Olfactory Disorders

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Olfactory Disorders Powered By Docstoc
					November 18, 2010

 Objectives: To develop an understanding of
  olfactory disorders
 To develop an understanding of synesthesia
 Question: What can happen if you lose your
  sense of smell? Danger wise….also think
  about memory.

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

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

 A redneck died and left his entire estate to his
  beloved widow…
 But she can’t touch it until she’s 14.

 Did you hear they’ve raised the minimum age
  for alcohol for rednecks to 32 years….
 They want to keep alcohol out of high school.
   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
Smell Disorders

 As per type of smell disorder : No smell, less
  smell, “weird” smells
 Taste problems
 One of earliest sx/sign of
   Alzheimers
   Parkinson’s
 Can it be lethal ?
 Yes ! When ?
   Can’t smell : Spoiled food, Fire, gas leak (45% of pt.s)
How can you tell if someone
   has a real olfactory
 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
Smell Test
   The UPSIT

 Commercial
 Most used
 Self-administered in 10-15 minutes
 Scored in < 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
                 The UPSIT

 Dysfunction classified as Mormosmia, anosmia,
  mild, moderate or severe microsmia, or
  probable malingering
     Threshold olfactory tests
 A dilutional series of a stimulus odor
 Uses an ascending concentration trial
 Must answer ‘yes’ or ‘no’
             Other Tests

 Pocket Smell test
 Brief Smell ID Test
 Squeeze bottle odor threshold test

 All commercial
 How do you know when your’re 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.”
Causes of Smell Disorders
   (Name some of them)

 Decreased smell occurs in the normal elderly
 The greatest correlation with olfactory
 More severe in men than women (Any
  conjecture on why?)
 Multifactorial causes
  Upper Respiratory Infections
 Most Common cause of permanent smell
 Damage olfactory epithelium & possibly central
 Common cold, hepatitis, influenza, HSV, rabies
  and a bunch I’ve never heard of &
  thus don’t care about

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

 Right-sided foci > left-sided
 Anti-seizure meds can correct problems
  Neurodegenerative Diseases
 Alzheimers & Parkinson’s :
   Usually ASX, but present   (Kevin, er… Homer)
    in 85-90% of pts
   Doesn’t respond to
   Magnitude not assoc
    with disease stage
Neurodegenerative Diseases

   Down’s Syndrome
   Huntington’s Disease
   Multiple Sclerosis
   Jacob-Creutzfeld
       Head Trauma

 About 20% of all chemosensory
   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
 Other Disorders

 Cerebellar Degeneration
 Schizophrenia
 Migraine
 Hyperemesis gravidarum & hyperosmia
 A number of systemic diseases
 Some Medicines
 Congenital anosmia
 Doty R. The Olfactory System and Its Disorders.
 Bromley S. Smell & Taste Disorders: A Primary
  Care Approach. AFP 2000;61:427-36.
 Diagnosis of Anosmia. Online Medical Books.
 Wilson RS, et al. Olfactory identification &
  incidence of mild cognitive impairment in older
  age. Arch Gen Psychiatry 2007;64:802-8.
Final 5

 Briefly describe one of the possible causes of
  the lack of smell.

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