Question:

I am a Male Diabetic in my late 50’s and four months ago I underwent surgery to partially remove my thyroid. Before the surgery my thyroid hormone levels were normal. During the surgery they had problems in inserting the breathing tube or in intubateing me. Immediately after the surgery, I was unable to speak above a whisper and unable to taste. The problem with my voice resolved itself in about 5 days but the inability to taste has persisted. My surgeon refereed me to an ENT in his group and I took a scratch and sniff smell test that I apparently failed. Since then they have done a CT-Scan of my nasal cavaity and the doctor said that it was normal. The doctor seems to think that the two remaining suspects are:

• A low Thyroid Hormone level which manifested itself about a month after my surgery and for which I have been taking thyroid medication for the last month.

• A small emboli that lodge in my olfactory lobe.

My most recent blood test shows that my thyroid levels are now normal and I can still not taste my food and I can only smell the very strongest odors. I am, as you might imagine, very much upset at the prospect of not being able to taste or smell normally. What is the probability that if this condition is the result of an emboli, I will eventually recover my smell or taste? Can you give me a time-frame for such a recovery? I am a patient person but this loss of smell and taste is really wearing on me.

Answer:

If your thyroid hormone level is now normal, then this is not the likely cause of your taste and smell problem. 

You may or may not know that our taste buds respond to only salt, sour, sweet, and bitter.  There are a total of 6 nerves that innervate our taste buds, so it is actually very rare to truly lose one’s sense of taste.  On the other hand, as we eat, odors are released from the food in our mouth and travel up through our throat to our nose to stimulate our smell.  As a result, the flavor of food is very much determined by our smell.  When smell is lost, it is quickly realized that food does not “taste” right or has no “taste”, although it is actually a part of flavor that has been lost. 

There is only one nerve that innervates our smell receptors, located within the roof of the nasal cavity, so it is a little more common to lose one’s sense of smell.  The most common causes of smell loss include a viral infection, head injury, or active nasal and sinus inflammatory disease. 

Although it is not common, smell loss can occur after surgery under general anesthesia.  It has been reported more commonly after open heart surgery, but can theoretically occur after any surgery (in fact, I recently did see a case of loss after thyroid surgery).  The mechanism is believed to be a small embolus that occurs, but this has not been proven.  

The smell receptors can regenerate, so theoretically smell can recover after this sort of insult.  Unfortunately, there are no long term studies in these sort of cases to give you a specific prognosis, and there are also no known avenues of therapy.  Therefore, all you can really do is wait, and in the meantime try to enhance other aspects of flavor: texture, temperature, and visual impact of food, along with tastes (be careful not to add too much salt or sugar), and possibly hot peppers and the like. 

For more information:

Go to the Ear, Nose, and Throat Disorders health topic.