Limb Ulceration and Gangrene

Question 1

What is gangrene?

Answer 1

Death of tissue from poor vascular supply, a sign of critical ischaemia

Question 2

What is dry gangrene?

Answer 2

• Necrosis in absence of infection
• Linear demarcation between living + dead tissue

Question 3

What is the management of dry gangrene?

Answer 3

Restoration of blood supply +/- amputation

Question 4

What is wet gangrene?

Answer 4

Tissue death and infection

Question 5

What is the management of wet gangrene?

Answer 5

• Analgesia
• Broad spectrum antibiotics
• Surgical debridement +/- amputation

Question 6

What is gas gangrene and risk factors??

Answer 6

• Subset of necrotising fascitis
• Caused by spore-forming clostridial species
• Rapid onset of myonecrosis, muscle swelling, gas production, sepsis + severe pain
• RFs → DM, trauma, malignancy

Question 7

What is the management of gas gangrene?

Answer 7

• Remove dead tissue eg. amputation
• Benzylpenicillin +/- clindamycin
• Hyperbaric O₂ can reduce number of debridements

Question 8

What are features of necrotising fascitis?

Answer 8

• Rapid progressive infection of deep fascia causing necrosis of subcut tissue
• Usually by Group A B-haemolytic strep, but mostly polymicrobial
• Sx → intense pain of skin and underlying muscle

Question 9

What is the management of necrotising fascitis?

Answer 9

• Radical debridement +/- amputation
• IV Abx eg. benzylpenicillin + clindamycin

Question 10

What are differentials for shin lesions?

Answer 10

• Erythema nodosum → symmetrical, erythematous, tender, heal without scarring; caused by strep, sarcoidosis, IBD, drugs (pencillins, sulphonamiddes, OCP)
• Pretibial myxoedema → symmetrical, erythematous lesions, Graves’; shiny orange peel skil
• Pyoderma gangrenosum → initially small red papule, later deep red necrotic ulcers, violaceous border, 50% idiopathic, also seen in IBD, connective tissue disorders
• Necrobiosis lipoidica diabeticorum → shiny, painless areas of yellow/red skin on shin in diabetics, associated w/ telangiectasia

Question 11

What are features of pyoderma gangrenosum?

Answer 11

• Typically on lower limbs
• Initially → small red papule
• Later → deep red necrotic ulcers + violaceous border
• +/- fever & myalgia

Question 12

What are causes of pyoderma gangrenosum?

Answer 12

• Idiopathic (50%)
• IBD: UC + Crohn’s
• Rheumatoid arthritis, SLE
• Myeloproliferative disorders
• Lymphoma, myeloid leukaemias
• Primary biliary cirrhosis
• Monoclonal gammopathy (IgA)

Question 13

What is the management of pyoderma gangrenosum?

Answer 13

• Potential for rapid progression is high in most pts
• Most drs advocate oral steroids as first-line treatment
• Other immunosuppressive therapy, eg. ciclosporin + infliximab have a role in difficult cases