Agents to Manipulate Immune Response pt 2

what is an anaphylactoid reaction?

An immediate systemic reaction that mimics anaphylaxis but is NOT IgE mediated

what causes anaphylactoid reaction?

a trigger such as a medication that directly trigger the release of mediators from mast cells and basophils

does an anaphylactoid reaction require a previous exposure?

NO

what are some examples of anaphylactoid reactions?

- Radiocontrast sensitivity reactions

- Vancomycin related infusion syndrome

- Opiates & ACE-I

what can you pre-medicate with for radiocontrast sensitivity reactions?

diphenhydramine & prednisone

what can you pre-medicate with for Vancomycin related infusion syndrome?

diphenhydramine

what is another (old) term for Vancomycin related infusion syndrome?

Red Man Syndrome

what is usually related to Vancomycin related infusion syndrome?

the RATE of the infusion

what anaphylactoid reaction can occur with ACE-I?

angioedema, due to increasing the levels of bradykinin, a chemical that causes blood vessels to leak and leads to swelling of tissues in the face, tongue, and airways

what is included in the management of insect stings?

- Remove stinging apparatus

- Ice or cold compress for local reactions

- Antihistamines and analgesics

- Oral corticosteroids

- Epinephrine for severely allergic

when should oral corticosteroids be given with insect stings for benefit?

within a couple hours of the sting

what are the types of adverse drug reactions?

- predictable

- unpredictable

- genetic

what is a predictable ADR related to?

drug action

what are some examples of drugs with predictable ADRs?

- miralax -> diarrhea

- benadryl -> drowsy

what is an unpredictable ADR related to?

the patient's immune system

what is a genetic ADR related to?

variability in drug sensitivity, such as genetic polymorphisms (ex CYP)

what is the true incidence of drug hypersensitivity?

5-10%

what is it important to understand to determine cause and treatment?

reaction type

what are the available treatments for mild-moderate Type I, II, III drug hypersensitivity?

- Antihistamines (for itching, hives)

- bronchodilator

- corticosteroids

what are the available treatments for severe Type I, II, III drug hypersensitivity?

- Systemic corticosteroids (IV or PO)

- plasmapheresis (separates and cleans out blood)

- transfusions

what should be considered when treating mild-moderate and severe Type I, II, III?

the symptoms

what is the treatment for Type III drug hypersensitivity?

NSAIDs

what pain can often be associated with Type III drug hypersensitivity?

musculoskeletal pain (joint pain, serum sickness)

what is the treatment for Type IV drug hypersensitivity?

- corticosteroids

- antihistamines

what kind of response is Type IV drug hypersensitivity?

cell mediated

what can be done to prevent drug hypersensitivity?

1. Discontinue offending agent

2. Immunotherapy

3. Desensitization

what is an example of when immunotherapy could be used to decrease drug hypersensitivity?

if a patient is diabetic and requires insulin but are hypersensitive, you can give them immunotherapy to tolerate insulin

what is an example of when densensitization could be used to decrease drug hypersensitivity?

- allergy shots

- pregnant patient with neurosyphilis and PCN allergy, give escalating doses of PCN over 12-24 hours until full amount is reached

what are common foods people are hypersensitive to?

crustaceans (shellfish), tree nuts, peanuts, fish

what is the best treatment for food hypersensitivity?

avoidance

what is some supportive therapy for food hypersensitivty?

- anti-emetic

- anti-diarrheals

- antihistamines

what causes urticaria and angioedema?

not specific to any allergen and are immunologically mediated

what is the common pathway of urticaria and angioedema?

potent inflammatory mediators released from mast cells

what is the general treatment for urticaria and angioedema?

treated by an allergy/ immunology specialist

what is hereditary angioedema?

rare autosomal dominant disorder with mutations that lead to the dysfunction of C1 esterase inhibitor (C1 INH), a protein that prevents the activation of inflammatory mediators

what does C1 esterase inhibitor (C1 INH) usually inhibit?

key proteases in the complement, coagulation, and contact systems such as plasma kallikrein, Factor XIIa, and the complement proteases C1s and C1r

what does the overactive proteases lead to with hereditary angioedema?

uncontrolled generation of bradykinin, a substance that causes blood vessel dilation and fluid leakage

what is the treatment for hereditary angioedema?

medications that inhibit bradykinins

what is the first-line treatment of urticaria and angioedema?

non-sedating 2nd generation antihistamines

what is the second-line treatment of urticaria and angioedema?

non-sedating 2nd generation antihistamines + 1st generation antihistamines if symptoms persist

what is the third-line treatment of urticaria and angioedema if 1st generation antihistamines don't work?

- Hydroxyzine (Atarax)

- Doxepin (Sinequan)

- Cyproheptadine (Periactin)

what is the last-line treatment of urticaria and angioedema?

- LTRAs (leukotriene receptor antagonists)

- PO corticosteroids (short term)

- IVIG (intravenous immunoglobulin), plasmapheresis

what is the treatment of HAE (hereditary angioedema)?

- Selective bradykinin B2 receptor antagonist (Icatibant [Firazyr],

- Plasma-derived C1 INH (Berinert or Cinryze), Recombinant C1 INH

(Ruconest)

who are within the special populations?

- pregnancy (category and trimester)

- pediatric (weight and age)

- geriatric

what is important to weigh for special populations?

risk vs benefits

what are questions to ask when taking an allergy history?

- Please describe the reaction.

- Did you start/stop any other medications at that time?

- Have you had any similar types of medications

- How old were you when the reaction occurred?

- When did the reaction occur? After the first dose? After the tenth dose?

- How was the penicillin administered? Orally? Intravenously?

- Were you taking any other medications at the same time?

- When the penicillin was stopped, what happened?

- Have you since taken a penicillin, cephalosporin, carbapenem, or monobactam

A 9-year-old boy presents with a chief complaint of runny nose for the past several weeks. Upon further questioning, he reveals that he has had symptoms of sneezing, rhinorrhea, itching eyes, and fatigue for the past 2 years that has recently become worse. His mother remarks that his symptoms seem to worsen during the spring months. On physical examination, the abnormalities that you find are dark circles under his eyes, an upturned nose, slightly injected conjunctiva, and clear, bilateral nasal discharge with pale, boggy

nasal mucosa.

What diagnosis are you considering for this patient and why? Which physical exam findings point to your diagnosis? How would you treat this patient?

allergic rhinitis, intranasal corticosteroids and 2nd gen antihistamines