الصفحة الرئيسية

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المجلة الطبية

موقع الوزارة




Retroperitoneal Abscess Presenting As

Thigh Abscess


There is a paucity of high level evidence concerning the management of intra-abdominal abscesses. The Retroperitoneal abscess is an abscess collected posterior to the peritoneal cavity. Presenting symptoms of retroperitoneal abscess are often insidious and clinical signs are subtle. As a result, the diagnosis is often delayed, with resulting high morbidity and mortality rates. Secondary thigh abscesses are rare, and their cause is often obscure. The aetiology is usually suggested by the presenting features.

Case report:

A male patient 20 years old admitted to the emergency room complaining of painful swelling in the left upper thigh since two weeks.

The left upper thigh swelling is large of a lemon in size; gradually increase in size, painful with redness of overlying skin.

There was limitation of left lower limb movement and associated with hectic fever.

The patient has no history of infection left lower limb, scrotal swelling, anal pain or ulceration and there is no impulse on cough.

The patient has past history of left flank and lower back shrapnleses injuries by explosive Israeli rocket since two years; he was put under observation and conservative treatment then discharge from the hospital.

On examination the patient is pale, toxic looking and dull, there is left iliac fossa diffuse mass 106 cm, deep to the anterior abdominal muscle, extended below the left inguinal ligament, not pulsatial, fixed, not tender, rounded edges, regular surface and you can not get below it.

Also there was swelling in Upper left thigh (antromedial aspect) 4*5cm, ill defined border, hyperaemic skin overlying, warm, tender, not pulsitile, with no impulse on cough and negative fluctuation test.

There are Enlarged left transverse inguinal group lymph nodes.

Normal left femoral artery and peripheral branches pulsation and WBCs 13.5 k/ul, Hb 8.2 g/dl,

chest and lumbosacral X-ray are free, tuberculin test was negative.

U/S abdomen and pelvis revealed huge retroperitoneal cystic mass with well formed mature wall.

C.T scan with double contrast shows multiple retroperitoneal cystic masses with well formed fibrous wall, the fluid has pus density, lying on the psoas muscle, extended posterior to the rectum just above the pelvic floor and mild deviation and compression on the middle rectum and the urinary bladder.

The proximal part of the left external iliac blood vessels is within the wall. Intravenous pyelography shows neither shifting nor dilatation of the left ureter.

Conservative treatment was begun earlier while doing the investigations. U/S guided drainage was done by wide pore tube 15 F., at first 1500c.c pus was drained then gradually decease in amount through the following days.

The left upper thigh swelling disappeared with progressive improvement of general condition of the patient.

Another C.T scan was done revealed persistence of retroperitoneal abscesses with incomplete drainage of the biggest one also.

Open drainage for the retroperitoneal abscesses was done by left sided lower oblique abdominal incision [extended left lumbar incision, retroperitoneal approach].

Multiple abscesses within psoas muscle fibres, thick wall with distorted anatomy, difficult to identify the left ureter and left external iliac vessels, thick pus discharge with derbies.

Complete drainage and irrigation of the multiple cavities, three pen rose drains where put in the large cavities and the wound was closed in layers.

The patient postoperatively improved progressive decrease of the amount of discharge, the fever and WBCs subsided.

Culture and sensitivity tests from the pus which had been taken intra-operatively were negative.

U/S abdomen follow up postoperatively shows regression in size with small negligible amount of fluid.


The clinical diagnosis of retroperitoneal abscess is often delayed or missed because of the insidious onset of symptoms and the paucity of localizing signs.

This delay in diagnosis and treatment contributes to a reported overall mortality rate between 22% and 46% 1,2.

The most common presentation includes pain and tenderness in the lower abdomen or flank and fever with or without an abdominal mass.

Less commonly, pain may be noted in the lower back, hip, or thigh.

Psoas sign, which was initially negative in this patient, was recorded to be positive in only 50% of patients with retroperitoneal abscesses involving the psoas muscle.

Hip flexion and scoliosis may also be seen.

Other symptoms include rigors, anorexia, weight loss, malaise, and hip or back weakness4.

Pollock6 described a characteristic triad of symptoms: diffuse poorly localized abdominal pain; extreme weakness; and intestinal distension.

Laboratory studies in patients with retroperitoneal abscesses commonly reveal leukocytosis with neutrophilia1.

Urine analysis is frequently normal or shows sterile pyuria.

Chest X-ray may reveal elevation or fixation of the diaphragm, pleural effusion, or basal atelectasis. Abnormal radiographic studies are reported in 40% to 90% of patients1,2.

Plain abdominal films may show an abnormal psoas shadow, scoliosis, or a soft tissue mass.

An intravenous pyelogram may demonstrate ureteric obstruction or deviation of the ureters.

