Weakness and Dizziness Answers 393hemianopsia, hemiparesis, hemisensory loss, memory loss, and ipsilateral
cranial nerve III palsy that is pupil sparing.
360.The answer is a.(Tintinalli et al, p 1405.)You should suspect BPV
in this patient. BPV is a transient positional vertigo associated with nystagmus.
The problem occurs secondary to the creation and movement of canaliths
(free-moving densities) in the semicircular canals of the inner ear that is
associated with a particular head movement. The Dix-Hallpike maneuver
is a diagnostic test designed to reproduce transient vertiginous symptoms
and nystagmus of BPV. The maneuver involves having the patient go from
sitting to a supine position with eyes open and head rotated to the affected
side. The test is positive if the maneuver reproduces vertigo and the patient
exhibits latent rotary nystagmus. A negative Dix-Hallpike maneuver does
not exclude the condition.
Caloric stimulation testing (b)is performed for acoustic nerve evaluation
by introducing cold or warm water or air into an ear canal and observing
transient nystagmus. It is unnecessary for BPV diagnosis. Orthostatic vital signs
(c)should be obtained if you suspect orthostatic hypotension. The patient in
this case is symptomatic when he lies down, not when he is standing or
sitting up, which is not consistent with this diagnosis. Head CT scan (d)
should be ordered if you suspect central, rather than peripheral causes of
vertigo. ECG (e)is necessary if you suspect a cardiac cause of dizziness.
361.The answer is b.(Rosen, p 1667.)This woman presents with iron-
deficiency anemiasecondary to menorrhagia.A history of chronic heavy
menses and pale conjunctiva on examination should make you suspicious
of this common disorder. About 20% of women and 3% of men are iron
deficient.Complete blood countprovides hemoglobin and hematocrit
levels to diagnose anemia. Typically, the mean corpuscular volume (MCV)
is low in iron-deficiency anemia. In addition, the patient usually exhibits low
serum iron, low serum ferritin, and a high total iron-binding capacity.
Electrolyte or renal function abnormalities (a)are unlikely in a young
healthy woman. Except for tachycardia, the ECG (c)will be normal unless
the patient has underlying cardiac disease, which can lead to ischemia in
the setting of anemia. Chest x-ray (d)is not useful as an initial diagnostic test.
It is appropriate to obtain it if you suspect a lung infiltrate, mass, congestive
heart failure, or other cardiopulmonary disease. Chest CT with contrast
(e)would help to diagnose a pulmonary embolism that may present with
weakness, dyspnea on exertion, and tachycardia. In this case, however, the