Thigh Abscess Secondary to Intra-abdominal Pathologic Conditions: Three Cases Progressing to Necrotizing Fasciitis

Necrotizing fasciitis (NF) is a progressive destruction of the fascia and overlying tissue.¹ It does not arise de novo; rather, it emerges as a result of infection.¹ Mortality primarily depends on the timing of medical care and the extent of the infection.^1,2 A significant diagnostic challenge leading to misdiagnosis of NF is the normal appearance of the overlying skin; in fact, the infection is located deeper in the soft tissues. 

Thigh abscesses are relatively rare and often spontaneously arise from surrounding soft tissues; however, they may also occur secondary to intraperitoneal, retroperitoneal, and pelvic pathologic conditions.^3-5 The mortality rate associated with thigh abscesses arising from intra-abdominal pathologic conditions was reported to be 34% when both the intra-abdominal pathologic condition and the thigh abscess were treated.⁴ However, a mortality rate of 93% was reported in cases that were managed locally without attention to the underlying causes.⁴ This article presents a case series of thigh abscesses that originated from intra-abdominal pathologic conditions and progressed to NF owing to a delay in diagnosis.  

Patient selection

The data of 3 patients with thigh abscesses that originated from an intra-abdominal pathologic condition and progressed to NF are presented.

Ethics

Owing to the retrospective design and small case number, no institutional review board approval was necessary. All patients were informed that their data might be used for research, and informed consent was obtained from all patients before surgery.

Case 1 

A 77-year-old male was admitted to the emergency department with left knee and hip pain of 5 days’ duration. He was a nonsmoker with a history of hypertension, coronary heart disease, and colon cancer, for which he had undergone left hemicolectomy 1 month previously. Following symptomatic treatment with nonsteroidal anti-inflammatory drugs, the patient was discharged. He returned to the emergency department 2 days later with abdominal pain and swelling in the left thigh. Physical examination revealed fever (38.3°C) and tachycardia. The abdomen was comfortable, hip flexion range of motion was limited, and a thigh abscess was detected on the left side. Laboratory tests revealed a white blood cell (WBC) count of 38.6×10⁹/L, hematocrit (HCT) of 38.3%, C-reactive protein (CRP) level of 25.9 mg/dL, and biochemical values in the normal range. Abdominal computed tomography (CT) showed a multilocular abscess begining at the level of the left renal vein and extending from the paracolic gutter down to the left knee (Figure 1). The patient was transferred to the general surgery unit. Percutaneous drainage catheters were inserted for both abdominal and thigh abscesses on day 4 of admission. The abscess, urine, and blood cultures were negative. The thigh abscess was surgically drained, and negative pressure wound therapy (NPWT) was applied on day 12 and day 19 of admission. The patient was discharged on day 24 because he declined further therapy. Four days after the patient was discharged, he was readmitted to the hospital with a recurrent thigh abscess. Laboratory tests revealed a WBC count of 11.2×10⁹/L, HCT of 34%, CRP level of 15.5 mg/dL, and biochemical values in the normal range. Abdominal CT findings were the same as those previously recorded, but the size of the abscess had decreased. A percutaneous drainage catheter was reinserted for the abdominal abscess. Surgical debridement and NPWT were used to treat NF of the thigh 5 times in 18 days. Tissue culture was positive for Klebsiella pneumoniae and enterobacteria. The patient died of overwhelming sepsis on day 18 of the third admission at the treating institution. A broad-spectrum antibiotic regimen had been started on second admission and subsequently de-escalated based on culture results and clinical response. 

