No ev­i­dence of harm from flu vac­cine

Times Colonist - - Diversions - DR. KEITH ROACH Your Good Health Dr. Roach re­grets that he is un­able to an­swer in­di­vid­ual let­ters, but will in­cor­po­rate them in the col­umn when­ever pos­si­ble. Read­ers may email ques­tions to [email protected]­

Dear Dr. Roach: I’ve read mixed re­views as to whether the flu shot can con­trib­ute to Alzheimer’s dis­ease. I’m anx­ious to see your in­put.

J.W. There is no re­li­able ev­i­dence, nor any good bi­o­log­i­cal plau­si­bil­ity, that in­fluenza vac­ci­na­tion in­creases the risk of ei­ther Alzheimer’s dis­ease or other types of de­men­tia. In fact, there are sev­eral stud­ies show­ing a re­duced risk of de­men­tia in peo­ple who get reg­u­lar in­fluenza vac­cines. I have read well­done stud­ies look­ing at peo­ple with heart fail­ure, peo­ple with kid­ney dis­ease and over­all peo­ple over age 65 — all show a de­creased risk of de­men­tia among those who reg­u­larly get the vac­cine.

There is a risk in these kinds of stud­ies, be­cause peo­ple who get reg­u­lar vac­cines are more likely to see their doc­tors, have blood pres­sure and blood su­gar well-con­trolled, eat bet­ter and ex­er­cise more, all of which help pro­tect against de­men­tia. How­ever, the authors did their best to sta­tis­ti­cally control for these fac­tors and still found a ben­e­fit from reg­u­lar vac­ci­na­tion.

One might think that re­duc­ing the risk of death by in­fluenza vac­ci­na­tion would be enough mo­ti­va­tion, but still too few peo­ple get the vac­cine. Maybe know­ing that there is no in­creased risk, and pos­si­bly a de­creased risk, for de­men­tia will en­cour­age peo­ple to get their vac­cine.

Dear Dr. Roach: What can you tell me about hy­per­e­osinophilic syn­drome? My brother is be­ing worked up for this or a pos­si­ble mu­ta­tion of this dis­ease. He has suf­fered for a few years with symp­toms. Many doc­tors later, one thinks this is the di­ag­no­sis. He’s had 10 biop­sies, so why did it take so long? Is it that rare? What is the treat­ment?

Anon. Hy­per­e­osinophilic syn­drome is in­deed very rare, seen in per­haps one in a mil­lion peo­ple. Eosinophils are a type of white blood cell that are help­ful for the body’s de­fences, es­pe­cially against par­a­sites. In HES, how­ever, the body makes far too many eosinophils (we of­ten say “eos,” for short), and these can in­fil­trate healthy tis­sues, es­pe­cially the lung, skin and gas­troin­testi­nal tract. As such, com­mon symp­toms are cough and short­ness of breath, rash and weight loss or stom­ach pain. Oc­ca­sion­ally, the dis­ease af­fects the brain, eye or heart.

The di­ag­no­sis is sus­pected when the eosinophils in the blood are present at too high a level.

A per­sis­tent to­tal eosinophil count over 1,500 should make the clin­i­cian sus­pect the di­ag­no­sis. Of­ten eosinophils are given only as a per­cent­age, so to get the to­tal count, you need to mul­ti­ply the per­cent­age by the to­tal white count. Since this is part of a com­plete blood count, I haven’t of­ten seen such a long de­lay in mak­ing the di­ag­no­sis. One par­a­site, Strongy­loides, can cause what looks like hy­per­e­osinophilic syn­drome, so this needs to be con­sid­ered be­fore treat­ment.

The biopsy I think you are re­fer­ring to is of the bone mar­row. The bone mar­row spec­i­mens should be eval­u­ated for ge­netic mu­ta­tions.

An ex­pert in eval­u­a­tion cer­tainly should be in­volved. A hema­tol­o­gist is usu­ally the per­son who makes the di­ag­no­sis in as­so­ci­a­tion with the hematopathol­o­gist.

Treat­ment de­pends on the un­der­ly­ing ge­netic mu­ta­tion, if present. Ima­tinib (Gleevec) is used for peo­ple with a mu­ta­tion called PDGFRA.

Steroids are used for peo­ple with­out ge­netic mu­ta­tions, but must be used with cau­tion be­cause it can cause a fa­tal out­come in peo­ple with Strongy­loides.

Peo­ple who don’t re­spond to steroids of­ten re­ceive chemo­ther­apy or even a bone mar­row trans­plant.

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