Cellulitis and Soft Tissue Infections Quiz

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Questions and Answers

What is the most common site for cellulitis to occur?

Face and lower legs (correct)

Arms and hands

Chest and abdomen

Back and shoulders

Which of the following is NOT a predisposing factor for cellulitis?

Dry skin

Insect bites

High blood pressure (correct)

Surgical wounds

Which treatment is often prescribed in addition to antibiotics for cellulitis?

Radiation therapy

Chemotherapy

Immune suppression

Pain relief (correct)

What condition can resemble cellulitis and requires leg ultrasound for investigation?

Deep vein thrombosis Signup and view all the answers

Which of the following types of bacteria is most commonly involved in the development of cellulitis?

Group A streptococci Signup and view all the answers

Which of the following best describes erysipelas?

An acute streptococcal infection with well-defined edges Signup and view all the answers

What is the significance of pain relief in the treatment of cellulitis?

It can mask symptoms of necrotising fasciitis. Signup and view all the answers

Which of the following could increase a person's risk of developing cellulitis?

Obesity Signup and view all the answers

What is the primary reason for administering high doses of intravenous antibiotics in necrotizing infections?

To quickly achieve bactericidal concentrations in the affected tissue Signup and view all the answers

Which combination of antibiotics would be appropriate for a patient with a penicillin allergy suffering from a necrotizing infection?

Clindamycin and ciprofloxacin Signup and view all the answers

In the prognosis of necrotizing soft tissue infections, which group category indicates the highest mortality risk based on admission variables?

Group 3 (6 points) Signup and view all the answers

Which of the following factors does NOT contribute to the scoring for mortality risk according to the admission variables?

Presence of lactic acidosis Signup and view all the answers

When considering empirical therapy for necrotizing infections, which antibiotic should always accompany a broad-spectrum beta-lactam?

An antibiotic active against anaerobes Signup and view all the answers

What is a characteristic feature that differentiates erysipelas from cellulitis?

Erysipelas typically presents with a raised, red rash. Signup and view all the answers

What type of infection is caused by the synergistic action of streptococci and staphylococci?

Synergistic gangrene Signup and view all the answers

Which statement is true regarding the treatment of synergistic gangrene?

Radical excision of the ulcerated lesion is often necessary. Signup and view all the answers

What is a common clinical finding associated with gas gangrene?

Presence of black necrotic tissue Signup and view all the answers

What is one of the key characteristic symptoms of gas gangrene?

Purplish-black affected area Signup and view all the answers

What is a critical factor that can increase the mortality rate of gas gangrene?

Delay in diagnosis Signup and view all the answers

Which preventive measure is critical after the resolution of an initial infection?

Use of prophylactic antibiotics Signup and view all the answers

Which of the following describes gas gangrene's bacterial involvement?

It is caused by anaerobic infection of muscle. Signup and view all the answers

What typical areas of the body are most commonly affected by erysipelas?

The face, arms, fingers, legs, and toes Signup and view all the answers

Which of the following organisms is primarily responsible for most cases of erysipelas?

Streptococcus pyogenes Signup and view all the answers

What is a distinguishing feature of erysipelas compared to cellulitis?

It has a sharply demarcated raised edge Signup and view all the answers

Which symptom is considered a constitutional symptom of erysipelas?

High fevers and shaking chills Signup and view all the answers

What is a common complication of untreated erysipelas?

Bacteremia leading to septic shock Signup and view all the answers

Which antibiotic is generally preferred for treating erysipelas?

Penicillin Signup and view all the answers

What occurs approximately 10 days after the onset of erysipelas?

Elevation of antistreptolysin O titers Signup and view all the answers

What may happen if erysipelas recurs after antibiotic treatment?

Increase in chronic swelling (lymphedema) Signup and view all the answers

What is the main reason for the immediate removal of muscle groups in gas gangrene?

If remaining viable muscles are insufficient for useful function Signup and view all the answers

What is the typical mortality rate for untreated gas gangrene?

Always fatal Signup and view all the answers

Which of the following is a common symptom of necrotizing fasciitis?

Intense pain at the site of infection Signup and view all the answers

What treatment is typically required after excision of the affected area in necrotizing fasciitis?

Skin grafting Signup and view all the answers

What agents are primarily responsible for necrotizing fasciitis?

Hemolytic streptococci and staphylococci Signup and view all the answers

What can hyperbaric oxygen treatments potentially reduce in cases of gas gangrene?

The need for debridement Signup and view all the answers

How quickly can symptoms of necrotizing fasciitis manifest after infection occurs?

Within hours to six days Signup and view all the answers

What is a characteristic feature of the tissue destruction caused by necrotizing fasciitis?

