Venous system
Cerebral venous system
• Superficial system:
– Drains into the venous
synuses
• Central system
– Drain in a large, short venous
trunk – the great vein of Galien
• Basal system
– Drains the blood into the
basilar vein and then to the
great vein of Galien
• Jugular veins
Cerebral venous trombosys
• Causes:
• Infectious – significantly decreased since antibiotics
– Local
– General
• Non infectious
– Local: trauma, surgical interventions, tumors, arterialtrombosys,
malformations
– General: surgicale, pregnancy, post partum/post abortum, drugs,
dehydration, advanced liver or kidney disease
• Idiopatic
Cerebral venous trombosys
• Venous synus thrombosis:
– Increased pressure in the preceding veins (depending on the
anastomosys system)
– increased intracranial pressre
• Superior longitudinal synus: role in resorbtion of the CSF
• Cerebral veins thrombosys
– Secondary hemorrhage is more frequent
– Cerebral edema, venous infarcts
– Seizures
Cerebral venous trombosys
• Clinical picture:
– Increased intracranian pressure (headache, nausea, papillary
edema, consciousness abnormalities)
– Focal or generalized seizures
– Meningean syndrome
– Focal signs
– Septic CVT: fever, other signs of severe infection
Cerebral venous trombosys
• Cavernous synus thrombosys
– Staphilococcus infections of the face, orbitary, synuses, teeth
other ENT infections
– Trauma
– Usually the clinical picture is marked by the septic syndrome
– Venous stasis:
• Palpebral edema, chemosis, exoftalmia
• VI-th and then IIIrd, IV-th, and ophtalmic ramus of the Vth nerves
palsies
– Often clinical signs are bilateral – the 2 synuses are conected
Cerebral venous trombosys
• Investigations
– CT, MRI
• Thrombus image
• Empty vessel (CT with contrast substance)
• Infarctus or hemorrhages images
– Arteriography
– CSF analysis – differential diagnosys of an infection
– EEG, funduscopy
• Treatment:
• Etyologic treatment
• Antithrombotic treatment (anticoagulants)
• Treatment of cerebral edema, raised intracranian pressure, seizures
Brainstem alternate syndroms
Medullary alternate syndromes
• A combination of the following, in various degrees,
depending on the exact position and size of the lesion:
• On the same side with the lesion
– Nucleus ambigus, vagus nerve nucleus, hipoglossal nerve
nucleus, accesory nerve nucleus
• Palatal weakness, bitonal voice,
• Tongue atrophies
• sternocleidomastoidian and trapesus muscle palsy,
• On the opposide side
– Loss of temperature and pain sensation
– Hemiparesis
Lateral medullary syndrome
(Wallenberg syndrome)
• This is the commonest of the
brain stem strokes
• Vertebral artery or posteroinferior cerebellar artery
• Sudden onset
– Intense vertigo, vomit, balance
problems, hiccup
• Most of the times: favourable
evolution
Lateral medullary
syndrome
(Wallenberg syndrome)
•
On the same side with the lesion:
– Involvement of the descending nucleus and tract of Vth nerve results in loss of pain
and temperature sensation on the face
– Vestibular syndrome
– Swallowing problems, palatal weakness and dysphagia - bitonal voice (involvement
of the nucleus ambiguus, IXth, Xth, XIth nerver palsy)
– Horner’ syndrome (involvement of descending autonomic fibers )
– Involvement of the inferior cerebellar peduncle (restiform body) causes ipsilateral
ataxia
•
On the opposite side:
– Loss of pain and temperature sensation
– Sometimes discrete hemiparesis
Infarction of the base of the pons
• In bylateral lesions: corticospinal and corticobulbar tracts
in the basis pontis are interrupted
• Locked in syndrome
– Tetraplegia, billateral facial palsy, billateral palsy of the abducens
nerve
– Vertical gaze is maintained
– Consciousness/higher functions are maintained, but the patient is
unable to speak or move
• Lesion spares the reticular formation above the caudal pons, and
therefore the patients remain awake
• The only way to communicate with these unfortunate patients is to
ask them to move their eyes in response to questions.
Millard-Gubler syndrome (pontine inferior)
• On the same side with the
lesion
– Peripheral facial palsy
– External oculomotor (VIth
nerve) palsy
• On the opposite side
– hemiplegia
Pontine lesions
• Lesions of the sixth nerve nucleus
– paralysis of gaze to the side of the lesion.
– Internuclear palsy (fibers from the opposite 6th nerve nucleus are
involved as they cross to the MLF, there is also weakness of the
ipsilateral medial rectus muscle).
• The ipsilateral seventh nerve can be involved since its
fibers course around the sixth nerve nucleus.
