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2009 AOA Review
Neurology
Contact Information
Dominic Peters
([email protected])
Jessica Nassar
([email protected])
Kevin Frey
([email protected])
A 48-year old man comes to the physician because of a 2-day
history of severe low back pain. He states that he has had
periodic low back pain for years, but this is more severe than
usual and radiates to the buttocks and down the right leg. His
temperature is 36.8 C. Examination shows some rigidity of the
lumbar spine. The pain is exacerbated by applying pressure on
the paravertebral region in the lower lumbar spine and by
passively raising the leg at 45 degrees while the patient lies
supine. A reduced Achilles tendon reflex is noted. He has had no
bowel or bladder incontinence. Which of the following is the most
appropriate next step in management?
A) MRI examination of vertebral column
B) Nonsteroidal and anti-inflammatory drugs (NSAIDs)
C) Plain x-ray examination of the lumbosacral spine
D) Radionuclide bone scanning
E) Surgical consultation
Answer: B , The clinical picture strongly suggests
herniation of an intervertebral disc causing compression of
a spinal roots (S1, considering radiation of the pain and
reflex alterations). Supporting such a diagnosis is also the
positive straight leg-raising test. When the history and
physical examination support a diagnosis of disc herniation,
conservative management is all that is needed. Current
recommendations include treatment with NSAIDS and bed
rest of short duration. Bed rest longer than 2 days has not
been shown to provide any additional benefit
A 38-year-old man comes to the physician because of slowly
progressive visual problems that make him “bump into objects” on
both sides. He also reports that, while driving he has trouble
switching lanes because he needs to turn his head all the way
backward to look for other cars. Ocular examination shows
bitemporal field loss with preserved visual acuity. Examination of
the fundus is unremarkable. Which of the following is the most
likely diagnosis?
A) Pituitary adenoma
B) Occipital lobe meningioma
C) Optic glioma
D) Optic nerve atrophy
E) Optic Neuritis
F) Retinal Detachment
Answer: A , The visual deficit presenent in this patient is
described as bilateral temporal hemianopia and is due to
chiasmatic lesions that compromise the crossing fibers
originating from the temporal retina. A large pituitary adenoma
(macroadenoma) that extends beyond the sella turcica into the
suprasellar region is the most common cause of temporal
hemianopia. Craniopharyngioma and meningioma are other
causes.
A 52-year old man comes to the physician because of slowly
progressive weakness in his legs. He also complains of clumsiness
with his right hand, which creates difficulty with buttons or turning
keys. Examination reveals mild bilateral footdrop and leg weakness.
Fasiculation and mild wasting are observed in the calf muscles.
There is no spasticity or impaired sensation. The speech is normal,
but fasciculation of the tongue is appreciated. Respiration, pulse,
and temperature are normal. A muscle biopsy shows evidence of
denervation with reinnervation. Which of the following is the most
likely diagnosis?
A) Amyotrophic lateral sclerosis (ALS)
B) Charcot-Marie-Tooth disease
C) Guillain-Barre syndrome
D) Myasthenia gravis
E) Spinal muscular atrophy
Answer: A , Flaccid paresis involving the lower extremities,
footdrop, hand clumsiness, muscle wasting, and especially
fasciculation in a middle-aged person are highly suggestive of
amyotrophic lateral sclerosis (ALS). This results from
degeneration of the motor neurons in the spinal cord (lower
motor neurons) and leads to denervation of skeletal muscle. His
tongue fasisculations result from degeneration of motor neurons
of cranial nerve nuclei. Continued bulbar involvement will likely
eventually affect pharyngeal and facial musculature, leading to
progressive dysarthria and dysphasia. Surviving neurons may
reinnervate denervated myofibers by sprouting of their axons.
The finding of denervation/reinnervation in a muscle biopsy is
confirmatory of the clinical diagnosis. The patient will later
develop evidence of corticospinal and cortico-bulbar (upper
motor neuron) degeneration as his disease progresses.
A 40-year-old man consults a physician because of dizziness. The
patient reports that the dizziness starts whenever he moves his
head. The dizziness is severe and lasts approximately 10-15
minutes, eventually resolving if he keeps his head still. He does not
experience tinnitus or hearing changes during these episodes.
Otoscopic examination is within normal limits. Which of the following
is the most likely diagnosis?
