Drug Reactions Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is an idiosyncratic reaction?

What is an example of this?

A

Not explained by pharmacologic properties of the drug

Infectious mononucleosis and penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which population is at increased risk of developing drug-induced lupus in response to procainamide or hydralazine?

A

Slow acetylators of N-acetyltransferase

HLA DR4 haplotype + C4 null allele

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a Jarisch-Herxheimer phenomenon?

A

Presence of a fever, arthralgias and tender lymphadenopathy with transient macular or urticarial eruptions

Seen with treponema pallidum with initiation of treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List an example of a hypersensitivity reaction for each type

A
  • Acute (IgE mediated)
    • Urticaria
    • Angioedema
    • Anaphylaxis
  • Cytotoxic (IgG-mediated)
    • Blood transfusion reaction
  • Immune-complex mediated
    • HSP
    • Serum sickness
  • Delayed (cell-mediated)
    • Contacter dermatitis
    • Photoallergic reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the most common type of drug eruption?

What is the typical onset of symptoms?

A

Morbilliform drug eruption

Starts centrally and moves peripherally

Difficult to determine if drug or bug

1-2 weeks after exposure (1-3 days on reexposure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the most common drug culprits of the morbilliform eruption?

What is the recommended management?

A
  • Penicillins
  • Cephalosporins
  • Sulfonamides
  • Allopurinol
  • Anti-convulsants
  • NSAIDs

Management

  • ​Identify and discontinue the causative drug
  • Treat symptomatically
    • Potent topical steroids
    • Oil-based emollients with menthol
    • Emollient baths
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name this dermatological diagnosis

Where is it commonly located?

What is the common presentation?

A

Fixed drug eruption

Acral, lips, genitalia

Plaque with hyperpigmentation at the centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How should you approach a suspected drug reaction?

A

Complete a drug calendar (usually 4-28 days prior to exposure; up to 8wks for anticonvulsants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name this dermatologic diagnosis

A

Erythrodysasthesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name this dermatologic diagnosis

A

Monomorphous pustular eruption 2˚ steroid-induced acne

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

List 5 red flag features of a severe drug reaction

What investigations are recommended?

A
  • Fever, dyspnea, hypotension
  • Confluent erythema
  • Blisters
  • +Nikolsky sign
  • Mucous membrane involvement
  • Angioedema/Tongue swelling
  • Palpable purpura
  • Skin necrosis
  • Lymphadenopathy

Investigations

  • CBC
  • Renal function
  • Liver function
  • Antihistone antibodies (drug-induced SLE)
  • Anti-Ro/SS-A antibodies (drug-induced SCLE)
  • Urinalysis
  • Skin biopsy
  • Patch test - AGEP
  • Lymphocyte transformation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name this dermatologic diagnosis

What are the associated features?

A

Acute Generalized Exanthematous Pustulosis (AGEP)

  • Fever > 38.5˚C
  • Rapid evolution (over hours) of sterile, nonfollicular pustules on erythematous swollen skin with accentuation in body folds
  • Facial edema
  • Leukocytosis + neutrophilia
  • onset < 3 days after 1st dose of an antibiotic (slower onset with other drugs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name this dermatological diagnosis

What are the typical features?

A

Drug Rash with Eosinophilia and Systemic Symptoms (DRESS)

7 = typical DRESS

  • Maculopapular rash >3 weeks after drug initiation
  • Clinical symptoms continuing >2 weeks after stopping therapy
  • Fever > 38˚ C
  • Liver abnormalities (ALT >100 IU/L) or other organ involvement (kidney, muscle, lung, heart, pancreas)
  • Hematological abnormalities
    • Leukocytosis (>11)
    • Atypical lymphocytes
    • Eosinophilia (>700)
    • Thrombocytopenia
  • Lymphadenopathy
  • HHV-6 reactivaation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the initial sites of involvement for SJS/TEN?

When is maximal involvement?

What typically do patients experience before skin signs?

What is the mortality for SJS? TEN?

A

Upper torso, proximal limbs, face

Day 5-7

Malaise, fever, URTI symptoms with ocular inflammation

<10%; 30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the body surface area amounts for epidermal detachment:

SJS

SJS/TEN

TEN

A

<10%

10-30%

>30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of hypersensitivity reaction is SJS?

What is the key mediator?

What is the mechanism?

A

Type IV

Granulysin

Keratinocyte apoptosis due to drug-induced cytotoxic T lymphocytes

17
Q

List 3 SCARs (severe cutaneous adverse reactions)

List 3 predisposing factors for SCAR

A
  • AGEP
  • DRESS
  • SJS/TEN

Predisposing factors

  • Previous drug eruption
  • Strong FMHx of drug eruptions
  • Underlying viral infection (EBV, HHV6/7)
  • Immunocompromised (malignancy, HIV, cystic fibrosis, autoimmune disorders)
  • Multiple medications
18
Q

List 4 common medications for SJS/TEN

A
  • Allopurinol
  • Carbamazepine
  • Lamotrigine
  • Nevirapine
  • NSAIDs
  • Phenobarbital
  • Phenytoin
  • Sulfamethoxazole
  • Sulfasalazine
19
Q

What criteria are used to predict mortality in SJS/TEN (SCORTEN)?

A
  1. Age >40yo
  2. Presence of malignancy
  3. HR > 120bpm
  4. Epidermal detachment >10% BSA at admission
  5. Serum urea > 10
  6. Serum glucose > 14
  7. Bicarbonate < 20

Mortality

  • 0 - 1%
  1. 4%
  2. 12%
  3. 32%
  4. 62%
  5. 85%
  6. 95%
  7. 99%
20
Q

List 5 specialties that should be consulted to manage SJS/TEN

What supportive measures should be used?

A
  1. ICU
  2. Urology
  3. Dermatology
  4. Ophthalmology
  5. Skin-care nursing
  6. ENT
  7. Plastics
  8. Pain team - avoid NSAIDs

Supportive Measures

  • Early nutrition - NG feeds
  • PPI
  • LMWH
  • Recombinant human G-CSF if neutropenic
21
Q

What should HIV patients be screened for before starting abacavir?

Why?

A

HLA B701

Increased risk of SJSTEN