General Surgery Resident Henry Ford Macomb Clinton Township, Michigan, United States
Introduction/Purpose: Anorectal abscesses are a common occurrence and are often managed with simple incision and drainage. The vast majority of anorectal abscesses are from cryptoglandular infections. Infection is thought to be due to cryptoglandular obstruction leading to inflammation, edema, and bacterial infection.Anorectal abscesses are classified based on anatomical location. Perianal location is the most common accounting for 60% of anorectal abscesses, ischiorectal 20%, supralevator and intersphincteric 5% and submucosal accounting for less than one percent. These abscesses will form a fistulous track in approximately 40% of cases. Fistulas are classified based on the Park classification, which describes the location/track. Intersphincteric track between the internal and external anal sphincters, transsphincteric track through both internal and external anal sphincters, suprasphincteric encircle the entire sphincter mechanism, and extrasphincteric course along the entire sphincter mechanism and levators.Fistula management of complex fistulas often require specialized training for optimal outcomes. This case highlights a rare presentation of supralevator abscess and reviews diagnosis and treatment of these difficult abscesses.
Methods or Case Description: A 74-year-old male was brought into the emergency department for worsening subjective fevers, weakness, and altered mental status over several weeks. Surgical history includes a small bowel resection for ileal carcinoid tumor with metastasis to the liver and hepatic arterial embolization 16 years prior. The patient was admitted to the medical service with concern for sepsis, fever of unknown origin, and non-ST elevation myocardial infarction (NSTEMI). The patient continued to have rising leukocytosis, gram negative bacteremia, which eventually grew E. coli and Proteus, and positive C. difficile infection. He also began complaining of left hip pain. CT abdomen and pelvis obtained on hospital day one showed air in the left aspect of the pelvis and presacral retroperitoneal area. Air was also infiltrating the soft tissue musculature of the left hip and surrounding the joint. Evaluation by Orthopedic surgery for left hip pain and concern for septic joint, found the patient to have no physical deficits, deformities, or crepitus on exam, but tenderness with movement of the left hip. General surgery was consulted and had no clinical suspicion for a necrotizing soft tissue infection, no intraperitoneal air, and a benign abdominal exam excluded concern for bowel perforation and no clear indication for surgery. Recommendation was made for a left hip and pelvis magnetic resonance imaging (MRI) after multi-departmental discussion. MRI was significant for left posterior perianal fluid collection with gas, suspicious for abscess and possible fistulous communication with anal canal and skin and gas dissecting from the collection along the left hemipelvis.
Outcomes: Colorectal Surgery was consulted on hospital day four, and was taken to the operating room for rectal exam under anesthesia. Operative findings of a complex transsphincteric fistula with connection to a large supralevator abscess. The fistula tract was partially opened outside of the sphincter complex and a seton placed. Given the large size of the abscess a Malecot drain was placed to assist and assure drainage of the abscess cavity. The patient had routine postoperative course with resolution of leukocytosis and fevers and was discharged home on postoperative day two. The patient had the Malecot drain removed on his two week follow up appointment, but retains a posterior silastic Seton drain in the trans-sphincteric fistula.
Conclusion: Supralevator abscesses are one of the least common types of abscess. There are rare causes such as appendicitis, diverticulitis, gynecologic origin, Crohn’s disease, or trauma. However, the majority are still due to cryptoglandular infection. Presentation of retroperitoneal air and hip pain due to supralevator abscess is rare and has not been previously described to this authors knowledge. Given supralevator space proximity to the hip, it is speculated that this is the reason for hip pain and gas presenting in or near the hip joint. The diagnosis of deep abscesses can be difficult, given patients will not always present with the typical symptoms and signs. The treatment, however, remains the same with incision and drainage. Imaging is not usually necessary for the diagnosis of anorectal abscess. If an abscess is suspected and can’t be diagnosed on physical exam due to patient cooperation or lack of physical features, exam under anesthesia should be done. Further diagnosis and surgical planning can be facilitates via pelvic MRI, which is considered gold standard for anorectal anatomy.
Patients may not always present with the typical symptom of rectal abscess. Although rare, anorectal abscess should be on the differential for patients presenting with retroperitoneal air, especially when in the pelvis.
