neurology 2 Flashcards
what is anisocoria
asymmetry of pupils. one needs to determine which pupil is abnormal, It can be done by observing pupils in bright and dim light settings
For anisocoria evaluation the dim light should increase oculosympathetic input and cause pupillary dilatation
so if in dim light the asymmetry increases—- it means smaller pupil is paralysed —- unable to dilate and normal one dilates increasing the difference.
In bright light asymmetery will reduce because parasympathetic CN3 induced miosis woulld still occurs in both eyes.
if asymmetry in anisocoria increases in bright light —it indicates ?
it indicates larger pupil which should ideally constrict in bright light is paralysis ie CN3 is not working properly
what is relative afferent pupillary defect
afferent pathway problem in pupillary reflex – ie retina or optic nerve abnormal.
it is decreased bilateral pupillary constriction in response to light in affected eye
associated with mono-ocular vision loss.
which part is affected most in alzheimers disease
hippocampus and then temporoparietal lobes
what is clasp knife rigidity
seen in UMN lesions- spasticity
passive flexion should relax extensors because of stretch reflex.
However in UMN extensors are having increased tone and resists passive stretch
can be overcomed by continuing the movement. This is mediated by golgi tendon
nissls bodies in neurons are
rough endoplasmic reticulum
what are red neurons
disappearence of nissls granules (blue) from cytoplasm of neurons gives it red colour.
Seen in acute irreversible ischemic injury.
what is axonal reaction
seen in nerve transection.
Cell body enlarges, nucleus pushed to periphery, nucleolus enlarges and nissles bodies are dispersed. in an effort for protein and lipid synthesis to regenerate the transected axon.
normal function of trochlear nerve
supplies superior oblique muscle– it intorts the eye and depresses it when adducted.
signs of trochlear nerve palsy
patients say they cannot see FLOOR
eye is in extortion and hypertropia (visual axis above the normal eye) . Patient has vertical diplopia
patient usually chin tucks and head tilts away from the side affected to compensate.
signs of abducens palsy
horizontal diplopia and invard deviation (esotropia)
aneurysm of ICA can impinge
lateral fibres of optic chiasma leading to ipsilateral nasal hemianopsia.
aneurysm of PCA can impinge and compress
3rd CN
contralateral homonymous hemianopsia with macular sparing
right primary visual cortex- occipital lobe. due to occlusion of PCA
macula is supplied by MCA and PCA and hence spared.
what is dialysis associated nerve compression?
these compressions affects hands bilaterally
beta2 microglobulin accumulates in carpal tunnel leading to median nerve compression
convergence pathway and pupillary light reflex in eyes bypasses
MLF medial longitudinal fasciculus
what is lateral geniculate nucleus
it is visual information (sensory) relaying centre. It relays vision to cortex.
damage to lateral geniculate thalamic nucleus causes contralateral homonymous hemianopia
upward (vertical gaze palsy - superior colliculus), absent pupillary light reflex and absend / impaired convergence
tectal midbrain lesions where superior colliculus is there- parinaud syndrome.
examples of dystonia
spasmodic torticollis, blepharospasm, writers cramps etc
what causes hemiballism
contralateral injury in or near subthalamic nucleus… flinging of limbs on one side of body.
signs of spinal accessory nerve injury distally in posterior triangle of neck
shoulder drooping
no overhead abduction above 100 degrees
lateral displacement of scapula.
middle meningeal artery branch of maxillary artery - terminal branch of ECA enters skull via?
foramen spinosum
decreased acetylcholine levels in hippocampus and NUCLEUS BASALIS OF MEYNERT
ALZHEIMERS DISEASE
because of deficiency of choline acetyl transferase enzyme.
location and function of nucleus basalis of meynert
it is located in basal forebrain.
widely projects into neocortex
functions for memory and cognition.
impaired in alzheimers disease
where is raphe nucleus located, what is its primary neurotransmitter
located in medial portion of reticular formation in ENTIRE brainstem.
neurons are serotonergic
impaired anorexia, depression and CIRCARDIUM RHYTHM -sleep disturbances,
WHERE IS RETICULAR ACTIVATING SYSTEM LOCATED
THROUGHOUT THE BRAIN STEM
WHAT ARE THE 4 COMPONENTS / SUBPORTIONS OF RETICULAR ACTIVATING SYSTEM
LOCUS COERULEUS
RAPHE NUCLEUS
POSTERIOR TUBERO-MAMILLARY HYPOTHALAMUS
PEDUNCULO-PONTINE TEGMENTUM
FUNCTIONS OF RAS RETICULAR ACTIVATING SYSTEM
ATTENTION
AROUSAL
ABILITY TO FOCUS
MODULATES THE MUSCLE TONE
HOW IS RAS ACTIVATED
WHEN IT RECIEVES SIGNALS FROM LATERAL HYPOTHALAMUS
LATERAL HYPOTHALAMUS IN TURN RELEASES OREXIN WHEN LIGHT STRIKES EYE THAT IS WHN THE PATIENT IS AWAKE
WHERE IS LOCUS COERULUS LOCATED
HOW DOES IT GET ACTIVATED
WHAT DOES IT SECRETE
DORSOLATERAL PONS UPPER PART
OREXIN FROM LATERAL HYPOTHALAMUS ACTIVATES IT
IT SECRETES NOR EPINEPHRINE
WHAT DOES TUBEROMAMILLARY NUCLEI IN HYPOTHALAMUS SECRETE
HISTAMINE– THEY ARE PRIMARY HISTAMINE PRODUCING REGION
CAUSE OF PATIENT DEATH IN HUNTINGTONS DZ
SUICIDE
RESPIRATORY ASPIRATION
CAUSES OF NEURONAL DEATH IN HUNTINGTON DZ– ATROPHY OF CAUDATE AND PUTAMEN
DOPAMINE INCREASES
ACH AND GABA DECREASES
HENCE GLUTAMATE EXCITOTOXICITY — NMDA-R BINDING
NEURONS EXCITED TOO MUCH AND DEATH
because mutated huntingtin protein contains numerous glutamate residues due to CAG repeats – more excitotoxicity
what inclusions are found in frontotemporal dementia
picks inclusions these are intracytoplasmic round inclusions of hyperphosphorylated tau protein
or
ubiquitinated TDP-43 proteins
visual hallucinations are seen in which dementia
lewy body dementia
lewy body intracellular eosinophillic inclusions are seenn in
parkinsons disease
lewy body dementia (will be associated with visual hallucinations and REM sleep disturbances)
startle myoclonus is seen in
CJD disease
symptoms of CJD
startle myoclonus dementia ataxia with periodic sharp waves on EEG and elevated 14-3-3 protein in CSF highly specific
elevated 14-3-3 protein in CSF is diagnostic of
creutzfeldt jacob disease
opsoclonus myoclonus syndrome is
paraneoplastic syndrome associated with
- small cell lung ca
- neuroblastoma in babies
what is the pathophysiology of papilloedema
raised ICT causes break or obstruction in axoplasmic flow of optic nerve
papilloedema is seen on visual field mapping as
optic disc edema- -ie enlarged blind spot and peripheral visual field constriction.
what is optic nerve sheath fenestration surgery
nicks / incision on optic nerve meninges to relieve intracranial tension effects
triad of normal pressure hydrocephalus
gait apraxia (magnetic gait- patient loses concentration over walking- tendency to freeze unable to initiate gait) urinary incontinence cognitive dysfunction
painful unilateral vision loss with marcus gunn pupil is associated with
acute optic neuritis
seen in MS
Internuclear ophthalmoplegia is commonly seen with
MULTIPLE SCLEROSIS
WHAT IS THE MNEMONIC TO REMEMBER INTERNUCLEAR OPHTHALMOPLEGIA INO
INO
ipsilateral eye has adduction failure
nystagmus in opposite eye
eg in patient with right INO– the right eye remains central shows adduction failure and left normal eyes goes into nystagmus on lateral gaze
why does normal eye go into nystagmus in INO internuclear ophthalmoplegia
because opposite MLF is damaged leading to no cn 3 and medial rectus function and hence adduction failure
to over come it – normal eye overfires cn6 – lateral recuts over works – nystagmus
what is the name of symptom– electric shock like sensation in cervical spine on neck flexion
LHERMITTE PHENOMENON
SEEN IN MS
WHAT ARE DISEASE MODIFYING DRUGS IN MULTIPLE SCLEROSIS
BETA INTERFERON
GLATIRA-MER
NATALI-ZUMAB
SPASTICITY OF MULTIPLE SCLEROSIS IS TREATED WITH
BACLOFEN
GABA -B RECEPTOR AGONISTS
WHAT IS AIDP
ACUTE INFLAMMATORY DEMYELINATING POLYRADICULOPATHY
SUBTYPE OF GBS
what is CSFhallmark of AIDP or GBS
albuminocytologic dissociated
albumin is raised
cell count is normal
if GBS symptoms stay for more than 2 months it is called
chronic IDP inflammatory demyelinating polyneuropathy
autoantibodies diagnositic in CIDP
GM1 gangliosides
hereditory motor and sensory peripheral nerve neuropathy is
charcot marie tooth disease
key clues in charcot marie tooth disease
pes cavus hammer toes inverted bottle shaped atrophy in legs foot drop sensory deficits
which is the most common charcot marie tooth diease and its gene
CMT 1a
caused by PMP22 gene duplication
PML progressive multifocal leukoencephalopathy is seen in
aids
natalizumab rituximab and immunosuppression recieving patients
episcleral hemangioma is seen in
sturge weber syndrome—
can lead to increased IOP and early onset glaucoma
genetic mutation in sturge weber syndrome
one copy of GNAQ (guanine nucleotide G(q) binding protein -alpha subunit)
this one copy undergoes somatic mosaicism activating mutation
when GNAQ gene one of the copy gets activating mutation it lead to
sturge weber syndrome— proliferation of capillary sized vessels — leptomeningeal angiomatosis
why – GNAQ– alpha subunit binds GTP and causes signalling for regulation and development of blood vessels. a mutated GNAQ cannot be turned off… leads to angiomas.
which tumor supressor genes are affected in tuberous sclerosis
TSC1 on chr 9
TSC2 on chr16
sphenoid wing dysplasia leading to exophthalmos and facial asymmetry is seen in
NF 1
what 4 diseases / characteristics can be seen in NF2
bilateral vestibular schwannoma
meningioma
ependymoma
juvenile cataracts
AD usually family history of meningioma or bilateral SNHL present
two neurocutaneous syndrome which can have pheochromocytoma
VHL disease
NF1
genetics of VHL mutation
VHL produces a protein which ubiquitinates (tags or marks) another protein HIF hypoxia inducible factor for degradation.
Normally HIF senses hypoxia and causes RBC proliferation by regulating erythropoeitin
when VHL is mutated. It cannot stop HIF and hence more erythropoeitin and BV proliferation tumour (hemangioblastomas) develop
VHL gene mutation and hemangioblastoma has which hormone increase
erythropoietin — hence polycythemia
three most common primaries metastatising to brain
lung
breast
kidney
function of astrocytes
physical support and BBB repair and reactive gliosis formation extracellular K buffer glycogen fuel reserve removes excess neurotransmitter
why is meningioma common in female
because meningioma pathogenesis has positive growth role of estrogen
pseudopalisading cells around necrosis is one feature of GBM
what is the other important features
endothelial cell proliferation- microvascular proliferation– these tumours have bleed areas on cut section
whorled pattern of cells with psammoma bodies (laminated calcification)
meningioma
s-100 positive tumour
schwannoma — s for s
histology of schwannoma
dense and light cellular areas
dense cellular areas – have spindle cells (antoni A)
hypocellular areas have myxoid matrix (antoni B)
fried egg cells— round nuclei with clear cytoplasm
chicken wire capillary pattern
oligodendroglioma
eggs and chicken
most common tumour in children GFAP positive tumour in children
pilocytic astrocytoma- cystic with enhancing mural nodule
histology of pilocytic astrocytoma
origin is astrocyte with shows pink thick ROSENTHAL CORKSCREW fibres.