Bacteria release toxins leading to tissue dissolution. Signup and view all the answers

Study Notes

Skin and Soft-Tissue Infections

Cellulitis is a diffuse inflammation of connective tissue (dermal and subcutaneous layers)
Commonly affects skin on the face or lower legs
Caused by normal skin flora or exogenous bacteria (e.g., Group A streptococci)
Bacteria easily breach defensive barriers due to toxins
Lymphatic system is involved

Predisposing Factors

Cracks in skin (dry skin, eczema, tattoos)
Cuts and blisters
Burns
Insect bites
Animal bites
Surgical wounds
Intravenous catheter insertion sites
Injecting drug use
Pregnancy, diabetes, obesity, chronic venous insufficiency, and varicose veins (affect circulation)
Breaks in the skin do not need to be visible

Diagnosis

Often a clinical diagnosis
Local cultures may not identify the causative organism
Blood cultures are positive only if generalized sepsis develops
Conditions that mimic cellulitis include deep vein thrombosis, stasis dermatitis, and Lyme disease

Treatment

Rest the affected limb/area
Clean the wound (with debridement of dead tissue if needed)
Oral antibiotics, but in severe cases, IV antibiotics are used
Example antibiotics: Flucloxacillin, benzylpenicillin, ampicillin/amoxicillin
Pain relief is important, but excessive pain may indicate necrotizing fasciitis (requires emergency surgery)
Hyperbaric oxygen therapy can be helpful but not widely available

Erysipelas

An acute streptococcal infection of the superficial dermis (upper subcutaneous dermis)
Results in inflammation
Has a well-defined edge
Often coexists with cellulitis, making differentiation difficult
Commonly affects the face, arms, fingers, legs, and toes.
Older people, infants, children are at increased risk
Risk factors include compromised immune systems, diabetes, alcoholism, skin ulceration, fungal infections, impaired lymphatic drainage (e.g., after mastectomy, pelvic surgery).

Signs and Symptoms Erysipelas

Constitutional symptoms (high fevers, chills, fatigue, headaches, vomiting)
Rapidly enlarging, erythematous (red) skin lesion
Sharply demarcated, raised edge
Warm, hardened, painful rash
Rash similar in consistency to an orange peel
More severe cases may result in vesicles, bullae, and petechiae, with possible skin necrosis
Lymph nodes may be swollen or lymphedema may occur
Fat tissue is particularly susceptible to infection

Etiology Erysipelas

Most cases are due to Streptococcus pyogenes (beta-hemolytic group A streptococci)

Diagnosis Erysipelas

Appearance of well-demarcated rash and inflammation
Blood cultures are unreliable
Distinguished from cellulitis by raised advancing edges and sharp borders
Elevation of antistreptolysin O titre around 10 days after illness

Complications

Spread to other body areas (bacteremia), including septic arthritis and infective endocarditis (heart valves)
Septic shock
Recurrence (18-30% even after antibiotic treatment)
Lymphatic damage
Necrotizing fasciitis (a potentially deadly exacerbation)
Death

Treatment (Erysipelas)

Oral or preferably intravenous antibiotics
- Penicillin
- Clindamycin
- Erythromycin
- Cephalosporins
Symptoms usually resolve in a day or two; skin may take weeks to return to normal

Prevention

Clean and appropriately dress wounds
Change bandages daily
Remove retained foreign bodies

Necrotizing Infections

Synergistic gangrene: Chronic, progressive bacterial gangrene caused by the synergistic action of streptococci and staphylococci
- Incubation period: 7-14 days
- Cellulitis progression with gangrenous ulceration
- Treatment: Radical excision of the ulcerated lesion and large systemic doses of penicillin
Gas gangrene: Anaerobic infection of muscle by Clostridium perfringens, producing toxins that destroy tissue and blood cells
- Disrupts and fragments normal muscle ,causes hemorrhage and edema, progresses to a purplish black
- Fluid discharge is commonly present and is brownish and malodorous
- Often affected areas initially are mottled (ecchymotic) and progress to blackening, and sloughing
- Diagnosis based on typical clinical findings in wound fluid, presence of large Gram-positive rods
- Delays in diagnosis, greatly increase the mortality
- Immediate removal of involved muscle groups may be necessary, with potential amputation
- High intravenous doses of penicillin and whole blood, possibly multiple hyperbaric oxygen treatments.
Necrotizing fasciitis: Serious mixed infection of hemolytic streptococci/staphylococci and peptostreptococci, producing toxins that destroy connective tissue
- Characterized by intense pain, rapid swelling, discoloration, blisters, necrosis, diarrhea, vomiting, high fever.
- Infection originates at operative wounds, lacerations, abrasions, or punctures.
- It may be immediately fulminant or dormant for several days before rapidly spreading
Aggressive surgical debridement and large intravenous doses antibiotics (including penicillin, vancomycin, and clindamycin)
- Possible amputation, intensive treatment, high fatality rate untreated.

Management of Necrotizing Infections

IV antibiotics in high doses, to quickly reach bactericidal concentrations.
Empirical therapy must comprehensively cover all possible pathogens (aerobes and anaerobes) and must be supplementary to surgical procedures.

Empirical therapy

Broad-spectrum penicillin (amoxicillin) + metronidazole + aminoglycoside (gentamicin)
Second-generation cephalosporin (cefuroxime) + metronidazole
Penicillin allergy: clindamycin + quinolone (e.g., ciprofloxacin)
Immunocompromised patients, require quinolones for possible Pseudomonas infections.

Prognosis (Mortality) - Necrotizing Soft Tissue Infections

Clinical score on admission can predict mortality.
High heart rate, low body temperature, high creatinine, advancing age, high white blood cell count, and high hematocrit are all risk factors.

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Description

Test your knowledge on cellulitis and related soft tissue infections with this quiz. Explore essential questions about causes, treatments, and characteristics, including the comparison with conditions that resemble cellulitis. Ideal for medical students and healthcare professionals alike.