• Involvement of the medial lemniscus
– contralateral loss of position and vibration sense
• descending corticospinal fibers in the base of the pons
– contralateral hemiparesis
Midbrain syndromes: Weber syndrome
• Are involved
– the descending corticospinal and
corticobulbar fibers in the
cerebral peduncle, and
– the fibers of the third nerve that
traverse the peduncle on exiting
the midbrain.
• On the opposite side:
hemiparesis
• On the lesion’s side: third nerve
palsy (ptosis, inability to move
the eye up, down or medially,
and [if fibers from the EdingerWestphal nucleus are involved]
pupillary dilitation).
Red nucleus syndromes
•
Third nerve palsy on the same
side, cerebellar syndrome on the
opposite side, chorea, thalamic
sensory syndromes
•
Chorea
•
Benedikt's syndrome
– homolateral third nerve palsy
– contralateral ataxia,
– midbrain stroke involving the third
nerve as it travels near the red
nucleus. A lesion of the red
nucleus interrupts fibers from the
opposite cerebellar hemisphere
(dentate nucleus of the cerebellum
superior cerebellar peduncle
crossing in midbrain red nucleus
VA/VL thalamus).
Cerebral lobe syndromes
Frontal lobe
Frontal lobe
• Highest level of brain evolution
• Involved in many functions
• Lesions in different parts lead to different syndromes
Frontal lobe
Frontal lobe syndrome
• Lesions of the motor area lead to motor deficits of the opposite half of
the body
– Irritative lesions – jacksonian motor seizures
• Lesions of premotor areas – less important motor deficit
– Irritative lesions in premotor areas – “adversive” seizures, or
supplementary motor area seizures
– Supplementary motor area seizures: cessation of all activity, tonical
contractions of proximal muscles, repetitions, pallilalia
– Premotory areas lesions: diminishment of spontaneous movements,
delay of voluntary actions (movements), eventually hyopkinesia,
akinesia, tremor
– Forced prehension
– Gait and posture abnormalities; frontal ataxia
Frontal lobe syndrome
• Prefrontal areas lesions
– Alteration of personality
– Diminishment of spontaneous activity - the patient does not feel the
need to do anything, is not able to plan the future events, may be
agitated
– Attention deficits – memory is normal, but the patient doesn’t bother to
use it
– Loss of abstract thinking
– Perseveration
– Afffective changes – either apathic, “flat”, either excessively exuberant
and childish; may show lack of inhibition, eventually sexually improper
actions
Frontal lobe syndrome
– Prefrontal dorsolateral cortex lesions
• Diminished fluency (verbal & nonverbal),
reasoning problems, reduction of spontaneous
responses inhibition, perseveration, attention
deficits
– Orbitofrontal cortex lesions – desinhibition,
anosmia
– Mezial frontal cortex, anterior cingullary
cortex lesions – apathy, abulia, memory
impairments
Cognitive function testing in frontal lobe
lesions
– MMS does not approach these problems
– Frontal lobe tests:
• “go-no go” tests – patient is told to lift 2 fingers, but the
evaluator lifts only 1
• Speech fluency – patient is asked to produce as many
words he can starting with letter “Z” – normally more
than 8 words/ 1 min
• Motor tests for perseveration – patient is asked to
execute series of 3 movements (fist, edge-palm tests –
Luria)
Parietal lobe
Parietal lobe
•
Anterior somatosensory area,
posterior association area
•
4th neuron of sensory tracts
(3, 1, 2 areas – primary
somatosensory cortex
•
5, 7, 39, 40 areas –
somatosensory association
areas; areas 5 and 7 are
important for stereognosis
•
Parietal regions appear when
the singers are used for more
than just mobility (catching,
throwing)
Parietal lobe syndromes
• Controlateral hemihypestesia (diminished sensation)
• Astereognosis (5 & 7 areas lesions)
• Sensory epilepsy (paresiae and sometimes paroxistical
pain)
• Asomatognosia (left hemisphere lesions lead to one side
asomatognosia, anosognosia, anosodiaforia, neglect of left
body half)
• Right parietal lobe – spatial component of activities
– Apraxia – loss of the ability to execute or carry out learned
purposeful movements, despite having the desire and the physical
ability to perform the movements
– Finger agnosia
– Left-right agnosia
Parietal lobe syndromes
• Left parietal lobe – symbol and experiences comprehension
– ideomotor (inability to carry out a motor command or a learned gesture,
for example, "act as if you are brushing your teeth" or "salute")
• limb apraxia when movements of the arms and legs are involved,
• nonverbal-oral or buccofacial (inability to carry out facial movements on
command, e.g., lick lips, whistle, cough, or wink),
– ideational (inability to create a plan for or idea of a specific movement,
for example, "pick up this pen and write down your name")
– Inability to use the informations on spatial relations
• Constructive apraxia
• Topographic agnosia
• Prosopagnosia
Parietal lobe syndromes
• Speech problems – frequently
associated with writing problems
• Motor abnormalities (diminishment
of spontaneous movements,
unstable hand, syncynesia)
• Balance problems
• Taste problems (area 43)
• hemianopia
Parietal lobe syndromes
• Gerstmann
syndrome (left
angulary girus)
• Digital agnosia
• Left-right confusion
• Agraphia
• Acalculia
Parietal lobe syndromes
•
Balint syndrome (bilateral posterior parietal
lesions)
– Patient looks only at 35-40 degrees to the right,
and describes only the objects in that area
– Can look at only one object a time
– Neglect of left hemispace
– Tactile functions impairment
– Visual or tactile agnosia
– Apraxia
– Speech problems (alexia, aphasia)
– Dyscalculia
– Immediate memory impairment
– Body scheme abnormalities
– Left-right confusion
– Problems with space orientation
– Eye movements problems
Parietal lobe
Constructive apraxia
• Adaptative
possibilities of
parietal lobes –
blind boy “reads”
with the tip of his
nose
Temporal lobe
Temporal lobe
• Below the sylvian sulcus, extends up to the limits of the parietal and
occipital lobes
• Primary and secondary auditory areas (41, 42), association areas
(38, 20, 21, 22);
– Taste (area 38)
– Areas 41 and 42: perception and comprehension of sounds, comprehension of
words
• Lymbic system (hyppocampic uncus, hypocampus, girus cinguli,
subcallosal areas, olfactory areas)- emotions and affect
• Optic radiations
• Left temporal lobe – comprehension and recognition of words,
language
• Right temporal lobe – intonation, music
Sindroame de lob temporal
•
Lezarea lobului temporal
–
–
tulburari de auz, echilibru, gust, miros, limbaj, vedere, memorie, comportament alimentar,
comportament sexual.
Convulsiile cu originea in aceste arii se manifesta ca si asocieri de tulburari ale ratiunii,
halucinatii, comportament anormal, detasat sau violent, necontrolabil
•
Afectarea auzului – lezarea ariei 41; leziune unilaterala – hipoacuzie; leziuni
bilaterale – surditate corticala. Leziunile iritative (epilepsie temporala) apar iluzii
auditive, halucinatii auditive
•
Tulburarile de echilibru – atacuri de vertij, uneori cu ataxie
•
Tulburarile de gust si miros – halucinatii olfactive pot apare ca parte a crizelor
epileptice. Distrugerea ariei olfactive din uncusul hipocampic si extinderea leziunilor
spre girusul hipocampic duc la anosmie. Halucinatiile olfactive pot uneori precede
convulsiile (aura)
•
Afectarea vizuala – hemianopsie, afectarea memoriei vizuale
•
Tulburari de vorbire de tip afazic receptiv (afazie Wernicke) – leziuni ale
ariei posteroinferioare a girusului temporal superior stang
Sindroame de lob temporal
• Tulburari de memorie
–
–
–
–
–
–
Tulburarile memoriei recente – leziuni hipocampice
inferioare bilaterale.
Lezarea bilaterala a corpilor mamilari duce la
afectarea memoriei pe termen scurt
Afectarea memoriei pentru cuvinte
Afectarea memoriei pentru cuvinte in leziunile
hipocampice inferioare bilaterale
Afectarea memoriei de lunga durata – leziuni
mamilotalamice sau leziuni corticale bilaterale
Inmagazinarea de elemente noi si intelegerea
acestora se realizeaza prin intermediul circuitului lui
Papez (hipocamp, corpi mamilari, talamus, girus
cinguli)
• Tulburari ale comportamentului
alimentar si sexual – nu numai in leziuni ale
lobului temporal, ci si in leziuni hipotalamice
• Epilepsia de lob temporal
–
–
–
Diagnostic electroencefalografic
Halucinatii psihosenzoriale simple sau complexe,
episoade de afazie, halucinatii olfactive sau auditive
Tulburarile de recunoastere si amintire – déjà vu,
deja pense, jamais vu
Papez circuit
•
•
•
•
James Papez in 1937
One of the major pathways of the limbic system
Chiefly involved in the cortical control of emotion.
Role in storing memory.
