Nervous system

History & Examination

Cardinal symptoms Altered sensorium Seizures Weakness Paresthesias Loss of function Abnormal movements Headache Abnormal behaviour

Nervous system Brain Cerebrum Midbrain Pons/medulla Cerebellum Cranial nerves- I-XII Spinal cord Peripheral nerves

Nervous system examination Consciousness Higher mental function Cranial nerves Motor system Sensory system Coordination Gait Meningial irritation, Skull, Spine

Consciousness Includes level (wakefulness) & content (awareness) Controlled by cerebral hemispheres & RAS in

brainstem Levels- Drowsy- arousable with verbal stimuli Stupor- arousable with painful stimuli Coma- not arousable Content- Confusion- a state of inattention & lack of clarity in thinking

(incoherent) Glasgow Coma Scale (GCS)- Eye.Motor.Vocal

Released reflexes In demented & confused patient Grasping- stroking of radial surface of palm, asso.

with C/L frontal lobe lesion Avoiding- stroking of ulnar surface of palm, asso. with

C/L parietal lobe lesion Glabellar tap Snout Sucking

Higher mental functions Orientation- time, place, person Memory- immediate, recent, remote Attention Calculation Language

Language Components- Articulation- Dysarthria Fluency Naming Repetition }Dysphasia Comprehension Reading Writing

Apraxia, Agnosia, Aphasia Apraxia- loss of ability to carry out learned

purposeful movements Agnosia- loss of ability to recognise, with

intact sensations & memory Aphasia- impairment of structure &

organization of language Receptive (fluent)- Wernicke’s Expressive (nonfluent)- Broca’s Dysarthria- defect in articulation &

enunciation of speech

Cranial nerves I- olfactory- sensory, smell II- optic- visual acuity/field, color vision III- oculomotor- MR,SR,IR,IO muscles,

sphincter pupillae (accomodation), levator palpebrae superioris

IV- trochlear- motor, superior oblique (SO4) VI- abducent- motor, lateral rectus (LR6)

AbR.OAd- abducted recti, obliques adducted

III, IV, VI nerve defect Squint/strabismus (paralytic)- secondary

(normal eye) > primary (affected eye) deviation

Diplopia- double image- true distinct & false indistinct/blurred

Head tilt- in the direction of affected muscle Past pointing- to same side on looking with

the affected eye Loss of accomodation Ptosis

Cranial nerves V- tr igeminal- sensory to face

(cornea), motor to muscles of mastication, controls oral secretion

VII- facial- motor to all scalp & facial muscles of expression except LPS, taste sensation in ant. 2/3rd of tongue

Facial palsy Supranuclear Lower face affected Emotional response

may be affected Taste intact Facial reflexes

increased No atrophy

Infranuclear Whole face affected Emotional response

& reflexes affected Taste affected Hyperacusis Corneal reflex -nt Atrophy

Cranial nerves VIII- vestibulocochlear- balance & hearing-

vertigo, nystagmus, tinnitus, impaired hearing, caloric tests, Rinne/Weber test

IX- glossopharyngeal- sensory to post. 1/3rd of tongue & pharynx

X- vagus- motor to palate & pharynx XI- accessory- motor to sternomastoid &

trapezius XII- hypoglossal- motor to tongue

Motor system Upper motor neurons-Corticospinal fibers from Frontal motor cortex

Internal capsule Pyramids in medulla crossover Lateral corticospinal tract (UM,LL) terminates in anterior horn

Lower motor neurons-Anterior horn cells Anterior spinal nerve root

Peripheral nerve

Lesion Upper motor neuron Weakness Disuse atrophy Spasticity Reflexes Extensor plantar NCV- normal No denervation

potentials in EMG

Lower motor neuron Pronounced weakness Wasting Flaccidity Loss of reflexes Fasciculations NCV- abnormal Denervation potentials

in EMG

Motor system examination Bulk Tone Power Reflexes Coordination Gait Involuntary movement