Case 2

A 53-year-old male was admitted to the neurosurgery outpatient clinic with back pain spreading to the right leg of 3 months’ duration. He was a nonsmoker and had a history of diabetes mellitus and rectal cancer, for which he had undergone low anterior resection and colorectal anastomosis 10 years earlier. Endoscopic follow-up had been performed for anastomotic stricture over the previous 5 years. Laboratory tests revealed a WBC count of 8×10⁹/L, HCT of 29.7%, and CRP level of 15.1 mg/dL. The patient underwent posterior foraminotomy and diskectomy for vertebral disk hernia based on physical examination and magnetic resonance imaging. On postoperative day 3, the patient had a fever of 38.4°C, and an abscess of the right thigh was detected. The abscess was drained percutaneously on postoperative day 8 when the patient was transferred to the orthopaedic surgery and traumatology unit. The abscess culture was positive for Escherichia coli. The patient was transferred to the infectious diseases unit on postoperative day 13. Although there was no sign of abdominal pain, the patient was transferred to the general surgery unit on postoperative day 19; a multilocular abscess beginning at the level of the colorectal anastomosis and extending into the gluteus bilaterally and down to the right thigh was identified by an abdominal CT scan (Figure 2), but the patient refused surgery. He was medically treated for the pericardial effusion, which developed on postoperative day 20. The colonoscopy, which was performed on day 26, revealed that the rectum was lateralized into a 10-cm pouch at 7 cm proximal to the anal verge. The patient was discharged on postoperative day 29. Ten days later, he was readmitted to the hospital with recurrent thigh abscess on the left side. Hyponatremia resulting from a syndrome of inappropriate antidiuretic hormone secretion was diagnosed. Resection of the stenosis and construction of a new coloanal anastomosis with ileostomy and debridement of the left thigh to manage NF were performed on day 13 of second admission. On postoperative day 14, cardiac arrest occurred due to cardiac tamponade. Sputum and blood cultures were positive for K pneumoniae and Pseudomonas aeruginosa. The patient died of overwhelming sepsis on postoperative day 36. A broad-spectrum antibiotic regimen had been started on initial admission and subsequently de-escalated based on culture results and clinical response. 

Case 3

A 68-year-old male without diabetes was admitted to the medical oncology unit with hip pain spreading to the right leg of 7 days’ duration. He had a 10 pack-year history of smoking and of rectal cancer, for which he had undergone low anterior resection 4 years previously. The patient did not have any recent hospitalization, except that he had been hospitalized at a different center owing to urosepsis over the previous 4 days. Physical examination revealed a fever of 38.8°C and tachycardia. The abdomen was comfortable, hip range of motion was limited, and a right-sided thigh abscess was detected. Laboratory tests revealed a WBC count of 14.1×10⁹/L, HCT of 41.9%, CRP level of 16.3 mg/dL, and lactate of 1.8 mmol/L. The thigh abscess was drained surgically by orthopaedic surgeons on day 2 of admission. The abscess culture was positive for E coli, and the urine culture was positive for Candida albicans. The patient was transferred to the general surgery unit on postoperative day 4 based on physical examination (colocutaneous fistula; Figure 3) and abdominal CT findings (a multilocular collection begining at the level of the colorectal anastomosis and extending into the gluteus bilaterally and down to the right thigh). Abdominoperineal resection, ilial resection with side-to-side anastomosis, and surgical debridement of the right thigh to manage NF were performed (Figure 4A). Surgical debridement followed by NPWT were performed and applied, respectively, 4 times in 30 days. Surgical debridement of the scrotum was performed to manage Fournier’s gangrene, and the urethra was repaired to manage urethral fistula on day 80 (Figure 4B). The tissue culture was positive for extended-spectrum β-lactamase–producing E coli, Klebsiella, and C albicans. Both urine and blood culture were positive for C albicans. The patient died of overwhelming sepsis on day 89. A broad-spectrum antibiotic regimen had been started on admission and subsequently de-escalated based on culture results and clinical response. 

Abscess of the groin, gluteus, and thigh may spontaneously arise from surrounding soft tissues, or it may be a sign of intraperitoneal, retroperitoneal, or pelvic pathologic conditions.^3,5-7 The abdominal contents may drain to the groin and down into the thigh directly through the subcutaneous tissues or via the psoas sheath, femoral canal, sacrosciatic notch, pudendal canal, and obturator foramen.^4,6 

