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What are some key questions that may prompt an investigation for an immunodeficiency, especially if surgical management fails to resolve?
• Need more than four courses of antibiotic treatment per year (in children) or more that two times per year (in adults)?
• Experience more than four new ear infections in one year after 4 years of age.
• Develop pneumonia twice over any time?
• Have more than three episodes of bacterial sinusitis in one year or the occurrence of chronic sinusitis?
• Need preventive antibiotics to decrease the number of infections?
• Develop unusually severe infections that started as common bacterial infections?
Specific to the ENT world, the main concern is whether there is an immunoglobulin deficiency. The algorithm put forth by AAAAI in this situation is outlined below.
What exactly is an immunoglobulin (Ig)?
They are specialized proteins that float around in the blood and tissues that attach to any germs it may encounter. By attaching itself to germs, it brings attention for our cells to attack, kill, and remove. Consider it like a homing beacon.
However, if there are not enough immunoglobulins (Ig) floating around, than some germs may escape detection leading to recurrent infections.
There are 3 main types of Ig... IgG, IgA, and IgM.
As such, diagnosis typically entails to measure the amount of each present in the blood. If some numbers are unusually low, than immunodeficiency is present. A referral to an immunologist would be warranted at this point.
Even if serum Ig levels are normal, other types of immunodeficiency may be present... for example, there could be a cell defect such that it has trouble recognizing Ig or has impaired ability to kill and remove germs identified by Ig.
Indeed, there are over 180 different immunodeficiencies that have been identified so far. IgA deficiency is the most common disorder affecting 1 in 300-500 people.
Other immune-related bloodwork may also include CH50, strep serotype titres, HiB titres, IgG1-4, etc, etc.
Practice parameter for the diagnosis and management of primary immunodeficiency. Ann Allergy Asthma Immunol 2005 May;94(5 Suppl 1):S1-63.