Judging by the comments on my last post about anosmia and my natural gas escapade, I think I should clarify things a bit further on the status of my non-functioning sniffer.
Although my ability to detect odors is seriously compromised, I can occasionally smell things completely randomly. What a gift it is to stick my nose in a bouquet of flowers and smell their fragrance. The senses of smell and taste are closely related : sometimes I can smell and taste a food on first exposure - like lifting the lid of a pot, or opening the door of an oven, or taking that first bite of moist carrot cake. With tangy cream cheese frosting. And crunchy pecans and sweet golden raisins.
*blink* OK. I'm back.
Perhaps the first bite, or two or three, will be abundantly flavorful. But once the initial rush to my senses has hit, it diminishes, so that by bite four or five, the characteristics of the food's scent and taste fade away. What I can count on, however, is the ability of my tongue to detect those basic tastes: sweet, sour, salty, and bitter. It's the nuances of flavor and scent that are lacking.
I can never count on being able to smell something, as my recent experience with natural gas demonstrated so vividly. Sometimes I have wonderful dreams in which I'm able to smell and taste with exceptional acuity. Sigh.
Technically, the fact that I have a limited ability to smell stuff means that my problem should be more accurately described as hyposmia. Anosmia means the ability is completely gone, and hyperosmia describes the abnormally increased ability to smell.
There can be a zillion things that impact one's ability to smell, and to understand those things, we probably should back up a bit and take a look at how our sense of smell works. Here is an illustration of a cross-section of our nasal passages. At the top of the passage, the olfactory bulb detects molecules that carry scent, and transmits this information as an electrical charge to the cranial nerve 1, and into specific areas of the brain: the hippocampus, amygdala, olfactory cortex, and hypothalamus.
|Adrenal cortical insufficiency|
|Local diseases and mechanical obstruction of the airways|
|Atrophic rhinitis (Ozena)|
|Deformity secondary to trauma|
|Exposure to toxic chemicals|
|Malignant disease of paranasal sinuses with extension into the nasal cavities|
|Tumors of the nasopharynx with extension into the nasal cavities|
|Chronic renal failure|
|Cyanocobalamin (vitamin B12) deficiency|
|Olfactory reference syndrome|
|Aneurysms of the anterior communicating bifurcation|
|Frontal lobe glioma|
|Internal carotid aneurysms extending over the pituitary fossa|
|Sphenoidal ridge meningioma|
|Squamous cell carcinoma|
|Viral and infectious|
|Acute viral hepatitis|