Stevens-Johnson Flashcards

1
Q

Name the disease: Target like lesions with less than 10% of the body affected, commonly triggered by herpes simplex virus or mycoplasma

A

Erythema Multiforme

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2
Q

What differentiates SJS from eryhtoderma and eryhtematous drug eruptions?

A

SJS has mucosal involvment, while eryhtoderma and drug eruptions do not

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3
Q

What is phototoxic eruption?

A

Reaction to recent sun exposure, drug induced

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4
Q

What are two important things about SJS?

A

They have sever mucocutaneous reactions

-triggered by medications (usually 4-8 weeks after starting)

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5
Q

What determines SJS, vs. SJS/TEN, vs TEN?

A

Body surface affected.

less than 10% is SJS

10-30% is SJS/TEN

greater than 30% is TEN

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6
Q

What is prevalence of SJS to TEN?

A

SJS to TEN is 3:1, with 2-7 cases per million people per year

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7
Q

What is prevelance in HIV pts?

A

HIV patients are at 100 fold increase of SJS or TEN

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8
Q

What is mortalits for SJS and TEN?

A

SJS is 10%

TEN is 30%

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9
Q

What is most common etiology of SJS/TEN?

A

almost 75% is drug related

  • happens 4-8 weeks after starting medication
  • common in allopurinol (treament of gout), anti-seizure (phenobarbital and carbamazepine)
  • antibacterial sulfonamides (like Bactrim)
  • lamotrigine
  • nevirapine
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10
Q

What are predisposing factors to SJS/TEN?

A
  • HIV
  • Genetics
  • Underlying imunnologic disease
  • medications
  • infections like mycoplasma penumonia
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11
Q

What are the genetics in SJS/TEN and what is important about them?

A

HLA-B*1501 and HLA-B*5801

  • must genetically test patients before starting anti-seizure medications
  • also more common in asians.
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12
Q

What are some genetic polymorphisms with SJS/TEN?

A

CYP2C19- coding for cytochrome p450, leads to reduced clearence of medications in the liver and increased risk of severe cutaneous reactions

IL-4 Receptor gene

Prostaglandin E receptor 3 gene

-using 2+ durgs with the same metabolic pathway will increase risk of SJS/TEN

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13
Q

What is the underlying pathogenesis is SJS/TEN?

A

killing of keratinocyts by massive apoptosis, usually through CTLs, Fas-FasL, and NK cells

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14
Q

What is Granzyme B?

A

A cytolytic protein secreted by CTLs and NK cells

  • induces apoptosis and a hihg level of ganzyme B is associated with disease
  • perforin creates hole for entry.
  • Granzyme B celaves Bid, recruits Bax and BAk, increases mitochondria permeability and release of cytochrome C
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15
Q

What is Granulysin?

A

Antimicrobial and cyottoxic chemical expressed by CTL and BK cells, causes the release of caspase 3 and keratinocyte death.

-found in blister fluid of lesions

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16
Q

Describe the histopathologic nature of thenecrosis found in SJS/TEN

A

Partial to full-thickness necrosis of the epidermis (keratinocytes)

17
Q

What is the term used to descrive the symptoms 1-3 days prior to the onset of skin lesions?

A

Prodrome.

18
Q

What is important about the cuatneous lesions of SJS/TEN?

A

They are tender to touch (painful), and start small and come togther with dark purple centers.

-start on face and torso and spread( spares the scalp, palsm, and soles)

19
Q

What is important about the mucosal lesions and urogenital things in SJS/TEN?

A

Mucosal lesions: 90% of cases, painful curstin lesions

Urogenital: Urethritis (scarring) - leads to urinary retention in 65% of cases

20
Q

What does this patient have?

A

Mucosal involvment with SJS/TEN, and infection

21
Q

Can patients with SJS/TEN have ocular lesions?

A

YES 80% do.

0can lead to cornealulceration and panophthalmtitis

22
Q

What will a CBC show in SJS/TEN?

A

It is not very helpful becuase it does not show the cause of the disease.

WIll see anemia, lymphoneia, neutropenia

23
Q

What is the clinical course of SJS/TEN?

A

8 to 12 days

  • fever
  • severe mucous membrane involvment
  • epidermal sloughing
24
Q

What are complications of SJS/TEN?

A

Hypovolemic shock and renal failure

infection, DIC

-may lead to fatality

25
Q

What is important about med hx relating to patient with SJS/TEN?

A

recent drug exposure or recent illness

  • within the last 4 to 8 weeks
  • recurrence of symptoms within 48 hours of restarting the offending medications (extremeley dangerous)
26
Q

What would be the direct IF results of a SJS/TEN pt?

A

Negative becasue no ab production involved in disease

27
Q

What test is used in diagnosis of SJS/TEN?

A

they will have positive nikolsky sign

-extension of the blister and or removal of epidermis in the rubbed area

28
Q

How do you treat SJS/TEN?

A

High dose steroids (to slow down process)

IVIg (protect against infections and mediate immune system)

  • cyclosporine (calcineurin inhibtor, stops NFAT)
  • anti-TNF monoclonal antibody
  • although all treatment remains controversial