Shock Syndromes II

Drugs are the most common cause of SJS and TEN and are implicated in more than 90% to 95% of

cases. More than 200 medications have been reported as causing SJS and TEN. The most common

agents implicated are sulfonamide antibiotics and aromatic anticonvulsants (phenytoin, phenobarbital,

and carbamazepine). Other agents/classes include:

Abacavir

Allopurinol

β-Lactam antibiotics

Nevirapine

NSAIDs, particularly the oxicams

Quinolones, particularly ciprofloxacin

Tetracyclines

rubella).

Exposure to industrial chemicals and fumigants

Infection with Mycoplasma pneumoniae can trigger SJS and TEN through a robust immune response

and molecular mimicry, leading to widespread skin and mucosal cell damage.

Primary clinical signs/symptoms associated with SJS and TEN are fever and malaise, followed by

cutaneous blisters and erosive mucosal lesions of the mouth, lips, eyes, and genital area. Distribution of

cutaneous lesions is predominantly central, with mucosal involvement of usually at least 2 sites. Lesions

consist of widespread, flat atypical targets or purpuric macules. TBSA is used to differentiate SJS from

TEN and to categorize the severity of cutaneous and mucosal involvement. TBSA is calculated by the

following:

Arms—9% each

Head and neck—9%

Legs—18% each

Trunk—Anterior 18%; posterior 18%

corroborated with clinical presentation. Early lesions have scattered necrotic keratinocytes in the

epidermis, whereas late-stage lesions have confluent full-thickness epidermal necrosis, which leads to

the formation of subepidermal bullae.

SCORTEN is a severity-of-illness system designed to predict mortality for TEN. It is computed

within the first 24 hours of presentation and on day 3 using the sum of 7 objective clinical variables

(each item present is worth 1 point):

Age older than 40 years

ii.

Pulse rate greater than 120 beats/min

iii.

Presence of cancer or hematologic malignancy

iv.

Epidermal detachment greater than 10% TBSA on day 1

Serum urea nitrogen greater than 28 mg/dL

vi.

Glucose greater than 252 mg/dL

vii.

HCO3 less than 20 mEq/L

Each of these parameters reflects the severity of the condition: Older age, high pulse rate, and

underlying malignancies compromise recovery potential; extensive skin loss increases the risk of

complications; and abnormalities in urea, HCO3, and glucose indicate organ stress and metabolic

disturbance, all of which correlate with increased mortality risk.