Sindromul Kluver Bucy
• Heinrich Kluver si Paul
Bucy, 1939
• Lobectomie temporala
bilaterala – prima dovada
experimentala a
implicarii circuitului luii
Papez in expresia
emotionala
• Lipsa de afect, agnozie
vizuala, expresie sexuala
nediscriminata, pierdere
severa a memoriei
Occipital lobe
Lobul occipital
• O mica parte a portiunii dorsolaterale a emisferelor
• Functiile sunt legate de vedere
–
–
–
–
Perceptie vizuala
Recunoastere in relatie cu spatiul si timpul
Ariile 17, 18 si 19 Brodmann
Aria 17 (striata) este localizata la nivelul scizurii calcarine si in vecinatatea
acesteia; este centrul de receptie al informatiei vizuale (culoare, dimensiuni,
forma, miscare, iluminare, transparenta)
– Aria 18 (parastriat) si aria 19 (peristriat) ocupa restul suprafetei
interemisferice la nivel occipital, avand rol de cortex de asociatie
• Tulburarile care rezulta din lezarea lobului occipital pot fi de natura
iritativa sau datorate unui deficit, cu simptomatologie uni sau bilaterala
Sindroame de lob occipital
•
•
Leziuni iritative:
Halucinatii vizuale – simple (elementare) sau complexe, avand aspecte
senzitive si cognitive
– Halucinatiile elementare includ stele, flashuri luminoase, culori, lumini forme
geometrice (cercuri, patrate, hexagoane), care pot fi mobile sau stationare (zigzag,
oscilatii, vibratii, pulsatii)
– Halucinatiile complexe include obiecte, persoane, animale de dimensiuni normale,
foarte mici sau foarte mari. Pacientul poate constientiza natura ireala a acestora
sau poate fi convins ca sunt reale.
•
Iluzii vizuale (metamorfopsia) – distorsionarea obiectelor (forma, dimensiuni,
culoare, miscare)
– Imaginile pot sau nu sa evoce amintiri vizuale. Efectul cumulat este asemanator cu
starea de vis care apare in epilepsia temporala.
– Micropsie, macropsie sau megalopsie, obiecte in miscare spre subiect, alungite,
umflate, modificari ale dimensiunilor orizontale sau verticale
– Coloratii iluzorii (erithropsia), lipsa culorilor (acromatopsia), vedere inversa,
iradierea contururilor, poliopie (un obiect apare multiplicat), diplopie monoculara,
iluzii de miscare a obiectelor stationare
– Pierderea vederii spatiale, reaparitia periodica a unor imagini dupa ce ele au incetat
sa se mai afle in campul vizual (palinopie sau palinopsie), o falsa orientare a
obiectelor in spatiu (allestezie optica)
•
Epilepsia de lob occipital – halucinatii vizuale elementare, care se misca sau
nu in campul vizual
Sindroame de lob occipital
• Sindroame de deficit
• Agnozia pentru culori – pierderea perceptiei corecte pentru o
culoare, imposibilitatea denumirii culorilor, a identificarii lor
• Leziunile distructive unilaterale duc la hemianopsie controlaterala
omonima (pierderea partiala sau completa a vederii care se
proiecteaza in aria corticala occipitala primara
• Cecitatea corticala apare atunci cand ambele arii vizuale primare din
lobul occipital sunt lezate.
– Pacientul nu este capabil sa proceseze informatia vizuala si se comporta
ca si in cazul unei cecitati periferice.
– Unii pacienti incearca totusi sa se comporte ca si cum ar vedea (nu isi
recunosc cecitatea). Acest tip de cecitate corticala se numeste sindromul
Anton, si are asociate leziuni parietale si neglijare senzitiva, in unele
cazuri si pentru alte modalitati ale sensibilitatii.
Sindroame de lob occipital
•
•
•
•
Leziunile ariilor 18 si 19 din emisferul dominant duc la agnozie vizuala
pentru obiecte (acestea pot fi recunoscute prin intermediul altor
simturi); de obicei este insotita de agnozie verbala si hemianopie
omonima.
Dislexia – tulburari de recunoastere a cuvantului scris. Cecitatea
pentru cuvinte este o tulburare rara (cortexul vizual primar este intact,
leziunea se afla in cortexul occipital de asociere pe partea stanga)
Prosopagnozia – leziunile sunt localizate in regiunile de asociere
ventromediala si occipitotemporala; frecvent insotita de agnozie pentru
culori
Sindromul Balint
– Lezarea bilaterala a lobilor occipitali, cel mai frecvent in ariile de granita (19
si 17) ale regiunii parieto occipitale
– Imposibilitatea dirijarii corecte a oculomotricitatii in timpul explorarii
spatiului; imposibilitatea privirii voluntare si a scanarii spatiului periferic,
imposibilitatea de a apuca si de a atinge un obiect cu ghidare vizuala.
– Inatentia vizuala care afecteaza in primul rand periferia campului vizual