CASES DISCUSSIONCharles Skin Infection.pptx

SKIN INFECTION

1. Skin Infections

2. Anatomy of the Skin The skin is a complex organ encompassing the body’s surface and continuous with the mucous membrane. The skin is divided into three layers: Epidermis Dermis Hypodermis

3. Epidermis The epidermis consists of stratified epithelium that undergoes continuous regeneration.

4. Dermis The dermis is a compressible, elastic connective tissue that supports and protects the epidermis, dermal appendages, and neurovascular plexuses.

5. Hypodermis Fatty tissue is the deepest part of the skin, separating it from the underlying muscle fascia or the periosteum . It plays an important role in the thermoregulation, insulation, storage of energy, and protection from mechanical injuries.

6. Cellulitis Cellulitis is a superficial, spreading infection of the skin and subcutaneous tissue. The most common organism associated with cellulitis are Group A streptococci and S. aureus. Manifested by Erythema , warmth, tenderness, and edema .

7. Folliculitis Folliculitis is an infection of the hair follicle. The causative agent is Usually Staphylococcus, but gram-negative organisms may cause follicular inflammation as well.

8. Furuncles Furuncle (boil) begins as folliculitis , but may eventually progress to form fluctuant nodule.

9. Carbuncles Carbuncles are more involved, deep-seated infections that result in multiple draining cutaneous sinuses.

10. Necrotizing Soft-Tissue Infections Deep soft-tissue infections are classified as either necrotiing fasciitis or necrotizing myositis . Necrotizing Fasciitis represents a rapid, extensive infection of the fascia deep to the adipose tissue. Necrotizing Myositis primarily involves the muscles but typically spreads to adjacent soft tissues.

11. Risk factors for necrotizing soft tissue infection include. Diabetes Mellitus Malnutrition Obesity Chronic alcoholism Peripheral vascular disease Chronic lymphocytic leukemia Steroid use Renal failure Cirrhosis Autoimmune deficiency syndrome

12. Hidradenitis Suppurativa Hidradenitis Suppurativa is a defect of the terminal follicular epithelium. Treatment of acute infection includes application of warm compresses, antibiotics, and open drainage. In cases of chronic infection wide excission is required and closure may be achieve via skin graft or local flap placement.

13. Actinomycosis Actinomyosis si a granulomatous suppurative bacterial disease caused by Actinomyses . 40% to 60% of the actinomyotic infections occur within the face or the head.

14. Viral Infections of the Skin and Subcutaneous Tissue Warts are epidermal growth resulting from Human Papilloma Virus (HPV) infection. Verruca vulgaris – fingers, and toes, rough and bulbous. Verruca Plantaris – plantar warts, soles and palms may resemble a callus. Venereal warts ( condylomata acuminata ) – around the vulva, anus and scrotum.

15. Drugs

16. Beta-Lactams Antibiotics and other cell wall Synthesis Inhibitors Penicillins and Cephalosporins are the major antibiotics that inhibit bacterial wall synthesis. The beta-lactams include some of the most effective, widely used, and well tolerated agents available for the treatment of microbial infections Clinical use include infections caused by common streptococci, meningococci , gram-positive bacilli, and spirochetes Toxicity includes allergy to penicillin and Gastrointestinal disturbances ( nausea and diarrhea )

17. Sulfonamides , trimethoprim , flouroquinolones Sulfonamides and triethoprim are antimetabolites selectively toxic to microorganisms because they interefere with folic acid synthesis. Fluoroquinolones , which selectively inhibit microbial nucleic acid metabolism, also have a broad spectrum of antimicrobial activity that includes many common pathogens.

18. Flouroquinolones Are classified by generation, based on their antimicrobial spectrum of activity. First generation flouroquinolone derived from nalidixic acid, has activity against the common pathogens that cause UTI. Second-generation flouroquinolone have greater activity against gram-negative bacteria and are also against gonococcus, many gram-positive cocci, mycobacteria, and agents of atypical pneumonia. Third-generation flouroquinolones have a greater activity against gram-positive cocci and more commonly referred to as respiratory flouroquinolones

19. Flouroquinolones interfere with bacterial DNA synthesis by inhibiting topoisomerase II (DNA gyrase ), especially in gram-negative bacteria and topoisomerase IV, in gram-positive bacteria. They have been used widely for respiratory tract, skin and soft tissue infection. Examples are Ciprofloxacin , Ofloxacin , Norfloxacin , Levofloxacin , Moxifloxacin , Gemifloxacin

20. Sources Schwartz’s Principles of Surgery 9 th edition Schwartz’s Principles of Surgery 10 th edition Katzung and Trevor’s Pharmacology 10 th edition

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