Common Brain Lesions

Question 1

Disinhibition and deficits in concentration, orientation, judgment; may have reemergence of primitive reflexes, and personality changes.

Answer 1

Frontal lobe lesion

Question 2

Eyes look toward (destructive) side of lesion. In seizures (irritative), eyes look away from side of the lesion.

Answer 2

Frontal eye fields

Question 3

Eyes look away from side of lesion. Associated with ipsilateral gaze palsy (inability to look toward side of lesion).

Answer 3

Paramedian pontine reticular formation (PPRF)

Question 4

Inter nuclear ophthalmoplegia (impaired adduction of ipsilateral eye; nystagmus of contralateral eye with abduction). Seen in patients with multiple sclerosis.

Answer 4

Medial Longitudinal fasciculus

Question 5

Lesion is characterized by agraphia, acalculia, agnostic of the fingers, and left-right disorientation. —> Gerstmann syndrome

Answer 5

Dominant Parietal cortex (if right handed, then its the left side)

Question 6

Agnostic of the contralateral side of the world. Associated with hemi-spatial neglect syndrome (makeup on only half of the face).

Answer 6

Nondominant parietal cortex (if right handed, then typically right side).

Question 7

Anterograde amnesia-inability to make new memories.

Answer 7

Hippocampus (bilateral)

Question 8

Contralateral hemiballismus (involuntary flailing of the limbs).

Answer 8

Subthalamic nucleus

Question 9

Wernicke-Korsakoff syndrome - Confusion, ataxia, nystagmus, ophthalmoplegia, memory loss (anterograde and retrograde amnesia), confabulation, personality changes. Seen in chronic alcoholics due to thiamine deficiency.

Answer 9

Mammillary bodies (bilateral)

Question 10

May result in tremor at rest, chorea, athetosis. Associated with patients with Parkinson’s disease and Huntington’s disease.

Answer 10

Basal ganglia

Question 11

Klüver-Bucy Syndrome - disinhibited behavior (e.g. hyperphagia, hypersexuality, hyperorality). Can be caused by HSV-1 encephalitis.

Answer 11

Amygdala (bilateral)

Question 12

Associated with Perinaud syndrome - vertical gaze palsy, pupillary light-near dissociation, lid retraction, convergence-retraction nystagmus. Assoc. with stroke, hydrocephalus, pinealoma.

Answer 12

Dorsal midbrain (superior colliculi)

Question 13

Reduced levels of arousal and wakefulness (eg, coma).

Answer 13

Reticular activating system (midbrain)

Question 14

Intention tremor, limb ataxia, loss of balance; damage to cerebellum —> ipsilateral deficits; fall toward side of lesion. Cerebellar hemispheres are laterally located—affect lateral limbs.

Answer 14

Cerebellar hemisphere

Question 15

Decorticating (flexor) posturing - lesion above ____ nucleus, presents with flexion of upper extremities ion of lower extremities. Decerebrate (extensor) posturing - lesion at or below _____ nucleus, presents with extension of upper and lower extremities. Worse prognosis with decerebrate posturing. In decorticate posturing, hands are near the cor (heart)

Answer 15

Red Nucleus

Question 16

Truncated ataxia (wide based, “drunken sailor” gait), dysarthria. ________ is centrally located - affects central body. Degeneration associated with chronic alcohol use.

Answer 16

Cerebellar vermis

Question 17

Epidural hematoma - where/what is the associated intracranial hemorrhage? What is the shape seen on imaging?

Answer 17

Rupture of middle meningeal artery (branch of maxillary artery)

Shape: Biconcave disk - eyepidural hematoma!

Question 18

Subdural hematoma - where/what is the associated intracranial hemorrhage? What shape is seen on imaging?

Answer 18

Rupture of bridging veins

Shape: Crescent!

Question 19

Subarachnoid hemorrhage - where/what is the associated intracranial hemorrhage?

Answer 19

Rupture of an aneurysm (such as a saccular aneurysm) or arteriorvenous malformation. Rapid course

Question 20

Intraparenchymal hemorrhage - where/what is the associated intracranial hemorrhage?

Answer 20

MCC is systemic hypertension. Also seen with amyloid angiopathy (recurrent lobar hemorrhagic stroke in elderly)

Question 21

If the right vagus nerve or nuclei is damaged, then to which side will the uvula deviate?

Answer 21

(Left) Opposite side of the lesion - since the muscles of the left soft palate work to raise it and the muscles of the right do not, the uvula will deviate to the left.

Question 22

If a patient presents with damage to the right hypoglossal nerve or nucleus, to which side will the tongue deviate when sticking out?

Answer 22

Since innervation is Ipsilateral, the tongue will be pushed to the affected side because the tongue muscles are not working (no opposing action).

Question 23

If the portion of the right motor cortex (or right corticobulbar tract) that innervates the tongue is damaged, to which side will the tongue deviate?

Answer 23

Left - because the tongue fibers from the right motor cortex travel to the left hypoglossal nucleus, the tongue will deviate to the left (away from the side of the motor cortex lesion because of the Ipsilateral innervation from the nucleus).

Question 24

How do the symptoms of a lesion to the cortical motor region of the face differ from a lesion of the facial nerve or nucleus?

Answer 24

Lesion of cortical motor face- paralysis of contralateral side of LOWER FACE

Lesion of facial nerve or nucleus - paralysis of Ipsilateral side of ENTIRE FACE

This is BC motor cortex of face is divided into upper and lower face; upper face receives signals from both motor cortices. Thus if a lesion to left motor cortex occurs, enough fibers from RU face exist and is ok. Left motor cortex only innervates right lower face, so paralysis occurs only in the R lower face.

Question 25

28 YO F is involved in a MVA, she initially feels fine but minutes later looses consciousness. A CT scan reveals intercranial hemorrhage that does not cross suture line. What bone and vessel are most likely injured in the crash?

Answer 25

Epidural hematoma - due to rupture of the middle meningeal artery, caused by injury to the temporal bone.