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OSCE 446: Widespread Skin Loss

Introduction

A 29 year-old girl is admitted to the intensive care unit. Following a recent course of antibiotics for a urinary tract infection she developed blistering around the mouth that rapidly developed with widespread blistering and sloughing across the trunk and limbs…

Question No. 2

Q: What do you consider the most likely diagnosis? (1 marks)

Answer No. 2

Given the mucosal lesions and the large body surface area involved the most likely diagnosis is Toxic Epidermal Necrolysis 1

1

Question No. 3

Q: What is the difference between SJS and TEN? (2 marks)

Answer No. 3

  • SJS and TEN are variants of the same disease spectrum but distinguished chiefly by severity
  • SJS is the less severe form, affecting <10% total body surface area (TBSA) 1
  • TEN is more severe and affects >30% TBSA 1
  • Cases that affect 10–30% are referred to as SJS/TEN overlap

2

Question No. 4

Q: Give 4 functions of skin relevant to critical illness? (4 marks)

Answer No. 4

Protection
  • Barrier function of stratum corneum protects against environmental, chemical, and microbial hazards 1
  • Limitation of inward and outward passage of water and electrolytes ensures the conservation of the internal milieu 1
  • vDurability and elasticity of dermis contributes to protection against physical injury 1
  • Melanin production protects against ultra-violet radiation
Regulation
  • Temperature homeostasis is maintained by alteration of skin blood flow, sweating, and pilo-erection 1
  • Minor role in maintaining fluid balance by avoiding excessive evaporative water loss that would otherwise cause dehydration and cooling
Immune
  • Dynamic role in innate and acquired defense systems 1
Metabolic
  • Role in Vitamin D synthesis 1
  • Capability in transformation of some drugs 1
Neurosensory
  • Terminal fibres of sensory nerves and specialized sensory receptors lying within the dermis enable skin to act as a large sensory organ 1
Social
  • Visible portion of body covering

4

Question No. 5

Q: What are the common causes of SJS / TEN? (4 marks)

Answer No. 5

  • Drugs (Most common, 4-28 days after initiation) 1
    • Allopurinol
    • Anticonvulsants
    • Cotrimoxazole
    • 'Sulfa' drugs
    • Oxicam NSAIDs
    • Nevirapine
  • Infections 1:
    • HIV
    • CMV
    • Mycoplasma
  • Malignancy 1
  • Bone marrow transplant 1
  • Genetic predisposition

4

Question No. 6

Q: What are the non-cutaneous (or mucocutaneous) manifestations of SJS / TEN? (4 marks)

Answer No. 6

Skin

Initial Phase:

  • Erythematous, dusky red, flat macules
  • Lesions symmetrically distributed on face, trunk and limbs

Late Phase:

  • Lesion coalesce to form flaccid blisters
  • Epidermal detachment
Mucous Membranes
  • Eyelid oedema, redness and discharge
  • Buccal erosive haemorrhagic lesions, white pseudomembranous crust
  • Crust on lips
  • Genital erosive haemorrhagic lesions, painful urination
Extracutaneous Sites
  • Respiratory Tract: Respiratory distress 1
  • GI Tract: Nausea 1, diarrhoea 1, malabsorption 1, colonic perforation 1
  • Renal Tract: Proteinuria 1, haematuria 1

4

Question No. 7

Q: Which scoring system is recognised for determining severity and prognosis in SJS / TEN? (1 marks)

Answer No. 7

  • The SCORTEN score1 is a validated scoring system to predict mortality

1

Question No. 8

Q: Name 4 components of the Scorten system? (2 marks)

Answer No. 8

  • This should be scored within 24 hours of admission.

    • Age >40 0.5

    • Malignancy 0.5

    • Initial area greater >10% 0.5

    • Heart rate >120 0.5

    • Serum urea >10 0.5

    • Serum glucose >14 0.5

    • Serum bicarbonate <20 0.5

    Max 2

Score
Predicted Mortality (%)
0-1
3.2
2
12.1
3
35.3
4
58.3
5 or more
90

2

Question No. 9

Q: When would you suggest surgical skin debridement in SJS / TEN? (2 marks)

Answer No. 9

  • Surgical debridement may be indicated, particularly if:
    • Local sepsis / subepidermal pus1
    • Extensive epidermal detachment1

2

Review:

Total Score: /13

Total Time: