Olfactory Disorders

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Olfactory Disorders

• B. Wayne Blount, MD, MPH

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What commercial product has caused 130 cases of
anosmia in the last decade and for which the FDA
just (this week) asked the manufacturer to
voluntarily withdraw ?
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Perspective
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Objectives

• Know the overall epidemiology of olfactory
  dysfunction (OD)
• Understand the olfactory circuitry
• List the main presentations types of smell
  dysfxcn
• Name the main tests of olfactory function
• Review several of the major causes of OD, their
  w/u possible treatments

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Epidemiology

• Age lt 65 about 2 ( No really good population
  study) (Hint, hint)
• Age 65 80 50
• Age gt 80 75

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The Circuitry

• 6 million receptor cells in roof of nasal chamber
• Axons project thru the cribiform plate of the
  ethmoids
• Join to form the olfactory bulbs at base of
  frontal lobe
• These project to the olfactory cortex in the
  subventricular zone
• CN I

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Types of Smell Disorders

• A redneck died and left his entire estate to his
  beloved widow
• But she cant touch it until shes 14.
• Did you hear theyve raised the minimum age for
  alcohol for rednecks to 32 years.
• They want to keep alcohol out of high school.

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Types of Smell Disorders

• Anosmia NO smell
• Hyposmia decreased smell
• Also called microsmia partial anosmia
• Dysosmia distortion
• Phantosmia smell w/o stimulus
• Hyperosmia Abnormally acute
• Olfactory agnosia
• Bilateral or unilateral

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Smell Disorders
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Presentation

• As per type of smell disorder No smell, less
  smell, weird smells
• Taste problems
• One of earliest sx/sign of
• Alzheimers
• Parkinsons
• Can it be lethal ?
• Yes ! When ?
• Cant smell Spoiled food, Fire, gas leak (45
  of pt.s)

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How can you tell if someone has a real olfactory
disorder?

• The ideal test Needs to assess for
• Any sense
• What level of sense
• Different smells
• Malingering
• Laterality (bi- or uni-)
• U Penn Smell ID Test (UPSIT)
• Threshold Olfactory Tests

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Smell Test
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The UPSIT

• Commercial
• Most used
• Self-administered in 10-15 minutes
• Scored in lt 1 minute by non-med person
• Available in various languages
• 40 scratch sniff patches
• Pt. chooses from 4 answers must choose 1
• Can detect malingering

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The UPSIT

• Dysfunction classified as Mormosmia, anosmia,
  mild, moderate or severe microsmia, or probable
  malingering

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Threshold olfactory tests

• A dilutional series of a stimulus odor
• Uses an ascending concentration trial
• Must answer yes or no

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Other Tests

• Pocket Smell test
• Brief Smell ID Test
• Squeeze bottle odor threshold test
• All commercial

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• How do you know when yourre staying in a redneck
  hotel?
• When you call the front desk and tell the mgr, I
  gotta leak in my sink. and he says,
• Go ahead.

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Causes of Smell Disorders(Name some of them)
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Age

• Decreased smell occurs in the normal elderly
• The greatest correlation with olfactory decline
• More severe in men than women (Any conjecture on
  why?)
• Multifactorial causes

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Upper Respiratory Infections

• Most Common cause of permanent smell problems
• Damage olfactory epithelium possibly central
  structures
• Common cold, hepatitis, influenza, HSV, rabies
  and a bunch Ive never heard of
• thus dont care about

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Toxins

• Herbicides
• Pesticides
• Solvents
• Heavy Metals, esp cadmium, nickel, chromium
  manganese
• Damage olfactory epithelium
• Enter brain, esp. cadmium, gold manganese

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Epilepsy

• Right-sided foci gt left-sided
• Anti-seizure meds can correct problems

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Neurodegenerative Diseases

• Alzheimers Parkinsons
• Usually ASX, but present (Kevin, er Homer)
• in 85-90 of pts
• Doesnt respond to
• meds
• Magnitude not assoc
• with disease stage

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Neurodegenerative Diseases

• Downs Syndrome
• Huntingtons Disease
• Multiple Sclerosis
• Jacob-Creutzfeld

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Head Trauma

• About 20 of all chemosensory
• disorders
• Directly related to degree of trauma
• Also related to strong deceleration injury
• Occipital and side injury more than frontal
• If recovery, occurs within 1st year of injury

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Other Disorders

• Cerebellar Degeneration
• Schizophrenia
• Migraine
• Hyperemesis gravidarum hyperosmia
• A number of systemic diseases
• Some Medicines
• Congenital anosmia

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OK So whats the work-up?

• H.P.I.
• Location Unilateral or bilateral
• Onset Acute or Chronic
• Context Occurs only with Sz, HA, after head
  trauma constant or intermittent
• Assoc Sx URI, memory loss, neuro sx
• Quality All smells, some smells, taste
• Severity Complete or partial
• Modifying factors What have you tried what
  makes it worse?

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History

• Social Hx
• Tobacco or Etoh or intranasal cocaine
• Family Hx
• Olfactory disorder Rheumatic dz, Huntingtons,
  PD, Alzheimers
• PMH
• Sz, M.S., allergic rhinitis, Alzheimers, PD,
  Huntingtons, Anemia, RHEUMATIC Dz, DM,
  Hypothyroid, renal or liver problems
• Meds
• R.O.S. Complete ,looking for any systemic dz

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So whats the History tell us?

• Recent URI More acute presentation
• Exposure to toxins More acute presentation
• Recent head injury More acute presentation
• Hx of epilepsy? Intermittent or phantosmia
• Medicines Captopril , DMARDS, penicillamine
  (Anosmia) and about 50 others (See AFP article
  in references.)
• Tobacco Use? Anosmia or hyposmia

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History

• Unilateral or bilateral ?
• If unilateral, think of olfactory groove or
  parietal lobe tumor
• Other Neurologic signs or sx Multiple Sclerosis
• Memory loss? Think Alzheimers
• Any of 3 cardinal signs of PD? Think PD
• Any signs of a systemic disease? Hypothyroidism,
  diabetes, renal failure, hepatic failure,
  pernicious anemia

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Physical Exam ?

• Grossly check CN I
• Soap, coffee, cologne, gum, breath mint,
  chocolate, alcohol, old penny
• Do unilaterally by occluding one side at a time
• Do a neuro exam
• Do a complete head neck exam
• Do a more detailed exam of a system(s) depending
  on hx.
• Do a quick survey of rest of body looking for
  systemic dz stigmata

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Laboratory

• If acute with recent URI, none
• If on med that can cause ,
• none
• If gradual onset and exam is negative,
• Get head CT
• If CT is negative, then
• W/U for systemic dz cbc, cmp, tsh, LFTs, FBS
  other labs as indicated for Rheumatic dz or toxin
  exposure
• If phantosmia or intermittent, do an EEG

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Treatment

• If find a treatable cause, Treat it. DUH!
• Sinusitis, allergic rhinitis, DM, Hypothyroidism,
  nasal polyps, neoplasm, vitamin deficiency,
  misuse of drugs, causative medicine, acute toxin
  exposure

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Treatment

• Some diseases with which olfactory disorders are
  associated, you can treat the disease, but not
  cure the olfactory problem Rheumatic Dz,
  Alzheimers, PD, head trauma

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Treatment

• If Cannot find a treatable cause,
• Refer to E.N.T. for specialized testing

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Summary

• A common, under-recognized set of disorders
• The common presentations
• The common causes
• Can be worked up, diagnosed and treated in
  primary care
• Specialized testing is done in E.N.T.

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References

• Doty R. The Olfactory System and Its Disorders.
  www.medscape.com/viewarticle/588523
• Bromley S. Smell Taste Disorders A Primary
  Care Approach. AFP 200061427-36.
• Diagnosis of Anosmia. Online Medical Books.
  www.wrongdiagnosis.com/a/anosmia/diagnosis.htm
• Wilson RS, et al. Olfactory identification
  incidence of mild cognitive impairment in older
  age. Arch Gen Psychiatry 200764802-8.

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