A) Benign positional vertigo
B) Cholesteatoma
C) Herpes zoster oticus
D) Meniere disease
E) Cerebellar Stroke
Answer: A , The patient has benign positional vertigo. The
pathophysiology appears to involve granular masses that sit in
the semicircular canals of the inner ear, stimulating hair cells,
thus setting off episodes of vertigo. The primary treatment
involves repositioning maneuvers (Epley Maneuver) that move
the otoliths in the semicircular canals into the broader utricle and
saccule. In addition, first generation antihistamines, such as
meclizine, can also be effective at symptom control.
A 65-year-old man comes to the physician because of an
increasingly severe tremor that affects the right hand. The tremor is
particularly marked at rest and disappears when the limb is in
movement. The man’s speech is soft but not monotonous. There is
increased resistance when the arms or neck are passively flexed.
Sensation and muscle strength appear intact. Short-term memory is
preserved. The patient’s blood pressure is 134/82 mm Hg,
temperature is 37 C, pulse is 70/min, and respirations are 10/min.
The patient has a history of a previous episode of narrow-angle
glaucoma. Which of the following drugs should be avoided in the
treatment of his neurologic condition?
A) Amantidine
B) Benztropine
C) Bromocriptine
D) Levodopa
E) Selegiline
Answer: B , The clinical picture is consistent with Parkinson
disease at a relatively early stage. Resting tremor may be
unilateral at first. ANticholinergic drugs such as benztropine,
are frequently used initially and are effective in alleviating
tremor and rigidity. The key to the correct answer is the fact
that the patient’s history includes narrow-angle glaucoma.
Use of anticholinergic drugs may lead to an acute increase of
intraocular pressure in predisposed individuals and
precipitation of narrow-angle glaucoma. The other drugs listed
in this question would all be appropriate for use in this patient.
A 45-year-old woman is involved in a head-on collision with a tree at
50 mph during which she hits her head on the windshield. In which
structure is she most likely to have an intracranial hemorrhage?
A) Putamen
B) Temporal lobe
C) Thalamus
D) Occipital lobe
E) Parietal lobe
Answer: B , Temporal lobe. Temporal lobes and inferior
frontal lobes frequently involved in traumatic brain injury.
Continued forward motion of brain within cranial vault, which
decelerated on impact, causes anterior brain structures to
strike inside of skull contusions. Rough cribriform plate
and middle cranial fossa contribute Coup injury: reflect direct
blow to brain Contrecoup injury: reflect injury at diametrically
opposed brain region (i.e., occipital lobes) where there is
rebound movement of overlying skull. Expanding
hematoma uncal herniation
Quick review of traumatic brain injury:
1) Epidural hematoma:
Rupture of middle meningeal artery from temporal
bone fracture
Lucid interval before decreased LOC
CT: biconvex hemorrhage not crossing suture lines
2) Subdural hematoma:
Rupture of bridging veins
Venous bleeding, delayed onset
Elderly, alcoholics, blunt trauma, skaen baby
CT: crescent-shaped hemorrhage that crosses suture
lines
A 30-year-old right-handed man experiences one week of
progressive ascending weakness. Examination demonstrates a
lower motor neuron pattern and CSF protein is elevated. The
patient reports his weakness was preceded by an episode of severe
diarrhea. Which infection likely preceded this patient’s current
neurological condition?
A) Mycoplasma pneumoniae
B) HIV
C) Clostridium difficile
D) Campylobacter jejuni
E) Cytomegalovirus
Answer: D , Campylobacter jejuni. C. jejuni most
common infection preceding Guillain-Barré syndrome. Less
common infections: CMV, HIV, Epstein-Barr, Lyme disease,
M. Pneumoniae. Other associations: surgical procedures,
exposure to thrombolytics, lymphoma, certain vaccines
Quick review of Guillain-Barré syndrome:
• Inflammation and demyelination of peripheral nerves
and motor fibers of ventral roots
• Sensory effect less severe than motor
• Symmetric ascending muscle weakness
• Autonomic function may be affected: cardiac
irregularities, hyper- or hypotension
• Most survive
• See increased CSF protein with normal cell count
(albuminocytologic dissociation)
Txt: Respiratory support, plasmapheresis, IVIG
A 35-year old man injured his thoracic spine in a car accident 2
years ago. Initially he had urinary urgency and a bilateral spastic
paraparesis which have since improved. He still has pain and
thermal sensation loss in his on part of his left body and
proprioception loss in his right foot. He also still experiences
paralysis of his right lower extremity. Which is the patient’s most
likely spinal cord condition?
