SMELL AND TASTE DISORDERS
Smell and taste are two of body’s senses that are often taken for granted, but when either one or both are affected, significant diminishment in quality of life can occur. A survey from 1994 estimated 2.7 million American adults suffered from some olfactory (smell) dysfunction, while 1.1 million adults reported some degree of gustatory (taste) diminishment. More recent studies, however, suggest that the incidence of smell and taste impairment may be much higher, particularly in the older adult population. In addition to causing a loss in quality of life, alterations in the sense of smell and taste can potentially be early indicators of other medical problems, such as sinus and allergy disease, vitamin and nutritional deficiencies, and central nervous system disorders.
THERE IS HOPE
We incorporate a multidisciplinary approach, working closely with our colleagues in neurology, radiology, and endocrinology to come up with a diagnosis and treatment strategy. In cases where a reversible cause is diagnosed, medical management, surgical management, or a combination of the two are utilized to help restore the sensory deficiencies.
HOW DOES THE BODY SMELL AND TASTE
The body’s sense of smell and taste are based on chemoreceptors, which are specialized structures that pick up molecules either carried by air into the nose or by saliva into the mouth. In the nose, these chemoreceptors lie directly on nerve cells called olfactory cells- these cells are located in the upper portion of the nasal cavity and have a direct connection to the brain. In the mouth, small bumps or growths on the tongue commonly referred to as taste buds, which contain clusters of specialized receptor cells. Food and drink particles are transferred via saliva onto these receptors, which then transmit the signal along a somewhat complicated neural pathway back to the brain. The signals generated food and drink particles can be broken down into five different taste qualities- salty, sweet, sour, bitter, and umami (the flavor associated with monosodium glutamate, or MSG). Recent research has shown that other possible taste qualities, including one for fats, may be present as well. Unlike olfaction, where one nerve transmits the sensory information back to the brain, multiple nerves are involved in the taste sensation. Taste is greatly affected by olfaction- anyone who has suffered through terrible nasal congestion can attest to this fact.
TYPES AND CAUSES OF SMELL DYSFUNCTION
Olfactoal disease, which include chronic sinus infections, nasal masses/anatomic blockages including nasal polf the nasal passageway can lead to blockage of the conductive pathway. Sensorineural deficits are problems affecting either the olfactory nerves or the brain pathways involved in processing and interpreting odors. The most common causes leading to sensorineural deficits include age-related degeneration of the olfactory nerves, injury from viral infections, head trauma leading to physical injury to the nerves, and nerve injury from chemical irritants, such as tobacco smoke. Other less common causes include medication-related nerve damage, endocrine (hormonal) imbalances, and brain tumors. Changes in olfaction are also linked with degenerative diseases of the brain and central nervous system, such as Alzheimer’s disease and Parkinson’s disease.
DIAGNOSIS AND TREATMENT
Diagnosis and treatment of smell and taste disorders begins with a comprehensive patient history and physical examination. Here at Northwest ENT Associates, we do a thorough examination of the upper airway, including an endoscopic evaluation of the nasal passageways, looking for any potential treatable causes of smell and taste dysfunction. Imaging modalities, including CT scans and MRI scans, are often utilized to help define the diagnosis. The University of Pennsylvania Smell Identification Test (UPSIT) is utilized in our clinic as past of the diagnostic evaluation of smell disorders. We also utilize Taste Strips in cases of taste disturbance. As mentioned earlier, ours is a multidisciplinary approach with the goal of developing an individualized plan that assures you the most effective outcome.
Causes of taste dysfunction
The sense of taste is strongly influenced by the sense of smell, which is why the primary source of taste dysfunction is alteration in olfaction. Olfactory dysfunction is responsible for up to 80% of taste disturbances. Other less common causes for taste impairment include:
- Viral upper respiratory infection
- Head trauma
- History of head and neck radiation
- Middle ear disease (one of the nerves involved in taste travels behind the eardrum)
- Chemical irritants
- Tobacco use (cigarette and smokeless tobacco)
- Oral cavity infections such as thrush
- Head and neck tumors
- Nutritional deficiencies
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