Typically, retroperitoneal sepsis may produce evidence of pressure on the left Ureter5.

In this patient their was no deviation. U/S abdomen and C.T scans are highly useful in establishing the diagnosis.

Rivera et al7 reported an uncommon presentation of retroperitoneal abscess as a painful inguinal swelling in a diabetic patient.

Lorimer and Eldus8 reported three cases of invasive clostridium septicum infection associated with colorectal carcinoma. Haiart et al9 reported leg pain as the sole mode of presentation for five cases of diverticulitis.

On occasions intraabdominal manifestation may remain occult and extra abdominal manifestation may be the only presenting symptoms.

The aetiology is usually suggested by the side of presentation.

The left thigh abscess is associated with sigmoid diverticulitis and rectal diseases.

The right is associated with caecal carcinoma and perforated retrocaecal appendicitis.

Peacock JE6 reported a case of unusual presentation of tuberculosis spondylitis .

The disease was complicated by fistulous involvement of the sigmoid colon which led to bowel perforation and dissection of the resulting retroperitoneal abscess into the thigh.

In reviewing the reported cases of thigh abscesses, the route of spread can be broadly separated into two groups3,4.

Direct soft tissue extension of infection down the thigh almost always originates from the rectum below the peritoneal reflection.

The second route of extension of infection into the thigh is through naturally occurring defects in the abdominal wall: along the psoas muscle deep to the inguinal ligament and iliofemoral vessels; through the femoral canal; through the obturator foramen; or through the sacrosciatic notch into the buttock thigh posteriorly.

The first three routes give rise to an abscess located in the anterior and medial aspects of the thigh, which was reported by Rotstein et al 4to be the commonest (25 patients) in comparison to the posteriorly situated thigh abscess (5 patients).

The diagnosis of a thigh abscess as such is not difficult, because it usually presents with the typical signs and symptoms of inflammation and gas that are reliably noted on X-ray of the soft tissue.

However, determination of the cause of the infection may be difficult on a clinical basis.

CT scan of the abdomen and thighs defines the presence and nature of the intra-abdominal pathological abnormalities.

 Bacteriologic study of the thigh abscess may also provide a clue to the cause.

All cases noted in the literature yielded enteric organisms, often multiple, when aspirates from the thigh were cultured. Both the retroperitoneal abscess and the thigh abscess must be treated.

In literature, when cases of thigh abscesses, secondary to intra-abdominal sepsis, were managed without attention to the underlying etiologic process, such as by local thigh drainage plus antibiotics, the mortality was 93%.

If some form of definitive therapy was added to the local management of the thigh abscess, such as appendicectomy, stoma, or debridement, the mortality was 34%.

 However, the overall mortality rate was 53%4. A thigh incision is mandatory to allow direct drainage of the pus and examination of the viability of the fascia and muscle.

 The location of the thigh incision is best determined by clinical examination assisted by CT scan findings that can accurately localize the collection and the gas distribution in the soft tissue.


Abscesses of the thigh are rare and, although easily diagnosed, their cause is often obscure.

We present a case of thigh abscess, which resulted from the extension of intra-abdominal sepsis.

The underlying pathological abnormality is retroperitoneal haematomas with secondary infection. Route of extension of infection into the thigh was through the left femoral canal and left obturator foramen. Effective treatment of this condition requires a high index of suspicion based on a firm knowledge of the pathogenesis and anatomy of the retroperitoneal space(s).

The overall mortality of this condition is high, but recognition of an abdominal source and appropriate treatment combined with local drainage of the thigh abscess appear to improve survival.


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Fox TA, Gomez J, Bravo J. Subcutaneous emphysema of the lower extremity of gastrointestinal origin. Dis Colon Rectum1978;21:357360

Rotstein OD, Pruett TL, Simmons RL. Thigh abscess: an uncommon presentation of intra-abdominal sepsis. Am J Surg 1986;151:414418

Meyers MA. Radiological features of the spread and localization of extraperitoneal gas and their relationship to its source:

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Rivera-HerrSera JL, Otheguy JN, Nieves-

Ortega J, Fortuno RF. Bol Asoc Med P R.1991 Sep;83(9):402-3. Painful inguinal

mass: uncommon presentation of a

retroperitoneal abscess.

8. Lorimer JW, Eldus LB. Invasive clostridium

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colorectal carcinoma. Can J Surg 1994; 37:245-9

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pain:J R CollSurg Edinb 1989; 34: 17-20

Consultant Surgeon

Surgical department, Shifa Hospital

F.R.C.S.L , Diploma in Paediatric Surgery


Spero El -Tawel

Ihab Mekhemer



  وزارة الصحة - مركز المعلومات - قسم النشر الالكتروني - 2005