A) Brown-Séquard (hemisection) syndrome
B) Syringomyelic Syndrome
C) Complete transection
D) Tabetic syndrome
E) Posterior column syndrome
Answer: A , Brown-Séquard (hemisection syndrome).
Spinothalamic damage contralateral loss of pain
and thermal sensation. Posterior column damage
ipsilateral loss of proprioception (also includes tactile
and vibration sense). Destruction of corticospinal and
rubrospinal tracts and motor neurons ipsilateral
motor paralysis. Also causes ipsiplateral loss of all
sensation at level of lesion and Horner’s syndrome if
lesion above T1 (ptosis, anhidrosis, miosis)
Quick review of other spinal cord lesion choices:
1) Syringomyelic syndrome:
from lesion of central gray matter;
pain and temp fibers that cross at anterior commissure are
affected bilateral loss of sensations over several
dermatomes but tactile sensation is spared
2) Complete transection of spinal cord:
bilateral spastic paralysis
no conscious appreciation of any cutaneous or deep sensation
in area below transection
3) Tabetic syndrome:
from damage to proprioceptive and other dorsal root fibers
classically caused by syphilis
symptoms are paresthesias, pain and gait abnormalities
gait is most affected
4) Posterior column syndrome:
bilateral loss of proprioception below lesion
preservation of pain and temperature sensation
A previously healthy 34-year-old man collapses while sitting at his
kitchen table. The patient’s wife reports a convulsion of 2 minutes’
duration. He appeared to fully recover within 1 hour. In the ER the
patient reports having new early morning headaches during the past
few weeks. A brain MRI demonstrates an enhancing right frontal
lesion which is likely a primary brain neoplasm. Which is the most
common type of primary brain tumor?
A) Meningioma
B) Lymphosarcoma
C) Oligodendroglioma
D) Astrocytoma
E) Medulloblastoma
Answer: B , Astrocytoma. Most common primary
brain tumors are malignant astrocytomas.
Classified as grade 3 or 4. Grade 4 astrocytoma
is called glioblastoma multiforme usually in
adults, men>women
Quick review of brain neoplasm basics:
1) Clinical presentation due to mass effect
2) Primary brain tumors rarely metastasize
3) Majority of adult primary tumors are
supratentorial
4) Majority of childhood primary tumors are
infratentorial
5) Half of adult brain tumors are metastases
6) Craniopharymgioma is most common
childhood supratentorial tumor
A 32-year-old man is involved in a motor vehicle accident. The
patient has multiple injuries including a displaced fracture of the
left humerus. He complains of an inability to open his left hand and
loss of sensation to a portion of his left hand. Which nerve has
most likely been damaged?
A) Musculocutaneous
B) Ulnar
C) Radial
D) Median
E) Axillary
Answer: C , Radial. Injury due to stretch or crush
injury of radial nerve as it spirals around midshaft
of humerus. Inability to open hand due to loss of
hand and wrist extensor innervation by radial
nerve radial nerve is “great extensor,”
innervates brachioradialis, extensors of wrist and
fingers, supinator and triceps. Likely location of
sensory deficit: lateral side of dorsum of hand
and dorsum of the thumb and index and middle
digits
Quick review of upper extremity nerve injury:
1) Median nerve:
Site of injury often supracondyle of humerus
No loss of power in arm muscles
Loss of forearm pronation, wrist flexion, finger flexion, several thumb
movements
Eventual thenar atrophy
Loss of sensation over lateral palm and thumb and radial 2 ½ fingers
2) Ulnar nerve:
Site of injury often medial epicondyle
Impaired wrist flexion and adduction
Impaired adduction of thumb and ulnar 2 fingers
“Claw hand”
Loss of sensation over medial palm and ulnar 1 ½ fingers
3) Axillary nerve:
Site of injury surgical neck of humerus of anterior shoulder dislocation
Loss of deltoid action
4) Musculocutaneous nerve:
Loss of function of coracobrachialis, biceps and brachialis muscles
A 29 y/o female suddenly develops a left hemiparesis. The
patient experienced a DVT in her right leg 3 years ago.
Which of the following conditions is the most likely cause
of this patient's deficit?
A) Nonvalvular Atrial Firbrillation
B) Lupus Anticoagulant
C) Mitral Valve Prolapse
D) Multiple Sclerosis (MS)
E) Astrocytoma
Answer: B , the lupus anticoagulant (an antiphospholipid
antidbody) is associated with peripheral venous thrombosis and
ischemic (arterial) stroke. In patients with a history of DVT, the
possibility of a paradoxical embolus causing a stroke (via rightto-left cardiac shunt) should also be considered. Nonvalvular
atrial fibrillation is a common cause of stroke in the elderly, but
there is no reason to suspect a rhythm disturbance in this
patient. Mitral valve prolapse has been associated with
cardiogenic emboli and stroke. However, a search for other
causes of stroke should always be made, because mitral valve
prolapse is a relatively common entity, and the association with
stroke in weak. Multiple sclerosis (MS) and an astrocytoma can
cause neurologic deficits in young patients; however, these
conditions are not associated with DVT unless the patient is
immobilized. These diagnoses should be considered in the
evaluation of patients with hemiparesis, but the patient's history
can often serve as a clue to guide diagnostic thinking.
A patient with a subarachnoid hemorrhage (SAH) caused by
a right anterior communicating artery aneurysm undergoes
surgery 2 days after the hemorrhage. Three days later, right
arm weakness develops. Which of the following diagnoses is
most likely?
A) Hydrocephalus
B) Meningitis
C) Repeat Hemorrhage
D) Vasospasm
E) Hyponatremia
Answer: D , vasospasm can develop several days after an
aneurysmal subarachnoid hemorrhage (SAH). Patients present with
progressive weakness and alterations in consciousness. Early in the
course, a CT scan may not reveal an ischemic infarction.
Hydrocephalus can occur immediately after an SAH or weeks to
months later. Symptoms are typically nonfocal and, if the
hydrocephalus develops acutely, it is often accompanied by a
depressed level of consciousness. Bacterial meningitis can develop
after a craniotomy. Typically, there is fever and impaired arousal.
Focal signs can develop but are rarely the presenting feature.
Although a repeat hemorrhage can occur after clipping of an
aneursym if the aneurysm is not completely isolated from the
circulation, it is unusual for this to happen and present with a focal
deficit, as opposed to depressed consciousness. Hyponatremia,
which can develop after SAH, can cause an altered sensorium and
seizures but not unilateral weakness.
*How would you treat vasospasm?
A) Heparin
B) Warfarin
C) Nimodipine
D) Phenytoin
E) Carbamazepine
Answer: C , Vasospasm is a relatively common complication of
subarachnoid blood and may result in stroke. Nimodipine (Ca2+
channel blocker, primary effect is upon cerebral arteries) is used
because it decreases the probability of stroke, but it does not
prevent it completely. Anticoagulation with heparin or warfarin
worsens the patient's prospects because it increases the risk of
additional bleeding. Antiepileptic drugs, such as phenytoin and
carbamazepine, may reduce the risk of seizure associated with
subarachnoid blood and are sometimes given prophylactically.
This patient does not have evidence of seizures, however.
A 62 y/o woman has a 2-month history of mild confusion. She
occasionally has difficulty following a conversation. On the
morning of presentation to the hospital, she developed 30
seconds of right face twitching, followed by increased
confusion. Examination shows difficulties in speech
comprehension and a subtle right homonymous hemianopia. A
brain CT scan shows a 2 x 3 cm ill-defined region of low density
in the left parietal lobe. The most likely diagnosis is:
A) Multiple Sclerosis
B) Stroke
C) Astrocytoma
D) Abscess
E) Metastsis
Answer: C , the patient presents with a 2 month
history of progressive neurologic deficits. The CT
scan shows an area of low density, and there is no
mention of mass effect. The most likely diagnosis is
an astrocystoma, which may not have much in the
way of mass effect or enhancement on CT scan.
The progressive history is against a stroke. Multiple
sclerosis rarely presents in this age group and
would not be expected to cause a large area of
decreased density on CT scan. An abscess or
metastasis would have substantial mass effect and
enhancement on CT scan.
A 57 y/o male has a 2-month history of severe, daily
headaches that involve the right frontotemporoparietal area.
The headaches typically last 60-90 minutes and occur once
to twice daily. Over-the-counter medications have not
provided relief. Chiropractic manipulation did not help. The
patient is desperate for relief because he cannot work during
the headache episodes. A reasonable treatment strategy is
to initiate:
A) Baclofen
B) Amitriptyline
C) Indomethacin
D) Corticosteroids
E) Sumatriptan
Answer: C , the patient's history is suggestive of
paroxysmal hemicrania, an indomethacinresponsive disorder. In fact, a positive response
to treatment with indomethacin can confirm a
diagnosis of paroxysmal hemicrania. The rest of
the drugs listed are not considered to be
beneficial for paroxysmal hemicrania.
A 79 y/o female is brushing her teeth when she has an intense
sensation that the room is moving as if she were on a ship.
Examination and testing reveal a cerebellar stroke. Cerebellar
damage may be associated with severe vertigo if the tissue
damaged is in the distribution of the:
A) Superior Cerebellar Artery
B) Posterior Inferior Cerebellar Artery (PICA)
C) Anterior Inferior Cerebellar Artery (AICA)
D) Anterior Spinal Artery
E) Posterior Cerebral Artery
Answer: B , the PICA has both medial and lateral
branches. The medial branches supply the
brainstem. With occlusion of these, vestibular
nuclei in the brainstem are infarcted, and vertigo
is common. Even with an occlusion limited to the
lateral branches, vertigo is likely. If no brainstem
damage occurs, cerebellar flocculonodular lobule
injury may induce vertigo.
A 25 y/o female with a history of epilepsy presents to the
emergency room with impaired attention and unsteadiness of
gait. Her phenytoin level is 37. She has WBCs in her urine
and has a mildly elevated TSH. Examination of the eyes
would be most likely to show which of the following?
A) Weakness of abduction of the left eye
B) Lateral beating movement of the eyes
C) Impaired convergence
D) Papilledema
E) Impaired upward gaze
Answer: B , most rhythmic to-and-fro movements of the eyes are called
nystagmus. Nystagmus has a fast component in one direction and a slow
component in the opposite direction. Nystagmus with a fast component to the
right is called right-bearing nystagmus. Phenytoin (Dilantin) may evoke
nystagmus at levels of 20 to 30 mg/dL. The eye movements typically appear as a
laterally beating nystagmus on gaze to either side; this type of nystagmus is
called gazed-evoked. If the patient has nystagmus on looking directly forward, he
or she is said to have nystagmus in the position of primary gaze. Therapeutic
levels of phenytoin are usually 10 to 20 mg/dL, and some patients develop
asymptomatic nystagmus even within that range. Ataxia, dysarthria, impaired
judgement, and lethargy may also occur at toxic levels of phenytoin. Many other
drugs also evoke nystagmus. Weakness of abduction of the left eye, or abducens
palsy, is due either to injury to the 6th cranial nerve or to increased ICP
(intracranial pressure). Impaired convergence can occur normally with age or may
be a sign of injury to the midbrain. Papilledema is a sign of increased ICP.
Impaired upward gaze may occur in many conditions, but would not be expected
to occur with toxic phenytoin level.
A 56 y/o male with epilepsy is brought into the emergency
room. He has been having continuous generalized tonic-clonic
seizures for the past 30 minutes. He is treated with 2mg of
intravenous lorazepam. Most physicians recommend using a
high dose of intravenous benzodiazepine as part of the
management of status epilepticus because of its:
A) Ability to suppress seizure activity for more than 24 hours
after one injections
B) Lack of respiratory depressant action
C) Rapid onset of action after intravenous administration
D) Lack of hypotensive effects
E) Lack of dependance on hepatic function for its
metabolism and clearance
Answer: C , until recently, the most popular benzodiazepine
for use in status epilepticus was diazepam (Valium), which
has a rapid onset of action but is cleared relatively quickly.
Because of this property, patients needed additional
medications, such as phenytoin, to protect them from
recurrent seizure activity as early as 20 minutes after
diazepam injection. A longer-acting benzodiazepine,
lorazepam (Ativan), has the advantage of being rapid-acting
like diazepam but being cleared more slowly from the body.
After extraction of a wisdom tooth, an 18-year old male student
was diagnosed as having subacute bacterial endocarditis. He
has a congenital heart disease which has been under control.
Which of the following is the most likely organism causing his
infection?
(A) Enterococcus faecalis
(B) S. aureus
(C) S. epidermidis
(D) S. pneumoniae
(E) S. viridans
The patient's seizing does not stop. A second intravenous
drug is given. Infusing which of the following antiepilecptic
drugs at more than 50 mg/min in an adult may evoke a
cardiac arrhythmia?