Power- grading 0- complete paralysis 1- flicker (any slightest movement) 2- movement with gravity excluded 3- movement against gravity but

not against resistance 4- mild weakness 5- normal power

Deep tendon reflexes (DTR) Jaw jerk- lesion

above trigeminal motor nucleus-pons

Supinator- C 5/6 Biceps- C 5/6 Triceps- C 6/7 Knee- L 2-4 Ankle- S 1/2

Grading 0- absent 1- present 2- brisk 3- very brisk 4- clonus

Superficial reflexes Corneal- trigeminal or facial nerve Palatal- IX-X cranial nerves Scapular- C5-T1 Abdominal- T7-12 Cremasteric- L1/2 Plantar- L5/S1- extensor always abnormal

except age <1 year & postictal Bulbocavernosus- S3/4 Anal- S3/4

Plantar reflex L5/S1 Normally flexion of toes Extensor plantar reflex- components Extension of big toe, fanning of other toes, dorsiflexion of ankle,

flexion of knee, flexion of hip How to elicit? Babinski- stroke plantar surface of foot laterally from heel to toe Chaddock- stroke dorsal surface of foot laterally Oppenheim- stroke shin downwards Gordon- pinch/squeeze calf muscles Shaeffer- pinch Achilles tendon Extensor response denotes UMN lesion

Spinal segment & vertebra Vertebral column is longer than spinal cord Vertebra & corresponding spinal cord

segment Cervical vertebrae- +1 Thoracic 1-6- +2 Thoracic 7-9- +3 T10- L1 & L2 T11- L3 & L4 T12- L5 L1- sacral segments

Coordination Needs sensory input (joint/position),

cerebellum (lobes) & muscle tone Tests- Finger-nose test Rapid finger movements (touching the thumb) Dysdiadochokinesia Heel-shin test Walking in straight line Tandem walking Romberg’s sign

Gait Legs exposed, feet bare Abnormal gait- Spastic- narrow base, knees extended, feet drag, circumduction Sensory ataxic- stamping with heel first Cerebellar ataxic- broad base, ‘drunken’ Festinant (parkinsonian)- rapid, short shuffling steps Waddling (myopathic)- body tilted backwards, feet wide apart,

body sways sideways with each step High-stepping (peripheral neuropathic)- high step, toes landing

first

Involuntary movements Mostly due to disease of basal ganglia &

extrapyramidal system Types- Myoclonus- rapid irregular jerks of a group of muscles Tremor- distal, oscillatory, resting (P)/intentional (C) Athetosis- distal writhing purposeless movement Chorea- arrythmic forcible, jerky, rapid, restless movements Dystonia- abnormally maintained posture, plastic rigidity Hemiballismus- involuntary rapid violent flailing of arm Tics- repetitive abnormal movements, embarassing

Sensory system Receptors in skin Peripheral nerves

Posterior roots Spinal cord (post. horn) Pain/temp./crude touch fibers crossover & ascend

in anterolateral spinothalamic tracts (UM,LL) Fine touch/position/vibration fibers ascend

ipsilaterally in posterior columns (LM,UL) that crossover in medulla & travel in medial lemniscus

Both join in thalamus, from where sensory fibers travel via internal capsule to Parietal cortex

Testing sensations From abnormal to normal areas Mark boundaries/dermatomes Touch & 2-point discrimination Vibration- tested at bony prominences Position- <10 degree movement can be appreciated

at all joints Pain- superficial (pin prick) & deep (muscle squeeze) Temperature Recognition of size/shape/weight/form

Other tests Meningeal irritation- neck rigidity,

Kernig’s sign (extend knee with hip flexed)

Straight leg raising test

Deformity of skull or spine

Abbreviated neuro. exam. Pupils & ocular movements & fundus Facial movements Speech Power in arms & legs DTR & plantar reflex Pain & vibration in hands & feet Gait

Supported by

LP, X-ray, EMG/NCV, CT & MRI