Carbuncle

Etiology and pathogenesis

The development of the disease is most often triggered by Staphylococcus aureus. Streptococcus is isolated somewhat less frequently, and mixed staphylococcal-streptococcal infection is sometimes diagnosed. A single pathogen is not enough for an extensive pathological process to occur. Predisposing factors are practically always present: weakened general resistance against the background of other diseases, hypovitaminosis and avitaminosis, as well as general exhaustion. Severe metabolic disorders play a special role, among which diabetes mellitus comes first.

Typical localization of the lesion is skin areas abundantly supplied with hair follicles and sebaceous glands: the back of the neck, occiput, back, lower back, as well as the upper and lower lip.

The morphological essence of a carbuncle lies in the formation of massive necrosis due to vascular disorders. The disease goes through several consecutive stages:

1. Appearance of an inflammatory infiltrate that immediately covers several neighboring hair follicles and sebaceous glands.
2. Development of local blood vessel thrombosis, leading to a sharp disruption of microcirculation.
3. Formation of necrosis of the skin, subcutaneous adipose tissue, and in advanced cases, deeper tissues.
4. Purulent melting of the dead structures.
5. Outflow of pus through the mouths of the affected hair follicles.
6. Spontaneous rejection of dead necrotic masses, after which a purulent wound with a deep tissue defect is formed.
7. Gradual healing of the wound by secondary intention.

Clinical manifestations and diagnostics

Subjectively, patients complain of severe pain at the inflammation site. The disease is always accompanied by a pronounced general intoxication syndrome: chills, malaise, general breakdown, loss of appetite, elevated body temperature, and severe headache occur. When collecting the anamnesis, the doctor should purposefully check for signs of exhaustion, avitaminosis, and, first of all, diabetes mellitus.

During an objective examination (Status localis), a massive bluish-purple swelling is determined, which noticeably rises above the surface of healthy skin. In the initial stages, several separate infiltrates can be palpated, but they merge together extremely quickly. The skin over the abscess is glossy and tense. The color of the inflammation is uneven: intensely bluish-purple in the very center, gradually paling toward the periphery. Purulent-necrotic pustules form on the surface, merging in the center into a single zone of necrosis.

The key diagnostic criterion of a formed carbuncle is the "sieve" sign. The thinned necrotic area of the skin breaks through in several places at once. As a result, multiple openings form, from which purulent exudate is released.

Palpation reveals a dense infiltrate accompanied by sharp tenderness. Pronounced soft tissue edema spreads around it. A reaction from the lymphatic system is observed in the form of regional lymphadenitis (lymph nodes are enlarged and painful), less commonly accompanied by lymphangitis.

Dynamics, complications, and adverse course

If the necrotic tissue is rejected spontaneously, an extensive cavity forms in its place. The bottom of such a cavity is covered with gray-green necrotic tissues, and an abundant amount of pus is discharged from it.

Progression of the purulent-necrotic process is extremely dangerous. The following alarming symptoms indicate the possible development of phlegmon or generalization of the infection (sepsis):

• Rapid increase in the area of surrounding tissue edema.
• Progressive spread of the necrosis zone.
• Sharp increase in systemic intoxication phenomena (tachycardia, increased headache, severe weakness).
• Occurrence of shaking chills, replaced by drenching sweats.
• Addition of secondary vascular and lymphatic complications: thrombophlebitis, lymphangitis, and lymphadenitis.

Carbuncles located on the face pose a particular threat. In this case, due to the anatomical features of the venous bed, there is a high risk of thrombosis of the facial veins, through which the infection can penetrate into the dural venous sinuses, causing severe purulent meningitis.

Principles of surgical treatment and prognosis

With timely consultation with a surgeon and adequately initiated treatment, the prognosis for life and health is considered favorable. The probability of a poor outcome increases significantly in severely depleted patients, in patients with decompensated forms of diabetes mellitus, and when the abscess is located on the face.

The basis of treatment for a formed carbuncle is surgery. Surgical tactics consist of radical dissection of the abscess (as a rule, a classic cruciate incision is used, capturing healthy tissues) followed by mandatory excision of all necrotic tissues. This allows stopping local thrombosis, reducing intoxication, and moving the purulent-necrotic process into the stage of healing by secondary intention.

Class and exam questions

What else to study on this topic

• Peculiarities of the cruciate incision technique and necrectomy in surgical treatment
• Management of a purulent wound after radical excision of necrotic masses
• Principles of conservative therapy (antibiotics, detoxification) at the infiltrate stage
• Differential diagnosis with anthrax carbuncle
• Features of the microflora of purulent foci in patients with decompensated diabetes mellitus

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.