Cellulitis

Etiology and stages of development

In the vast majority of cases, phlegmon is a secondary disease. Primary infection is rare (e.g., in penetrating chest wounds). The infection enters hematogenously, directly, or spreads from neighboring foci (in osteomyelitis, purulent arthritis, or pyelonephritis).

The disease goes through several consecutive stages:

1. Serous edema of the tissue.
2. Formation of an inflammatory infiltrate.
3. Appearance of coalescing areas of necrosis.
4. Purulent tissue lysis (abscess formation).

The nature of the lesion depends on the microflora: cocci cause purulent lysis, while putrefactive and anaerobic infections lead to necrosis with gas bubble formation (gas abscess).

Classification and localization features

Phlegmons are classified by location into subcutaneous, intermuscular, and retroperitoneal. Inflammation of specific cellular spaces has its own names:

• Purulent mediastinitis — involvement of the mediastinum.
• Paraproctitis — inflammation of the perirectal tissue.
• Paranephritis — purulent process around the kidney.
• Adenophlegmon — develops when inflammation spreads from lymph nodes.

Anatomical structure strongly affects the severity of the course. For example, deep phlegmon of the forearm in the Pirogov-Parona space is dangerous due to direct communication with the midpalmar space of the hand. In the neck, due to the rich network of lymphatic vessels and fascial clefts, pus spreads extremely rapidly. A rare form in the neck is "woody phlegmon" — a dense, mildly painful infiltrate with cyanotic skin that develops slowly and is accompanied by mild intoxication.

Symptoms and diagnosis

The clinical picture consists of general signs of intoxication and local changes.

General symptoms: fever ranging from low-grade to high, chills, loss of appetite, headache. Blood tests reveal leukocytosis, neutrophilia, a left shift in the differential white blood cell count, and an elevated ESR. In severe cases, purulent-resorptive fever and sepsis develop.

Local manifestations:

• Superficial phlegmons: the skin over the focus becomes red and glossy. A sharply painful, immobile, and hot-to-the-touch infiltrate without clear boundaries is palpated. As the tissues undergo lysis, the fluctuation sign appears.
• Deep (intermuscular) phlegmons: the volume of the affected limb increases visually and by measurement (with a tape measure). Any movement causes sharp pain, and a protective painful muscle contracture develops.

In doubtful cases, puncture of the infiltrate is of decisive importance for diagnosis and antibiotic selection.

Principles of treatment

Conservative therapy (bed rest, antibiotics, UHF therapy, regional novocaine blockades) is indicated exclusively in the initial stage (serous inflammation). If there is no clear improvement within 12–24 hours or the process progresses, emergency surgery is necessary.

Surgical treatment:

1. Opening (incision): layer-by-layer dissection of tissues under anesthesia in the area of greatest fluctuation, taking into account the topography of vessels and nerves.
2. Debridement (sanation): excision of necrotic tissue, washing the wound with hydrogen peroxide and antiseptics. Enzymatic necrolysis is possible.
3. Drainage: for adequate outflow of pus, muscle septa are bluntly opened. If a single incision is not enough, counter-incisions (additional incisions) are placed parallel to it.
4. Wound management: tubes for active or passive aspiration are installed, and treatment is continued according to the principles of purulent wound management.

Class and exam questions

What else to study on this topic

• Topography of the spread of purulent streaks in the upper and lower limbs
• Deep neck phlegmons and surgical approaches to them
• Features of the Pirogov-Parona space
• Necrotic and phlegmonous forms of the disease
• Pathogenesis of purulent-resorptive fever in phlegmons

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.