Thigh abscesses have a wide range of clinical presentations. Thus, they are subject to misinterpretation, which may cause delays in management, especially when subspecialty consultations are not well directed to the appropriate department. This study demonstrated that delays in surgical and radiologic consultations and incorrect assessment of the clinical urgency contributed to increased mortality in patients with thigh abscesses. The 3 cases reported arose from colorectal perforation to the retroperitoneum, resulting in an infection spreading down to the thigh. All patients had undergone previous colorectal surgery for malignancy, and all 3 presented with a deep, vague pain in the back or hip area that spread down to the buttock and leg. Patients’ symptoms were misinterpreted as a nonspecific complaint in case 1, vertebral disk herniation in case 2, and urinary tract infection in case 3, which led to diagnostic delays of 2 or more days. Additionally, inadequate consultation processes led to surgical delays of 2 or more days. Two patients were initially treated with percutaneous drainage based on the surgeon’s preference, while 1 patient underwent surgery for thigh abcesses. Failure of percutaneous drainage required surgery in both patients with persistent symptoms. Negative pressure wound therapy is a form of treatment that promotes wound healing via application of subatmospheric pressure through a sealed vacuum system consisting of a suction pump, tubing, and a dressing; it removes excess exudate and increases blood supply.⁸ In this case study, NPWT was used as a component of wound management. The reasons for NPWT application included failed surgery and the presence of NF. Application of NPWT was not possible in case 2 due to the rapid death of the patient following surgical debridement of NF. 

As noted previously, the mortality rate in patients with thigh abscesses arising from intra-abdominal pathologic conditions is 34% in cases in which both the preceding pathologic condition and the thigh abscess are treated.⁴ However, the mortality rate can reach 93% in cases that are managed locally without attention to the underlying causes.⁴ In case 1 reported herein, percutaneous drainage was performed to manage abdominal abscess, but it was not as effective as the surgeons had hoped. In case 2, definitive surgery was delayed due to the patient’s refusal and misdiagnosis. In case 3, definitive surgery was performed too late to prevent NF. 

Although this was a small case series without a comparator, it could be concluded that thigh abscesses arising from intra-abdominal pathologic conditions should not be treated locally. Failed NPWT indicates that the elimination of the underlying pathologic condition was necessary. It might be possible to infer that percutaneous drainage should not be the treatment of choice for a secondary intra-abdominal pathologic condition; instead, definitive surgery should be performed immediately. The underlying pathologic condition may only be defined intraoperatively, as stated previously.⁴ Hsieh et al⁹ successfully managed a thigh abscess in a patient with ruptured retrocecal appendicitis, with timely surgical intervention for both the thigh abscess and intra-abdominal pathologic condition. They⁹ stated that surgery is advantageous over percutaneous drainage in patients with conditions such as perforated appendicitis, diverticulitis, or malignancy. Lal et al¹⁰ also successfully treated a patient with a perforated appendicitis, but surgery for the intra-abdominal pathologic condition was delayed because of diagnostic problems. Although an attempt at definitive therapy was made, Rotstein et al⁴ reported mortality in 2 cases. They concluded a delay in diagnosis was responsible for mortality. Mair et al¹¹ reported a mortality rate of 50% in 4 patients with thigh abscess secondary to colon cancer. Both wide local drainage and fecal diversion were performed in 3 patients, and 1 patient was treated with local drainage.

Prompt diagnosis and immediate surgical intervention are the keys to successful outcomes in a patient with NF; extension of the necrotizing infection beyond the urogenital and/or anorectal triangle has been independently associated with mortality.^12,13 Unfortunately, all 3 patients died of overwhelming sepsis, reflecting poor prognosis in this group of patients, especially when definitive surgery was delayed. This study recommended strategies aimed at improving the education of health care practitioners about NF, especially in patients with thigh abscess originating from an intra-abdominal pathologic condition. 

This was a retrospective case series without a comparator. No standardized approach was used for thigh abscesses arising from intra-abdominal pathologic conditions. Definitive therapy was delayed because of misdiagnosis. Thus, it cannot be used to make conclusions on management strategy. 

Thigh abscess may spontaneously arise from surrounding soft tissues, or it may be a sign of an intraperitoneal, retroperitoneal, or pelvic pathologic condition. A deep, vague pain in the back or hip area that spreads to the buttock and leg may be an early symptom of such pathologic conditions. Clinical suspicion may effectively reduce mortality by allowing early surgical intervention, especially in the patient with a previous history of abdominal surgery, radiotherapy, or inflammatory or malignant disease.

Authors: Arife Simsek, MD

Affiliation: Inonu University, School of Medicine, Department of General Surgery, Malatya, Turkey

Correspondence: Arife Simsek, MD, Inonu University, School of Medicine, Department of General Surgery, 44100, Malatya, Turkey; draksimsek@yahoo.com.tr

Disclosure: The author discloses no financial or other conflicts of interest.