CELL WHICH GIVES RISE TO MOST COMMON TUMOUR IN CHILD AS WELL AS ADULT IS
ASTROCYTES
CHILD - PILOCYTIC ASTROCYTOMA
ADULT - GBM
BELLS PALSY CAN BE PERIPHERAL OR CENTRAL
HOW TO ASCERTAIN
IN CENTRAL - pt is able to wrinkle forehead
in peripheral no wrinkling of forehead
bilateral bells palsy is also known as facial diplegia. It is seen in
lymes disease
neurosarcoidosis
GBS
melkerson rosenthal syndrome— (lip and mouth swelling from granulomatosis, tongue furrows and recurrent bilateral facial palsy)
what are homer wright rosettes
seen in medulloblastoma (type of PNET round cell tumour)
round blue cells rosette around pink areas of neuritic processes
in exam histo shows palisading pattern with central vessel
ependymoma
in exam histo —-palisading pattern with central acellular pink area ie necrosis
GBM
patho signs of ependymoma
perivascular pseudorosettes and rod shaped basal ciliary bodies near nucleus (blepharoplasts)
pituitary region tumour in a child gross cut surface shows motor oil like fluid what is it
they are cholesterol crystals in craniopharyngioma
pinealoblastoma is associated with
precocious puberty because it secretes Bhcg
vertical gaze palsy - tectal compression parinaud syndrome
obstructive hydrocephalus because of aqueductal compression.
pineal tumour closely resembles which other germ cell tumour
testicular seminoma
grandfather gets huntingtons at 60
father gets at 50 and son gets at 40
what is this phenomenon of earlier onset in subsequent generations
ANTICIPATION
BECAUSE GERM CELLS CONTINUE AND HAVE INCREASED TRINUCLEOTIDE REPEATS
MORE IN SPERMATOGENESIS
HENCE FATHER TO SON TO SON WOULD HAVE ANTICIPATION PHENOMENON
WHAT IS THE CAUSE OF SPONGIFORM ENCEPHALOPATHY
PRION PROTEINS
B SHEETS WHICH CANNOT BE DEGRADED AND ACCUMULATES IN NEURONS AND GLIAL CELLS
LEADING TO INTRACELLULAR VACUOLES
b sheets cause more conversion of pre-existing normal alpha sheet proteins to B sheets- hence are considered infection. Once a B sheet — exponential b sheet production due to this phenomenon
WHAT IS VARIANT CJD
YOUNGER PATIENTS
BY CONSUMPTION OF MEAT OF COWS HAVING SPONGIFORM ENCEPHALOPATHY– MAD COW DISEASE– BOVINE SPONGIFORM ENCEPHALOPATHY
WHAT IS FAMILIAL FATAL INSOMNIA
INHERITED PRION DISEASE HAVING
1 INSOMNIA
2 EXAGGERATED STARTLE RESPONSE
WHAT IS LISSAUER TRACT
spinal cord posterolateral tract is also known as lissauer tract
it is just before the nerve from dorsal root ganglion enters posterior horn.
what two tracts are the only ones spared in anterior spinal artery occlusion
dorsal column and posterolateral tracts (lissauer tract)
what is artery of adamkiewicz
it is a dominant radiculomedullary artery (usually radicular ie nerve root arteries disappear post natally) but adamkeiwics is a named normally persistent artery
supplying cord below T8. It is largest spinal artery.
