Necrotising Fasciitis

Question 1

What is necrotising fasciitis (NF)?

Answer 1

A rare, life-threatening infection of deep soft tissue compartments (dermis, subcutaneous tissue, fascia, muscle)

NF is characterized by rapid progression and can lead to significant morbidity and mortality.

Question 2

How does necrotising fasciitis develop?

Answer 2

When organisms migrate from subcutaneous tissue along fascial planes

This process can involve a variety of infectious agents.

Question 3

Name two types of organisms associated with necrotising fasciitis.

Answer 3

• Group A streptococcus
• Gram-negative organisms (e.g. Vibrio spp, Aeromonas hydrophilia)

Gram-negative organisms are often linked to seawater contaminated wounds.

Question 4

What is the most common type of necrotising fasciitis?

Answer 4

Type 1

Type 1 is characterized by mixed anaerobes and aerobes and is often seen post-surgery in diabetics.

Question 5

What organism is specifically associated with Type 2 necrotising fasciitis?

Answer 5

Streptococcus pyogenes

Type 2 NF is typically associated with a more aggressive clinical course.

Question 6

List three risk factors for necrotising fasciitis.

Answer 6

• Skin injury (e.g. bites, trauma, wounds)
• Diabetes mellitus (especially if on SGLT2i)
• Impaired immunity (e.g. malignancy, immunosuppressed)

IV drug use is also a significant risk factor.

Question 7

What is the most common site for necrotising fasciitis?

Answer 7

Perineum

This condition in the perineum is referred to as Fournier’s gangrene.

Question 8

What are typical symptoms of necrotising fasciitis?

Answer 8

• Pain out of proportion to clinical findings
• Rapidly worsening cellulitis (skin discolouration, blistering)
• Fever, malaise

The severity of pain often exceeds the apparent clinical findings.

Question 9

What clinical examination findings are indicative of necrotising fasciitis?

Answer 9

• Local pain, swelling, erythema
• Poorly defined margins
• Crepitus on palpation
• Offensive discharge, ‘dishwater’ appearance
• Bullae

Systemic signs may include fever, hypotension, and tachycardia.

Question 10

What types of investigations are performed for necrotising fasciitis?

Answer 10

• Blood tests and cultures
• Microbiology - wound swabs, gram staining
• Imaging - CT if not delaying treatment
• Bedside finger test

The bedside finger test involves probing the tissue and assessing for specific findings.

Question 11

What are the findings during the bedside finger test for necrotising fasciitis?

Answer 11

• Absence of bleeding
• Purulent pus
• Lack of normal tissue resistance

These findings help confirm the diagnosis of necrotising fasciitis.

Question 12

What is the initial management approach for necrotising fasciitis?

Answer 12

ABCDE

This mnemonic refers to the initial assessment and management of acute conditions.

Question 13

What type of antibiotics is used for necrotising fasciitis?

Answer 13

Broad spectrum antibiotics

Early administration of appropriate antibiotics is crucial for managing the infection.

Question 14

What surgical intervention is often required in the management of necrotising fasciitis?

Answer 14

Debridement

Surgical intervention is essential to remove necrotic tissue and control the spread of infection.