General Surgery 6 Skin and subcutaneous tissue - Infections

  1. What is cellulitis?
    • It is spreading non suppurative inflammation of subcutaneous and fascial planes.
    • Commonly due to Streptococcus pyogenes and other Gram +ve organisms.
  2. What is erysipleas?
    • It is a spreading inflammation of the skin and subcutaneous tissues due to infection caused by Streptococcus pyogenes.
    • There will be always cutaneous lymphangitis with development of rose pink rash with cutaneous lymphatic oedema.
  3. What is Abscess?
    It is a localized collection of pus in a cavity lined by granulation tissue, covered by pyogenic membrane.
  4. What is furuncle?
    Furuncle or boil is an acute staphylococcal infection of a hair follicle with perifolliculitis which usually proceeds to suppuration and central necrosis. Often boil opens on its own and subsides (S. aureus infection).
  5. What is carbuncle?
    • It is an infective gangrene of skin and subcutaneous tissue.
    • Staphylococcus aureus is the main culprit.
    • Common site of occurrence is nape of the neck and back.
    • It is common in diabetics and after forty years of age.
  6. Describe Necrotising Fascitis. Mention its clinical features and explain its principles of management. [TU 2069] 

    Short note on NF. [TU 2065/5,73/7]

    What is Necrotising fascitis?
    • It is spreading inflammation and infective gangrene of the skin, deep fascia and soft tissues with extensive destruction, toxaemia commonly due to Streptococcus pyogenes infection, but often due to mixed infections like anaerobes, coliforms, gram-negative organisms.
    • Also called as flesh eating disease. 
    • It is the spreading infection of skin and subcutaneous tissue, easily spreading across the fascial planes within the subcutaneous tissue. 

    • Types -
    • Type I (Polymicrobial infection)—It is due to mixed infection.
    • Type II (Monomicrobial infection)—It is due to Streptococcus pyogenes, usually due to minor trauma like abrasions
    • Type III - Clostridium myonecrosis 

    • Clinical features 
    • - Pain and swelling
    • - Foul smelling discharge 
    • - Bullae, dish water like water, crepitus
    • - Features of toxemia 
    • - Finger test - 2 cm incision is made in skin deep to deep fascia, lack bleeding and discharge and dish water color fluid suggestive of NF
    • - Oliguria, SIRS, MODS 

    • Diagnosis 
    • - Laboratory Risk Indicator for Necrotiing fascitis score (LRINEC) - CRP, WBC, Hb, Serum sodium, serum creatine, plasma glucose. Score ≥ 6 = NF.  

    • Treatment - 
    • - Resuscitation 
    • - Antibiotics 
    • - Extensive debridement 
    • - Hyperbaric oxygen 
    • - Amputation may be necessary
  7. What is compartment syndrome. Describe the sites and management of this syndrome 65/5
    It is the increase in hydrostatic pressure in closed osteofascial space resulting in decreased perfusion of muscle and nerves within compartment.

    Pathophysiology - Increased compartment pressure - Increased venous pressure - decreased blood flow - decreased perfusion. 

    • Muscle Ischemia 
    • • 4 hours - reversible damage
    • • 8 hours - irreversible changes
    • • 4-8 hours - variable

    • Nerve ischemia 
    • • 1 hour - normal conduction
    • • 1- 4 hours - neuropraxic damage reversible
    • • 8 hours - axonotmesis and irreversible change

    • Clinical features 
    • - Pain on passive muscle stretching, pain disproportionate to that expected for the injury, progressive, not relieved by immobiliation 
    • - Established compartment syndrome - 6P 

    • Most common locations 
    • - In leg - deep posterior and anterior compartment 
    • - In forearm - volar compartment, especially in the deep flexor area 

    • Treatment 
    • - Remove restricting cast 
    • - Serial exams 
    • - When diagnosis made - Immediate fasciotomy
  8. Fasciotomy 72/6
    It is the clinical procedure indicated when the diagnosis of compartment syndrome is made. 

    • Indications 
    • - Compartment syndrome due to vascular injuries, soft tissue trauma and systemic hypotension in the patient with traumatized extremity. 
    • - Fracture 
    • - Physical compression 
    • - Burn
    • - Post operative hematoma 
    • - Tight fitting cast 

    • Principles of fasciotomy 
    • - Long incision 
    • - Release of all compartments 
    • - Preserve all neurovascular structures 
    • - Debride necrotic tissue 
    • - Coverage within 7-10 days

    • Technique 
    • A. Upper extremity 
    • - Volar incision is used to decompress the volar compartment.  A 'S' shaped incision is given. Distal landmark is distal extent of carpel tunnel. Proximal landmark is the ulnar side of elbow flexor crease. 
    • - Dorsal incision - Used to decompress dorsal compartment. It is a straight incision. Proximal landmark is 2cm distal to lateral epicondyle, distal landmark is middle of wrist. 
    • Image Upload 1

    • B. Lower extremity 
    • 1. Thigh fasciotomy - Lateral incisions to decompress anterior and posterior compartment. Medial incision to release medial compartment. 
    • 2. Leg fasciotomy 
    • - Double incision - four compartment fasciotomy 
    • - Anterolateral fasciotomy - lateral skin incision given 1 finger breath anterior to edge of fibula
    • - Posterior compartment fasciotomy - posterior medial incision is given 1 finger breath posterior to medial edge of tibia. 
    • Image Upload 2

    • Complications of fasciotomy 
    • - Metabolic complications - reperfusion injury 
    • - Wound complications 
    • - Technical complications - incomplete fasciotomy, neurovascular injuries, vascular insufficiency, limb loss 
  9. Short note on Crush syndrome. [TU 2072/2]
    It is due to crushing of muscles causing extravasation of blood and release of myohaemoglobin into the circulation leading to acute tubular necrosis and acute renal failure.

    Initially tension increases in the muscle compartment commonly in the limb, which itself impedes the circulation and increases the ischaemic damage. In 3 days, urine becomes discoloured and scanty, patient becomes restless, apathy and delirious with onset of uraemia. Crush syndrome is often life threatening. Injury is much worser than initial look.

    • Effects of crush syndrome
    • • Renal failure
    • • Toxaemia
    • • Septicaemia
    • • Disability with extensive tissue loss
    • • Gas gangrene

    • Treatment 
    • - Fasciotomy 
    • - Renal protection
Card Set
General Surgery 6 Skin and subcutaneous tissue - Infections
Cellulitis, Skin infections