest and renal failure, the patient died on the fourth hospital day. The postmortem examination revealed a 3-cm ecchymotic area superior and lateral to the scapula and a large subscapular abscess that contained 300 mL of pus.

The case of our patient underlines the importance of prompt diagnosis and immediate, aggressive treatment in the management of a subscapular abscess. A delay in instituting treatment has been reported to be the most important factor leading to a poor result in the treatment of pyogenic arthritis of the shoulder in adults. When a subscapular abscess is suspected, we recommend immediate aspiration and magnetic resonance imaging or computed tomographic studies, followed by emergent incision and drainage along with appropriate antibiotic therapy.

Reference

1. Nowinski RJ, Duchene C. Spontaneous septic subscapular abscess. a case report. J Bone Joint Surg Am. 2004;86:1302-4.