arises from left posterior intercostal artery
where is spinal cord water shed area
mid thoracic ASA territory. Because below it there is artery of adamkeiwicz supplying at T8 to L2 level taking care of blood supply
major and only feeder of anterior spinal artery below T8
artery of adamkeiwicz.. need to safeguard it during thoracic aortic repairs
Dorsal column decussates in
Medulla
And then ascends contralaterally as the medial lemniscus
Muscles of mastication which close jaw
Munchies
Temporalis
Medial pterygoid
Masseter
Lateral pterygoid muscle action
Only muscle to open the jaw
Lateral pterygoid
Remember chewing is hard work hence needs more 3 muscles
Components of corneal reflex
Afferent - nasociliary branch V1 of trigeminal n
Efferent is eye closure- facial nerve temporal branch supplying orbicularis oculi
Name the three vagal nuclei
Nucleus tractus solitarius - visceral sensory— 7 9 10
Nucleus ambiguus— motor to pharynx larynx and upper esophagus—-9 10 11
Dorsal motor nucleus— parasympathetic to heart lungs upper GI— 10
Mixed cranial nerve are
5 7 9 10
Are both motor and sensory
Elevation of pharynx and larynx is by which muscle and nerve supply
Stylopharyngeus— glossopharyngeal nerve
Which cranial nerve maintains uvula in midline
Vagus
Vagus also elevates soft palate
Monitoring of carotid body receptors
9 th cranial nervd
Monitoring of aortic arch receptors
Vagus
Salivation in parotid gland is by
Salivation in submandibular and sublingual gland is by
Glossopharyngeal nerve
Smg and slg —seventh nerve facial
Which cranial nerve arise medially
3 4 6
12
Which cranial nerve arises dorsally
Cn4
Dorsal and medially
Man in barrel syn
Bilateral proximal muscle weakness in both upper and lower limb
Due to bilateral watershed infarcts in ACA-MCA territories
Site of shlder arm and hip thigh region
Location of wernickes area
Posterior portion of superior temporal gyrus
Location of brocas area
Lower portion of left frontal lobe
What is conduction aphasia
Lesion in perisylvian region affects arcuate fasciculus
Which are curved fibres connecting broaca and wernickes area
Pt is unable to repeat phrases but his own speech and comprehension is otherwise clear
What are areas 44 and 45
Broaca speech area
Motor
Area 22 broadmans is
Wernickes area
PO2 regulates cerebral perfusion only in cases of
severe hypoxia. when PO2 falls below 50mmhg
Rest of the times PCo2 is the one maintaing perfusion
two factors causing reduction in cerebral perfusion
reduced mean arterial pressure
increased intracranial pressure
what is the effect of therapeutic hyperventilation
wash out of CO2
vasoconstriction intracranially
reduced blood flow and
reduction in ICT
used to treat acute cerebral edema secondary to stroke
at what level of hypoxemia does CPP increase
when Po2 falls below 50 mmHg
CPP increases
Pco2 directly affects Cerebral perfusion untill a threshold— after which no increase in CPP occurs. That value of pCO2 is
more than 90 mm Hg.
ie increase in PCO2 causes increase in cerebral blood flow and hence perfusion only till 90 mm Hg.
After this value further increase in CPP is prevented to avoid raised ICT.
5F OF LIMBIC SYSTEM
FEEDING FLEEING FIGHTING FEELINGS SEX-- FUCK
PARTS OF LIMBIC SYSTEM
HIPPOCAMPUS AND AMYGDALA
MAMILLARY BODIES AND ANTERIOR THALAMIC NUCLEI
CINGULATE GYRUS
ENTORHINAL CORTEX
Where is entorhinal cortex
in medial temporal lobe
below hippocampus
it acts as an interface between hippocampus and neocortex