A) Carbamazepine
B) Diazepam
C) Phenobarbital
D) Clonazepam
E) Phenytoin
Answer: E , rapid infusion of phenytoin may produce a conduction block or other
basis for cardiac arrhythmia. Phenytoin should not be administered at rates
greater than 50 mg/min in adults or 1 mg/(kg x minutes) in children to reduce the
chances of this reaction occurring. Thus, it usually requires approximately 20
minutes to administer 1000 to 1500 standard loading dose of phenytoin in an
emergent setting such as status epilepticus. Fosphenytoin, a water-soluble
prodrug of phenytoin that has recently become available, has the advantage of
causing fewer infusion reactions. It can be given at doses of up to 150 mg/min in
an adult, with risk of cardiac dysrhythmia similar to those of phenytoin. Another
advantage of fosphenytoin is that it can be administered intramuscularly when IV
access is problematic. Carbamazepine is not administered IV at all. Rapid
infusion of phenobarbital may produce hypotension or respiratory arrest, but is
much less likely to depress cardiac activity. Diazepam and clonazepam are safer
than phenobarbital, but rapid infusion of excessively high doses may depress
blood pressure and other autonomic functions.
An 18 y/o male brought into the emergency room after a
diving accident. He is awake and alert, has intact cranial
nerves, and is able to move his shoulders, but he cannot
move his arms or legs. He is flaccid and has a sensory level
at C5. Appropriate management includes:
A) Naloxone hydrocholoride
B) Intravenous methylprednisolone
C) Oral dexmethasone
D) Phenytoin 100mg TID
E) Hyperbaric oxygen therapy
Answer: B , high-dose intravenous methylprednisolone
(30mg/kg IV bolus followed by 5.4 mg/[kg x hour] for 23
hours) has been shown to have a statistically significant, if
clinically modest, benefit on the outcome after spinal cord
injury when given within 8 hours of the injury. Naloxone
hydrochloride and other agents, such as GM1 ganglioside,
have not been shown to be of benefit. The role of surgical
decompression, removal of hemorrhage, and correction of
bone displacement is controversial. Most American
neurosurgeons do not advocate surgery, and instead
propose external spinal fixation.
A 41 y/o homosexual male is brought to medical attention by
his partner because of headache, sluggish mentation, and
impaired ambulation worsening over the previous week. The
patient is known is known to be HIV-seropositive, but has
done well in the past and has not sought regular medical
attention. On examination, his responses are slow and he
has some difficulty sustaining attention. He has a right
hemiparesis with increased reflexes on the right. Routine cell
counts and chemistries are normal. A contrast head CT
reveals several ring-enhancing lesions. Eventually surgical
aspiration of one of the lesions reveals that they are
abscesses.
Abscesses in the brain most often develop from?
A) Hematogenous spread of infection
B) Penetrating head wounds
C) Superinfection of neoplastic foci
D) Dental trauma
E) Neurosurgical intervention
Answer: A , there are many bases for abscess formation
in the brain, but the most frequent causes are blood-borne
infections from sources in the lung, heart, sinuses, and
ears. Extension of infection from a chronic otitis or
mastoiditis was much more common before the
introduction of antibiotics. Facial or dental infections may
spread to the brain through valveless veins draining about
the muscles of mastication and communicating with the
venous drainage of the brain.
The most common site for abscess formation in the brain is
the:
A) Putamen
B) Thalamus
C) Sueprinfection of neoplastic foci
D) Gray-white junction
E) Subthalamus
Answer: D , brain abscess usually start from a
microscopic focus of infection at the junction of gray
matter and white matter. As the infection develops, a
cerebritis appears, and subsequently this focus of
infection becomes necrotic and liquefies. Around the
enlarging abscess there is usually a large area of
edema.
1) Most common organism found in brain abscesses are:
Answer: Streptococcal , both anaerobic and aerobic bacteria occur in
more than half of allbrain abscesses. Staphyloccocus aureus most often
occurs in patients who have had penetrating head wounds or have
undergone neurosurgical procedures. Enteric bacteria (E. coli, proteus,
and pseudomonas) account for twice as many abscess as S. aureus.
2) Most common abscess in AIDS patients?
Answer: Toxoplasma gondii (most common), then Cryptococcus,
Candida, Mucor, and Aspergillus.
Questions?