SJS/TEN

Question 1

Difference between SJS and TEN?

Answer 1

SJS < 10% BSA detached
TEN > 30% BSA detached

Question 2

Characteristics of SJS/TEN

Answer 2

Widespread, blistering and sloughing of skin

Question 3

Progression of SJS/TEN?

Answer 3

5-7 days of acute progressive phase -> disease arrest -> skin re-epithelises over 7-21 days

Question 4

What is pt at risk of due to extensive skin detachment during acute progressive phase?

Answer 4

• Fluid & electrolyte imbalances
• Increase metabolic demands
• Sepsis
• Hypothermia
• Organ decompensation
• Death

Question 5

Which parts of the body are involved in SJS/TEN?

Answer 5

Everywhere, starting from face (buccal, oro/nasopharyngeal) & thorax -> spread to anogenital, lungs, liver etc

Question 6

Prodromal symptoms of SJS/TEN?

Answer 6

Fever, malaise, myalgia, sore throat, conjunctivitis

Question 7

What can cause SJS/TEN?

Answer 7

Medications, infection (HIV, viral infx in kids)

Question 8

What are common drugs causing SJS/TEN?

Answer 8

• allopurinol (HLA-B*58:01)
• carbamazepine (HLA-B*15:02), oxcarbazepine, fosphenytoin, lamotrigine, phenobarbital, phenytoin
• NSAIDs (oxicam: meloxicam, piroxicam, tenoxicam)
• sulfur related: sulfasalazine, co-trimoxazole, sulfamethoxazole
• cancer drugs: pemetrexed, EGFR inhibitors (-tinib), immune therapy (-mab)

Question 9

What do the ASMs that cause SJS/TEN have in common? Why does it cause SJS/TEN?

Answer 9

Aromatic ring -> form arene-oxide intermediate -> become immunogenic thru interactions with proteins / cellular macromolecules

Question 10

Pathogenesis of SJS/TEN?

Answer 10

• delayed type IV hypersensitivity reaction (by 1-3w)
• immune response to antigenic complex formed by reaction of drug metabolites with certain host tissues
• apoptosis of epithelial keratinocytes triggered by drug-induced cytotoxic T cells
• pro-apoptotic proteins & molecules

Question 11

Pharmacotherapy for SJS/TEN?

Answer 11

• corticosteroids (prednisolone, dexamethasone, methylprednisolone)
• cyclosporine
• IVIG
• TNF inhibitors
  (insufficient evidence)

Question 12

What kind of env should pts with SJS/TEN heal in?

Answer 12

Room controlled for humidity, pressure-relieving mattress, 25-28C temp

Question 13

Should the causative medication be stopped?

Answer 13

Yes, immediately

Question 14

What kind of supportive care should be provided for the patient?

Answer 14

• fluid & electrolyte management (due to increased water loss and decreased oral intake cos of mucosal involvement)
• nutritional support: 20-25 kcal/kg/day (early catabolic phase), 25-30 kcal/kg/day (recovery phase)
• temperature management
• pain control: analgesics, opioids
• infx prevention & management
• ocular care: lubricating ointment, topical abx (broad spectrum), topical steroid drops
• mouth care: WSP to lips, mucoprotectant mouthwash, benzydamine mouth spray for pain
• organ support (CI: noninvasive ventilation)
• wound care: warm sterile water, saline or antimicrobial to irrigate & cleanse skin, WSP etc