Retroperitoneal phlegmon

Clinical presentation and physical examination

The pathognomonic (most specific) sign of inflammation in the retroperitoneal space proper is the psoas sign. It occurs due to pressure from the abscess, as well as concomitant lymphangitis or lymphadenitis on the iliopsoas muscle (m. iliopsoas), causing its reflex contraction.

The patient assumes a characteristic position: the leg is flexed, slightly adducted, and internally rotated. Any attempt to straighten the leg causes a sharp increase in pain.

Physical examination findings:

• Palpation: tenderness is elicited in the corresponding half of the abdomen (in the iliac fossa, lumbar region, lateral to the rectus abdominis muscle). An inflammatory infiltrate may be palpated through the anterior abdominal wall.
• Features in paranephritis: the infiltrate is palpated in the hypochondrium, extends along the edge of the rectus muscle, and may spread toward the umbilicus or midline.
• Muscle tone: lumbar muscle rigidity directly indicates a process in the retroperitoneal adipose tissue proper.
• Visual changes: the contours of the corresponding lumbar region are smoothed out.

Important: the fluctuation sign is not detected in retroperitoneal phlegmons, even with very extensive abscesses.

Instrumental diagnostics

To confirm the diagnosis, basic instrumental examinations are used:

1. X-ray imaging — allows detection of spinal scoliosis and obliteration of the psoas muscle contour on the affected side.
2. Ultrasound (US) — used for accurate detection of an inflammatory infiltrate or an already formed abscess cavity.

Management tactics

Conservative therapy is possible only in the early stages of the disease. It includes potent broad-spectrum antibiotics and detoxification therapy.

Surgical treatment is indicated for:

• failure of conservative therapy;
• abscess formation within the infiltrate;
• deterioration of general condition, evening temperature spikes, and chills;
• progression of swelling, pain, and increased hip contracture.

The main goal of surgery is pus removal and drainage of the space. Exclusively an extraperitoneal approach is used.

The technique of the intervention depends on the location of the focus:

• For purulent paranephritis, a vertical lumbotomy incision is performed along the lateral margin of the erector spinae muscles (from the 12th rib to the iliac crest).
• For phlegmon without a precise localization, an oblique lumbar incision is used (Pirogov or Shevkunenko incision).

At the end of the operation, a drainage tube is placed at the lowest point of the abscess (taking into account the patient's supine position) and brought out through the wound or an additional incision (counter-opening).

Class and exam questions

What else to study on this topic

• Topographic anatomy of the retroperitoneal adipose tissue of the lumbar and iliac regions.
• Technique for performing the oblique lumbar incision according to Pirogov and Shevkunenko.
• Differential diagnosis of purulent paranephritis and retroperitoneal phlegmon without a precise localization.
• The relationship between retroperitoneal lymphangitis and lymphadenitis and the development of the psoas sign.

Other topics from the section "CHAPTER 11. SURGICAL INFECTION (PURULENT-INFLAMMATORY DISEASES)"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.