Imaging features of cellulitis

The article was written by MSc Tong Diu Huong - Radiologist, Department of Diagnostic Imaging - Vinmec Nha Trang International General Hospital

Cellulitis is an acute infection of the dermis and subcutaneous tissues, also known as the hypodermis. It leads to pain, redness, edema, and heat. Because it does not involve the epidermis (epidermis), cellulitis is not transmitted by person-to-person contact.

Hình 1. Hình giải phẫu cấu tạo của da người

1. Epidemiology of cellulitis

Predisposing risk factors for cellulitis include:
Peripheral vascular disease Diabetes Intravenous drug use

2. Clinical manifestations

Cellulitis can affect any area of the body and usually affects the lower extremities.
Clinical manifestations include erythema without obvious contours, elevated skin temperature, swelling of the affected area, regional lymphadenopathy, and lymphadenitis.
In addition, systemic signs such as fever and chills may also be present.

3. Complications of cellulitis

If the infection spreads to deeper tissue, complications can occur, such as soft tissue abscess, infectious myositis, necrotizing fasciitis, or osteomyelitis (osteomyelitis).
Sometimes sepsis is possible.
Particular attention should be paid to geriatric patients in whom cellulitis of the lower extremities is more likely to develop into thrombophlebitis.

4. Pathology

Cellulitis occurs after the skin breaks down and microorganisms enter the subcutaneous tissue layer. Such microorganisms are usually bacteria normally present in the skin, such as staphylococcus aureus (Staphylococcus aureus), or others.
Patients with peripheral vascular disease or diabetes are particularly susceptible to cellulitis because small cuts in the skin or cracked skin on the feet or toes can be entry points for germs.

5. Imaging features of cellulitis

5.1. Ultrasonography Ultrasound is usually the first exploratory method of evaluation when clinical examination of cellulitis is suspected.
Normally subcutaneous tissue has a hypoechoic appearance with few hyperechoic fibers (the image of connective fibers). Above the subcutaneous tissue, there is a thin, relatively hyperechoic, epidermal-epidermal layer. The fascia is located deep beneath the subcutaneous tissue.

Hình 3: Các lớp của da trên hình ảnh siêu âm

Ultrasound signs of cellulitis include: thickened epidermal layer, abnormal echogenicity, hyperechoic subcutaneous tissue, and unclear boundary between epidermal and subcutaneous tissue. It is often useful to compare adjacent or contralateral normal areas.
Gradual accumulation of edema in the subcutaneous tissue results in the appearance of ramified, anechoic bands that give rise to lobes or "cobble-stones".
This image can also be seen in other edematous states. Presence of thickened skin and abnormal echoes above would favor cellulitis rather than edema. Bands of negative empty lines due to deep internal fluid. subcutaneous tissue indicates lymphedema.

Hình4: a: hình ảnh da bình thường. b: phù nề mô dưới da. c: viêm mô tế bào

Hình 5: Hình ảnh "đá cuội"(cobble-stone)

5.2. CT Scanner CT Scan is used to accurately differentiate between superficial cellulitis and deep cellulitis.
In uncomplicated cellulitis, CT shows thickened skin, septa in the subcutaneous fat layer, and thickened underlying superficial fascia. If the infection spreads to deeper tissues, soft tissue abscesses, infective myositis, necrotizing fasciitis, and osteomyelitis can all be detected by CT.

Hình 6: Viêm mô tế bào thành bụng sau hút mỡ mười ngày trước, biểu hiện sốt, sưng và đau thành bụng.

6. Treatment and prognosis

Uncomplicated cellulitis is usually treated conservatively with antibiotics and local supportive measures.

7. Differential diagnosis

The clinical differential diagnoses include:
Erysipelas, Deep vein thrombosis, Erythema non-infectious, Vinmec International General Hospital is one of the hospitals that not only ensures professional quality. with a team of leading medical doctors, a system of modern equipment and technology. The hospital provides comprehensive and professional medical examination, consultation and treatment services, with a civilized, polite, safe and sterile medical examination and treatment space.

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Bài viết này được viết cho người đọc tại Sài Gòn, Hà Nội, Hồ Chí Minh, Phú Quốc, Nha Trang, Hạ Long, Hải Phòng, Đà Nẵng.