Chapter 20. Disturbances of Taste and Smell

Question 1

Question 20-1:
A patient presents with seizures and is found on examination to have unilateral anosmia. Which is the most likely diagnosis?
A. Olfactory groove meningioma
B. Idiopathic seizure with incidental anosmia due to sinus disease
C. Temporal lobe mass with extension into the inferior frontal region
D. Sinus disease with extension into the brain

Answer 1

Answer 20-1: A.
Olfactory groove meningioma can present
with seizures, headache, visual loss, or
dementia. Anosmia may be the first symptom,
but unfortunately, most patients do not seek
medical evaluation until more defmite
neurologic symptoms develop. The other
disorders are all possible, but less likely

Question 2

Question 20-2:
A young man returns to the clinic six months following a closed head injury. Headaches and dizziness have abated, but he has anosmia. Which of the following statements are true?
A. The prognosis for recovery of smell is good
B. Anosmia means that the patient had a skuII fracture
C. The anosmia is likely to be permanent
D. Anosmia is always bilateral

Answer 2

Answer 20-2: C.
Anosmia at least six months from a head
injury is likely to be permanent. Recovery
after one year is not expected. Anosmia can
develop whether or not the patient had a skull
fracture. Anosmia can be unilateral or
bilateral. MRI changes are seen in 88% of
patients who develop anosmia

Question 3

Question 20-3:
Which of the following are normal aging changes in olfaction?
A. Reduced sensitivity
B. Impaired discrimination
C. Resultant alteration in food choices
D. Impaired odor identification
E. All of the above

Answer 3

Answer 20-3: E.
All of these are potential effects of normal
aging, with reduced sensitivity, intensity,
identification, and discrimination. This may
result in altered food choices which may
adversely affect nutritional intake in elderly
patients

Question 4

Question 20-4: 
Which of the following agents produces impaired taste sensation? 
A.  Pipe smoke 
B.  Calcium channel blockers 
C.  Antifungal agents 
D.  Sumatriptan nasal spray 
E.  All of  these

Answer 4

Answer 20-4: E.
All of these agents can produce impaired taste.
Smoke, especially of pipes, diltiazem and
nifedipine, penicillamine, captopril, antifungal
agents, some anticonvulsants, and sumatriptan
nasal spray are among the agents which can
impair taste function

Question 5

Question 20-5:
Which of the following are true regarding taste dysfunction after head injury?
A. Taste disorder is uncommon after head injury
B. Recovery is much less complete than recovery of olfaction after head injury
C. Taste deficit from head injury is due to peripheral nerve lesion and not due to brain damage
D. Cerebral injury does not produce
taste defect

Answer 5

Answer 20-5: A.
Taste disorder is uncommon after head injury,
affecting less than I %, whereas smell defect is
present in 10-20% of head injury patients.
About 6% of patients with post-traumatic
anosmia also have ageusia. Recovery tends to
be better than for anosmia, with improvement
in weeks to months. Taste deficit can be due
to central or peripheral nerve damage

Question 6

Question 20-6:
Which of the following statements is true regarding function of the trigeminal nerve in olfactory sensation?
A. Trigeminal nerve carries a portion of primary olfactory afferent axons
B. Trigeminal nerve carries sensation of olfactory region irritability which adds to the olfactory perception
C. Trigeminal nerve plays no significant role in olfactory sensation
D. Trigeminal nerve efferents modulate the sensitivity of olfactory sensation

Answer 6

Answer 20-6: B.
The trigeminal nerve carries sensation from
the olfactory region which indicates irritability
rather than primary olfactory sensation. When
the olfactory processes are disordered,
primary olfaction is lost but this sense of
irritability is preserved. This effect can be
useful in evaluation of malingering where
odorants of irritative quality should be
detectable even in the absence of primary odor
sensation

Question 7

Question 20-7: 
The olfactory tract terminates in which of the following regions? 
A.  Piriform cortex 
B.  Hippocampus
C.  Uncus 
D.  Amygdaloid complex 
E.  All of the above

Answer 7

Answer 20-7: E.
The olfactory tract terminates in all of these
regions. These are primitive cortical areas.
These and other areas of the frontal cortex and
cingulate gyrus are activated by olfactory
stimulation

Question 8

Question 20-8:
Unilateral loss of smell is not noticed by the patient
T. True
F. False

Answer 8

Answer 20-8: T.
True. Unilateral loss of smell is typically not
noticed by the patient but can be an important
exam finding

Question 9

Question 20-9:
Patients with Parkinson’s disease have impaired olfactory detection.
T. True
F. False

Answer 9

Answer 20-9: T.
True. Patients with Parkinson’s disease have
impaired olfactory detection and
discrimination. However, there is no
correlation between PD severity and duration
and degree of olfactory deficit. Interestingly,
PSP is not associated with olfactory deficit

Question 10

Question 20-10:
Bell’s palsy can cause loss of taste over the posterior third of the tongue.
T. True
F. False

Answer 10

Answer 20-10: F.
False. Bell’s palsy can produce unilateral loss
of taste over ,he anterior two-thirds of the
tongue. This is due to damage to the nervus
intermedius portion of the facial nerve.
Patients are often unaware of taste loss, but
may state thaI items taste differently