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28 Cards in this Set
- Front
- Back
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The art of IT
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Escalation
balancing safety and efficacy Science : starting dose.... |
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Goal
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Induce tolerance, like a vaccine
Get to the highest tolerated dose without causing adverse systemic or local reactions |
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Candidates?
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Most pts with AR. AR wont kill them. IT could.
Need to have failed conservative measures Not appropriate for trivial, equivocal, or evanescent symptoms.....need 2 or more seasons. |
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Starting dose
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Weight anaphylaxis, pt health, compliance. Vs severity of sx, med use, QOL.
And how well you tested them ... 5 different testing methods can be used tondetermine starting dose |
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With IDT, start with....
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Tailored dose for each allergen.
5 fold dilutions. Conc is 1:20 w/v Continue through vial #6 Give 0.05 ml of your endpoint dilution for a first dose, this has less ag than was given during the confirming wheal on IDT. |
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Escalate to
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O.5 ml injections is max volume
increasing from 0.05 ml in increments of 0.05 ml injections every 5-7 days O.5 ml volume starts to get uncomfortable, so stop here. Use smaller volumes of higher concentrations to get more than 1 ag per injection. |
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Math for adding antigens
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5 ml of #4 = 1 ml of #3 = 0.2 ml of #2
You use 25x concentrate, then just do the math. |
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Glycerine
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If using phenolated. Saline stores for 6-8 weeks.
Glycerine keeps ag for 3 months. Vial volume usually lasts for 10 weeks. Need 10% conc. so take 50% glycerine at a 1:5 dilution ( put 1 ml into a 5 ml vial. |
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In vitro testing .....start with a more conservative dose and use vial tests because in vitro isn't as good.
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Theoretically a sIgE class 4 correlates with IDT endpoint.
* antigen isnt the same, pt not challenged with ag yet, so startbwith RAST-1. Start with a #5 instead of #4, have lost 10 weeks of treatment. |
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MQT
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Use algorithm then teat like IDT calculations.
If prick positive, start with # 6 dilution |
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Vial test
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Give 0.01 cc injection and wait. Gage response before giving firstbdose. This helps with injury from mixing errors, differences in concentrate between batches or manufacturers, not sure how patients will respond if used MQT or in vitro.
* some practicioners use vial test with every new vial. 4 mm wheal, wait 10 mm. If wheal < 13 mm, give first dose. If 13 mm, wait 72 hrs before first dose. If > 13 mm, dilute with 1 cc and repeat vial test. |
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Multiple txmvials
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Divide vials if patients wont escalate. Grasses and molds may be holding you back because they're high sensitivity antigens
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High and low proteilytic extracts
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High - insects and molds can decrease potency or breakdown of low proteolytic extracts.
Low- pollen, mite, dander May not actually happen because glycerine stabilizing. |
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Allergy RN who is mixing.....
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Two people to look and double check.
Needs quiet Write clearly. |
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Escalation
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Need to deliver an adequate dose to change the immune response.
For at least 3-5 yrs |
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Risks
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Local rxn, anaphylaxis, non compliance, failed benefit.
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Why go to 0.05 ml when escalating treatment levels?
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Safety. 0.5 ml of a tx level is equivalent to 0.1 ml of the tx level
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Rapid escalation
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0.05 to 0.1 to 0.2 to ....0.5
Want a 2.5 ml vial Takes 6 weeks instead of 10 weeks per treatment level. To mix use half the amount you would ( 0.1 cc instead of 0.2 cc) 1 week escalation patients have 20% risk of systemic reaction. Good for bee keeper, abx allergies, asa desensitization. |
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Decision making
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Asthma symptoms, allergy symptoms, overall allergen load during bad seasons for the patient. Consider holding a dose or scaling back.
If local rxn is 25-35 mm, same dose If larger 35-40 mm, decrease dose Late reactions - mild - same dose. Severe - decrease dose. |
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When patient misses a dose
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If miss 1 wk, repeat last tolerated dose.
2 weeks, reduce dose 3-4 weeks, repeat vial test. Consistent non compliance....probably not working, should consider discontinuing. |
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Vial mix for #2
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All the math is the same, but you increase treatment level on each antigen.
When you reach concentrate....stop the escalation because you're at an efficacious level. Just continue to mix with 0.2 ml of concentrate |
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Glycerine
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50% is irritating. When pts reach concentrate, you no longer need to add 1 ml of 50% glycerine.
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Maintenance
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Cumulative dose - total amount of antigen received during IT. There is an observed benefit from higher total ag given.
Known Pt mite 7-12 micrograms... See chart. Literature shows that significantly higher doses of Cat are needed than for other antigens Low dose tx doesn't seem to work If you aim for a 25-50 mm local reaction, but nonsystemic reactions, you're probably giving max safely tolerated dose. May need 1 ml concentrate in maintenance vial for cat, others need 0.2 ml of a 1# dilution. When you cant escalate, efficacy is not clear. Try to split vials. |
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Discontinuing therapy
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Not great data. No objective test to say when pt is ready.
Min 3 yrs. Hold maintenance for at least a year. Wait until worst season is over, then space injections to 2 weeks. Do this for a year. If stable sx, then may discontinue |
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Restarting therapy
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If > 1 yr, start over.
2-12 months start with vial test < 2 months, start at half last tolerated dose. |
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Limits
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Age. None really, but child needs to be cooperative.
Pregnancy. Ok to continue, but not escalate or start. Might discontinue if they've just started. Autoimmune or immunodeficiency: as long as CD4 os ok, and no hx of opportunistic infection. Asthma. Pts stand to benefit the most, but also high risk. Get them optimally controlled. Need to be careful and reassess every week prior to injection |
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Troubleshooting notes
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Might be ok to test during URI, panel was split, seemed to say SPT was ok, but not IDT.
If histamine is neg, and get some positives, in general need to retest if contemplating IT. If no IT, then can treat with meds If a food allergy shows up on in vitro testing that does not correlate with pt symptoms, ex peanut allergy in a child who eats peanut better sandwiches. Response: child has passed the stress test, but make sure mom knows and has an epipen because the pt is at higher risk. There are 8 different epitopes for peanut, Ara 1-3 are assoc with anaphylaxis, but 5-8 are not. Pt has developed a tolerance, should keep eating them regularly. Athletic female getting IT starts to have systemic reaction. What next: vitals, ? Epi, proceed with tx formearly anaphylactic rxn. Why: changes in allergen load with season, mixing error, etc. |
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More trouble shooting
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Pt in escalation phase of IT, goes away for a month. Had been doing well with local reactions only.
Escalation is the danger phase with higher risk of anaphylaxis. Local reactions are safe, but are abyield sign. Also, pt would go to 1 step before the last tolerated dose, even consider go back a tx level. If it has been 3 months, start at tx level over with a vial test. If had been in maintenance, ....depends how long, but don't need to be as cautious. Maybe step back 1 escalation step. If happening alot, need to emphasize need for 6 months of reliable compliance during the escalation phase, maybe switch to SLIT. What do you do with a significant late phate reaction- if no concerning sx, just take some NsAIDS, antihistamines, cold compress. Consider slowing escalation or splitting vials. What do you do with tongue tingling after SLIT. Reactions tend to be dose related and are expected, tend to go away with therapy, can slow escalation. If pt has swelling, may have pt come into clinic fur us to see swelling. If GI sx, can spit instead of swallow. Give first dose in the office....shows how to do it, can discuss any local reactions. |
